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 // Copyright 2001, 2002, 2003 Ximian, Inc.
   9 // Copyright 2003-2008 Novell, Inc.
  10 //
  11 //
  12
  13 namespace Mono.CSharp {
  14         using System;
  15         using System.Collections;
  16         using System.Diagnostics;
  17         using System.Reflection;
  18         using System.Reflection.Emit;
  19         using System.Text;
  20
  21         /// <remarks>
  22         ///   The ExprClass class contains the is used to pass the
  23         ///   classification of an expression (value, variable, namespace,
  24         ///   type, method group, property access, event access, indexer access,
  25         ///   nothing).
  26         /// </remarks>
  27         public enum ExprClass : byte {
  28                 Invalid,
  29
  30                 Value,
  31                 Variable,
  32                 Namespace,
  33                 Type,
  34                 TypeParameter,
  35                 MethodGroup,
  36                 PropertyAccess,
  37                 EventAccess,
  38                 IndexerAccess,
  39                 Nothing,
  40         }
  41
  42         /// <remarks>
  43         ///   This is used to tell Resolve in which types of expressions we're
  44         ///   interested.
  45         /// </remarks>
  46         [Flags]
  47         public enum ResolveFlags {
  48                 // Returns Value, Variable, PropertyAccess, EventAccess or IndexerAccess.
  49                 VariableOrValue         = 1,
  50
  51                 // Returns a type expression.
  52                 Type                    = 1 << 1,
  53
  54                 // Returns a method group.
  55                 MethodGroup             = 1 << 2,
  56
  57                 TypeParameter   = 1 << 3,
  58
  59                 // Mask of all the expression class flags.
  60                 MaskExprClass = VariableOrValue | Type | MethodGroup | TypeParameter,
  61
  62                 // Disable control flow analysis while resolving the expression.
  63                 // This is used when resolving the instance expression of a field expression.
  64                 DisableFlowAnalysis     = 1 << 10,
  65
  66                 // Set if this is resolving the first part of a MemberAccess.
  67                 Intermediate            = 1 << 11,
  68
  69                 // Disable control flow analysis _of struct_ while resolving the expression.
  70                 // This is used when resolving the instance expression of a field expression.
  71                 DisableStructFlowAnalysis       = 1 << 12,
  72
  73         }
  74
  75         //
  76         // This is just as a hint to AddressOf of what will be done with the
  77         // address.
  78         [Flags]
  79         public enum AddressOp {
  80                 Store = 1,
  81                 Load  = 2,
  82                 LoadStore = 3
  83         };
  84
  85         /// <summary>
  86         ///   This interface is implemented by variables
  87         /// </summary>
  88         public interface IMemoryLocation {
  89                 /// <summary>
  90                 ///   The AddressOf method should generate code that loads
  91                 ///   the address of the object and leaves it on the stack.
  92                 ///
  93                 ///   The `mode' argument is used to notify the expression
  94                 ///   of whether this will be used to read from the address or
  95                 ///   write to the address.
  96                 ///
  97                 ///   This is just a hint that can be used to provide good error
  98                 ///   reporting, and should have no other side effects.
  99                 /// </summary>
 100                 void AddressOf (EmitContext ec, AddressOp mode);
 101         }
 102
 103         //
 104         // An expressions resolved as a direct variable reference
 105         //
 106         public interface IVariableReference : IFixedExpression
 107         {
 108                 bool IsHoisted { get; }
 109                 string Name { get; }
 110                 VariableInfo VariableInfo { get; }
 111
 112                 void SetHasAddressTaken ();
 113         }
 114
 115         //
 116         // Implemented by an expression which could be or is always
 117         // fixed
 118         //
 119         public interface IFixedExpression
 120         {
 121                 bool IsFixed { get; }
 122         }
 123
 124         /// <remarks>
 125         ///   Base class for expressions
 126         /// </remarks>
 127         public abstract class Expression {
 128                 public ExprClass eclass;
 129                 protected Type type;
 130                 protected Location loc;
 131
 132                 public Type Type {
 133                         get { return type; }
 134                         set { type = value; }
 135                 }
 136
 137                 public virtual Location Location {
 138                         get { return loc; }
 139                 }
 140
 141                 /// <summary>
 142                 ///   Utility wrapper routine for Error, just to beautify the code
 143                 /// </summary>
 144                 public void Error (int error, string s)
 145                 {
 146                         Report.Error (error, loc, s);
 147                 }
 148
 149                 // Not nice but we have broken hierarchy.
 150                 public virtual void CheckMarshalByRefAccess (EmitContext ec)
 151                 {
 152                 }
 153
 154                 public virtual bool GetAttributableValue (EmitContext ec, Type value_type, out object value)
 155                 {
 156                         Attribute.Error_AttributeArgumentNotValid (loc);
 157                         value = null;
 158                         return false;
 159                 }
 160
 161                 public virtual string GetSignatureForError ()
 162                 {
 163                         return TypeManager.CSharpName (type);
 164                 }
 165
 166                 public static bool IsAccessorAccessible (Type invocation_type, MethodInfo mi, out bool must_do_cs1540_check)
 167                 {
 168                         MethodAttributes ma = mi.Attributes & MethodAttributes.MemberAccessMask;
 169
 170                         must_do_cs1540_check = false; // by default we do not check for this
 171
 172                         if (ma == MethodAttributes.Public)
 173                                 return true;
 174
 175                         //
 176                         // If only accessible to the current class or children
 177                         //
 178                         if (ma == MethodAttributes.Private)
 179                                 return TypeManager.IsPrivateAccessible (invocation_type, mi.DeclaringType) ||
 180                                         TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType);
 181
 182                         if (TypeManager.IsThisOrFriendAssembly (mi.DeclaringType.Assembly)) {
 183                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamORAssem)
 184                                         return true;
 185                         } else {
 186                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamANDAssem)
 187                                         return false;
 188                         }
 189
 190                         // Family and FamANDAssem require that we derive.
 191                         // FamORAssem requires that we derive if in different assemblies.
 192                         if (!TypeManager.IsNestedFamilyAccessible (invocation_type, mi.DeclaringType))
 193                                 return false;
 194
 195                         if (!TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType))
 196                                 must_do_cs1540_check = true;
 197
 198                         return true;
 199                 }
 200
 201                 public virtual bool IsNull {
 202                         get {
 203                                 return false;
 204                         }
 205                 }
 206
 207                 /// <summary>
 208                 ///   Performs semantic analysis on the Expression
 209                 /// </summary>
 210                 ///
 211                 /// <remarks>
 212                 ///   The Resolve method is invoked to perform the semantic analysis
 213                 ///   on the node.
 214                 ///
 215                 ///   The return value is an expression (it can be the
 216                 ///   same expression in some cases) or a new
 217                 ///   expression that better represents this node.
 218                 ///
 219                 ///   For example, optimizations of Unary (LiteralInt)
 220                 ///   would return a new LiteralInt with a negated
 221                 ///   value.
 222                 ///
 223                 ///   If there is an error during semantic analysis,
 224                 ///   then an error should be reported (using Report)
 225                 ///   and a null value should be returned.
 226                 ///
 227                 ///   There are two side effects expected from calling
 228                 ///   Resolve(): the the field variable "eclass" should
 229                 ///   be set to any value of the enumeration
 230                 ///   `ExprClass' and the type variable should be set
 231                 ///   to a valid type (this is the type of the
 232                 ///   expression).
 233                 /// </remarks>
 234                 public abstract Expression DoResolve (EmitContext ec);
 235
 236                 public virtual Expression DoResolveLValue (EmitContext ec, Expression right_side)
 237                 {
 238                         return null;
 239                 }
 240
 241                 //
 242                 // This is used if the expression should be resolved as a type or namespace name.
 243                 // the default implementation fails.
 244                 //
 245                 public virtual FullNamedExpression ResolveAsTypeStep (IResolveContext rc,  bool silent)
 246                 {
 247                         if (!silent) {
 248                                 Expression e = this;
 249                                 EmitContext ec = rc as EmitContext;
 250                                 if (ec != null)
 251                                         e = e.Resolve (ec);
 252                                 if (e != null)
 253                                         e.Error_UnexpectedKind (ResolveFlags.Type, loc);
 254                         }
 255                         return null;
 256                 }
 257
 258                 //
 259                 // C# 3.0 introduced contextual keywords (var) which behaves like a type if type with
 260                 // same name exists or as a keyword when no type was found
 261                 //
 262                 public virtual TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
 263                 {
 264                         return ResolveAsTypeTerminal (rc, silent);
 265                 }
 266
 267                 //
 268                 // This is used to resolve the expression as a type, a null
 269                 // value will be returned if the expression is not a type
 270                 // reference
 271                 //
 272                 public virtual TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
 273                 {
 274                         TypeExpr te = ResolveAsBaseTerminal (ec, silent);
 275                         if (te == null)
 276                                 return null;
 277
 278                         if (!silent) { // && !(te is TypeParameterExpr)) {
 279                                 ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (te.Type);
 280                                 if (obsolete_attr != null && !ec.IsInObsoleteScope) {
 281                                         AttributeTester.Report_ObsoleteMessage (obsolete_attr, te.GetSignatureForError (), Location);
 282                                 }
 283                         }
 284
 285                         GenericTypeExpr ct = te as GenericTypeExpr;
 286                         if (ct != null) {
 287                                 // Skip constrains check for overrides and explicit implementations
 288                                 // TODO: they should use different overload
 289                                 GenericMethod gm = ec.GenericDeclContainer as GenericMethod;
 290                                 if (gm != null && ((gm.ModFlags & Modifiers.OVERRIDE) != 0 || gm.MemberName.Left != null)) {
 291                                         te.loc = loc;
 292                                         return te;
 293                                 }
 294
 295                                 // TODO: silent flag is ignored
 296                                 ct.CheckConstraints (ec);
 297                         }
 298
 299                         return te;
 300                 }
 301
 302                 public TypeExpr ResolveAsBaseTerminal (IResolveContext ec, bool silent)
 303                 {
 304                         int errors = Report.Errors;
 305
 306                         FullNamedExpression fne = ResolveAsTypeStep (ec, silent);
 307
 308                         if (fne == null)
 309                                 return null;
 310
 311                         TypeExpr te = fne as TypeExpr;
 312                         if (te == null) {
 313                                 if (!silent && errors == Report.Errors)
 314                                         fne.Error_UnexpectedKind (null, "type", loc);
 315                                 return null;
 316                         }
 317
 318                         if (!te.CheckAccessLevel (ec.GenericDeclContainer)) {
 319                                 Report.SymbolRelatedToPreviousError (te.Type);
 320                                 ErrorIsInaccesible (loc, TypeManager.CSharpName (te.Type));
 321                                 return null;
 322                         }
 323
 324                         te.loc = loc;
 325                         return te;
 326                 }
 327
 328                 public static void ErrorIsInaccesible (Location loc, string name)
 329                 {
 330                         Report.Error (122, loc, "`{0}' is inaccessible due to its protection level", name);
 331                 }
 332
 333                 protected static void Error_CannotAccessProtected (Location loc, MemberInfo m, Type qualifier, Type container)
 334                 {
 335                         Report.Error (1540, loc, "Cannot access protected member `{0}' via a qualifier of type `{1}'."
 336                                 + " The qualifier must be of type `{2}' or derived from it",
 337                                 TypeManager.GetFullNameSignature (m),
 338                                 TypeManager.CSharpName (qualifier),
 339                                 TypeManager.CSharpName (container));
 340
 341                 }
 342
 343                 public static void Error_InvalidExpressionStatement (Location loc)
 344                 {
 345                         Report.Error (201, loc, "Only assignment, call, increment, decrement, and new object " +
 346                                        "expressions can be used as a statement");
 347                 }
 348
 349                 public void Error_InvalidExpressionStatement ()
 350                 {
 351                         Error_InvalidExpressionStatement (loc);
 352                 }
 353
 354                 protected void Error_CannotAssign (string to, string roContext)
 355                 {
 356                         Report.Error (1656, loc, "Cannot assign to `{0}' because it is a `{1}'",
 357                                 to, roContext);
 358                 }
 359
 360                 public static void Error_VoidInvalidInTheContext (Location loc)
 361                 {
 362                         Report.Error (1547, loc, "Keyword `void' cannot be used in this context");
 363                 }
 364
 365                 public virtual void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
 366                 {
 367                         Error_ValueCannotBeConvertedCore (ec, loc, target, expl);
 368                 }
 369
 370                 protected void Error_ValueCannotBeConvertedCore (EmitContext ec, Location loc, Type target, bool expl)
 371                 {
 372                         // The error was already reported as CS1660
 373                         if (type == TypeManager.anonymous_method_type)
 374                                 return;
 375
 376                         if (TypeManager.IsGenericParameter (Type) && TypeManager.IsGenericParameter (target) && type.Name == target.Name) {
 377 #if GMCS_SOURCE
 378                                 string sig1 = type.DeclaringMethod == null ?
 379                                         TypeManager.CSharpName (type.DeclaringType) :
 380                                         TypeManager.CSharpSignature (type.DeclaringMethod);
 381                                 string sig2 = target.DeclaringMethod == null ?
 382                                         TypeManager.CSharpName (target.DeclaringType) :
 383                                         TypeManager.CSharpSignature (target.DeclaringMethod);
 384                                 Report.ExtraInformation (loc,
 385                                         String.Format (
 386                                                 "The generic parameter `{0}' of `{1}' cannot be converted to the generic parameter `{0}' of `{2}' (in the previous ",
 387                                                 Type.Name, sig1, sig2));
 388 #endif
 389                         } else if (Type.FullName == target.FullName){
 390                                 Report.ExtraInformation (loc,
 391                                         String.Format (
 392                                         "The type `{0}' has two conflicting definitions, one comes from `{1}' and the other from `{2}' (in the previous ",
 393                                         Type.FullName, Type.Assembly.FullName, target.Assembly.FullName));
 394                         }
 395
 396                         if (expl) {
 397                                 Report.Error (30, loc, "Cannot convert type `{0}' to `{1}'",
 398                                         TypeManager.CSharpName (type), TypeManager.CSharpName (target));
 399                                 return;
 400                         }
 401
 402                         Report.DisableReporting ();
 403                         bool expl_exists = Convert.ExplicitConversion (ec, this, target, Location.Null) != null;
 404                         Report.EnableReporting ();
 405
 406                         if (expl_exists) {
 407                                 Report.Error (266, loc, "Cannot implicitly convert type `{0}' to `{1}'. " +
 408                                               "An explicit conversion exists (are you missing a cast?)",
 409                                         TypeManager.CSharpName (Type), TypeManager.CSharpName (target));
 410                                 return;
 411                         }
 412
 413                         Report.Error (29, loc, "Cannot implicitly convert type `{0}' to `{1}'",
 414                                 TypeManager.CSharpName (type),
 415                                 TypeManager.CSharpName (target));
 416                 }
 417
 418                 public virtual void Error_VariableIsUsedBeforeItIsDeclared (string name)
 419                 {
 420                         Report.Error (841, loc, "A local variable `{0}' cannot be used before it is declared", name);
 421                 }
 422
 423                 protected virtual void Error_TypeDoesNotContainDefinition (Type type, string name)
 424                 {
 425                         Error_TypeDoesNotContainDefinition (loc, type, name);
 426                 }
 427
 428                 public static void Error_TypeDoesNotContainDefinition (Location loc, Type type, string name)
 429                 {
 430                         Report.SymbolRelatedToPreviousError (type);
 431                         Report.Error (117, loc, "`{0}' does not contain a definition for `{1}'",
 432                                 TypeManager.CSharpName (type), name);
 433                 }
 434
 435                 protected static void Error_ValueAssignment (Location loc)
 436                 {
 437                         Report.Error (131, loc, "The left-hand side of an assignment must be a variable, a property or an indexer");
 438                 }
 439
 440                 ResolveFlags ExprClassToResolveFlags
 441                 {
 442                         get {
 443                                 switch (eclass) {
 444                                 case ExprClass.Type:
 445                                 case ExprClass.Namespace:
 446                                         return ResolveFlags.Type;
 447
 448                                 case ExprClass.MethodGroup:
 449                                         return ResolveFlags.MethodGroup;
 450
 451                                 case ExprClass.TypeParameter:
 452                                         return ResolveFlags.TypeParameter;
 453
 454                                 case ExprClass.Value:
 455                                 case ExprClass.Variable:
 456                                 case ExprClass.PropertyAccess:
 457                                 case ExprClass.EventAccess:
 458                                 case ExprClass.IndexerAccess:
 459                                         return ResolveFlags.VariableOrValue;
 460
 461                                 default:
 462                                         throw new InternalErrorException (loc.ToString () + " " +  GetType () + " ExprClass is Invalid after resolve");
 463                                 }
 464                         }
 465                 }
 466
 467                 /// <summary>
 468                 ///   Resolves an expression and performs semantic analysis on it.
 469                 /// </summary>
 470                 ///
 471                 /// <remarks>
 472                 ///   Currently Resolve wraps DoResolve to perform sanity
 473                 ///   checking and assertion checking on what we expect from Resolve.
 474                 /// </remarks>
 475                 public Expression Resolve (EmitContext ec, ResolveFlags flags)
 476                 {
 477                         if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
 478                                 return ResolveAsTypeStep (ec, false);
 479
 480                         bool do_flow_analysis = ec.DoFlowAnalysis;
 481                         bool omit_struct_analysis = ec.OmitStructFlowAnalysis;
 482                         if ((flags & ResolveFlags.DisableFlowAnalysis) != 0)
 483                                 do_flow_analysis = false;
 484                         if ((flags & ResolveFlags.DisableStructFlowAnalysis) != 0)
 485                                 omit_struct_analysis = true;
 486
 487                         Expression e;
 488                         using (ec.WithFlowAnalysis (do_flow_analysis, omit_struct_analysis)) {
 489                                 if (this is SimpleName) {
 490                                         bool intermediate = (flags & ResolveFlags.Intermediate) == ResolveFlags.Intermediate;
 491                                         e = ((SimpleName) this).DoResolve (ec, intermediate);
 492                                 } else {
 493                                         e = DoResolve (ec);
 494                                 }
 495                         }
 496
 497                         if (e == null)
 498                                 return null;
 499
 500                         if ((flags & e.ExprClassToResolveFlags) == 0) {
 501                                 e.Error_UnexpectedKind (flags, loc);
 502                                 return null;
 503                         }
 504
 505                         if (e.type == null && !(e is Namespace)) {
 506                                 throw new Exception (
 507                                         "Expression " + e.GetType () +
 508                                         " did not set its type after Resolve\n" +
 509                                         "called from: " + this.GetType ());
 510                         }
 511
 512                         return e;
 513                 }
 514
 515                 /// <summary>
 516                 ///   Resolves an expression and performs semantic analysis on it.
 517                 /// </summary>
 518                 public Expression Resolve (EmitContext ec)
 519                 {
 520                         Expression e = Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
 521
 522                         if (e != null && e.eclass == ExprClass.MethodGroup && RootContext.Version == LanguageVersion.ISO_1) {
 523                                 ((MethodGroupExpr) e).ReportUsageError ();
 524                                 return null;
 525                         }
 526                         return e;
 527                 }
 528
 529                 public Constant ResolveAsConstant (EmitContext ec, MemberCore mc)
 530                 {
 531                         Expression e = Resolve (ec);
 532                         if (e == null)
 533                                 return null;
 534
 535                         Constant c = e as Constant;
 536                         if (c != null)
 537                                 return c;
 538
 539                         if (type != null && TypeManager.IsReferenceType (type))
 540                                 Const.Error_ConstantCanBeInitializedWithNullOnly (type, loc, mc.GetSignatureForError ());
 541                         else
 542                                 Const.Error_ExpressionMustBeConstant (loc, mc.GetSignatureForError ());
 543
 544                         return null;
 545                 }
 546
 547                 /// <summary>
 548                 ///   Resolves an expression for LValue assignment
 549                 /// </summary>
 550                 ///
 551                 /// <remarks>
 552                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 553                 ///   checking and assertion checking on what we expect from Resolve
 554                 /// </remarks>
 555                 public Expression ResolveLValue (EmitContext ec, Expression right_side, Location loc)
 556                 {
 557                         int errors = Report.Errors;
 558                         bool out_access = right_side == EmptyExpression.OutAccess;
 559
 560                         Expression e = DoResolveLValue (ec, right_side);
 561
 562                         if (e != null && out_access && !(e is IMemoryLocation)) {
 563                                 // FIXME: There's no problem with correctness, the 'Expr = null' handles that.
 564                                 //        Enabling this 'throw' will "only" result in deleting useless code elsewhere,
 565
 566                                 //throw new InternalErrorException ("ResolveLValue didn't return an IMemoryLocation: " +
 567                                 //                                e.GetType () + " " + e.GetSignatureForError ());
 568                                 e = null;
 569                         }
 570
 571                         if (e == null) {
 572                                 if (errors == Report.Errors) {
 573                                         if (out_access)
 574                                                 Report.Error (1510, loc, "A ref or out argument must be an assignable variable");
 575                                         else
 576                                                 Error_ValueAssignment (loc);
 577                                 }
 578                                 return null;
 579                         }
 580
 581                         if (e.eclass == ExprClass.Invalid)
 582                                 throw new Exception ("Expression " + e + " ExprClass is Invalid after resolve");
 583
 584                         if ((e.type == null) && !(e is GenericTypeExpr))
 585                                 throw new Exception ("Expression " + e + " did not set its type after Resolve");
 586
 587                         return e;
 588                 }
 589
 590                 /// <summary>
 591                 ///   Emits the code for the expression
 592                 /// </summary>
 593                 ///
 594                 /// <remarks>
 595                 ///   The Emit method is invoked to generate the code
 596                 ///   for the expression.
 597                 /// </remarks>
 598                 public abstract void Emit (EmitContext ec);
 599
 600                 // Emit code to branch to @target if this expression is equivalent to @on_true.
 601                 // The default implementation is to emit the value, and then emit a brtrue or brfalse.
 602                 // Subclasses can provide more efficient implementations, but those MUST be equivalent,
 603                 // including the use of conditional branches.  Note also that a branch MUST be emitted
 604                 public virtual void EmitBranchable (EmitContext ec, Label target, bool on_true)
 605                 {
 606                         Emit (ec);
 607                         ec.ig.Emit (on_true ? OpCodes.Brtrue : OpCodes.Brfalse, target);
 608                 }
 609
 610                 // Emit this expression for its side effects, not for its value.
 611                 // The default implementation is to emit the value, and then throw it away.
 612                 // Subclasses can provide more efficient implementations, but those MUST be equivalent
 613                 public virtual void EmitSideEffect (EmitContext ec)
 614                 {
 615                         Emit (ec);
 616                         ec.ig.Emit (OpCodes.Pop);
 617                 }
 618
 619                 /// <summary>
 620                 ///   Protected constructor.  Only derivate types should
 621                 ///   be able to be created
 622                 /// </summary>
 623
 624                 protected Expression ()
 625                 {
 626                         eclass = ExprClass.Invalid;
 627                         type = null;
 628                 }
 629
 630                 /// <summary>
 631                 ///   Returns a fully formed expression after a MemberLookup
 632                 /// </summary>
 633                 ///
 634                 public static Expression ExprClassFromMemberInfo (Type container_type, MemberInfo mi, Location loc)
 635                 {
 636                         if (mi is EventInfo)
 637                                 return new EventExpr ((EventInfo) mi, loc);
 638                         else if (mi is FieldInfo) {
 639                                 FieldInfo fi = (FieldInfo) mi;
 640                                 if (fi.IsLiteral || (fi.IsInitOnly && fi.FieldType == TypeManager.decimal_type))
 641                                         return new ConstantExpr (fi, loc);
 642                                 return new FieldExpr (fi, loc);
 643                         } else if (mi is PropertyInfo)
 644                                 return new PropertyExpr (container_type, (PropertyInfo) mi, loc);
 645                         else if (mi is Type) {
 646                                 return new TypeExpression ((System.Type) mi, loc);
 647                         }
 648
 649                         return null;
 650                 }
 651
 652                 // TODO: [Obsolete ("Can be removed")]
 653                 protected static ArrayList almost_matched_members = new ArrayList (4);
 654
 655                 //
 656                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 657                 //
 658                 // This code could use some optimizations, but we need to do some
 659                 // measurements.  For example, we could use a delegate to `flag' when
 660                 // something can not any longer be a method-group (because it is something
 661                 // else).
 662                 //
 663                 // Return values:
 664                 //     If the return value is an Array, then it is an array of
 665                 //     MethodBases
 666                 //
 667                 //     If the return value is an MemberInfo, it is anything, but a Method
 668                 //
 669                 //     null on error.
 670                 //
 671                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 672                 // the arguments here and have MemberLookup return only the methods that
 673                 // match the argument count/type, unlike we are doing now (we delay this
 674                 // decision).
 675                 //
 676                 // This is so we can catch correctly attempts to invoke instance methods
 677                 // from a static body (scan for error 120 in ResolveSimpleName).
 678                 //
 679                 //
 680                 // FIXME: Potential optimization, have a static ArrayList
 681                 //
 682
 683                 public static Expression MemberLookup (Type container_type, Type queried_type, string name,
 684                                                        MemberTypes mt, BindingFlags bf, Location loc)
 685                 {
 686                         return MemberLookup (container_type, null, queried_type, name, mt, bf, loc);
 687                 }
 688
 689                 //
 690                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 691                 // `qualifier_type' or null to lookup members in the current class.
 692                 //
 693
 694                 public static Expression MemberLookup (Type container_type,
 695                                                        Type qualifier_type, Type queried_type,
 696                                                        string name, MemberTypes mt,
 697                                                        BindingFlags bf, Location loc)
 698                 {
 699                         almost_matched_members.Clear ();
 700
 701                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 702                                                                      queried_type, mt, bf, name, almost_matched_members);
 703
 704                         if (mi == null)
 705                                 return null;
 706
 707                         if (mi.Length > 1) {
 708                                 bool is_interface = qualifier_type != null && qualifier_type.IsInterface;
 709                                 ArrayList methods = new ArrayList (2);
 710                                 ArrayList non_methods = null;
 711
 712                                 foreach (MemberInfo m in mi) {
 713                                         if (m is MethodBase) {
 714                                                 methods.Add (m);
 715                                                 continue;
 716                                         }
 717
 718                                         if (non_methods == null) {
 719                                                 non_methods = new ArrayList (2);
 720                                                 non_methods.Add (m);
 721                                                 continue;
 722                                         }
 723
 724                                         foreach (MemberInfo n_m in non_methods) {
 725                                                 if (m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (m.DeclaringType, n_m.DeclaringType))
 726                                                         continue;
 727
 728                                                 Report.SymbolRelatedToPreviousError (m);
 729                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 730                                                         TypeManager.GetFullNameSignature (m), TypeManager.GetFullNameSignature (n_m));
 731                                                 return null;
 732                                         }
 733                                 }
 734
 735                                 if (methods.Count == 0)
 736                                         return ExprClassFromMemberInfo (container_type, (MemberInfo)non_methods [0], loc);
 737
 738                                 if (non_methods != null) {
 739                                         MethodBase method = (MethodBase) methods [0];
 740                                         MemberInfo non_method = (MemberInfo) non_methods [0];
 741                                         if (method.DeclaringType == non_method.DeclaringType) {
 742                                                 // Cannot happen with C# code, but is valid in IL
 743                                                 Report.SymbolRelatedToPreviousError (method);
 744                                                 Report.SymbolRelatedToPreviousError (non_method);
 745                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 746                                                               TypeManager.GetFullNameSignature (non_method),
 747                                                               TypeManager.CSharpSignature (method));
 748                                                 return null;
 749                                         }
 750
 751                                         if (is_interface) {
 752                                                 Report.SymbolRelatedToPreviousError (method);
 753                                                 Report.SymbolRelatedToPreviousError (non_method);
 754                                                 Report.Warning (467, 2, loc, "Ambiguity between method `{0}' and non-method `{1}'. Using method `{0}'",
 755                                                                 TypeManager.CSharpSignature (method), TypeManager.GetFullNameSignature (non_method));
 756                                         }
 757                                 }
 758
 759                                 return new MethodGroupExpr (methods, queried_type, loc);
 760                         }
 761
 762                         if (mi [0] is MethodBase)
 763                                 return new MethodGroupExpr (mi, queried_type, loc);
 764
 765                         return ExprClassFromMemberInfo (container_type, mi [0], loc);
 766                 }
 767
 768                 public const MemberTypes AllMemberTypes =
 769                         MemberTypes.Constructor |
 770                         MemberTypes.Event       |
 771                         MemberTypes.Field       |
 772                         MemberTypes.Method      |
 773                         MemberTypes.NestedType  |
 774                         MemberTypes.Property;
 775
 776                 public const BindingFlags AllBindingFlags =
 777                         BindingFlags.Public |
 778                         BindingFlags.Static |
 779                         BindingFlags.Instance;
 780
 781                 public static Expression MemberLookup (Type container_type, Type queried_type,
 782                                                        string name, Location loc)
 783                 {
 784                         return MemberLookup (container_type, null, queried_type, name,
 785                                              AllMemberTypes, AllBindingFlags, loc);
 786                 }
 787
 788                 public static Expression MemberLookup (Type container_type, Type qualifier_type,
 789                                                        Type queried_type, string name, Location loc)
 790                 {
 791                         return MemberLookup (container_type, qualifier_type, queried_type,
 792                                              name, AllMemberTypes, AllBindingFlags, loc);
 793                 }
 794
 795                 public static MethodGroupExpr MethodLookup (Type container_type, Type queried_type,
 796                                                        string name, Location loc)
 797                 {
 798                         return (MethodGroupExpr)MemberLookup (container_type, null, queried_type, name,
 799                                              MemberTypes.Method, AllBindingFlags, loc);
 800                 }
 801
 802                 /// <summary>
 803                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 804                 ///   to find a final definition.  If the final definition is not found, we
 805                 ///   look for private members and display a useful debugging message if we
 806                 ///   find it.
 807                 /// </summary>
 808                 protected Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 809                                                             Type queried_type, string name,
 810                                                             MemberTypes mt, BindingFlags bf,
 811                                                             Location loc)
 812                 {
 813                         Expression e;
 814
 815                         int errors = Report.Errors;
 816                         e = MemberLookup (ec.ContainerType, qualifier_type, queried_type, name, mt, bf, loc);
 817
 818                         if (e != null || errors != Report.Errors)
 819                                 return e;
 820
 821                         // No errors were reported by MemberLookup, but there was an error.
 822                         return Error_MemberLookupFailed (ec.ContainerType, qualifier_type, queried_type,
 823                                         name, null, mt, bf);
 824                 }
 825
 826                 protected virtual Expression Error_MemberLookupFailed (Type container_type, Type qualifier_type,
 827                                                        Type queried_type, string name, string class_name,
 828                                                            MemberTypes mt, BindingFlags bf)
 829                 {
 830                         MemberInfo[] lookup = null;
 831                         if (queried_type == null) {
 832                                 class_name = "global::";
 833                         } else {
 834                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 835                                         mt, (bf & ~BindingFlags.Public) | BindingFlags.NonPublic,
 836                                         name, null);
 837
 838                                 if (lookup != null) {
 839                                         Expression e = Error_MemberLookupFailed (queried_type, lookup);
 840
 841                                         //
 842                                         // FIXME: This is still very wrong, it should be done inside
 843                                         // OverloadResolve to do correct arguments matching.
 844                                         // Requires MemberLookup accessiblity check removal
 845                                         //
 846                                         if (e == null || (mt & (MemberTypes.Method | MemberTypes.Constructor)) == 0) {
 847                                                 MemberInfo mi = lookup[0];
 848                                                 Report.SymbolRelatedToPreviousError (mi);
 849                                                 if (qualifier_type != null && container_type != null && qualifier_type != container_type &&
 850                                                         TypeManager.IsNestedFamilyAccessible (container_type, mi.DeclaringType)) {
 851                                                         // Although a derived class can access protected members of
 852                                                         // its base class it cannot do so through an instance of the
 853                                                         // base class (CS1540).  If the qualifier_type is a base of the
 854                                                         // ec.ContainerType and the lookup succeeds with the latter one,
 855                                                         // then we are in this situation.
 856                                                         Error_CannotAccessProtected (loc, mi, qualifier_type, container_type);
 857                                                 } else {
 858                                                         ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (mi));
 859                                                 }
 860                                         }
 861
 862                                         return e;
 863                                 }
 864
 865                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 866                                         AllMemberTypes, AllBindingFlags | BindingFlags.NonPublic,
 867                                         name, null);
 868                         }
 869
 870                         if (lookup == null) {
 871                                 if (class_name != null) {
 872                                         Report.Error (103, loc, "The name `{0}' does not exist in the current context",
 873                                                 name);
 874                                 } else {
 875                                         Error_TypeDoesNotContainDefinition (queried_type, name);
 876                                 }
 877                                 return null;
 878                         }
 879
 880                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 881                                                       AllMemberTypes, AllBindingFlags |
 882                                                       BindingFlags.NonPublic, name, null) == null) {
 883                                 if ((lookup.Length == 1) && (lookup [0] is Type)) {
 884                                         Type t = (Type) lookup [0];
 885
 886                                         Report.Error (305, loc,
 887                                                       "Using the generic type `{0}' " +
 888                                                       "requires {1} type arguments",
 889                                                       TypeManager.CSharpName (t),
 890                                                       TypeManager.GetNumberOfTypeArguments (t).ToString ());
 891                                         return null;
 892                                 }
 893                         }
 894
 895                         return Error_MemberLookupFailed (queried_type, lookup);
 896                 }
 897
 898                 protected virtual Expression Error_MemberLookupFailed (Type type, MemberInfo[] members)
 899                 {
 900                         for (int i = 0; i < members.Length; ++i) {
 901                                 if (!(members [i] is MethodBase))
 902                                         return null;
 903                         }
 904
 905                         // By default propagate the closest candidates upwards
 906                         return new MethodGroupExpr (members, type, loc, true);
 907                 }
 908
 909                 protected virtual void Error_NegativeArrayIndex (Location loc)
 910                 {
 911                         throw new NotImplementedException ();
 912                 }
 913
 914                 protected void Error_PointerInsideExpressionTree ()
 915                 {
 916                         Report.Error (1944, loc, "An expression tree cannot contain an unsafe pointer operation");
 917                 }
 918
 919                 /// <summary>
 920                 ///   Returns an expression that can be used to invoke operator true
 921                 ///   on the expression if it exists.
 922                 /// </summary>
 923                 static public Expression GetOperatorTrue (EmitContext ec, Expression e, Location loc)
 924                 {
 925                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 926                 }
 927
 928                 /// <summary>
 929                 ///   Returns an expression that can be used to invoke operator false
 930                 ///   on the expression if it exists.
 931                 /// </summary>
 932                 static public Expression GetOperatorFalse (EmitContext ec, Expression e, Location loc)
 933                 {
 934                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 935                 }
 936
 937                 static Expression GetOperatorTrueOrFalse (EmitContext ec, Expression e, bool is_true, Location loc)
 938                 {
 939                         MethodGroupExpr operator_group;
 940                         string mname = Operator.GetMetadataName (is_true ? Operator.OpType.True : Operator.OpType.False);
 941                         operator_group = MethodLookup (ec.ContainerType, e.Type, mname, loc) as MethodGroupExpr;
 942                         if (operator_group == null)
 943                                 return null;
 944
 945                         ArrayList arguments = new ArrayList (1);
 946                         arguments.Add (new Argument (e, Argument.AType.Expression));
 947                         operator_group = operator_group.OverloadResolve (
 948                                 ec, ref arguments, false, loc);
 949
 950                         if (operator_group == null)
 951                                 return null;
 952
 953                         return new UserOperatorCall (operator_group, arguments, null, loc);
 954                 }
 955
 956                 /// <summary>
 957                 ///   Resolves the expression `e' into a boolean expression: either through
 958                 ///   an implicit conversion, or through an `operator true' invocation
 959                 /// </summary>
 960                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 961                 {
 962                         e = e.Resolve (ec);
 963                         if (e == null)
 964                                 return null;
 965
 966                         if (e.Type == TypeManager.bool_type)
 967                                 return e;
 968
 969                         Expression converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, Location.Null);
 970
 971                         if (converted != null)
 972                                 return converted;
 973
 974                         //
 975                         // If no implicit conversion to bool exists, try using `operator true'
 976                         //
 977                         converted = Expression.GetOperatorTrue (ec, e, loc);
 978                         if (converted == null){
 979                                 e.Error_ValueCannotBeConverted (ec, loc, TypeManager.bool_type, false);
 980                                 return null;
 981                         }
 982                         return converted;
 983                 }
 984
 985                 public virtual string ExprClassName
 986                 {
 987                         get {
 988                                 switch (eclass){
 989                                 case ExprClass.Invalid:
 990                                         return "Invalid";
 991                                 case ExprClass.Value:
 992                                         return "value";
 993                                 case ExprClass.Variable:
 994                                         return "variable";
 995                                 case ExprClass.Namespace:
 996                                         return "namespace";
 997                                 case ExprClass.Type:
 998                                         return "type";
 999                                 case ExprClass.MethodGroup:
1000                                         return "method group";
1001                                 case ExprClass.PropertyAccess:
1002                                         return "property access";
1003                                 case ExprClass.EventAccess:
1004                                         return "event access";
1005                                 case ExprClass.IndexerAccess:
1006                                         return "indexer access";
1007                                 case ExprClass.Nothing:
1008                                         return "null";
1009                                 case ExprClass.TypeParameter:
1010                                         return "type parameter";
1011                                 }
1012                                 throw new Exception ("Should not happen");
1013                         }
1014                 }
1015
1016                 /// <summary>
1017                 ///   Reports that we were expecting `expr' to be of class `expected'
1018                 /// </summary>
1019                 public void Error_UnexpectedKind (DeclSpace ds, string expected, Location loc)
1020                 {
1021                         Error_UnexpectedKind (ds, expected, ExprClassName, loc);
1022                 }
1023
1024                 public void Error_UnexpectedKind (DeclSpace ds, string expected, string was, Location loc)
1025                 {
1026                         string name = GetSignatureForError ();
1027                         if (ds != null)
1028                                 name = ds.GetSignatureForError () + '.' + name;
1029
1030                         Report.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
1031                               name, was, expected);
1032                 }
1033
1034                 public void Error_UnexpectedKind (ResolveFlags flags, Location loc)
1035                 {
1036                         string [] valid = new string [4];
1037                         int count = 0;
1038
1039                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
1040                                 valid [count++] = "variable";
1041                                 valid [count++] = "value";
1042                         }
1043
1044                         if ((flags & ResolveFlags.Type) != 0)
1045                                 valid [count++] = "type";
1046
1047                         if ((flags & ResolveFlags.MethodGroup) != 0)
1048                                 valid [count++] = "method group";
1049
1050                         if (count == 0)
1051                                 valid [count++] = "unknown";
1052
1053                         StringBuilder sb = new StringBuilder (valid [0]);
1054                         for (int i = 1; i < count - 1; i++) {
1055                                 sb.Append ("', `");
1056                                 sb.Append (valid [i]);
1057                         }
1058                         if (count > 1) {
1059                                 sb.Append ("' or `");
1060                                 sb.Append (valid [count - 1]);
1061                         }
1062
1063                         Report.Error (119, loc,
1064                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
1065                 }
1066
1067                 public static void UnsafeError (Location loc)
1068                 {
1069                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
1070                 }
1071
1072                 //
1073                 // Load the object from the pointer.
1074                 //
1075                 public static void LoadFromPtr (ILGenerator ig, Type t)
1076                 {
1077                         if (t == TypeManager.int32_type)
1078                                 ig.Emit (OpCodes.Ldind_I4);
1079                         else if (t == TypeManager.uint32_type)
1080                                 ig.Emit (OpCodes.Ldind_U4);
1081                         else if (t == TypeManager.short_type)
1082                                 ig.Emit (OpCodes.Ldind_I2);
1083                         else if (t == TypeManager.ushort_type)
1084                                 ig.Emit (OpCodes.Ldind_U2);
1085                         else if (t == TypeManager.char_type)
1086                                 ig.Emit (OpCodes.Ldind_U2);
1087                         else if (t == TypeManager.byte_type)
1088                                 ig.Emit (OpCodes.Ldind_U1);
1089                         else if (t == TypeManager.sbyte_type)
1090                                 ig.Emit (OpCodes.Ldind_I1);
1091                         else if (t == TypeManager.uint64_type)
1092                                 ig.Emit (OpCodes.Ldind_I8);
1093                         else if (t == TypeManager.int64_type)
1094                                 ig.Emit (OpCodes.Ldind_I8);
1095                         else if (t == TypeManager.float_type)
1096                                 ig.Emit (OpCodes.Ldind_R4);
1097                         else if (t == TypeManager.double_type)
1098                                 ig.Emit (OpCodes.Ldind_R8);
1099                         else if (t == TypeManager.bool_type)
1100                                 ig.Emit (OpCodes.Ldind_I1);
1101                         else if (t == TypeManager.intptr_type)
1102                                 ig.Emit (OpCodes.Ldind_I);
1103                         else if (TypeManager.IsEnumType (t)) {
1104                                 if (t == TypeManager.enum_type)
1105                                         ig.Emit (OpCodes.Ldind_Ref);
1106                                 else
1107                                         LoadFromPtr (ig, TypeManager.GetEnumUnderlyingType (t));
1108                         } else if (TypeManager.IsStruct (t) || TypeManager.IsGenericParameter (t))
1109                                 ig.Emit (OpCodes.Ldobj, t);
1110                         else if (t.IsPointer)
1111                                 ig.Emit (OpCodes.Ldind_I);
1112                         else
1113                                 ig.Emit (OpCodes.Ldind_Ref);
1114                 }
1115
1116                 //
1117                 // The stack contains the pointer and the value of type `type'
1118                 //
1119                 public static void StoreFromPtr (ILGenerator ig, Type type)
1120                 {
1121                         if (TypeManager.IsEnumType (type))
1122                                 type = TypeManager.GetEnumUnderlyingType (type);
1123                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1124                                 ig.Emit (OpCodes.Stind_I4);
1125                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1126                                 ig.Emit (OpCodes.Stind_I8);
1127                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1128                                  type == TypeManager.ushort_type)
1129                                 ig.Emit (OpCodes.Stind_I2);
1130                         else if (type == TypeManager.float_type)
1131                                 ig.Emit (OpCodes.Stind_R4);
1132                         else if (type == TypeManager.double_type)
1133                                 ig.Emit (OpCodes.Stind_R8);
1134                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1135                                  type == TypeManager.bool_type)
1136                                 ig.Emit (OpCodes.Stind_I1);
1137                         else if (type == TypeManager.intptr_type)
1138                                 ig.Emit (OpCodes.Stind_I);
1139                         else if (TypeManager.IsStruct (type) || TypeManager.IsGenericParameter (type))
1140                                 ig.Emit (OpCodes.Stobj, type);
1141                         else
1142                                 ig.Emit (OpCodes.Stind_Ref);
1143                 }
1144
1145                 //
1146                 // Returns the size of type `t' if known, otherwise, 0
1147                 //
1148                 public static int GetTypeSize (Type t)
1149                 {
1150                         t = TypeManager.TypeToCoreType (t);
1151                         if (t == TypeManager.int32_type ||
1152                             t == TypeManager.uint32_type ||
1153                             t == TypeManager.float_type)
1154                                 return 4;
1155                         else if (t == TypeManager.int64_type ||
1156                                  t == TypeManager.uint64_type ||
1157                                  t == TypeManager.double_type)
1158                                 return 8;
1159                         else if (t == TypeManager.byte_type ||
1160                                  t == TypeManager.sbyte_type ||
1161                                  t == TypeManager.bool_type)
1162                                 return 1;
1163                         else if (t == TypeManager.short_type ||
1164                                  t == TypeManager.char_type ||
1165                                  t == TypeManager.ushort_type)
1166                                 return 2;
1167                         else if (t == TypeManager.decimal_type)
1168                                 return 16;
1169                         else
1170                                 return 0;
1171                 }
1172
1173                 protected void Error_CannotCallAbstractBase (string name)
1174                 {
1175                         Report.Error (205, loc, "Cannot call an abstract base member `{0}'", name);
1176                 }
1177
1178                 protected void Error_CannotModifyIntermediateExpressionValue (EmitContext ec)
1179                 {
1180                         Report.SymbolRelatedToPreviousError (type);
1181                         if (ec.CurrentInitializerVariable != null) {
1182                                 Report.Error (1918, loc, "Members of value type `{0}' cannot be assigned using a property `{1}' object initializer",
1183                                         TypeManager.CSharpName (type), GetSignatureForError ());
1184                         } else {
1185                                 Report.Error (1612, loc, "Cannot modify a value type return value of `{0}'. Consider storing the value in a temporary variable",
1186                                         GetSignatureForError ());
1187                         }
1188                 }
1189
1190                 public void Error_ExpressionCannotBeGeneric (Location loc)
1191                 {
1192                         Report.Error (307, loc, "The {0} `{1}' cannot be used with type arguments",
1193                                 ExprClassName, GetSignatureForError ());
1194                 }
1195
1196                 //
1197                 // Converts `source' to an int, uint, long or ulong.
1198                 //
1199                 public Expression ConvertExpressionToArrayIndex (EmitContext ec, Expression source)
1200                 {
1201                         Expression converted;
1202
1203                         using (ec.With (EmitContext.Flags.CheckState, true)) {
1204                                 converted = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, source.loc);
1205                                 if (converted == null)
1206                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, source.loc);
1207                                 if (converted == null)
1208                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, source.loc);
1209                                 if (converted == null)
1210                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, source.loc);
1211
1212                                 if (converted == null) {
1213                                         source.Error_ValueCannotBeConverted (ec, source.loc, TypeManager.int32_type, false);
1214                                         return null;
1215                                 }
1216                         }
1217
1218                         //
1219                         // Only positive constants are allowed at compile time
1220                         //
1221                         Constant c = converted as Constant;
1222                         if (c != null) {
1223                                 if (c.IsNegative) {
1224                                         Error_NegativeArrayIndex (source.loc);
1225                                 }
1226                                 return c;
1227                         }
1228
1229                         return new ArrayIndexCast (converted).Resolve (ec);
1230                 }
1231
1232                 //
1233                 // Derived classes implement this method by cloning the fields that
1234                 // could become altered during the Resolve stage
1235                 //
1236                 // Only expressions that are created for the parser need to implement
1237                 // this.
1238                 //
1239                 protected virtual void CloneTo (CloneContext clonectx, Expression target)
1240                 {
1241                         throw new NotImplementedException (
1242                                 String.Format (
1243                                         "CloneTo not implemented for expression {0}", this.GetType ()));
1244                 }
1245
1246                 //
1247                 // Clones an expression created by the parser.
1248                 //
1249                 // We only support expressions created by the parser so far, not
1250                 // expressions that have been resolved (many more classes would need
1251                 // to implement CloneTo).
1252                 //
1253                 // This infrastructure is here merely for Lambda expressions which
1254                 // compile the same code using different type values for the same
1255                 // arguments to find the correct overload
1256                 //
1257                 public Expression Clone (CloneContext clonectx)
1258                 {
1259                         Expression cloned = (Expression) MemberwiseClone ();
1260                         CloneTo (clonectx, cloned);
1261
1262                         return cloned;
1263                 }
1264
1265                 //
1266                 // Implementation of expression to expression tree conversion
1267                 //
1268                 public abstract Expression CreateExpressionTree (EmitContext ec);
1269
1270                 protected Expression CreateExpressionFactoryCall (string name, ArrayList args)
1271                 {
1272                         return CreateExpressionFactoryCall (name, null, args, loc);
1273                 }
1274
1275                 protected Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args)
1276                 {
1277                         return CreateExpressionFactoryCall (name, typeArguments, args, loc);
1278                 }
1279
1280                 public static Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args, Location loc)
1281                 {
1282                         return new Invocation (new MemberAccess (CreateExpressionTypeExpression (loc), name, typeArguments, loc), args);
1283                 }
1284
1285                 protected static TypeExpr CreateExpressionTypeExpression (Location loc)
1286                 {
1287                         TypeExpr texpr = TypeManager.expression_type_expr;
1288                         if (texpr == null) {
1289                                 Type t = TypeManager.CoreLookupType ("System.Linq.Expressions", "Expression", Kind.Class, true);
1290                                 if (t == null)
1291                                         return null;
1292
1293                                 TypeManager.expression_type_expr = texpr = new TypeExpression (t, Location.Null);
1294                         }
1295
1296                         return texpr;
1297                 }
1298
1299                 public virtual void MutateHoistedGenericType (AnonymousMethodStorey storey)
1300                 {
1301                         // TODO: It should probably be type = storey.MutateType (type);
1302                 }
1303         }
1304
1305         /// <summary>
1306         ///   This is just a base class for expressions that can
1307         ///   appear on statements (invocations, object creation,
1308         ///   assignments, post/pre increment and decrement).  The idea
1309         ///   being that they would support an extra Emition interface that
1310         ///   does not leave a result on the stack.
1311         /// </summary>
1312         public abstract class ExpressionStatement : Expression {
1313
1314                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1315                 {
1316                         Expression e = Resolve (ec);
1317                         if (e == null)
1318                                 return null;
1319
1320                         ExpressionStatement es = e as ExpressionStatement;
1321                         if (es == null)
1322                                 Error_InvalidExpressionStatement ();
1323
1324                         return es;
1325                 }
1326
1327                 /// <summary>
1328                 ///   Requests the expression to be emitted in a `statement'
1329                 ///   context.  This means that no new value is left on the
1330                 ///   stack after invoking this method (constrasted with
1331                 ///   Emit that will always leave a value on the stack).
1332                 /// </summary>
1333                 public abstract void EmitStatement (EmitContext ec);
1334
1335                 public override void EmitSideEffect (EmitContext ec)
1336                 {
1337                         EmitStatement (ec);
1338                 }
1339         }
1340
1341         /// <summary>
1342         ///   This kind of cast is used to encapsulate the child
1343         ///   whose type is child.Type into an expression that is
1344         ///   reported to return "return_type".  This is used to encapsulate
1345         ///   expressions which have compatible types, but need to be dealt
1346         ///   at higher levels with.
1347         ///
1348         ///   For example, a "byte" expression could be encapsulated in one
1349         ///   of these as an "unsigned int".  The type for the expression
1350         ///   would be "unsigned int".
1351         ///
1352         /// </summary>
1353         public abstract class TypeCast : Expression
1354         {
1355                 protected readonly Expression child;
1356
1357                 protected TypeCast (Expression child, Type return_type)
1358                 {
1359                         eclass = child.eclass;
1360                         loc = child.Location;
1361                         type = return_type;
1362                         this.child = child;
1363                 }
1364
1365                 public override Expression CreateExpressionTree (EmitContext ec)
1366                 {
1367                         ArrayList args = new ArrayList (2);
1368                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1369                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1370
1371                         if (type.IsPointer || child.Type.IsPointer)
1372                                 Error_PointerInsideExpressionTree ();
1373
1374                         return CreateExpressionFactoryCall (ec.CheckState ? "ConvertChecked" : "Convert", args);
1375                 }
1376
1377                 public override Expression DoResolve (EmitContext ec)
1378                 {
1379                         // This should never be invoked, we are born in fully
1380                         // initialized state.
1381
1382                         return this;
1383                 }
1384
1385                 public override void Emit (EmitContext ec)
1386                 {
1387                         child.Emit (ec);
1388                 }
1389
1390                 public override bool GetAttributableValue (EmitContext ec, Type value_type, out object value)
1391                 {
1392                         return child.GetAttributableValue (ec, value_type, out value);
1393                 }
1394
1395                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1396                 {
1397                         type = storey.MutateType (type);
1398                         child.MutateHoistedGenericType (storey);
1399                 }
1400
1401                 protected override void CloneTo (CloneContext clonectx, Expression t)
1402                 {
1403                         // Nothing to clone
1404                 }
1405
1406                 public override bool IsNull {
1407                         get { return child.IsNull; }
1408                 }
1409         }
1410
1411         public class EmptyCast : TypeCast {
1412                 EmptyCast (Expression child, Type target_type)
1413                         : base (child, target_type)
1414                 {
1415                 }
1416
1417                 public static Expression Create (Expression child, Type type)
1418                 {
1419                         Constant c = child as Constant;
1420                         if (c != null)
1421                                 return new EmptyConstantCast (c, type);
1422
1423                         EmptyCast e = child as EmptyCast;
1424                         if (e != null)
1425                                 return new EmptyCast (e.child, type);
1426
1427                         return new EmptyCast (child, type);
1428                 }
1429
1430                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1431                 {
1432                         child.EmitBranchable (ec, label, on_true);
1433                 }
1434
1435                 public override void EmitSideEffect (EmitContext ec)
1436                 {
1437                         child.EmitSideEffect (ec);
1438                 }
1439         }
1440
1441         //
1442         // Used for predefined class library user casts (no obsolete check, etc.)
1443         //
1444         public class OperatorCast : TypeCast {
1445                 MethodInfo conversion_operator;
1446
1447                 public OperatorCast (Expression child, Type target_type)
1448                         : this (child, target_type, false)
1449                 {
1450                 }
1451
1452                 public OperatorCast (Expression child, Type target_type, bool find_explicit)
1453                         : base (child, target_type)
1454                 {
1455                         conversion_operator = GetConversionOperator (find_explicit);
1456                         if (conversion_operator == null)
1457                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1458                 }
1459
1460                 // Returns the implicit operator that converts from
1461                 // 'child.Type' to our target type (type)
1462                 MethodInfo GetConversionOperator (bool find_explicit)
1463                 {
1464                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1465
1466                         MemberInfo [] mi;
1467
1468                         mi = TypeManager.MemberLookup (child.Type, child.Type, child.Type, MemberTypes.Method,
1469                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1470
1471                         if (mi == null){
1472                                 mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1473                                                                BindingFlags.Static | BindingFlags.Public, operator_name, null);
1474                         }
1475
1476                         foreach (MethodInfo oper in mi) {
1477                                 AParametersCollection pd = TypeManager.GetParameterData (oper);
1478
1479                                 if (pd.Types [0] == child.Type && TypeManager.TypeToCoreType (oper.ReturnType) == type)
1480                                         return oper;
1481                         }
1482
1483                         return null;
1484                 }
1485
1486                 public override void Emit (EmitContext ec)
1487                 {
1488                         child.Emit (ec);
1489                         ec.ig.Emit (OpCodes.Call, conversion_operator);
1490                 }
1491         }
1492
1493         /// <summary>
1494         ///     This is a numeric cast to a Decimal
1495         /// </summary>
1496         public class CastToDecimal : OperatorCast {
1497                 public CastToDecimal (Expression child)
1498                         : this (child, false)
1499                 {
1500                 }
1501
1502                 public CastToDecimal (Expression child, bool find_explicit)
1503                         : base (child, TypeManager.decimal_type, find_explicit)
1504                 {
1505                 }
1506         }
1507
1508         /// <summary>
1509         ///     This is an explicit numeric cast from a Decimal
1510         /// </summary>
1511         public class CastFromDecimal : TypeCast
1512         {
1513                 static IDictionary operators;
1514
1515                 public CastFromDecimal (Expression child, Type return_type)
1516                         : base (child, return_type)
1517                 {
1518                         if (child.Type != TypeManager.decimal_type)
1519                                 throw new InternalErrorException (
1520                                         "The expected type is Decimal, instead it is " + child.Type.FullName);
1521                 }
1522
1523                 // Returns the explicit operator that converts from an
1524                 // express of type System.Decimal to 'type'.
1525                 public Expression Resolve ()
1526                 {
1527                         if (operators == null) {
1528                                  MemberInfo[] all_oper = TypeManager.MemberLookup (TypeManager.decimal_type,
1529                                         TypeManager.decimal_type, TypeManager.decimal_type, MemberTypes.Method,
1530                                         BindingFlags.Static | BindingFlags.Public, "op_Explicit", null);
1531
1532                                 operators = new System.Collections.Specialized.HybridDictionary ();
1533                                 foreach (MethodInfo oper in all_oper) {
1534                                         AParametersCollection pd = TypeManager.GetParameterData (oper);
1535                                         if (pd.Types [0] == TypeManager.decimal_type)
1536                                                 operators.Add (TypeManager.TypeToCoreType (oper.ReturnType), oper);
1537                                 }
1538                         }
1539
1540                         return operators.Contains (type) ? this : null;
1541                 }
1542
1543                 public override void Emit (EmitContext ec)
1544                 {
1545                         ILGenerator ig = ec.ig;
1546                         child.Emit (ec);
1547
1548                         ig.Emit (OpCodes.Call, (MethodInfo)operators [type]);
1549                 }
1550         }
1551
1552
1553         //
1554         // Constant specialization of EmptyCast.
1555         // We need to special case this since an empty cast of
1556         // a constant is still a constant.
1557         //
1558         public class EmptyConstantCast : Constant
1559         {
1560                 public readonly Constant child;
1561
1562                 public EmptyConstantCast(Constant child, Type type)
1563                         : base (child.Location)
1564                 {
1565                         eclass = child.eclass;
1566                         this.child = child;
1567                         this.type = type;
1568                 }
1569
1570                 public override string AsString ()
1571                 {
1572                         return child.AsString ();
1573                 }
1574
1575                 public override object GetValue ()
1576                 {
1577                         return child.GetValue ();
1578                 }
1579
1580                 public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
1581                 {
1582                         // FIXME: check that 'type' can be converted to 'target_type' first
1583                         return child.ConvertExplicitly (in_checked_context, target_type);
1584                 }
1585
1586                 public override Expression CreateExpressionTree (EmitContext ec)
1587                 {
1588                         ArrayList args = new ArrayList (2);
1589                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1590                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1591                         if (type.IsPointer)
1592                                 Error_PointerInsideExpressionTree ();
1593
1594                         return CreateExpressionFactoryCall ("Convert", args);
1595                 }
1596
1597                 public override Constant Increment ()
1598                 {
1599                         return child.Increment ();
1600                 }
1601
1602                 public override bool IsDefaultValue {
1603                         get { return child.IsDefaultValue; }
1604                 }
1605
1606                 public override bool IsNegative {
1607                         get { return child.IsNegative; }
1608                 }
1609
1610                 public override bool IsNull {
1611                         get { return child.IsNull; }
1612                 }
1613
1614                 public override bool IsZeroInteger {
1615                         get { return child.IsZeroInteger; }
1616                 }
1617
1618                 public override void Emit (EmitContext ec)
1619                 {
1620                         child.Emit (ec);
1621                 }
1622
1623                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1624                 {
1625                         child.EmitBranchable (ec, label, on_true);
1626
1627 #if GMCS_SOURCE
1628                         // Only to make verifier happy
1629                         if (TypeManager.IsGenericParameter (type) && child.IsNull)
1630                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
1631 #endif
1632                 }
1633
1634                 public override void EmitSideEffect (EmitContext ec)
1635                 {
1636                         child.EmitSideEffect (ec);
1637                 }
1638
1639                 public override Constant ConvertImplicitly (Type target_type)
1640                 {
1641                         // FIXME: Do we need to check user conversions?
1642                         if (!Convert.ImplicitStandardConversionExists (this, target_type))
1643                                 return null;
1644                         return child.ConvertImplicitly (target_type);
1645                 }
1646
1647                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1648                 {
1649                         child.MutateHoistedGenericType (storey);
1650                 }
1651         }
1652
1653
1654         /// <summary>
1655         ///  This class is used to wrap literals which belong inside Enums
1656         /// </summary>
1657         public class EnumConstant : Constant {
1658                 public Constant Child;
1659
1660                 public EnumConstant (Constant child, Type enum_type):
1661                         base (child.Location)
1662                 {
1663                         eclass = child.eclass;
1664                         this.Child = child;
1665                         type = enum_type;
1666                 }
1667
1668                 public override Expression DoResolve (EmitContext ec)
1669                 {
1670                         // This should never be invoked, we are born in fully
1671                         // initialized state.
1672
1673                         return this;
1674                 }
1675
1676                 public override void Emit (EmitContext ec)
1677                 {
1678                         Child.Emit (ec);
1679                 }
1680
1681                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1682                 {
1683                         Child.EmitBranchable (ec, label, on_true);
1684                 }
1685
1686                 public override void EmitSideEffect (EmitContext ec)
1687                 {
1688                         Child.EmitSideEffect (ec);
1689                 }
1690
1691                 public override bool GetAttributableValue (EmitContext ec, Type value_type, out object value)
1692                 {
1693                         value = GetTypedValue ();
1694                         return true;
1695                 }
1696
1697                 public override string GetSignatureForError()
1698                 {
1699                         return TypeManager.CSharpName (Type);
1700                 }
1701
1702                 public override object GetValue ()
1703                 {
1704                         return Child.GetValue ();
1705                 }
1706
1707                 public override object GetTypedValue ()
1708                 {
1709                         // FIXME: runtime is not ready to work with just emited enums
1710                         if (!RootContext.StdLib) {
1711                                 return Child.GetValue ();
1712                         }
1713
1714 #if MS_COMPATIBLE
1715                         // Small workaround for big problem
1716                         // System.Enum.ToObject cannot be called on dynamic types
1717                         // EnumBuilder has to be used, but we cannot use EnumBuilder
1718                         // because it does not properly support generics
1719                         //
1720                         // This works only sometimes
1721                         //
1722                         if (type.Module == RootContext.ToplevelTypes.Builder)
1723                                 return Child.GetValue ();
1724 #endif
1725
1726                         return System.Enum.ToObject (type, Child.GetValue ());
1727                 }
1728
1729                 public override string AsString ()
1730                 {
1731                         return Child.AsString ();
1732                 }
1733
1734                 public override Constant Increment()
1735                 {
1736                         return new EnumConstant (Child.Increment (), type);
1737                 }
1738
1739                 public override bool IsDefaultValue {
1740                         get {
1741                                 return Child.IsDefaultValue;
1742                         }
1743                 }
1744
1745                 public override bool IsZeroInteger {
1746                         get { return Child.IsZeroInteger; }
1747                 }
1748
1749                 public override bool IsNegative {
1750                         get {
1751                                 return Child.IsNegative;
1752                         }
1753                 }
1754
1755                 public override Constant ConvertExplicitly(bool in_checked_context, Type target_type)
1756                 {
1757                         if (Child.Type == target_type)
1758                                 return Child;
1759
1760                         return Child.ConvertExplicitly (in_checked_context, target_type);
1761                 }
1762
1763                 public override Constant ConvertImplicitly (Type type)
1764                 {
1765                         Type this_type = TypeManager.DropGenericTypeArguments (Type);
1766                         type = TypeManager.DropGenericTypeArguments (type);
1767
1768                         if (this_type == type) {
1769                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1770                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1771                                         return this;
1772
1773                                 Type child_type = TypeManager.DropGenericTypeArguments (Child.Type);
1774                                 if (type.UnderlyingSystemType != child_type)
1775                                         Child = Child.ConvertImplicitly (type.UnderlyingSystemType);
1776                                 return this;
1777                         }
1778
1779                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1780                                 return null;
1781                         }
1782
1783                         return Child.ConvertImplicitly(type);
1784                 }
1785
1786         }
1787
1788         /// <summary>
1789         ///   This kind of cast is used to encapsulate Value Types in objects.
1790         ///
1791         ///   The effect of it is to box the value type emitted by the previous
1792         ///   operation.
1793         /// </summary>
1794         public class BoxedCast : TypeCast {
1795
1796                 public BoxedCast (Expression expr, Type target_type)
1797                         : base (expr, target_type)
1798                 {
1799                         eclass = ExprClass.Value;
1800                 }
1801
1802                 public override Expression DoResolve (EmitContext ec)
1803                 {
1804                         // This should never be invoked, we are born in fully
1805                         // initialized state.
1806
1807                         return this;
1808                 }
1809
1810                 public override void Emit (EmitContext ec)
1811                 {
1812                         base.Emit (ec);
1813
1814                         ec.ig.Emit (OpCodes.Box, child.Type);
1815                 }
1816
1817                 public override void EmitSideEffect (EmitContext ec)
1818                 {
1819                         // boxing is side-effectful, since it involves runtime checks, except when boxing to Object or ValueType
1820                         // so, we need to emit the box+pop instructions in most cases
1821                         if (TypeManager.IsStruct (child.Type) &&
1822                             (type == TypeManager.object_type || type == TypeManager.value_type))
1823                                 child.EmitSideEffect (ec);
1824                         else
1825                                 base.EmitSideEffect (ec);
1826                 }
1827         }
1828
1829         public class UnboxCast : TypeCast {
1830                 public UnboxCast (Expression expr, Type return_type)
1831                         : base (expr, return_type)
1832                 {
1833                 }
1834
1835                 public override Expression DoResolve (EmitContext ec)
1836                 {
1837                         // This should never be invoked, we are born in fully
1838                         // initialized state.
1839
1840                         return this;
1841                 }
1842
1843                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1844                 {
1845                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
1846                                 Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1847                         return base.DoResolveLValue (ec, right_side);
1848                 }
1849
1850                 public override void Emit (EmitContext ec)
1851                 {
1852                         base.Emit (ec);
1853
1854                         ILGenerator ig = ec.ig;
1855
1856 #if GMCS_SOURCE
1857                         ig.Emit (OpCodes.Unbox_Any, type);
1858 #else
1859                         ig.Emit (OpCodes.Unbox, type);
1860                         LoadFromPtr (ig, type);
1861 #endif
1862                 }
1863
1864                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
1865                 {
1866                         type = storey.MutateType (type);
1867                         base.MutateHoistedGenericType (storey);
1868                 }
1869         }
1870
1871         /// <summary>
1872         ///   This is used to perform explicit numeric conversions.
1873         ///
1874         ///   Explicit numeric conversions might trigger exceptions in a checked
1875         ///   context, so they should generate the conv.ovf opcodes instead of
1876         ///   conv opcodes.
1877         /// </summary>
1878         public class ConvCast : TypeCast {
1879                 public enum Mode : byte {
1880                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1881                         U1_I1, U1_CH,
1882                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1883                         U2_I1, U2_U1, U2_I2, U2_CH,
1884                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1885                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1886                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH,
1887                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH,
1888                         CH_I1, CH_U1, CH_I2,
1889                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1890                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4
1891                 }
1892
1893                 Mode mode;
1894
1895                 public ConvCast (Expression child, Type return_type, Mode m)
1896                         : base (child, return_type)
1897                 {
1898                         mode = m;
1899                 }
1900
1901                 public override Expression DoResolve (EmitContext ec)
1902                 {
1903                         // This should never be invoked, we are born in fully
1904                         // initialized state.
1905
1906                         return this;
1907                 }
1908
1909                 public override string ToString ()
1910                 {
1911                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1912                 }
1913
1914                 public override void Emit (EmitContext ec)
1915                 {
1916                         ILGenerator ig = ec.ig;
1917
1918                         base.Emit (ec);
1919
1920                         if (ec.CheckState){
1921                                 switch (mode){
1922                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1923                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1924                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1925                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1926                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1927
1928                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1929                                 case Mode.U1_CH: /* nothing */ break;
1930
1931                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1932                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1933                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1934                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1935                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1936                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1937
1938                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1939                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1940                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1941                                 case Mode.U2_CH: /* nothing */ break;
1942
1943                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1944                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1945                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1946                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1947                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1948                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1949                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1950
1951                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1952                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1953                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1954                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1955                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1956                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1957
1958                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1959                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1960                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1961                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1962                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1963                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1964                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1965                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1966
1967                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1968                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1969                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1970                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1971                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1972                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1973                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1974                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1975
1976                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1977                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1978                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1979
1980                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1981                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1982                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1983                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1984                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1985                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1986                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1987                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1988                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1989
1990                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1991                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1992                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1993                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1994                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1995                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1996                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1997                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1998                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1999                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
2000                                 }
2001                         } else {
2002                                 switch (mode){
2003                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
2004                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
2005                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
2006                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
2007                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
2008
2009                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
2010                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
2011
2012                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
2013                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
2014                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
2015                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
2016                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
2017                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
2018
2019                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
2020                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
2021                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
2022                                 case Mode.U2_CH: /* nothing */ break;
2023
2024                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
2025                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
2026                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
2027                                 case Mode.I4_U4: /* nothing */ break;
2028                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
2029                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
2030                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
2031
2032                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
2033                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
2034                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
2035                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
2036                                 case Mode.U4_I4: /* nothing */ break;
2037                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
2038
2039                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
2040                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
2041                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
2042                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
2043                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
2044                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
2045                                 case Mode.I8_U8: /* nothing */ break;
2046                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
2047
2048                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
2049                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
2050                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
2051                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
2052                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
2053                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
2054                                 case Mode.U8_I8: /* nothing */ break;
2055                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
2056
2057                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
2058                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
2059                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
2060
2061                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
2062                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
2063                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
2064                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
2065                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
2066                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
2067                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
2068                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
2069                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
2070
2071                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
2072                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
2073                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
2074                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
2075                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
2076                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
2077                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
2078                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
2079                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
2080                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
2081                                 }
2082                         }
2083                 }
2084         }
2085
2086         public class OpcodeCast : TypeCast {
2087                 readonly OpCode op;
2088
2089                 public OpcodeCast (Expression child, Type return_type, OpCode op)
2090                         : base (child, return_type)
2091                 {
2092                         this.op = op;
2093                 }
2094
2095                 public override Expression DoResolve (EmitContext ec)
2096                 {
2097                         // This should never be invoked, we are born in fully
2098                         // initialized state.
2099
2100                         return this;
2101                 }
2102
2103                 public override void Emit (EmitContext ec)
2104                 {
2105                         base.Emit (ec);
2106                         ec.ig.Emit (op);
2107                 }
2108
2109                 public Type UnderlyingType {
2110                         get { return child.Type; }
2111                 }
2112         }
2113
2114         /// <summary>
2115         ///   This kind of cast is used to encapsulate a child and cast it
2116         ///   to the class requested
2117         /// </summary>
2118         public sealed class ClassCast : TypeCast {
2119                 readonly bool forced;
2120
2121                 public ClassCast (Expression child, Type return_type)
2122                         : base (child, return_type)
2123                 {
2124                 }
2125
2126                 public ClassCast (Expression child, Type return_type, bool forced)
2127                         : base (child, return_type)
2128                 {
2129                         this.forced = forced;
2130                 }
2131
2132                 public override void Emit (EmitContext ec)
2133                 {
2134                         base.Emit (ec);
2135
2136 #if GMCS_SOURCE
2137                         bool gen = TypeManager.IsGenericParameter (child.Type);
2138                         if (gen)
2139                                 ec.ig.Emit (OpCodes.Box, child.Type);
2140
2141                         if (type.IsGenericParameter) {
2142                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2143                                 return;
2144                         }
2145
2146                         if (gen && !forced)
2147                                 return;
2148 #endif
2149
2150                         ec.ig.Emit (OpCodes.Castclass, type);
2151                 }
2152         }
2153
2154         //
2155         // Created during resolving pahse when an expression is wrapped or constantified
2156         // and original expression can be used later (e.g. for expression trees)
2157         //
2158         public class ReducedExpression : Expression
2159         {
2160                 sealed class ReducedConstantExpression : EmptyConstantCast
2161                 {
2162                         readonly Expression orig_expr;
2163
2164                         public ReducedConstantExpression (Constant expr, Expression orig_expr)
2165                                 : base (expr, expr.Type)
2166                         {
2167                                 this.orig_expr = orig_expr;
2168                         }
2169
2170                         public override Constant ConvertImplicitly (Type target_type)
2171                         {
2172                                 Constant c = base.ConvertImplicitly (target_type);
2173                                 if (c != null)
2174                                         c = new ReducedConstantExpression (c, orig_expr);
2175                                 return c;
2176                         }
2177
2178                         public override Expression CreateExpressionTree (EmitContext ec)
2179                         {
2180                                 return orig_expr.CreateExpressionTree (ec);
2181                         }
2182
2183                         public override bool GetAttributableValue (EmitContext ec, Type value_type, out object value)
2184                         {
2185                                 //
2186                                 // Even if resolved result is a constant original expression was not
2187                                 // and attribute accepts constants only
2188                                 //
2189                                 Attribute.Error_AttributeArgumentNotValid (orig_expr.Location);
2190                                 value = null;
2191                                 return false;
2192                         }
2193
2194                         public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
2195                         {
2196                                 Constant c = base.ConvertExplicitly (in_checked_context, target_type);
2197                                 if (c != null)
2198                                         c = new ReducedConstantExpression (c, orig_expr);
2199                                 return c;
2200                         }
2201                 }
2202
2203                 sealed class ReducedExpressionStatement : ExpressionStatement
2204                 {
2205                         readonly Expression orig_expr;
2206                         readonly ExpressionStatement stm;
2207
2208                         public ReducedExpressionStatement (ExpressionStatement stm, Expression orig)
2209                         {
2210                                 this.orig_expr = orig;
2211                                 this.stm = stm;
2212                                 this.loc = orig.Location;
2213                         }
2214
2215                         public override Expression CreateExpressionTree (EmitContext ec)
2216                         {
2217                                 return orig_expr.CreateExpressionTree (ec);
2218                         }
2219
2220                         public override Expression DoResolve (EmitContext ec)
2221                         {
2222                                 eclass = stm.eclass;
2223                                 type = stm.Type;
2224                                 return this;
2225                         }
2226
2227                         public override void Emit (EmitContext ec)
2228                         {
2229                                 stm.Emit (ec);
2230                         }
2231
2232                         public override void EmitStatement (EmitContext ec)
2233                         {
2234                                 stm.EmitStatement (ec);
2235                         }
2236
2237                         public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2238                         {
2239                                 stm.MutateHoistedGenericType (storey);
2240                         }
2241                 }
2242
2243                 readonly Expression expr, orig_expr;
2244
2245                 private ReducedExpression (Expression expr, Expression orig_expr)
2246                 {
2247                         this.expr = expr;
2248                         this.orig_expr = orig_expr;
2249                         this.loc = orig_expr.Location;
2250                 }
2251
2252                 public static Constant Create (Constant expr, Expression original_expr)
2253                 {
2254                         return new ReducedConstantExpression (expr, original_expr);
2255                 }
2256
2257                 public static ExpressionStatement Create (ExpressionStatement s, Expression orig)
2258                 {
2259                         return new ReducedExpressionStatement (s, orig);
2260                 }
2261
2262                 public static Expression Create (Expression expr, Expression original_expr)
2263                 {
2264                         Constant c = expr as Constant;
2265                         if (c != null)
2266                                 return Create (c, original_expr);
2267
2268                         ExpressionStatement s = expr as ExpressionStatement;
2269                         if (s != null)
2270                                 return Create (s, original_expr);
2271
2272                         return new ReducedExpression (expr, original_expr);
2273                 }
2274
2275                 public override Expression CreateExpressionTree (EmitContext ec)
2276                 {
2277                         return orig_expr.CreateExpressionTree (ec);
2278                 }
2279
2280                 public override Expression DoResolve (EmitContext ec)
2281                 {
2282                         eclass = expr.eclass;
2283                         type = expr.Type;
2284                         return this;
2285                 }
2286
2287                 public override void Emit (EmitContext ec)
2288                 {
2289                         expr.Emit (ec);
2290                 }
2291
2292                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
2293                 {
2294                         expr.EmitBranchable (ec, target, on_true);
2295                 }
2296
2297                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2298                 {
2299                         expr.MutateHoistedGenericType (storey);
2300                 }
2301         }
2302
2303         //
2304         // Unresolved type name expressions
2305         //
2306         public abstract class ATypeNameExpression : FullNamedExpression
2307         {
2308                 public readonly string Name;
2309                 protected TypeArguments targs;
2310
2311                 protected ATypeNameExpression (string name, Location l)
2312                 {
2313                         Name = name;
2314                         loc = l;
2315                 }
2316
2317                 protected ATypeNameExpression (string name, TypeArguments targs, Location l)
2318                 {
2319                         Name = name;
2320                         this.targs = targs;
2321                         loc = l;
2322                 }
2323
2324                 public bool HasTypeArguments {
2325                         get {
2326                                 return targs != null;
2327                         }
2328                 }
2329
2330                 public override bool Equals (object obj)
2331                 {
2332                         ATypeNameExpression atne = obj as ATypeNameExpression;
2333                         return atne != null && atne.Name == Name &&
2334                                 (targs == null || targs.Equals (atne.targs));
2335                 }
2336
2337                 public override int GetHashCode ()
2338                 {
2339                         return Name.GetHashCode ();
2340                 }
2341
2342                 public override string GetSignatureForError ()
2343                 {
2344                         if (targs != null) {
2345                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2346                                         targs.GetSignatureForError () + ">";
2347                         }
2348
2349                         return Name;
2350                 }
2351         }
2352
2353         /// <summary>
2354         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2355         ///   of a dotted-name.
2356         /// </summary>
2357         public class SimpleName : ATypeNameExpression {
2358                 bool in_transit;
2359
2360                 public SimpleName (string name, Location l)
2361                         : base (name, l)
2362                 {
2363                 }
2364
2365                 public SimpleName (string name, TypeArguments args, Location l)
2366                         : base (name, args, l)
2367                 {
2368                 }
2369
2370                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2371                         : base (name, l)
2372                 {
2373                         targs = new TypeArguments ();
2374                         foreach (TypeParameter type_param in type_params)
2375                                 targs.Add (new TypeParameterExpr (type_param, l));
2376                 }
2377
2378                 public static string RemoveGenericArity (string name)
2379                 {
2380                         int start = 0;
2381                         StringBuilder sb = null;
2382                         do {
2383                                 int pos = name.IndexOf ('`', start);
2384                                 if (pos < 0) {
2385                                         if (start == 0)
2386                                                 return name;
2387
2388                                         sb.Append (name.Substring (start));
2389                                         break;
2390                                 }
2391
2392                                 if (sb == null)
2393                                         sb = new StringBuilder ();
2394                                 sb.Append (name.Substring (start, pos-start));
2395
2396                                 pos++;
2397                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2398                                         pos++;
2399
2400                                 start = pos;
2401                         } while (start < name.Length);
2402
2403                         return sb.ToString ();
2404                 }
2405
2406                 public SimpleName GetMethodGroup ()
2407                 {
2408                         return new SimpleName (RemoveGenericArity (Name), targs, loc);
2409                 }
2410
2411                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
2412                 {
2413                         if (ec.IsInFieldInitializer)
2414                                 Report.Error (236, l,
2415                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2416                                         name);
2417                         else
2418                                 Report.Error (120, l,
2419                                         "An object reference is required to access non-static member `{0}'",
2420                                         name);
2421                 }
2422
2423                 public bool IdenticalNameAndTypeName (EmitContext ec, Expression resolved_to, Location loc)
2424                 {
2425                         return resolved_to != null && resolved_to.Type != null &&
2426                                 resolved_to.Type.Name == Name &&
2427                                 (ec.DeclContainer.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2428                 }
2429
2430                 public override Expression DoResolve (EmitContext ec)
2431                 {
2432                         return SimpleNameResolve (ec, null, false);
2433                 }
2434
2435                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
2436                 {
2437                         return SimpleNameResolve (ec, right_side, false);
2438                 }
2439
2440
2441                 public Expression DoResolve (EmitContext ec, bool intermediate)
2442                 {
2443                         return SimpleNameResolve (ec, null, intermediate);
2444                 }
2445
2446                 static bool IsNestedChild (Type t, Type parent)
2447                 {
2448                         while (parent != null) {
2449                                 if (TypeManager.IsNestedChildOf (t, TypeManager.DropGenericTypeArguments (parent)))
2450                                         return true;
2451
2452                                 parent = parent.BaseType;
2453                         }
2454
2455                         return false;
2456                 }
2457
2458                 FullNamedExpression ResolveNested (IResolveContext ec, Type t)
2459                 {
2460                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2461                                 return null;
2462
2463                         DeclSpace ds = ec.DeclContainer;
2464                         while (ds != null && !IsNestedChild (t, ds.TypeBuilder))
2465                                 ds = ds.Parent;
2466
2467                         if (ds == null)
2468                                 return null;
2469
2470                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2471
2472                         int arg_count = targs != null ? targs.Count : 0;
2473
2474                         for (; (ds != null) && ds.IsGeneric; ds = ds.Parent) {
2475                                 if (arg_count + ds.CountTypeParameters == gen_params.Length) {
2476                                         TypeArguments new_args = new TypeArguments ();
2477                                         foreach (TypeParameter param in ds.TypeParameters)
2478                                                 new_args.Add (new TypeParameterExpr (param, loc));
2479
2480                                         if (targs != null)
2481                                                 new_args.Add (targs);
2482
2483                                         return new GenericTypeExpr (t, new_args, loc);
2484                                 }
2485                         }
2486
2487                         return null;
2488                 }
2489
2490                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2491                 {
2492                         FullNamedExpression fne = ec.GenericDeclContainer.LookupGeneric (Name, loc);
2493                         if (fne != null)
2494                                 return fne.ResolveAsTypeStep (ec, silent);
2495
2496                         int errors = Report.Errors;
2497                         fne = ec.DeclContainer.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2498
2499                         if (fne != null) {
2500                                 if (fne.Type == null)
2501                                         return fne;
2502
2503                                 FullNamedExpression nested = ResolveNested (ec, fne.Type);
2504                                 if (nested != null)
2505                                         return nested.ResolveAsTypeStep (ec, false);
2506
2507                                 if (targs != null) {
2508                                         GenericTypeExpr ct = new GenericTypeExpr (fne.Type, targs, loc);
2509                                         return ct.ResolveAsTypeStep (ec, false);
2510                                 }
2511
2512                                 return fne;
2513                         }
2514
2515                         if (silent || errors != Report.Errors)
2516                                 return null;
2517
2518                         Error_TypeOrNamespaceNotFound (ec);
2519                         return null;
2520                 }
2521
2522                 protected virtual void Error_TypeOrNamespaceNotFound (IResolveContext ec)
2523                 {
2524                         MemberCore mc = ec.DeclContainer.GetDefinition (Name);
2525                         if (mc != null) {
2526                                 Error_UnexpectedKind (ec.DeclContainer, "type", GetMemberType (mc), loc);
2527                                 return;
2528                         }
2529
2530                         string ns = ec.DeclContainer.NamespaceEntry.NS.Name;
2531                         string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2532                         foreach (Assembly a in GlobalRootNamespace.Instance.Assemblies) {
2533                                 Type type = a.GetType (fullname);
2534                                 if (type != null) {
2535                                         Report.SymbolRelatedToPreviousError (type);
2536                                         Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type));
2537                                         return;
2538                                 }
2539                         }
2540
2541                         Type t = ec.DeclContainer.LookupAnyGeneric (Name);
2542                         if (t != null) {
2543                                 Namespace.Error_InvalidNumberOfTypeArguments (t, loc);
2544                                 return;
2545                         }
2546
2547                         if (targs != null) {
2548                                 FullNamedExpression retval = ec.DeclContainer.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2549                                 if (retval != null) {
2550                                         Namespace.Error_TypeArgumentsCannotBeUsed (retval, loc);
2551                                         return;
2552                                 }
2553                         }
2554
2555                         NamespaceEntry.Error_NamespaceNotFound (loc, Name);
2556                 }
2557
2558                 // TODO: I am still not convinced about this. If someone else will need it
2559                 // implement this as virtual property in MemberCore hierarchy
2560                 public static string GetMemberType (MemberCore mc)
2561                 {
2562                         if (mc is Property)
2563                                 return "property";
2564                         if (mc is Indexer)
2565                                 return "indexer";
2566                         if (mc is FieldBase)
2567                                 return "field";
2568                         if (mc is MethodCore)
2569                                 return "method";
2570                         if (mc is EnumMember)
2571                                 return "enum";
2572                         if (mc is Event)
2573                                 return "event";
2574
2575                         return "type";
2576                 }
2577
2578                 Expression SimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2579                 {
2580                         if (in_transit)
2581                                 return null;
2582
2583                         in_transit = true;
2584                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2585                         in_transit = false;
2586
2587                         if (e == null)
2588                                 return null;
2589
2590                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2591                                 return e;
2592
2593                         return null;
2594                 }
2595
2596                 /// <remarks>
2597                 ///   7.5.2: Simple Names.
2598                 ///
2599                 ///   Local Variables and Parameters are handled at
2600                 ///   parse time, so they never occur as SimpleNames.
2601                 ///
2602                 ///   The `intermediate' flag is used by MemberAccess only
2603                 ///   and it is used to inform us that it is ok for us to
2604                 ///   avoid the static check, because MemberAccess might end
2605                 ///   up resolving the Name as a Type name and the access as
2606                 ///   a static type access.
2607                 ///
2608                 ///   ie: Type Type; .... { Type.GetType (""); }
2609                 ///
2610                 ///   Type is both an instance variable and a Type;  Type.GetType
2611                 ///   is the static method not an instance method of type.
2612                 /// </remarks>
2613                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2614                 {
2615                         Expression e = null;
2616
2617                         //
2618                         // Stage 1: Performed by the parser (binding to locals or parameters).
2619                         //
2620                         Block current_block = ec.CurrentBlock;
2621                         if (current_block != null){
2622                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2623                                 if (vi != null){
2624                                         LocalVariableReference var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2625                                         if (right_side != null) {
2626                                                 return var.ResolveLValue (ec, right_side, loc);
2627                                         } else {
2628                                                 ResolveFlags rf = ResolveFlags.VariableOrValue;
2629                                                 if (intermediate)
2630                                                         rf |= ResolveFlags.DisableFlowAnalysis;
2631                                                 return var.Resolve (ec, rf);
2632                                         }
2633                                 }
2634
2635                                 Expression expr = current_block.Toplevel.GetParameterReference (Name, loc);
2636                                 if (expr != null) {
2637                                         if (right_side != null)
2638                                                 return expr.ResolveLValue (ec, right_side, loc);
2639
2640                                         return expr.Resolve (ec);
2641                                 }
2642                         }
2643
2644                         //
2645                         // Stage 2: Lookup members
2646                         //
2647
2648                         Type almost_matched_type = null;
2649                         ArrayList almost_matched = null;
2650                         for (DeclSpace lookup_ds = ec.DeclContainer; lookup_ds != null; lookup_ds = lookup_ds.Parent) {
2651                                 // either RootDeclSpace or GenericMethod
2652                                 if (lookup_ds.TypeBuilder == null)
2653                                         continue;
2654
2655                                 e = MemberLookup (ec.ContainerType, lookup_ds.TypeBuilder, Name, loc);
2656                                 if (e != null) {
2657                                         PropertyExpr pe = e as PropertyExpr;
2658                                         if (pe != null) {
2659                                                 AParametersCollection param = TypeManager.GetParameterData (pe.PropertyInfo);
2660
2661                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2662                                                 // it doesn't know which accessor to check permissions against
2663                                                 if (param.IsEmpty && pe.IsAccessibleFrom (ec.ContainerType, right_side != null))
2664                                                         break;
2665                                         } else if (e is EventExpr) {
2666                                                 if (((EventExpr) e).IsAccessibleFrom (ec.ContainerType))
2667                                                         break;
2668                                         } else if (targs != null && e is TypeExpression) {
2669                                                 e = new GenericTypeExpr (e.Type, targs, loc).ResolveAsTypeStep (ec, false);
2670                                                 break;
2671                                         } else {
2672                                                 break;
2673                                         }
2674                                         e = null;
2675                                 }
2676
2677                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2678                                         almost_matched_type = lookup_ds.TypeBuilder;
2679                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2680                                 }
2681                         }
2682
2683                         if (e == null) {
2684                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2685                                         almost_matched_type = ec.ContainerType;
2686                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2687                                 }
2688                                 e = ResolveAsTypeStep (ec, true);
2689                         }
2690
2691                         if (e == null) {
2692                                 if (current_block != null) {
2693                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2694                                         if (ikv != null) {
2695                                                 LocalInfo li = ikv as LocalInfo;
2696                                                 // Supress CS0219 warning
2697                                                 if (li != null)
2698                                                         li.Used = true;
2699
2700                                                 Error_VariableIsUsedBeforeItIsDeclared (Name);
2701                                                 return null;
2702                                         }
2703                                 }
2704
2705                                 if (RootContext.EvalMode){
2706                                         FieldInfo fi = Evaluator.LookupField (Name);
2707                                         if (fi != null)
2708                                                 return new FieldExpr (fi, loc).Resolve (ec);
2709                                 }
2710
2711                                 if (almost_matched != null)
2712                                         almost_matched_members = almost_matched;
2713                                 if (almost_matched_type == null)
2714                                         almost_matched_type = ec.ContainerType;
2715                                 return Error_MemberLookupFailed (ec.ContainerType, null, almost_matched_type, Name,
2716                                         ec.DeclContainer.Name, AllMemberTypes, AllBindingFlags);
2717                         }
2718
2719                         if (e is MemberExpr) {
2720                                 MemberExpr me = (MemberExpr) e;
2721
2722                                 Expression left;
2723                                 if (me.IsInstance) {
2724                                         if (ec.IsStatic || ec.IsInFieldInitializer) {
2725                                                 //
2726                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2727                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2728                                                 // and each predicate is true if the MethodGroupExpr contains
2729                                                 // at least one of that kind of method.
2730                                                 //
2731
2732                                                 if (!me.IsStatic &&
2733                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2734                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2735                                                         return null;
2736                                                 }
2737
2738                                                 //
2739                                                 // Pass the buck to MemberAccess and Invocation.
2740                                                 //
2741                                                 left = EmptyExpression.Null;
2742                                         } else {
2743                                                 left = ec.GetThis (loc);
2744                                         }
2745                                 } else {
2746                                         left = new TypeExpression (ec.ContainerType, loc);
2747                                 }
2748
2749                                 me = me.ResolveMemberAccess (ec, left, loc, null);
2750                                 if (me == null)
2751                                         return null;
2752
2753                                 if (targs != null) {
2754                                         if (!targs.Resolve (ec))
2755                                                 return null;
2756
2757                                         me.SetTypeArguments (targs);
2758                                 }
2759
2760                                 if (!me.IsStatic && (me.InstanceExpression != null && me.InstanceExpression != EmptyExpression.Null) &&
2761                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2762                                     me.InstanceExpression.Type != me.DeclaringType &&
2763                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2764                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2765                                         Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2766                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2767                                         return null;
2768                                 }
2769
2770                                 return (right_side != null)
2771                                         ? me.DoResolveLValue (ec, right_side)
2772                                         : me.DoResolve (ec);
2773                         }
2774
2775                         return e;
2776                 }
2777         }
2778
2779         /// <summary>
2780         ///   Represents a namespace or a type.  The name of the class was inspired by
2781         ///   section 10.8.1 (Fully Qualified Names).
2782         /// </summary>
2783         public abstract class FullNamedExpression : Expression
2784         {
2785                 protected override void CloneTo (CloneContext clonectx, Expression target)
2786                 {
2787                         // Do nothing, most unresolved type expressions cannot be
2788                         // resolved to different type
2789                 }
2790
2791                 public override Expression CreateExpressionTree (EmitContext ec)
2792                 {
2793                         throw new NotSupportedException ("ET");
2794                 }
2795
2796                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2797                 {
2798                         throw new NotSupportedException ();
2799                 }
2800
2801                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2802                 {
2803                         return this;
2804                 }
2805
2806                 public override void Emit (EmitContext ec)
2807                 {
2808                         throw new InternalErrorException ("FullNamedExpression `{0}' found in resolved tree",
2809                                 GetSignatureForError ());
2810                 }
2811         }
2812
2813         /// <summary>
2814         ///   Expression that evaluates to a type
2815         /// </summary>
2816         public abstract class TypeExpr : FullNamedExpression {
2817                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2818                 {
2819                         TypeExpr t = DoResolveAsTypeStep (ec);
2820                         if (t == null)
2821                                 return null;
2822
2823                         eclass = ExprClass.Type;
2824                         return t;
2825                 }
2826
2827                 override public Expression DoResolve (EmitContext ec)
2828                 {
2829                         return ResolveAsTypeTerminal (ec, false);
2830                 }
2831
2832                 public virtual bool CheckAccessLevel (DeclSpace ds)
2833                 {
2834                         return ds.CheckAccessLevel (Type);
2835                 }
2836
2837                 public virtual bool IsClass {
2838                         get { return Type.IsClass; }
2839                 }
2840
2841                 public virtual bool IsValueType {
2842                         get { return TypeManager.IsStruct (Type); }
2843                 }
2844
2845                 public virtual bool IsInterface {
2846                         get { return Type.IsInterface; }
2847                 }
2848
2849                 public virtual bool IsSealed {
2850                         get { return Type.IsSealed; }
2851                 }
2852
2853                 public virtual bool CanInheritFrom ()
2854                 {
2855                         if (Type == TypeManager.enum_type ||
2856                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2857                             Type == TypeManager.multicast_delegate_type ||
2858                             Type == TypeManager.delegate_type ||
2859                             Type == TypeManager.array_type)
2860                                 return false;
2861
2862                         return true;
2863                 }
2864
2865                 protected abstract TypeExpr DoResolveAsTypeStep (IResolveContext ec);
2866
2867                 public override bool Equals (object obj)
2868                 {
2869                         TypeExpr tobj = obj as TypeExpr;
2870                         if (tobj == null)
2871                                 return false;
2872
2873                         return Type == tobj.Type;
2874                 }
2875
2876                 public override int GetHashCode ()
2877                 {
2878                         return Type.GetHashCode ();
2879                 }
2880
2881                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
2882                 {
2883                         type = storey.MutateType (type);
2884                 }
2885         }
2886
2887         /// <summary>
2888         ///   Fully resolved Expression that already evaluated to a type
2889         /// </summary>
2890         public class TypeExpression : TypeExpr {
2891                 public TypeExpression (Type t, Location l)
2892                 {
2893                         Type = t;
2894                         eclass = ExprClass.Type;
2895                         loc = l;
2896                 }
2897
2898                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2899                 {
2900                         return this;
2901                 }
2902
2903                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2904                 {
2905                         return this;
2906                 }
2907         }
2908
2909         //
2910         // Used to create types from a fully qualified name.  These are just used
2911         // by the parser to setup the core types.
2912         //
2913         public sealed class TypeLookupExpression : TypeExpr {
2914                 readonly string ns_name;
2915                 readonly string name;
2916
2917                 public TypeLookupExpression (string ns, string name)
2918                 {
2919                         this.name = name;
2920                         this.ns_name = ns;
2921                         eclass = ExprClass.Type;
2922                 }
2923
2924                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2925                 {
2926                         //
2927                         // It's null only during mscorlib bootstrap when DefineType
2928                         // nees to resolve base type of same type
2929                         //
2930                         // For instance struct Char : IComparable<char>
2931                         //
2932                         // TODO: it could be removed when Resolve starts to use
2933                         // DeclSpace instead of Type
2934                         //
2935                         if (type == null) {
2936                                 Namespace ns = GlobalRootNamespace.Instance.GetNamespace (ns_name, false);
2937                                 FullNamedExpression fne = ns.Lookup (null, name, loc);
2938                                 if (fne != null)
2939                                         type = fne.Type;
2940                         }
2941
2942                         return this;
2943                 }
2944
2945                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2946                 {
2947                         return this;
2948                 }
2949
2950                 public override string GetSignatureForError ()
2951                 {
2952                         if (type == null)
2953                                 return TypeManager.CSharpName (ns_name + "." + name, null);
2954
2955                         return base.GetSignatureForError ();
2956                 }
2957         }
2958
2959         /// <summary>
2960         ///   This class denotes an expression which evaluates to a member
2961         ///   of a struct or a class.
2962         /// </summary>
2963         public abstract class MemberExpr : Expression
2964         {
2965                 protected bool is_base;
2966
2967                 /// <summary>
2968                 ///   The name of this member.
2969                 /// </summary>
2970                 public abstract string Name {
2971                         get;
2972                 }
2973
2974                 //
2975                 // When base.member is used
2976                 //
2977                 public bool IsBase {
2978                         get { return is_base; }
2979                         set { is_base = value; }
2980                 }
2981
2982                 /// <summary>
2983                 ///   Whether this is an instance member.
2984                 /// </summary>
2985                 public abstract bool IsInstance {
2986                         get;
2987                 }
2988
2989                 /// <summary>
2990                 ///   Whether this is a static member.
2991                 /// </summary>
2992                 public abstract bool IsStatic {
2993                         get;
2994                 }
2995
2996                 /// <summary>
2997                 ///   The type which declares this member.
2998                 /// </summary>
2999                 public abstract Type DeclaringType {
3000                         get;
3001                 }
3002
3003                 /// <summary>
3004                 ///   The instance expression associated with this member, if it's a
3005                 ///   non-static member.
3006                 /// </summary>
3007                 public Expression InstanceExpression;
3008
3009                 public static void error176 (Location loc, string name)
3010                 {
3011                         Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
3012                                       "with an instance reference, qualify it with a type name instead", name);
3013                 }
3014
3015                 public static void Error_BaseAccessInExpressionTree (Location loc)
3016                 {
3017                         Report.Error (831, loc, "An expression tree may not contain a base access");
3018                 }
3019
3020                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3021                 {
3022                         if (InstanceExpression != null)
3023                                 InstanceExpression.MutateHoistedGenericType (storey);
3024                 }
3025
3026                 // TODO: possible optimalization
3027                 // Cache resolved constant result in FieldBuilder <-> expression map
3028                 public virtual MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3029                                                                SimpleName original)
3030                 {
3031                         //
3032                         // Precondition:
3033                         //   original == null || original.Resolve (...) ==> left
3034                         //
3035
3036                         if (left is TypeExpr) {
3037                                 left = left.ResolveAsBaseTerminal (ec, false);
3038                                 if (left == null)
3039                                         return null;
3040
3041                                 // TODO: Same problem as in class.cs, TypeTerminal does not
3042                                 // always do all necessary checks
3043                                 ObsoleteAttribute oa = AttributeTester.GetObsoleteAttribute (left.Type);
3044                                 if (oa != null && !ec.IsInObsoleteScope) {
3045                                         AttributeTester.Report_ObsoleteMessage (oa, left.GetSignatureForError (), loc);
3046                                 }
3047
3048                                 GenericTypeExpr ct = left as GenericTypeExpr;
3049                                 if (ct != null && !ct.CheckConstraints (ec))
3050                                         return null;
3051                                 //
3052
3053                                 if (!IsStatic) {
3054                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3055                                         return null;
3056                                 }
3057
3058                                 return this;
3059                         }
3060
3061                         if (!IsInstance) {
3062                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3063                                         return this;
3064
3065                                 return ResolveExtensionMemberAccess (left);
3066                         }
3067
3068                         InstanceExpression = left;
3069                         return this;
3070                 }
3071
3072                 protected virtual MemberExpr ResolveExtensionMemberAccess (Expression left)
3073                 {
3074                         error176 (loc, GetSignatureForError ());
3075                         return this;
3076                 }
3077
3078                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
3079                 {
3080                         if (IsStatic)
3081                                 return;
3082
3083                         if (InstanceExpression == EmptyExpression.Null) {
3084                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3085                                 return;
3086                         }
3087
3088                         if (TypeManager.IsValueType (InstanceExpression.Type)) {
3089                                 if (InstanceExpression is IMemoryLocation) {
3090                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3091                                 } else {
3092                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3093                                         InstanceExpression.Emit (ec);
3094                                         t.Store (ec);
3095                                         t.AddressOf (ec, AddressOp.Store);
3096                                 }
3097                         } else
3098                                 InstanceExpression.Emit (ec);
3099
3100                         if (prepare_for_load)
3101                                 ec.ig.Emit (OpCodes.Dup);
3102                 }
3103
3104                 public virtual void SetTypeArguments (TypeArguments ta)
3105                 {
3106                         // TODO: need to get correct member type
3107                         Report.Error (307, loc, "The property `{0}' cannot be used with type arguments",
3108                                 GetSignatureForError ());
3109                 }
3110         }
3111
3112         ///
3113         /// Represents group of extension methods
3114         ///
3115         public class ExtensionMethodGroupExpr : MethodGroupExpr
3116         {
3117                 readonly NamespaceEntry namespace_entry;
3118                 public Expression ExtensionExpression;
3119                 Argument extension_argument;
3120
3121                 public ExtensionMethodGroupExpr (ArrayList list, NamespaceEntry n, Type extensionType, Location l)
3122                         : base (list, extensionType, l)
3123                 {
3124                         this.namespace_entry = n;
3125                 }
3126
3127                 public override bool IsStatic {
3128                         get { return true; }
3129                 }
3130
3131                 public bool IsTopLevel {
3132                         get { return namespace_entry == null; }
3133                 }
3134
3135                 public override void EmitArguments (EmitContext ec, ArrayList arguments)
3136                 {
3137                         if (arguments == null)
3138                                 arguments = new ArrayList (1);
3139                         arguments.Insert (0, extension_argument);
3140                         base.EmitArguments (ec, arguments);
3141                 }
3142
3143                 public override void EmitCall (EmitContext ec, ArrayList arguments)
3144                 {
3145                         if (arguments == null)
3146                                 arguments = new ArrayList (1);
3147                         arguments.Insert (0, extension_argument);
3148                         base.EmitCall (ec, arguments);
3149                 }
3150
3151                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3152                 {
3153                         extension_argument.Expr.MutateHoistedGenericType (storey);
3154                         base.MutateHoistedGenericType (storey);
3155                 }
3156
3157                 public override MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList arguments, bool may_fail, Location loc)
3158                 {
3159                         if (arguments == null)
3160                                 arguments = new ArrayList (1);
3161
3162                         arguments.Insert (0, new Argument (ExtensionExpression));
3163                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, arguments, namespace_entry, loc);
3164
3165                         // Store resolved argument and restore original arguments
3166                         if (mg != null)
3167                                 ((ExtensionMethodGroupExpr)mg).extension_argument = (Argument)arguments [0];
3168                         arguments.RemoveAt (0);
3169
3170                         return mg;
3171                 }
3172
3173                 MethodGroupExpr ResolveOverloadExtensions (EmitContext ec, ArrayList arguments, NamespaceEntry ns, Location loc)
3174                 {
3175                         // Use normal resolve rules
3176                         MethodGroupExpr mg = base.OverloadResolve (ec, ref arguments, ns != null, loc);
3177                         if (mg != null)
3178                                 return mg;
3179
3180                         if (ns == null)
3181                                 return null;
3182
3183                         // Search continues
3184                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, null, Name, loc);
3185                         if (e == null)
3186                                 return base.OverloadResolve (ec, ref arguments, false, loc);
3187
3188                         e.ExtensionExpression = ExtensionExpression;
3189                         e.SetTypeArguments (type_arguments);
3190                         return e.ResolveOverloadExtensions (ec, arguments, e.namespace_entry, loc);
3191                 }
3192         }
3193
3194         /// <summary>
3195         ///   MethodGroupExpr represents a group of method candidates which
3196         ///   can be resolved to the best method overload
3197         /// </summary>
3198         public class MethodGroupExpr : MemberExpr
3199         {
3200                 public interface IErrorHandler
3201                 {
3202                         bool AmbiguousCall (MethodBase ambiguous);
3203                         bool NoExactMatch (EmitContext ec, MethodBase method);
3204                 }
3205
3206                 public IErrorHandler CustomErrorHandler;
3207                 public MethodBase [] Methods;
3208                 MethodBase best_candidate;
3209                 // TODO: make private
3210                 public TypeArguments type_arguments;
3211                 bool identical_type_name;
3212                 bool has_inaccessible_candidates_only;
3213                 Type delegate_type;
3214                 Type queried_type;
3215
3216                 public MethodGroupExpr (MemberInfo [] mi, Type type, Location l)
3217                         : this (type, l)
3218                 {
3219                         Methods = new MethodBase [mi.Length];
3220                         mi.CopyTo (Methods, 0);
3221                 }
3222
3223                 public MethodGroupExpr (MemberInfo[] mi, Type type, Location l, bool inacessibleCandidatesOnly)
3224                         : this (mi, type, l)
3225                 {
3226                         has_inaccessible_candidates_only = inacessibleCandidatesOnly;
3227                 }
3228
3229                 public MethodGroupExpr (ArrayList list, Type type, Location l)
3230                         : this (type, l)
3231                 {
3232                         try {
3233                                 Methods = (MethodBase[])list.ToArray (typeof (MethodBase));
3234                         } catch {
3235                                 foreach (MemberInfo m in list){
3236                                         if (!(m is MethodBase)){
3237                                                 Console.WriteLine ("Name " + m.Name);
3238                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
3239                                         }
3240                                 }
3241                                 throw;
3242                         }
3243
3244
3245                 }
3246
3247                 protected MethodGroupExpr (Type type, Location loc)
3248                 {
3249                         this.loc = loc;
3250                         eclass = ExprClass.MethodGroup;
3251                         this.type = typeof (MethodGroupExpr);
3252                         queried_type = type;
3253                 }
3254
3255                 public override Type DeclaringType {
3256                         get {
3257                                 return queried_type;
3258                         }
3259                 }
3260
3261                 public Type DelegateType {
3262                         set {
3263                                 delegate_type = value;
3264                         }
3265                 }
3266
3267                 public bool IdenticalTypeName {
3268                         get {
3269                                 return identical_type_name;
3270                         }
3271                 }
3272
3273                 public override string GetSignatureForError ()
3274                 {
3275                         if (best_candidate != null)
3276                                 return TypeManager.CSharpSignature (best_candidate);
3277
3278                         return TypeManager.CSharpSignature (Methods [0]);
3279                 }
3280
3281                 public override string Name {
3282                         get {
3283                                 return Methods [0].Name;
3284                         }
3285                 }
3286
3287                 public override bool IsInstance {
3288                         get {
3289                                 if (best_candidate != null)
3290                                         return !best_candidate.IsStatic;
3291
3292                                 foreach (MethodBase mb in Methods)
3293                                         if (!mb.IsStatic)
3294                                                 return true;
3295
3296                                 return false;
3297                         }
3298                 }
3299
3300                 public override bool IsStatic {
3301                         get {
3302                                 if (best_candidate != null)
3303                                         return best_candidate.IsStatic;
3304
3305                                 foreach (MethodBase mb in Methods)
3306                                         if (mb.IsStatic)
3307                                                 return true;
3308
3309                                 return false;
3310                         }
3311                 }
3312
3313                 public static explicit operator ConstructorInfo (MethodGroupExpr mg)
3314                 {
3315                         return (ConstructorInfo)mg.best_candidate;
3316                 }
3317
3318                 public static explicit operator MethodInfo (MethodGroupExpr mg)
3319                 {
3320                         return (MethodInfo)mg.best_candidate;
3321                 }
3322
3323                 //
3324                 //  7.4.3.3  Better conversion from expression
3325                 //  Returns :   1    if a->p is better,
3326                 //              2    if a->q is better,
3327                 //              0 if neither is better
3328                 //
3329                 static int BetterExpressionConversion (EmitContext ec, Argument a, Type p, Type q)
3330                 {
3331                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3332                         if (argument_type == TypeManager.anonymous_method_type && RootContext.Version > LanguageVersion.ISO_2) {
3333                                 //
3334                                 // Uwrap delegate from Expression<T>
3335                                 //
3336                                 if (TypeManager.DropGenericTypeArguments (p) == TypeManager.expression_type) {
3337                                         p = TypeManager.GetTypeArguments (p) [0];
3338                                 }
3339                                 if (TypeManager.DropGenericTypeArguments (q) == TypeManager.expression_type) {
3340                                         q = TypeManager.GetTypeArguments (q) [0];
3341                                 }
3342
3343                                 p = Delegate.GetInvokeMethod (null, p).ReturnType;
3344                                 q = Delegate.GetInvokeMethod (null, q).ReturnType;
3345                                 if (p == TypeManager.void_type && q != TypeManager.void_type)
3346                                         return 2;
3347                                 if (q == TypeManager.void_type && p != TypeManager.void_type)
3348                                         return 1;
3349                         } else {
3350                                 if (argument_type == p)
3351                                         return 1;
3352
3353                                 if (argument_type == q)
3354                                         return 2;
3355                         }
3356
3357                         return BetterTypeConversion (ec, p, q);
3358                 }
3359
3360                 //
3361                 // 7.4.3.4  Better conversion from type
3362                 //
3363                 public static int BetterTypeConversion (EmitContext ec, Type p, Type q)
3364                 {
3365                         if (p == null || q == null)
3366                                 throw new InternalErrorException ("BetterTypeConversion got a null conversion");
3367
3368                         if (p == TypeManager.int32_type) {
3369                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3370                                         return 1;
3371                         } else if (p == TypeManager.int64_type) {
3372                                 if (q == TypeManager.uint64_type)
3373                                         return 1;
3374                         } else if (p == TypeManager.sbyte_type) {
3375                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3376                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3377                                         return 1;
3378                         } else if (p == TypeManager.short_type) {
3379                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3380                                         q == TypeManager.uint64_type)
3381                                         return 1;
3382                         }
3383
3384                         if (q == TypeManager.int32_type) {
3385                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3386                                         return 2;
3387                         } if (q == TypeManager.int64_type) {
3388                                 if (p == TypeManager.uint64_type)
3389                                         return 2;
3390                         } else if (q == TypeManager.sbyte_type) {
3391                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3392                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3393                                         return 2;
3394                         } if (q == TypeManager.short_type) {
3395                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3396                                         p == TypeManager.uint64_type)
3397                                         return 2;
3398                         }
3399
3400                         // TODO: this is expensive
3401                         Expression p_tmp = new EmptyExpression (p);
3402                         Expression q_tmp = new EmptyExpression (q);
3403
3404                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3405                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3406
3407                         if (p_to_q && !q_to_p)
3408                                 return 1;
3409
3410                         if (q_to_p && !p_to_q)
3411                                 return 2;
3412
3413                         return 0;
3414                 }
3415
3416                 /// <summary>
3417                 ///   Determines "Better function" between candidate
3418                 ///   and the current best match
3419                 /// </summary>
3420                 /// <remarks>
3421                 ///    Returns a boolean indicating :
3422                 ///     false if candidate ain't better
3423                 ///     true  if candidate is better than the current best match
3424                 /// </remarks>
3425                 static bool BetterFunction (EmitContext ec, ArrayList args, int argument_count,
3426                         MethodBase candidate, bool candidate_params,
3427                         MethodBase best, bool best_params)
3428                 {
3429                         AParametersCollection candidate_pd = TypeManager.GetParameterData (candidate);
3430                         AParametersCollection best_pd = TypeManager.GetParameterData (best);
3431
3432                         bool better_at_least_one = false;
3433                         bool same = true;
3434                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3435                         {
3436                                 Argument a = (Argument) args [j];
3437
3438                                 Type ct = candidate_pd.Types [c_idx];
3439                                 Type bt = best_pd.Types [b_idx];
3440
3441                                 if (candidate_params && candidate_pd.FixedParameters [c_idx].ModFlags == Parameter.Modifier.PARAMS)
3442                                 {
3443                                         ct = TypeManager.GetElementType (ct);
3444                                         --c_idx;
3445                                 }
3446
3447                                 if (best_params && best_pd.FixedParameters [b_idx].ModFlags == Parameter.Modifier.PARAMS)
3448                                 {
3449                                         bt = TypeManager.GetElementType (bt);
3450                                         --b_idx;
3451                                 }
3452
3453                                 if (ct.Equals (bt))
3454                                         continue;
3455
3456                                 same = false;
3457                                 int result = BetterExpressionConversion (ec, a, ct, bt);
3458
3459                                 // for each argument, the conversion to 'ct' should be no worse than
3460                                 // the conversion to 'bt'.
3461                                 if (result == 2)
3462                                         return false;
3463
3464                                 // for at least one argument, the conversion to 'ct' should be better than
3465                                 // the conversion to 'bt'.
3466                                 if (result != 0)
3467                                         better_at_least_one = true;
3468                         }
3469
3470                         if (better_at_least_one)
3471                                 return true;
3472
3473                         //
3474                         // This handles the case
3475                         //
3476                         //   Add (float f1, float f2, float f3);
3477                         //   Add (params decimal [] foo);
3478                         //
3479                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3480                         // first candidate would've chosen as better.
3481                         //
3482                         if (!same)
3483                                 return false;
3484
3485                         //
3486                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3487                         //
3488                         if (TypeManager.IsGenericMethod (best)) {
3489                                 if (!TypeManager.IsGenericMethod (candidate))
3490                                         return true;
3491                         } else if (TypeManager.IsGenericMethod (candidate)) {
3492                                 return false;
3493                         }
3494
3495                         //
3496                         // This handles the following cases:
3497                         //
3498                         //   Trim () is better than Trim (params char[] chars)
3499                         //   Concat (string s1, string s2, string s3) is better than
3500                         //     Concat (string s1, params string [] srest)
3501                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3502                         //
3503                         if (!candidate_params && best_params)
3504                                 return true;
3505                         if (candidate_params && !best_params)
3506                                 return false;
3507
3508                         int candidate_param_count = candidate_pd.Count;
3509                         int best_param_count = best_pd.Count;
3510
3511                         if (candidate_param_count != best_param_count)
3512                                 // can only happen if (candidate_params && best_params)
3513                                 return candidate_param_count > best_param_count;
3514
3515                         //
3516                         // now, both methods have the same number of parameters, and the parameters have the same types
3517                         // Pick the "more specific" signature
3518                         //
3519
3520                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3521                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3522
3523                         AParametersCollection orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3524                         AParametersCollection orig_best_pd = TypeManager.GetParameterData (orig_best);
3525
3526                         bool specific_at_least_once = false;
3527                         for (int j = 0; j < candidate_param_count; ++j)
3528                         {
3529                                 Type ct = orig_candidate_pd.Types [j];
3530                                 Type bt = orig_best_pd.Types [j];
3531                                 if (ct.Equals (bt))
3532                                         continue;
3533                                 Type specific = MoreSpecific (ct, bt);
3534                                 if (specific == bt)
3535                                         return false;
3536                                 if (specific == ct)
3537                                         specific_at_least_once = true;
3538                         }
3539
3540                         if (specific_at_least_once)
3541                                 return true;
3542
3543                         // FIXME: handle lifted operators
3544                         // ...
3545
3546                         return false;
3547                 }
3548
3549                 protected override MemberExpr ResolveExtensionMemberAccess (Expression left)
3550                 {
3551                         if (!IsStatic)
3552                                 return base.ResolveExtensionMemberAccess (left);
3553
3554                         //
3555                         // When left side is an expression and at least one candidate method is
3556                         // static, it can be extension method
3557                         //
3558                         InstanceExpression = left;
3559                         return this;
3560                 }
3561
3562                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3563                                                                 SimpleName original)
3564                 {
3565                         if (!(left is TypeExpr) &&
3566                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3567                                 identical_type_name = true;
3568
3569                         return base.ResolveMemberAccess (ec, left, loc, original);
3570                 }
3571
3572                 public override Expression CreateExpressionTree (EmitContext ec)
3573                 {
3574                         if (best_candidate == null) {
3575                                 Report.Error (1953, loc, "An expression tree cannot contain an expression with method group");
3576                                 return null;
3577                         }
3578
3579                         if (best_candidate.IsConstructor)
3580                                 return new TypeOfConstructorInfo (best_candidate, loc);
3581
3582                         IMethodData md = TypeManager.GetMethod (best_candidate);
3583                         if (md != null && md.IsExcluded ())
3584                                 Report.Error (765, loc,
3585                                         "Partial methods with only a defining declaration or removed conditional methods cannot be used in an expression tree");
3586
3587                         return new TypeOfMethodInfo (best_candidate, loc);
3588                 }
3589
3590                 override public Expression DoResolve (EmitContext ec)
3591                 {
3592                         if (InstanceExpression != null) {
3593                                 InstanceExpression = InstanceExpression.DoResolve (ec);
3594                                 if (InstanceExpression == null)
3595                                         return null;
3596                         }
3597
3598                         return this;
3599                 }
3600
3601                 public void ReportUsageError ()
3602                 {
3603                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
3604                                       Name + "()' is referenced without parentheses");
3605                 }
3606
3607                 override public void Emit (EmitContext ec)
3608                 {
3609                         ReportUsageError ();
3610                 }
3611
3612                 public virtual void EmitArguments (EmitContext ec, ArrayList arguments)
3613                 {
3614                         Invocation.EmitArguments (ec, arguments, false, null);
3615                 }
3616
3617                 public virtual void EmitCall (EmitContext ec, ArrayList arguments)
3618                 {
3619                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3620                 }
3621
3622                 void Error_AmbiguousCall (MethodBase ambiguous)
3623                 {
3624                         if (CustomErrorHandler != null && CustomErrorHandler.AmbiguousCall (ambiguous))
3625                                 return;
3626
3627                         Report.SymbolRelatedToPreviousError (best_candidate);
3628                         Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
3629                                 TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate));
3630                 }
3631
3632                 protected virtual void Error_InvalidArguments (EmitContext ec, Location loc, int idx, MethodBase method,
3633                                                                                                         Argument a, AParametersCollection expected_par, Type paramType)
3634                 {
3635                         ExtensionMethodGroupExpr emg = this as ExtensionMethodGroupExpr;
3636
3637                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3638                                 Report.SymbolRelatedToPreviousError (method);
3639                                 if ((expected_par.FixedParameters [idx].ModFlags & Parameter.Modifier.ISBYREF) != 0) {
3640                                         Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3641                                                 TypeManager.CSharpSignature (method));
3642                                         return;
3643                                 }
3644                                 Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3645                                           TypeManager.CSharpSignature (method));
3646                         } else if (TypeManager.IsDelegateType (method.DeclaringType)) {
3647                                 Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3648                                         TypeManager.CSharpName (method.DeclaringType));
3649                         } else {
3650                                 Report.SymbolRelatedToPreviousError (method);
3651                                 if (emg != null) {
3652                                         Report.Error (1928, loc,
3653                                                 "Type `{0}' does not contain a member `{1}' and the best extension method overload `{2}' has some invalid arguments",
3654                                                 emg.ExtensionExpression.GetSignatureForError (),
3655                                                 emg.Name, TypeManager.CSharpSignature (method));
3656                                 } else {
3657                                         Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3658                                                 TypeManager.CSharpSignature (method));
3659                                 }
3660                         }
3661
3662                         Parameter.Modifier mod = idx >= expected_par.Count ? 0 : expected_par.FixedParameters [idx].ModFlags;
3663
3664                         string index = (idx + 1).ToString ();
3665                         if (((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) ^
3666                                 (a.Modifier & (Parameter.Modifier.REF | Parameter.Modifier.OUT))) != 0) {
3667                                 if ((mod & Parameter.Modifier.ISBYREF) == 0)
3668                                         Report.Error (1615, loc, "Argument `#{0}' does not require `{1}' modifier. Consider removing `{1}' modifier",
3669                                                 index, Parameter.GetModifierSignature (a.Modifier));
3670                                 else
3671                                         Report.Error (1620, loc, "Argument `#{0}' is missing `{1}' modifier",
3672                                                 index, Parameter.GetModifierSignature (mod));
3673                         } else {
3674                                 string p1 = a.GetSignatureForError ();
3675                                 string p2 = TypeManager.CSharpName (paramType);
3676
3677                                 if (p1 == p2) {
3678                                         Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3679                                         Report.SymbolRelatedToPreviousError (a.Expr.Type);
3680                                         Report.SymbolRelatedToPreviousError (paramType);
3681                                 }
3682
3683                                 if (idx == 0 && emg != null) {
3684                                         Report.Error (1929, loc,
3685                                                 "Extension method instance type `{0}' cannot be converted to `{1}'", p1, p2);
3686                                 } else {
3687                                         Report.Error (1503, loc,
3688                                                 "Argument `#{0}' cannot convert `{1}' expression to type `{2}'", index, p1, p2);
3689                                 }
3690                         }
3691                 }
3692
3693                 public override void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
3694                 {
3695                         Report.Error (428, loc, "Cannot convert method group `{0}' to non-delegate type `{1}'. Consider using parentheses to invoke the method",
3696                                 Name, TypeManager.CSharpName (target));
3697                 }
3698
3699                 void Error_ArgumentCountWrong (int arg_count)
3700                 {
3701                         Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
3702                                       Name, arg_count.ToString ());
3703                 }
3704
3705                 protected virtual int GetApplicableParametersCount (MethodBase method, AParametersCollection parameters)
3706                 {
3707                         return parameters.Count;
3708                 }
3709
3710                 public static bool IsAncestralType (Type first_type, Type second_type)
3711                 {
3712                         return first_type != second_type &&
3713                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3714                                 TypeManager.ImplementsInterface (second_type, first_type));
3715                 }
3716
3717                 ///
3718                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3719                 /// to the given set of arguments
3720                 /// A return value rates candidate method compatibility,
3721                 /// 0 = the best, int.MaxValue = the worst
3722                 ///
3723                 public int IsApplicable (EmitContext ec,
3724                                                  ArrayList arguments, int arg_count, ref MethodBase method, ref bool params_expanded_form)
3725                 {
3726                         MethodBase candidate = method;
3727
3728                         AParametersCollection pd = TypeManager.GetParameterData (candidate);
3729                         int param_count = GetApplicableParametersCount (candidate, pd);
3730
3731                         if (arg_count != param_count) {
3732                                 if (!pd.HasParams)
3733                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3734                                 if (arg_count < param_count - 1)
3735                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3736
3737                                 // Initialize expanded form of a method with 1 params parameter
3738                                 params_expanded_form = param_count == 1 && pd.HasParams;
3739                         }
3740
3741 #if GMCS_SOURCE
3742                         //
3743                         // 1. Handle generic method using type arguments when specified or type inference
3744                         //
3745                         if (TypeManager.IsGenericMethod (candidate)) {
3746                                 if (type_arguments != null) {
3747                                         Type [] g_args = candidate.GetGenericArguments ();
3748                                         if (g_args.Length != type_arguments.Count)
3749                                                 return int.MaxValue - 20000 + Math.Abs (type_arguments.Count - g_args.Length);
3750
3751                                         // TODO: Don't create new method, create Parameters only
3752                                         method = ((MethodInfo) candidate).MakeGenericMethod (type_arguments.Arguments);
3753                                         candidate = method;
3754                                         pd = TypeManager.GetParameterData (candidate);
3755                                 } else {
3756                                         int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3757                                         if (score != 0)
3758                                                 return score - 20000;
3759
3760                                         if (TypeManager.IsGenericMethodDefinition (candidate))
3761                                                 throw new InternalErrorException ("A generic method `{0}' definition took part in overload resolution",
3762                                                         TypeManager.CSharpSignature (candidate));
3763
3764                                         pd = TypeManager.GetParameterData (candidate);
3765                                 }
3766                         } else {
3767                                 if (type_arguments != null)
3768                                         return int.MaxValue - 15000;
3769                         }
3770 #endif
3771
3772                         //
3773                         // 2. Each argument has to be implicitly convertible to method parameter
3774                         //
3775                         method = candidate;
3776                         Parameter.Modifier p_mod = 0;
3777                         Type pt = null;
3778                         for (int i = 0; i < arg_count; i++) {
3779                                 Argument a = (Argument) arguments [i];
3780                                 Parameter.Modifier a_mod = a.Modifier &
3781                                         ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3782
3783                                 if (p_mod != Parameter.Modifier.PARAMS) {
3784                                         p_mod = pd.FixedParameters [i].ModFlags & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3785
3786                                         if (p_mod == Parameter.Modifier.ARGLIST) {
3787                                                 if (a.Type == typeof (ArglistAccess))
3788                                                         continue;
3789
3790                                                 p_mod = 0;
3791                                         }
3792
3793                                         pt = pd.Types [i];
3794                                 } else {
3795                                         params_expanded_form = true;
3796                                 }
3797
3798                                 int score = 1;
3799                                 if (!params_expanded_form)
3800                                         score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
3801
3802                                 if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0 && delegate_type == null) {
3803                                         // It can be applicable in expanded form
3804                                         score = IsArgumentCompatible (ec, a_mod, a, 0, TypeManager.GetElementType (pt));
3805                                         if (score == 0)
3806                                                 params_expanded_form = true;
3807                                 }
3808
3809                                 if (score != 0) {
3810                                         if (params_expanded_form)
3811                                                 ++score;
3812                                         return (arg_count - i) * 2 + score;
3813                                 }
3814                         }
3815
3816                         if (arg_count != param_count)
3817                                 params_expanded_form = true;
3818
3819                         return 0;
3820                 }
3821
3822                 int IsArgumentCompatible (EmitContext ec, Parameter.Modifier arg_mod, Argument argument, Parameter.Modifier param_mod, Type parameter)
3823                 {
3824                         //
3825                         // Types have to be identical when ref or out modifer is used
3826                         //
3827                         if (arg_mod != 0 || param_mod != 0) {
3828                                 if (TypeManager.HasElementType (parameter))
3829                                         parameter = TypeManager.GetElementType (parameter);
3830
3831                                 Type a_type = argument.Type;
3832                                 if (TypeManager.HasElementType (a_type))
3833                                         a_type = TypeManager.GetElementType (a_type);
3834
3835                                 if (a_type != parameter)
3836                                         return 2;
3837                         } else {
3838                                 if (!Convert.ImplicitConversionExists (ec, argument.Expr, parameter))
3839                                         return 2;
3840                         }
3841
3842                         if (arg_mod != param_mod)
3843                                 return 1;
3844
3845                         return 0;
3846                 }
3847
3848                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
3849                 {
3850                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
3851                                 return false;
3852
3853                         AParametersCollection cand_pd = TypeManager.GetParameterData (cand_method);
3854                         AParametersCollection base_pd = TypeManager.GetParameterData (base_method);
3855
3856                         if (cand_pd.Count != base_pd.Count)
3857                                 return false;
3858
3859                         for (int j = 0; j < cand_pd.Count; ++j)
3860                         {
3861                                 Parameter.Modifier cm = cand_pd.FixedParameters [j].ModFlags;
3862                                 Parameter.Modifier bm = base_pd.FixedParameters [j].ModFlags;
3863                                 Type ct = cand_pd.Types [j];
3864                                 Type bt = base_pd.Types [j];
3865
3866                                 if (cm != bm || ct != bt)
3867                                         return false;
3868                         }
3869
3870                         return true;
3871                 }
3872
3873                 public static MethodGroupExpr MakeUnionSet (MethodGroupExpr mg1, MethodGroupExpr mg2, Location loc)
3874                 {
3875                         if (mg1 == null) {
3876                                 if (mg2 == null)
3877                                         return null;
3878                                 return mg2;
3879                         }
3880
3881                         if (mg2 == null)
3882                                 return mg1;
3883
3884                         ArrayList all = new ArrayList (mg1.Methods);
3885                         foreach (MethodBase m in mg2.Methods){
3886                                 if (!TypeManager.ArrayContainsMethod (mg1.Methods, m, false))
3887                                         all.Add (m);
3888                         }
3889
3890                         return new MethodGroupExpr (all, null, loc);
3891                 }
3892
3893                 static Type MoreSpecific (Type p, Type q)
3894                 {
3895                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
3896                                 return q;
3897                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
3898                                 return p;
3899
3900                         if (TypeManager.HasElementType (p))
3901                         {
3902                                 Type pe = TypeManager.GetElementType (p);
3903                                 Type qe = TypeManager.GetElementType (q);
3904                                 Type specific = MoreSpecific (pe, qe);
3905                                 if (specific == pe)
3906                                         return p;
3907                                 if (specific == qe)
3908                                         return q;
3909                         }
3910                         else if (TypeManager.IsGenericType (p))
3911                         {
3912                                 Type[] pargs = TypeManager.GetTypeArguments (p);
3913                                 Type[] qargs = TypeManager.GetTypeArguments (q);
3914
3915                                 bool p_specific_at_least_once = false;
3916                                 bool q_specific_at_least_once = false;
3917
3918                                 for (int i = 0; i < pargs.Length; i++)
3919                                 {
3920                                         Type specific = MoreSpecific (pargs [i], qargs [i]);
3921                                         if (specific == pargs [i])
3922                                                 p_specific_at_least_once = true;
3923                                         if (specific == qargs [i])
3924                                                 q_specific_at_least_once = true;
3925                                 }
3926
3927                                 if (p_specific_at_least_once && !q_specific_at_least_once)
3928                                         return p;
3929                                 if (!p_specific_at_least_once && q_specific_at_least_once)
3930                                         return q;
3931                         }
3932
3933                         return null;
3934                 }
3935
3936                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
3937                 {
3938                         base.MutateHoistedGenericType (storey);
3939
3940                         MethodInfo mi = best_candidate as MethodInfo;
3941                         if (mi != null) {
3942                                 best_candidate = storey.MutateGenericMethod (mi);
3943                                 return;
3944                         }
3945
3946                         best_candidate = storey.MutateConstructor ((ConstructorInfo) this);
3947                 }
3948
3949                 /// <summary>
3950                 ///   Find the Applicable Function Members (7.4.2.1)
3951                 ///
3952                 ///   me: Method Group expression with the members to select.
3953                 ///       it might contain constructors or methods (or anything
3954                 ///       that maps to a method).
3955                 ///
3956                 ///   Arguments: ArrayList containing resolved Argument objects.
3957                 ///
3958                 ///   loc: The location if we want an error to be reported, or a Null
3959                 ///        location for "probing" purposes.
3960                 ///
3961                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
3962                 ///            that is the best match of me on Arguments.
3963                 ///
3964                 /// </summary>
3965                 public virtual MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList Arguments,
3966                         bool may_fail, Location loc)
3967                 {
3968                         bool method_params = false;
3969                         Type applicable_type = null;
3970                         int arg_count = 0;
3971                         ArrayList candidates = new ArrayList (2);
3972                         ArrayList candidate_overrides = null;
3973
3974                         //
3975                         // Used to keep a map between the candidate
3976                         // and whether it is being considered in its
3977                         // normal or expanded form
3978                         //
3979                         // false is normal form, true is expanded form
3980                         //
3981                         Hashtable candidate_to_form = null;
3982
3983                         if (Arguments != null)
3984                                 arg_count = Arguments.Count;
3985
3986                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
3987                                 if (!may_fail)
3988                                         Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
3989                                 return null;
3990                         }
3991
3992                         int nmethods = Methods.Length;
3993
3994                         if (!IsBase) {
3995                                 //
3996                                 // Methods marked 'override' don't take part in 'applicable_type'
3997                                 // computation, nor in the actual overload resolution.
3998                                 // However, they still need to be emitted instead of a base virtual method.
3999                                 // So, we salt them away into the 'candidate_overrides' array.
4000                                 //
4001                                 // In case of reflected methods, we replace each overriding method with
4002                                 // its corresponding base virtual method.  This is to improve compatibility
4003                                 // with non-C# libraries which change the visibility of overrides (#75636)
4004                                 //
4005                                 int j = 0;
4006                                 for (int i = 0; i < Methods.Length; ++i) {
4007                                         MethodBase m = Methods [i];
4008                                         if (TypeManager.IsOverride (m)) {
4009                                                 if (candidate_overrides == null)
4010                                                         candidate_overrides = new ArrayList ();
4011                                                 candidate_overrides.Add (m);
4012                                                 m = TypeManager.TryGetBaseDefinition (m);
4013                                         }
4014                                         if (m != null)
4015                                                 Methods [j++] = m;
4016                                 }
4017                                 nmethods = j;
4018                         }
4019
4020                         //
4021                         // Enable message recording, it's used mainly by lambda expressions
4022                         //
4023                         Report.IMessageRecorder msg_recorder = new Report.MessageRecorder ();
4024                         Report.IMessageRecorder prev_recorder = Report.SetMessageRecorder (msg_recorder);
4025
4026                         //
4027                         // First we construct the set of applicable methods
4028                         //
4029                         bool is_sorted = true;
4030                         int best_candidate_rate = int.MaxValue;
4031                         for (int i = 0; i < nmethods; i++) {
4032                                 Type decl_type = Methods [i].DeclaringType;
4033
4034                                 //
4035                                 // If we have already found an applicable method
4036                                 // we eliminate all base types (Section 14.5.5.1)
4037                                 //
4038                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
4039                                         continue;
4040
4041                                 //
4042                                 // Check if candidate is applicable (section 14.4.2.1)
4043                                 //
4044                                 bool params_expanded_form = false;
4045                                 int candidate_rate = IsApplicable (ec, Arguments, arg_count, ref Methods [i], ref params_expanded_form);
4046
4047                                 if (candidate_rate < best_candidate_rate) {
4048                                         best_candidate_rate = candidate_rate;
4049                                         best_candidate = Methods [i];
4050                                 }
4051
4052                                 if (params_expanded_form) {
4053                                         if (candidate_to_form == null)
4054                                                 candidate_to_form = new PtrHashtable ();
4055                                         MethodBase candidate = Methods [i];
4056                                         candidate_to_form [candidate] = candidate;
4057                                 }
4058
4059                                 if (candidate_rate != 0 || has_inaccessible_candidates_only) {
4060                                         if (msg_recorder != null)
4061                                                 msg_recorder.EndSession ();
4062                                         continue;
4063                                 }
4064
4065                                 msg_recorder = null;
4066                                 candidates.Add (Methods [i]);
4067
4068                                 if (applicable_type == null)
4069                                         applicable_type = decl_type;
4070                                 else if (applicable_type != decl_type) {
4071                                         is_sorted = false;
4072                                         if (IsAncestralType (applicable_type, decl_type))
4073                                                 applicable_type = decl_type;
4074                                 }
4075                         }
4076
4077                         Report.SetMessageRecorder (prev_recorder);
4078                         if (msg_recorder != null && !msg_recorder.IsEmpty) {
4079                                 if (!may_fail)
4080                                         msg_recorder.PrintMessages ();
4081
4082                                 return null;
4083                         }
4084
4085                         int candidate_top = candidates.Count;
4086
4087                         if (applicable_type == null) {
4088                                 //
4089                                 // When we found a top level method which does not match and it's
4090                                 // not an extension method. We start extension methods lookup from here
4091                                 //
4092                                 if (InstanceExpression != null) {
4093                                         ExtensionMethodGroupExpr ex_method_lookup = ec.TypeContainer.LookupExtensionMethod (type, Name, loc);
4094                                         if (ex_method_lookup != null) {
4095                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
4096                                                 ex_method_lookup.SetTypeArguments (type_arguments);
4097                                                 return ex_method_lookup.OverloadResolve (ec, ref Arguments, may_fail, loc);
4098                                         }
4099                                 }
4100
4101                                 if (may_fail)
4102                                         return null;
4103
4104                                 //
4105                                 // Okay so we have failed to find exact match so we
4106                                 // return error info about the closest match
4107                                 //
4108                                 if (best_candidate != null) {
4109                                         if (CustomErrorHandler != null && CustomErrorHandler.NoExactMatch (ec, best_candidate))
4110                                                 return null;
4111
4112                                         AParametersCollection pd = TypeManager.GetParameterData (best_candidate);
4113                                         bool cand_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4114                                         if (arg_count == pd.Count || pd.HasParams) {
4115                                                 if (TypeManager.IsGenericMethodDefinition (best_candidate)) {
4116                                                         if (type_arguments == null) {
4117                                                                 Report.Error (411, loc,
4118                                                                         "The type arguments for method `{0}' cannot be inferred from " +
4119                                                                         "the usage. Try specifying the type arguments explicitly",
4120                                                                         TypeManager.CSharpSignature (best_candidate));
4121                                                                 return null;
4122                                                         }
4123
4124                                                         Type[] g_args = TypeManager.GetGenericArguments (best_candidate);
4125                                                         if (type_arguments.Count != g_args.Length) {
4126                                                                 Report.SymbolRelatedToPreviousError (best_candidate);
4127                                                                 Report.Error (305, loc, "Using the generic method `{0}' requires `{1}' type argument(s)",
4128                                                                         TypeManager.CSharpSignature (best_candidate),
4129                                                                         g_args.Length.ToString ());
4130                                                                 return null;
4131                                                         }
4132                                                 } else {
4133                                                         if (type_arguments != null && !TypeManager.IsGenericMethod (best_candidate)) {
4134                                                                 Namespace.Error_TypeArgumentsCannotBeUsed (best_candidate, loc);
4135                                                                 return null;
4136                                                         }
4137                                                 }
4138
4139                                                 if (has_inaccessible_candidates_only) {
4140                                                         if (InstanceExpression != null && type != ec.ContainerType && TypeManager.IsNestedFamilyAccessible (ec.ContainerType, best_candidate.DeclaringType)) {
4141                                                                 // Although a derived class can access protected members of
4142                                                                 // its base class it cannot do so through an instance of the
4143                                                                 // base class (CS1540).  If the qualifier_type is a base of the
4144                                                                 // ec.ContainerType and the lookup succeeds with the latter one,
4145                                                                 // then we are in this situation.
4146                                                                 Error_CannotAccessProtected (loc, best_candidate, queried_type, ec.ContainerType);
4147                                                         } else {
4148                                                                 Report.SymbolRelatedToPreviousError (best_candidate);
4149                                                                 ErrorIsInaccesible (loc, GetSignatureForError ());
4150                                                         }
4151                                                 }
4152
4153                                                 if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate, cand_params, may_fail, loc))
4154                                                         return null;
4155
4156                                                 if (has_inaccessible_candidates_only)
4157                                                         return null;
4158
4159                                                 throw new InternalErrorException ("VerifyArgumentsCompat didn't find any problem with rejected candidate " + best_candidate);
4160                                         }
4161                                 }
4162
4163                                 //
4164                                 // We failed to find any method with correct argument count
4165                                 //
4166                                 if (Name == ConstructorInfo.ConstructorName) {
4167                                         Report.SymbolRelatedToPreviousError (queried_type);
4168                                         Report.Error (1729, loc,
4169                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4170                                                 TypeManager.CSharpName (queried_type), arg_count);
4171                                 } else {
4172                                         Error_ArgumentCountWrong (arg_count);
4173                                 }
4174
4175                                 return null;
4176                         }
4177
4178                         if (!is_sorted) {
4179                                 //
4180                                 // At this point, applicable_type is _one_ of the most derived types
4181                                 // in the set of types containing the methods in this MethodGroup.
4182                                 // Filter the candidates so that they only contain methods from the
4183                                 // most derived types.
4184                                 //
4185
4186                                 int finalized = 0; // Number of finalized candidates
4187
4188                                 do {
4189                                         // Invariant: applicable_type is a most derived type
4190
4191                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4192                                         // eliminating all it's base types.  At the same time, we'll also move
4193                                         // every unrelated type to the end of the array, and pick the next
4194                                         // 'applicable_type'.
4195
4196                                         Type next_applicable_type = null;
4197                                         int j = finalized; // where to put the next finalized candidate
4198                                         int k = finalized; // where to put the next undiscarded candidate
4199                                         for (int i = finalized; i < candidate_top; ++i) {
4200                                                 MethodBase candidate = (MethodBase) candidates [i];
4201                                                 Type decl_type = candidate.DeclaringType;
4202
4203                                                 if (decl_type == applicable_type) {
4204                                                         candidates [k++] = candidates [j];
4205                                                         candidates [j++] = candidates [i];
4206                                                         continue;
4207                                                 }
4208
4209                                                 if (IsAncestralType (decl_type, applicable_type))
4210                                                         continue;
4211
4212                                                 if (next_applicable_type != null &&
4213                                                         IsAncestralType (decl_type, next_applicable_type))
4214                                                         continue;
4215
4216                                                 candidates [k++] = candidates [i];
4217
4218                                                 if (next_applicable_type == null ||
4219                                                         IsAncestralType (next_applicable_type, decl_type))
4220                                                         next_applicable_type = decl_type;
4221                                         }
4222
4223                                         applicable_type = next_applicable_type;
4224                                         finalized = j;
4225                                         candidate_top = k;
4226                                 } while (applicable_type != null);
4227                         }
4228
4229                         //
4230                         // Now we actually find the best method
4231                         //
4232
4233                         best_candidate = (MethodBase) candidates [0];
4234                         method_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4235
4236                         for (int ix = 1; ix < candidate_top; ix++) {
4237                                 MethodBase candidate = (MethodBase) candidates [ix];
4238
4239                                 if (candidate == best_candidate)
4240                                         continue;
4241
4242                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4243
4244                                 if (BetterFunction (ec, Arguments, arg_count,
4245                                         candidate, cand_params,
4246                                         best_candidate, method_params)) {
4247                                         best_candidate = candidate;
4248                                         method_params = cand_params;
4249                                 }
4250                         }
4251                         //
4252                         // Now check that there are no ambiguities i.e the selected method
4253                         // should be better than all the others
4254                         //
4255                         MethodBase ambiguous = null;
4256                         for (int ix = 1; ix < candidate_top; ix++) {
4257                                 MethodBase candidate = (MethodBase) candidates [ix];
4258
4259                                 if (candidate == best_candidate)
4260                                         continue;
4261
4262                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4263                                 if (!BetterFunction (ec, Arguments, arg_count,
4264                                         best_candidate, method_params,
4265                                         candidate, cand_params))
4266                                 {
4267                                         if (!may_fail)
4268                                                 Report.SymbolRelatedToPreviousError (candidate);
4269                                         ambiguous = candidate;
4270                                 }
4271                         }
4272
4273                         if (ambiguous != null) {
4274                                 Error_AmbiguousCall (ambiguous);
4275                                 return this;
4276                         }
4277
4278                         //
4279                         // If the method is a virtual function, pick an override closer to the LHS type.
4280                         //
4281                         if (!IsBase && best_candidate.IsVirtual) {
4282                                 if (TypeManager.IsOverride (best_candidate))
4283                                         throw new InternalErrorException (
4284                                                 "Should not happen.  An 'override' method took part in overload resolution: " + best_candidate);
4285
4286                                 if (candidate_overrides != null) {
4287                                         Type[] gen_args = null;
4288                                         bool gen_override = false;
4289                                         if (TypeManager.IsGenericMethod (best_candidate))
4290                                                 gen_args = TypeManager.GetGenericArguments (best_candidate);
4291
4292                                         foreach (MethodBase candidate in candidate_overrides) {
4293                                                 if (TypeManager.IsGenericMethod (candidate)) {
4294                                                         if (gen_args == null)
4295                                                                 continue;
4296
4297                                                         if (gen_args.Length != TypeManager.GetGenericArguments (candidate).Length)
4298                                                                 continue;
4299                                                 } else {
4300                                                         if (gen_args != null)
4301                                                                 continue;
4302                                                 }
4303
4304                                                 if (IsOverride (candidate, best_candidate)) {
4305                                                         gen_override = true;
4306                                                         best_candidate = candidate;
4307                                                 }
4308                                         }
4309
4310                                         if (gen_override && gen_args != null) {
4311 #if GMCS_SOURCE
4312                                                 best_candidate = ((MethodInfo) best_candidate).MakeGenericMethod (gen_args);
4313 #endif
4314                                         }
4315                                 }
4316                         }
4317
4318                         //
4319                         // And now check if the arguments are all
4320                         // compatible, perform conversions if
4321                         // necessary etc. and return if everything is
4322                         // all right
4323                         //
4324                         if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate,
4325                                 method_params, may_fail, loc))
4326                                 return null;
4327
4328                         if (best_candidate == null)
4329                                 return null;
4330
4331                         MethodBase the_method = TypeManager.DropGenericMethodArguments (best_candidate);
4332                         if (TypeManager.IsGenericMethodDefinition (the_method) &&
4333                             !ConstraintChecker.CheckConstraints (ec, the_method, best_candidate, loc))
4334                                 return null;
4335
4336                         //
4337                         // Check ObsoleteAttribute on the best method
4338                         //
4339                         ObsoleteAttribute oa = AttributeTester.GetMethodObsoleteAttribute (the_method);
4340                         if (oa != null && !ec.IsInObsoleteScope)
4341                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc);
4342
4343                         IMethodData data = TypeManager.GetMethod (the_method);
4344                         if (data != null)
4345                                 data.SetMemberIsUsed ();
4346
4347                         return this;
4348                 }
4349
4350                 public override void SetTypeArguments (TypeArguments ta)
4351                 {
4352                         type_arguments = ta;
4353                 }
4354
4355                 public bool VerifyArgumentsCompat (EmitContext ec, ref ArrayList arguments,
4356                                                           int arg_count, MethodBase method,
4357                                                           bool chose_params_expanded,
4358                                                           bool may_fail, Location loc)
4359                 {
4360                         AParametersCollection pd = TypeManager.GetParameterData (method);
4361
4362                         int errors = Report.Errors;
4363                         Parameter.Modifier p_mod = 0;
4364                         Type pt = null;
4365                         int a_idx = 0, a_pos = 0;
4366                         Argument a = null;
4367                         ArrayList params_initializers = null;
4368                         bool has_unsafe_arg = false;
4369
4370                         for (; a_idx < arg_count; a_idx++, ++a_pos) {
4371                                 a = (Argument) arguments [a_idx];
4372                                 if (p_mod != Parameter.Modifier.PARAMS) {
4373                                         p_mod = pd.FixedParameters [a_idx].ModFlags;
4374                                         pt = pd.Types [a_idx];
4375                                         has_unsafe_arg |= pt.IsPointer;
4376
4377                                         if (p_mod == Parameter.Modifier.ARGLIST) {
4378                                                 if (a.Type != typeof (ArglistAccess))
4379                                                         break;
4380                                                 continue;
4381                                         }
4382
4383                                         if (p_mod == Parameter.Modifier.PARAMS) {
4384                                                 if (chose_params_expanded) {
4385                                                         params_initializers = new ArrayList (arg_count - a_idx);
4386                                                         pt = TypeManager.GetElementType (pt);
4387                                                 }
4388                                         }
4389                                 }
4390
4391                                 //
4392                                 // Types have to be identical when ref or out modifer is used
4393                                 //
4394                                 if (a.Modifier != 0 || (p_mod & ~Parameter.Modifier.PARAMS) != 0) {
4395                                         if ((p_mod & ~Parameter.Modifier.PARAMS) != a.Modifier)
4396                                                 break;
4397
4398                                         if (!TypeManager.IsEqual (a.Expr.Type, pt))
4399                                                 break;
4400
4401                                         continue;
4402                                 }
4403
4404                                 if (delegate_type != null && !Delegate.IsTypeCovariant (a.Expr, pt))
4405                                         break;
4406
4407                                 Expression conv = Convert.ImplicitConversion (ec, a.Expr, pt, loc);
4408                                 if (conv == null)
4409                                         break;
4410
4411                                 //
4412                                 // Convert params arguments to an array initializer
4413                                 //
4414                                 if (params_initializers != null) {
4415                                         // we choose to use 'a.Expr' rather than 'conv' so that
4416                                         // we don't hide the kind of expression we have (esp. CompoundAssign.Helper)
4417                                         params_initializers.Add (a.Expr);
4418                                         arguments.RemoveAt (a_idx--);
4419                                         --arg_count;
4420                                         continue;
4421                                 }
4422
4423                                 // Update the argument with the implicit conversion
4424                                 a.Expr = conv;
4425                         }
4426
4427                         if (a_idx != arg_count) {
4428                                 if (!may_fail && Report.Errors == errors) {
4429                                         if (CustomErrorHandler != null)
4430                                                 CustomErrorHandler.NoExactMatch (ec, best_candidate);
4431                                         else
4432                                                 Error_InvalidArguments (ec, loc, a_pos, method, a, pd, pt);
4433                                 }
4434                                 return false;
4435                         }
4436
4437                         //
4438                         // Fill not provided arguments required by params modifier
4439                         //
4440                         int param_count = GetApplicableParametersCount (method, pd);
4441                         if (params_initializers == null && pd.HasParams && arg_count + 1 == param_count) {
4442                                 if (arguments == null)
4443                                         arguments = new ArrayList (1);
4444
4445                                 pt = pd.Types [param_count - 1];
4446                                 pt = TypeManager.GetElementType (pt);
4447                                 has_unsafe_arg |= pt.IsPointer;
4448                                 params_initializers = new ArrayList (0);
4449                         }
4450
4451                         //
4452                         // Append an array argument with all params arguments
4453                         //
4454                         if (params_initializers != null) {
4455                                 arguments.Add (new Argument (
4456                                                        new ArrayCreation (new TypeExpression (pt, loc), "[]",
4457                                                                           params_initializers, loc).Resolve (ec)));
4458                                 arg_count++;
4459                         }
4460
4461                         if (arg_count < param_count) {
4462                                 if (!may_fail)
4463                                         Error_ArgumentCountWrong (arg_count);
4464                                 return false;
4465                         }
4466
4467                         if (has_unsafe_arg && !ec.InUnsafe) {
4468                                 if (!may_fail)
4469                                         UnsafeError (loc);
4470                                 return false;
4471                         }
4472
4473                         return true;
4474                 }
4475         }
4476
4477         public class ConstantExpr : MemberExpr
4478         {
4479                 FieldInfo constant;
4480
4481                 public ConstantExpr (FieldInfo constant, Location loc)
4482                 {
4483                         this.constant = constant;
4484                         this.loc = loc;
4485                 }
4486
4487                 public override string Name {
4488                         get { throw new NotImplementedException (); }
4489                 }
4490
4491                 public override bool IsInstance {
4492                         get { return !IsStatic; }
4493                 }
4494
4495                 public override bool IsStatic {
4496                         get { return constant.IsStatic; }
4497                 }
4498
4499                 public override Type DeclaringType {
4500                         get { return constant.DeclaringType; }
4501                 }
4502
4503                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc, SimpleName original)
4504                 {
4505                         constant = TypeManager.GetGenericFieldDefinition (constant);
4506
4507                         IConstant ic = TypeManager.GetConstant (constant);
4508                         if (ic == null) {
4509                                 if (constant.IsLiteral) {
4510                                         ic = new ExternalConstant (constant);
4511                                 } else {
4512                                         ic = ExternalConstant.CreateDecimal (constant);
4513                                         // HACK: decimal field was not resolved as constant
4514                                         if (ic == null)
4515                                                 return new FieldExpr (constant, loc).ResolveMemberAccess (ec, left, loc, original);
4516                                 }
4517                                 TypeManager.RegisterConstant (constant, ic);
4518                         }
4519
4520                         return base.ResolveMemberAccess (ec, left, loc, original);
4521                 }
4522
4523                 public override Expression CreateExpressionTree (EmitContext ec)
4524                 {
4525                         throw new NotSupportedException ("ET");
4526                 }
4527
4528                 public override Expression DoResolve (EmitContext ec)
4529                 {
4530                         IConstant ic = TypeManager.GetConstant (constant);
4531                         if (ic.ResolveValue ()) {
4532                                 if (!ec.IsInObsoleteScope)
4533                                         ic.CheckObsoleteness (loc);
4534                         }
4535
4536                         return ic.CreateConstantReference (loc);
4537                 }
4538
4539                 public override void Emit (EmitContext ec)
4540                 {
4541                         throw new NotSupportedException ();
4542                 }
4543
4544                 public override string GetSignatureForError ()
4545                 {
4546                         return TypeManager.GetFullNameSignature (constant);
4547                 }
4548         }
4549
4550         /// <summary>
4551         ///   Fully resolved expression that evaluates to a Field
4552         /// </summary>
4553         public class FieldExpr : MemberExpr, IAssignMethod, IMemoryLocation, IVariableReference {
4554                 public FieldInfo FieldInfo;
4555                 readonly Type constructed_generic_type;
4556                 VariableInfo variable_info;
4557
4558                 LocalTemporary temp;
4559                 bool prepared;
4560
4561                 protected FieldExpr (Location l)
4562                 {
4563                         loc = l;
4564                 }
4565
4566                 public FieldExpr (FieldInfo fi, Location l)
4567                 {
4568                         FieldInfo = fi;
4569                         type = TypeManager.TypeToCoreType (fi.FieldType);
4570                         loc = l;
4571                 }
4572
4573                 public FieldExpr (FieldInfo fi, Type genericType, Location l)
4574                         : this (fi, l)
4575                 {
4576                         if (TypeManager.IsGenericTypeDefinition (genericType))
4577                                 return;
4578                         this.constructed_generic_type = genericType;
4579                 }
4580
4581                 public override string Name {
4582                         get {
4583                                 return FieldInfo.Name;
4584                         }
4585                 }
4586
4587                 public override bool IsInstance {
4588                         get {
4589                                 return !FieldInfo.IsStatic;
4590                         }
4591                 }
4592
4593                 public override bool IsStatic {
4594                         get {
4595                                 return FieldInfo.IsStatic;
4596                         }
4597                 }
4598
4599                 public override Type DeclaringType {
4600                         get {
4601                                 return FieldInfo.DeclaringType;
4602                         }
4603                 }
4604
4605                 public override string GetSignatureForError ()
4606                 {
4607                         return TypeManager.GetFullNameSignature (FieldInfo);
4608                 }
4609
4610                 public VariableInfo VariableInfo {
4611                         get {
4612                                 return variable_info;
4613                         }
4614                 }
4615
4616                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
4617                                                                 SimpleName original)
4618                 {
4619                         FieldInfo fi = TypeManager.GetGenericFieldDefinition (FieldInfo);
4620                         Type t = fi.FieldType;
4621
4622                         if (t.IsPointer && !ec.InUnsafe) {
4623                                 UnsafeError (loc);
4624                         }
4625
4626                         return base.ResolveMemberAccess (ec, left, loc, original);
4627                 }
4628
4629                 public void SetHasAddressTaken ()
4630                 {
4631                         IVariableReference vr = InstanceExpression as IVariableReference;
4632                         if (vr != null)
4633                                 vr.SetHasAddressTaken ();
4634                 }
4635
4636                 public override Expression CreateExpressionTree (EmitContext ec)
4637                 {
4638                         Expression instance;
4639                         if (InstanceExpression == null) {
4640                                 instance = new NullLiteral (loc);
4641                         } else {
4642                                 instance = InstanceExpression.CreateExpressionTree (ec);
4643                         }
4644
4645                         ArrayList args = new ArrayList (2);
4646                         args.Add (new Argument (instance));
4647                         args.Add (new Argument (CreateTypeOfExpression ()));
4648                         return CreateExpressionFactoryCall ("Field", args);
4649                 }
4650
4651                 public Expression CreateTypeOfExpression ()
4652                 {
4653                         return new TypeOfField (GetConstructedFieldInfo (), loc);
4654                 }
4655
4656                 override public Expression DoResolve (EmitContext ec)
4657                 {
4658                         return DoResolve (ec, false, false);
4659                 }
4660
4661                 Expression DoResolve (EmitContext ec, bool lvalue_instance, bool out_access)
4662                 {
4663                         if (!FieldInfo.IsStatic){
4664                                 if (InstanceExpression == null){
4665                                         //
4666                                         // This can happen when referencing an instance field using
4667                                         // a fully qualified type expression: TypeName.InstanceField = xxx
4668                                         //
4669                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4670                                         return null;
4671                                 }
4672
4673                                 // Resolve the field's instance expression while flow analysis is turned
4674                                 // off: when accessing a field "a.b", we must check whether the field
4675                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
4676
4677                                 if (lvalue_instance) {
4678                                         using (ec.With (EmitContext.Flags.DoFlowAnalysis, false)) {
4679                                                 Expression right_side =
4680                                                         out_access ? EmptyExpression.LValueMemberOutAccess : EmptyExpression.LValueMemberAccess;
4681
4682                                                 if (InstanceExpression != EmptyExpression.Null)
4683                                                         InstanceExpression = InstanceExpression.ResolveLValue (ec, right_side, loc);
4684                                         }
4685                                 } else {
4686                                         ResolveFlags rf = ResolveFlags.VariableOrValue | ResolveFlags.DisableFlowAnalysis;
4687
4688                                         if (InstanceExpression != EmptyExpression.Null)
4689                                                 InstanceExpression = InstanceExpression.Resolve (ec, rf);
4690                                 }
4691
4692                                 if (InstanceExpression == null)
4693                                         return null;
4694
4695                                 using (ec.Set (EmitContext.Flags.OmitStructFlowAnalysis)) {
4696                                         InstanceExpression.CheckMarshalByRefAccess (ec);
4697                                 }
4698                         }
4699
4700                         // TODO: the code above uses some non-standard multi-resolve rules
4701                         if (eclass != ExprClass.Invalid)
4702                                 return this;
4703
4704                         if (!ec.IsInObsoleteScope) {
4705                                 FieldBase f = TypeManager.GetField (FieldInfo);
4706                                 if (f != null) {
4707                                         f.CheckObsoleteness (loc);
4708                                 } else {
4709                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
4710                                         if (oa != null)
4711                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
4712                                 }
4713                         }
4714
4715                         IFixedBuffer fb = AttributeTester.GetFixedBuffer (FieldInfo);
4716                         IVariableReference var = InstanceExpression as IVariableReference;
4717
4718                         if (fb != null) {
4719                                 IFixedExpression fe = InstanceExpression as IFixedExpression;
4720                                 if (!ec.InFixedInitializer && (fe == null || !fe.IsFixed)) {
4721                                         Report.Error (1666, loc, "You cannot use fixed size buffers contained in unfixed expressions. Try using the fixed statement");
4722                                 }
4723
4724                                 if (InstanceExpression.eclass != ExprClass.Variable) {
4725                                         Report.SymbolRelatedToPreviousError (FieldInfo);
4726                                         Report.Error (1708, loc, "`{0}': Fixed size buffers can only be accessed through locals or fields",
4727                                                 TypeManager.GetFullNameSignature (FieldInfo));
4728                                 } else if (var != null && var.IsHoisted) {
4729                                         AnonymousMethodExpression.Error_AddressOfCapturedVar (var, loc);
4730                                 }
4731
4732                                 return new FixedBufferPtr (this, fb.ElementType, loc).Resolve (ec);
4733                         }
4734
4735                         eclass = ExprClass.Variable;
4736
4737                         // If the instance expression is a local variable or parameter.
4738                         if (var == null || var.VariableInfo == null)
4739                                 return this;
4740
4741                         VariableInfo vi = var.VariableInfo;
4742                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
4743                                 return null;
4744
4745                         variable_info = vi.GetSubStruct (FieldInfo.Name);
4746                         eclass = ExprClass.Variable;
4747                         return this;
4748                 }
4749
4750                 static readonly int [] codes = {
4751                         191,    // instance, write access
4752                         192,    // instance, out access
4753                         198,    // static, write access
4754                         199,    // static, out access
4755                         1648,   // member of value instance, write access
4756                         1649,   // member of value instance, out access
4757                         1650,   // member of value static, write access
4758                         1651    // member of value static, out access
4759                 };
4760
4761                 static readonly string [] msgs = {
4762                         /*0191*/ "A readonly field `{0}' cannot be assigned to (except in a constructor or a variable initializer)",
4763                         /*0192*/ "A readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4764                         /*0198*/ "A static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4765                         /*0199*/ "A static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
4766                         /*1648*/ "Members of readonly field `{0}' cannot be modified (except in a constructor or a variable initializer)",
4767                         /*1649*/ "Members of readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4768                         /*1650*/ "Fields of static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4769                         /*1651*/ "Fields of static readonly field `{0}' cannot be passed ref or out (except in a static constructor)"
4770                 };
4771
4772                 // The return value is always null.  Returning a value simplifies calling code.
4773                 Expression Report_AssignToReadonly (Expression right_side)
4774                 {
4775                         int i = 0;
4776                         if (right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4777                                 i += 1;
4778                         if (IsStatic)
4779                                 i += 2;
4780                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4781                                 i += 4;
4782                         Report.Error (codes [i], loc, msgs [i], GetSignatureForError ());
4783
4784                         return null;
4785                 }
4786
4787                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
4788                 {
4789                         IVariableReference var = InstanceExpression as IVariableReference;
4790                         if (var != null && var.VariableInfo != null)
4791                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
4792
4793                         bool lvalue_instance = !FieldInfo.IsStatic && TypeManager.IsValueType (FieldInfo.DeclaringType);
4794                         bool out_access = right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess;
4795
4796                         Expression e = DoResolve (ec, lvalue_instance, out_access);
4797
4798                         if (e == null)
4799                                 return null;
4800
4801                         FieldBase fb = TypeManager.GetField (FieldInfo);
4802                         if (fb != null)
4803                                 fb.SetAssigned ();
4804
4805                         if (FieldInfo.IsInitOnly) {
4806                                 // InitOnly fields can only be assigned in constructors or initializers
4807                                 if (!ec.IsInFieldInitializer && !ec.IsConstructor)
4808                                         return Report_AssignToReadonly (right_side);
4809
4810                                 if (ec.IsConstructor) {
4811                                         Type ctype = ec.TypeContainer.CurrentType;
4812                                         if (ctype == null)
4813                                                 ctype = ec.ContainerType;
4814
4815                                         // InitOnly fields cannot be assigned-to in a different constructor from their declaring type
4816                                         if (!TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
4817                                                 return Report_AssignToReadonly (right_side);
4818                                         // static InitOnly fields cannot be assigned-to in an instance constructor
4819                                         if (IsStatic && !ec.IsStatic)
4820                                                 return Report_AssignToReadonly (right_side);
4821                                         // instance constructors can't modify InitOnly fields of other instances of the same type
4822                                         if (!IsStatic && !(InstanceExpression is This))
4823                                                 return Report_AssignToReadonly (right_side);
4824                                 }
4825                         }
4826
4827                         if (right_side == EmptyExpression.OutAccess &&
4828                             !IsStatic && !(InstanceExpression is This) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type)) {
4829                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4830                                 Report.Warning (197, 1, loc,
4831                                                 "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",
4832                                                 GetSignatureForError ());
4833                         }
4834
4835                         eclass = ExprClass.Variable;
4836                         return this;
4837                 }
4838
4839                 bool is_marshal_by_ref ()
4840                 {
4841                         return !IsStatic && TypeManager.IsStruct (Type) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type);
4842                 }
4843
4844                 public override void CheckMarshalByRefAccess (EmitContext ec)
4845                 {
4846                         if (is_marshal_by_ref () && !(InstanceExpression is This)) {
4847                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4848                                 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",
4849                                                 GetSignatureForError ());
4850                         }
4851                 }
4852
4853                 public override int GetHashCode ()
4854                 {
4855                         return FieldInfo.GetHashCode ();
4856                 }
4857
4858                 public bool IsFixed {
4859                         get {
4860                                 //
4861                                 // A variable of the form V.I is fixed when V is a fixed variable of a struct type
4862                                 //
4863                                 IVariableReference variable = InstanceExpression as IVariableReference;
4864                                 if (variable != null)
4865                                         return TypeManager.IsStruct (InstanceExpression.Type) && variable.IsFixed;
4866
4867                                 IFixedExpression fe = InstanceExpression as IFixedExpression;
4868                                 return fe != null && fe.IsFixed;
4869                         }
4870                 }
4871
4872                 public bool IsHoisted {
4873                         get {
4874                                 IVariableReference hv = InstanceExpression as IVariableReference;
4875                                 return hv != null && hv.IsHoisted;
4876                         }
4877                 }
4878
4879                 public override bool Equals (object obj)
4880                 {
4881                         FieldExpr fe = obj as FieldExpr;
4882                         if (fe == null)
4883                                 return false;
4884
4885                         if (FieldInfo != fe.FieldInfo)
4886                                 return false;
4887
4888                         if (InstanceExpression == null || fe.InstanceExpression == null)
4889                                 return true;
4890
4891                         return InstanceExpression.Equals (fe.InstanceExpression);
4892                 }
4893
4894                 public void Emit (EmitContext ec, bool leave_copy)
4895                 {
4896                         ILGenerator ig = ec.ig;
4897                         bool is_volatile = false;
4898
4899                         FieldBase f = TypeManager.GetField (FieldInfo);
4900                         if (f != null){
4901                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4902                                         is_volatile = true;
4903
4904                                 f.SetMemberIsUsed ();
4905                         }
4906
4907                         if (FieldInfo.IsStatic){
4908                                 if (is_volatile)
4909                                         ig.Emit (OpCodes.Volatile);
4910
4911                                 ig.Emit (OpCodes.Ldsfld, GetConstructedFieldInfo ());
4912                         } else {
4913                                 if (!prepared)
4914                                         EmitInstance (ec, false);
4915
4916                                 // Optimization for build-in types
4917                                 // TODO: Iterators don't set current container
4918                                 if (TypeManager.IsStruct (type) && type == ec.DeclContainer.TypeBuilder && ec.CurrentIterator == null) {
4919                                         LoadFromPtr (ig, type);
4920                                 } else {
4921                                         IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
4922                                         if (ff != null) {
4923                                                 ig.Emit (OpCodes.Ldflda, GetConstructedFieldInfo ());
4924                                                 ig.Emit (OpCodes.Ldflda, ff.Element);
4925                                         } else {
4926                                                 if (is_volatile)
4927                                                         ig.Emit (OpCodes.Volatile);
4928
4929                                                 ig.Emit (OpCodes.Ldfld, GetConstructedFieldInfo ());
4930                                         }
4931                                 }
4932                         }
4933
4934                         if (leave_copy) {
4935                                 ec.ig.Emit (OpCodes.Dup);
4936                                 if (!FieldInfo.IsStatic) {
4937                                         temp = new LocalTemporary (this.Type);
4938                                         temp.Store (ec);
4939                                 }
4940                         }
4941                 }
4942
4943                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
4944                 {
4945                         FieldAttributes fa = FieldInfo.Attributes;
4946                         bool is_static = (fa & FieldAttributes.Static) != 0;
4947                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
4948                         ILGenerator ig = ec.ig;
4949
4950                         if (is_readonly && !ec.IsConstructor){
4951                                 Report_AssignToReadonly (source);
4952                                 return;
4953                         }
4954
4955                         prepared = prepare_for_load;
4956                         EmitInstance (ec, prepared);
4957
4958                         source.Emit (ec);
4959                         if (leave_copy) {
4960                                 ec.ig.Emit (OpCodes.Dup);
4961                                 if (!FieldInfo.IsStatic) {
4962                                         temp = new LocalTemporary (this.Type);
4963                                         temp.Store (ec);
4964                                 }
4965                         }
4966
4967                         FieldBase f = TypeManager.GetField (FieldInfo);
4968                         if (f != null){
4969                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4970                                         ig.Emit (OpCodes.Volatile);
4971
4972                                 f.SetAssigned ();
4973                         }
4974
4975                         if (is_static)
4976                                 ig.Emit (OpCodes.Stsfld, GetConstructedFieldInfo ());
4977                         else
4978                                 ig.Emit (OpCodes.Stfld, GetConstructedFieldInfo ());
4979
4980                         if (temp != null) {
4981                                 temp.Emit (ec);
4982                                 temp.Release (ec);
4983                                 temp = null;
4984                         }
4985                 }
4986
4987                 public override void Emit (EmitContext ec)
4988                 {
4989                         Emit (ec, false);
4990                 }
4991
4992                 public override void EmitSideEffect (EmitContext ec)
4993                 {
4994                         FieldBase f = TypeManager.GetField (FieldInfo);
4995                         bool is_volatile = f != null && (f.ModFlags & Modifiers.VOLATILE) != 0;
4996
4997                         if (is_volatile || is_marshal_by_ref ())
4998                                 base.EmitSideEffect (ec);
4999                 }
5000
5001                 public override void Error_VariableIsUsedBeforeItIsDeclared (string name)
5002                 {
5003                         Report.Error (844, loc,
5004                                 "A local variable `{0}' cannot be used before it is declared. Consider renaming the local variable when it hides the field `{1}'",
5005                                 name, GetSignatureForError ());
5006                 }
5007
5008                 public void AddressOf (EmitContext ec, AddressOp mode)
5009                 {
5010                         ILGenerator ig = ec.ig;
5011
5012                         FieldBase f = TypeManager.GetField (FieldInfo);
5013                         if (f != null){
5014                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0){
5015                                         Report.Warning (420, 1, loc, "`{0}': A volatile field references will not be treated as volatile",
5016                                                         f.GetSignatureForError ());
5017                                 }
5018
5019                                 if ((mode & AddressOp.Store) != 0)
5020                                         f.SetAssigned ();
5021                                 if ((mode & AddressOp.Load) != 0)
5022                                         f.SetMemberIsUsed ();
5023                         }
5024
5025                         //
5026                         // Handle initonly fields specially: make a copy and then
5027                         // get the address of the copy.
5028                         //
5029                         bool need_copy;
5030                         if (FieldInfo.IsInitOnly){
5031                                 need_copy = true;
5032                                 if (ec.IsConstructor){
5033                                         if (FieldInfo.IsStatic){
5034                                                 if (ec.IsStatic)
5035                                                         need_copy = false;
5036                                         } else
5037                                                 need_copy = false;
5038                                 }
5039                         } else
5040                                 need_copy = false;
5041
5042                         if (need_copy){
5043                                 LocalBuilder local;
5044                                 Emit (ec);
5045                                 local = ig.DeclareLocal (type);
5046                                 ig.Emit (OpCodes.Stloc, local);
5047                                 ig.Emit (OpCodes.Ldloca, local);
5048                                 return;
5049                         }
5050
5051
5052                         if (FieldInfo.IsStatic){
5053                                 ig.Emit (OpCodes.Ldsflda, GetConstructedFieldInfo ());
5054                         } else {
5055                                 if (!prepared)
5056                                         EmitInstance (ec, false);
5057                                 ig.Emit (OpCodes.Ldflda, GetConstructedFieldInfo ());
5058                         }
5059                 }
5060
5061                 FieldInfo GetConstructedFieldInfo ()
5062                 {
5063                         if (constructed_generic_type == null)
5064                                 return FieldInfo;
5065 #if GMCS_SOURCE
5066                         return TypeBuilder.GetField (constructed_generic_type, FieldInfo);
5067 #else
5068                         throw new NotSupportedException ();
5069 #endif
5070                 }
5071
5072                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
5073                 {
5074                         FieldInfo = storey.MutateField (FieldInfo);
5075                         base.MutateHoistedGenericType (storey);
5076                 }
5077         }
5078
5079
5080         /// <summary>
5081         ///   Expression that evaluates to a Property.  The Assign class
5082         ///   might set the `Value' expression if we are in an assignment.
5083         ///
5084         ///   This is not an LValue because we need to re-write the expression, we
5085         ///   can not take data from the stack and store it.
5086         /// </summary>
5087         public class PropertyExpr : MemberExpr, IAssignMethod {
5088                 public readonly PropertyInfo PropertyInfo;
5089                 MethodInfo getter, setter;
5090                 bool is_static;
5091
5092                 bool resolved;
5093
5094                 LocalTemporary temp;
5095                 bool prepared;
5096
5097                 public PropertyExpr (Type container_type, PropertyInfo pi, Location l)
5098                 {
5099                         PropertyInfo = pi;
5100                         eclass = ExprClass.PropertyAccess;
5101                         is_static = false;
5102                         loc = l;
5103
5104                         type = TypeManager.TypeToCoreType (pi.PropertyType);
5105
5106                         ResolveAccessors (container_type);
5107                 }
5108
5109                 public override string Name {
5110                         get {
5111                                 return PropertyInfo.Name;
5112                         }
5113                 }
5114
5115                 public override bool IsInstance {
5116                         get {
5117                                 return !is_static;
5118                         }
5119                 }
5120
5121                 public override bool IsStatic {
5122                         get {
5123                                 return is_static;
5124                         }
5125                 }
5126
5127                 public override Expression CreateExpressionTree (EmitContext ec)
5128                 {
5129                         ArrayList args;
5130                         if (IsSingleDimensionalArrayLength ()) {
5131                                 args = new ArrayList (1);
5132                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5133                                 return CreateExpressionFactoryCall ("ArrayLength", args);
5134                         }
5135
5136                         if (is_base) {
5137                                 Error_BaseAccessInExpressionTree (loc);
5138                                 return null;
5139                         }
5140
5141                         args = new ArrayList (2);
5142                         if (InstanceExpression == null)
5143                                 args.Add (new Argument (new NullLiteral (loc)));
5144                         else
5145                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5146                         args.Add (new Argument (new TypeOfMethodInfo (getter, loc)));
5147                         return CreateExpressionFactoryCall ("Property", args);
5148                 }
5149
5150                 public Expression CreateSetterTypeOfExpression ()
5151                 {
5152                         return new TypeOfMethodInfo (setter, loc);
5153                 }
5154
5155                 public override Type DeclaringType {
5156                         get {
5157                                 return PropertyInfo.DeclaringType;
5158                         }
5159                 }
5160
5161                 public override string GetSignatureForError ()
5162                 {
5163                         return TypeManager.GetFullNameSignature (PropertyInfo);
5164                 }
5165
5166                 void FindAccessors (Type invocation_type)
5167                 {
5168                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
5169                                 BindingFlags.Static | BindingFlags.Instance |
5170                                 BindingFlags.DeclaredOnly;
5171
5172                         Type current = PropertyInfo.DeclaringType;
5173                         for (; current != null; current = current.BaseType) {
5174                                 MemberInfo[] group = TypeManager.MemberLookup (
5175                                         invocation_type, invocation_type, current,
5176                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
5177
5178                                 if (group == null)
5179                                         continue;
5180
5181                                 if (group.Length != 1)
5182                                         // Oooops, can this ever happen ?
5183                                         return;
5184
5185                                 PropertyInfo pi = (PropertyInfo) group [0];
5186
5187                                 if (getter == null)
5188                                         getter = pi.GetGetMethod (true);
5189
5190                                 if (setter == null)
5191                                         setter = pi.GetSetMethod (true);
5192
5193                                 MethodInfo accessor = getter != null ? getter : setter;
5194
5195                                 if (!accessor.IsVirtual)
5196                                         return;
5197                         }
5198                 }
5199
5200                 //
5201                 // We also perform the permission checking here, as the PropertyInfo does not
5202                 // hold the information for the accessibility of its setter/getter
5203                 //
5204                 // TODO: Refactor to use some kind of cache together with GetPropertyFromAccessor
5205                 void ResolveAccessors (Type container_type)
5206                 {
5207                         FindAccessors (container_type);
5208
5209                         if (getter != null) {
5210                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
5211                                 IMethodData md = TypeManager.GetMethod (the_getter);
5212                                 if (md != null)
5213                                         md.SetMemberIsUsed ();
5214
5215                                 is_static = getter.IsStatic;
5216                         }
5217
5218                         if (setter != null) {
5219                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
5220                                 IMethodData md = TypeManager.GetMethod (the_setter);
5221                                 if (md != null)
5222                                         md.SetMemberIsUsed ();
5223
5224                                 is_static = setter.IsStatic;
5225                         }
5226                 }
5227
5228                 public override void MutateHoistedGenericType (AnonymousMethodStorey storey)
5229                 {
5230                         if (InstanceExpression != null)
5231                                 InstanceExpression.MutateHoistedGenericType (storey);
5232
5233                         type = storey.MutateType (type);
5234                         if (getter != null)
5235                                 getter = storey.MutateGenericMethod (getter);
5236                         if (setter != null)
5237                                 setter = storey.MutateGenericMethod (setter);
5238                 }
5239
5240                 bool InstanceResolve (EmitContext ec, bool lvalue_instance, bool must_do_cs1540_check)
5241                 {
5242                         if (is_static) {
5243                                 InstanceExpression = null;
5244                                 return true;
5245                         }
5246
5247                         if (InstanceExpression == null) {
5248                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5249                                 return false;
5250                         }
5251
5252                         InstanceExpression = InstanceExpression.DoResolve (ec);
5253                         if (lvalue_instance && InstanceExpression != null)
5254                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess, loc);
5255
5256                         if (InstanceExpression == null)
5257                                 return false;
5258
5259                         InstanceExpression.CheckMarshalByRefAccess (ec);
5260
5261                         if (must_do_cs1540_check && (InstanceExpression != EmptyExpression.Null) &&
5262                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.ContainerType) &&
5263                             !TypeManager.IsNestedChildOf (ec.ContainerType, InstanceExpression.Type) &&
5264                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.ContainerType)) {
5265                                 Report.SymbolRelatedToPreviousError (PropertyInfo);
5266                                 Error_CannotAccessProtected (loc, PropertyInfo, InstanceExpression.Type, ec.ContainerType);
5267                                 return false;
5268                         }
5269
5270                         return true;
5271                 }
5272
5273                 void Error_PropertyNotFound (MethodInfo mi, bool getter)
5274                 {
5275                         // TODO: correctly we should compare arguments but it will lead to bigger changes
5276                         if (mi is MethodBuilder) {
5277                                 Error_TypeDoesNotContainDefinition (loc, PropertyInfo.DeclaringType, Name);
5278                                 return;
5279                         }
5280
5281                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
5282                         sig.Append ('.');
5283                         AParametersCollection iparams = TypeManager.GetParameterData (mi);
5284                         sig.Append (getter ? "get_" : "set_");
5285                         sig.Append (Name);
5286                         sig.Append (iparams.GetSignatureForError ());
5287
5288                         Report.SymbolRelatedToPreviousError (mi);
5289                         Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
5290                                 Name, sig.ToString ());
5291                 }
5292
5293                 public bool IsAccessibleFrom (Type invocation_type, bool lvalue)
5294                 {
5295                         bool dummy;
5296                         MethodInfo accessor = lvalue ? setter : getter;
5297                         if (accessor == null && lvalue)
5298                                 accessor = getter;
5299                         return accessor != null && IsAccessorAccessible (invocation_type, accessor, out dummy);
5300                 }
5301
5302                 bool IsSingleDimensionalArrayLength ()
5303                 {
5304                         if (DeclaringType != TypeManager.array_type || getter == null || Name != "Length")
5305                                 return false;
5306
5307                         string t_name = InstanceExpression.Type.Name;
5308                         int t_name_len = t_name.Length;
5309                         return t_name_len > 2 && t_name [t_name_len - 2] == '[';
5310                 }
5311
5312                 override public Expression DoResolve (EmitContext ec)
5313                 {
5314                         if (resolved)
5315                                 return this;
5316
5317                         if (getter != null){
5318                                 if (TypeManager.GetParameterData (getter).Count != 0){
5319                                         Error_PropertyNotFound (getter, true);
5320                                         return null;
5321                                 }
5322                         }
5323
5324                         if (getter == null){
5325                                 //
5326                                 // The following condition happens if the PropertyExpr was
5327                                 // created, but is invalid (ie, the property is inaccessible),
5328                                 // and we did not want to embed the knowledge about this in
5329                                 // the caller routine.  This only avoids double error reporting.
5330                                 //
5331                                 if (setter == null)
5332                                         return null;
5333
5334                                 if (InstanceExpression != EmptyExpression.Null) {
5335                                         Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
5336                                                 TypeManager.GetFullNameSignature (PropertyInfo));
5337                                         return null;
5338                                 }
5339                         }
5340
5341                         bool must_do_cs1540_check = false;
5342                         if (getter != null &&
5343                             !IsAccessorAccessible (ec.ContainerType, getter, out must_do_cs1540_check)) {
5344                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter) as PropertyBase.PropertyMethod;
5345                                 if (pm != null && pm.HasCustomAccessModifier) {
5346                                         Report.SymbolRelatedToPreviousError (pm);
5347                                         Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
5348                                                 TypeManager.CSharpSignature (getter));
5349                                 }
5350                                 else {
5351                                         Report.SymbolRelatedToPreviousError (getter);
5352                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter));
5353                                 }
5354                                 return null;
5355                         }
5356
5357                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
5358                                 return null;
5359
5360                         //
5361                         // Only base will allow this invocation to happen.
5362                         //
5363                         if (IsBase && getter.IsAbstract) {
5364                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5365                         }
5366
5367                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe){
5368                                 UnsafeError (loc);
5369                         }
5370
5371                         if (!ec.IsInObsoleteScope) {
5372                                 PropertyBase pb = TypeManager.GetProperty (PropertyInfo);
5373                                 if (pb != null) {
5374                                         pb.CheckObsoleteness (loc);
5375                                 } else {
5376                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (PropertyInfo);
5377                                         if (oa != null)
5378                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc);
5379                                 }
5380                         }
5381
5382                         resolved = true;
5383
5384                         return this;
5385                 }
5386
5387                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5388                 {
5389                         if (right_side == EmptyExpression.OutAccess) {
5390                                 if (ec.CurrentBlock.Toplevel.GetParameterReference (PropertyInfo.Name, loc) is MemberAccess) {
5391                                         Report.Error (1939, loc, "A range variable `{0}' may not be passes as `ref' or `out' parameter",
5392                                             PropertyInfo.Name);
5393                                 } else {
5394                                         Report.Error (206, loc, "A property or indexer `{0}' may not be passed as `ref' or `out' parameter",
5395                                               GetSignatureForError ());
5396                                 }
5397                                 return null;
5398                         }
5399
5400                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess) {
5401                                 Error_CannotModifyIntermediateExpressionValue (ec);
5402                         }
5403
5404                         if (setter == null){
5405                                 //
5406                                 // The following condition happens if the PropertyExpr was
5407                                 // created, but is invalid (ie, the property is inaccessible),
5408                                 // and we did not want to embed the knowledge about this in
5409                                 // the caller routine.  This only avoids double error reporting.
5410                                 //
5411                                 if (getter == null)
5412                                         return null;
5413
5414                                 if (ec.CurrentBlock.Toplevel.GetParameterReference (PropertyInfo.Name, loc) is MemberAccess) {
5415                                         Report.Error (1947, loc, "A range variable `{0}' cannot be assigned to. Consider using `let' clause to store the value",
5416                                                 PropertyInfo.Name);
5417                                 } else {
5418                                         Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
5419                                                 GetSignatureForError ());
5420                                 }
5421                                 return null;
5422                         }
5423
5424                         if (TypeManager.GetParameterData (setter).Count != 1){
5425                                 Error_PropertyNotFound (setter, false);
5426                                 return null;
5427                         }
5428
5429                         bool must_do_cs1540_check;
5430                         if (!IsAccessorAccessible (ec.ContainerType, setter, out must_do_cs1540_check)) {
5431                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter) as PropertyBase.PropertyMethod;
5432                                 if (pm != null && pm.HasCustomAccessModifier) {
5433                                         Report.SymbolRelatedToPreviousError (pm);
5434                                         Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
5435                                                 TypeManager.CSharpSignature (setter));
5436                                 }
5437                                 else {
5438                                         Report.SymbolRelatedToPreviousError (setter);
5439                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter));
5440                                 }
5441                                 return null;
5442                         }
5443
5444                         if (!InstanceResolve (ec, TypeManager.IsStruct (PropertyInfo.DeclaringType), must_do_cs1540_check))
5445                                 return null;
5446
5447                         //
5448                         // Only base will allow this invocation to happen.
5449                         //
5450                         if (IsBase && setter.IsAbstract){
5451                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5452                         }
5453
5454                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe) {
5455                                 UnsafeError (loc);
5456                         }
5457
5458                         if (!ec.IsInObsoleteScope) {
5459                                 PropertyBase pb = TypeManager.GetProperty (PropertyInfo);
5460                                 if (pb != null) {
5461                                         pb.CheckObsoleteness (loc);
5462                                 } else {
5463                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (PropertyInfo);
5464                                         if (oa != null)
5465                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc);
5466                                 }
5467                         }
5468
5469                         return this;
5470                 }
5471
5472                 public override void Emit (EmitContext ec)
5473                 {
5474                         Emit (ec, false);
5475                 }
5476
5477                 public void Emit (EmitContext ec, bool leave_copy)
5478                 {
5479                         //
5480                         // Special case: length of single dimension array property is turned into ldlen
5481                         //
5482                         if (IsSingleDimensionalArrayLength ()) {
5483                                 if (!prepared)
5484                                         EmitInstance (ec, false);
5485                                 ec.ig.Emit (OpCodes.Ldlen);
5486                                 ec.ig.Emit (OpCodes.Conv_I4);
5487                                 return;
5488                         }
5489
5490                         Invocation.EmitCall (ec, IsBase, InstanceExpression, getter, null, loc, prepared, false);
5491
5492                         if (leave_copy) {
5493                                 ec.ig.Emit (OpCodes.Dup);
5494                                 if (!is_static) {
5495                                         temp = new LocalTemporary (this.Type);
5496                                         temp.Store (ec);
5497                                 }
5498                         }
5499                 }
5500
5501                 //
5502                 // Implements the IAssignMethod interface for assignments
5503                 //
5504                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5505                 {
5506                         Expression my_source = source;
5507
5508                         if (prepare_for_load) {
5509                                 prepared = true;
5510                                 source.Emit (ec);
5511
5512                                 if (leave_copy) {
5513                                         ec.ig.Emit (OpCodes.Dup);
5514                                         if (!is_static) {
5515                                                 temp = new LocalTemporary (this.Type);
5516                                                 temp.Store (ec);
5517                                         }
5518                                 }
5519                         } else if (leave_copy) {
5520                                 source.Emit (ec);
5521                                 temp = new LocalTemporary (this.Type);
5522                                 temp.Store (ec);
5523                                 my_source = temp;
5524                         }
5525
5526                         ArrayList args = new ArrayList (1);
5527                         args.Add (new Argument (my_source, Argument.AType.Expression));
5528
5529                         Invocation.EmitCall (ec, IsBase, InstanceExpression, setter, args, loc, false, prepared);
5530
5531                         if (temp != null) {
5532                                 temp.Emit (ec);
5533                                 temp.Release (ec);
5534                         }
5535                 }
5536         }
5537
5538         /// <summary>
5539         ///   Fully resolved expression that evaluates to an Event
5540         /// </summary>
5541         public class EventExpr : MemberExpr {
5542                 public readonly EventInfo EventInfo;
5543
5544                 bool is_static;
5545                 MethodInfo add_accessor, remove_accessor;
5546
5547                 public EventExpr (EventInfo ei, Location loc)
5548                 {
5549                         EventInfo = ei;
5550                         this.loc = loc;
5551                         eclass = ExprClass.EventAccess;
5552
5553                         add_accessor = TypeManager.GetAddMethod (ei);
5554                         remove_accessor = TypeManager.GetRemoveMethod (ei);
5555                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
5556                                 is_static = true;
5557
5558                         if (EventInfo is MyEventBuilder){
5559                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
5560                                 type = eb.EventType;
5561                                 eb.SetUsed ();
5562                         } else
5563                                 type = EventInfo.EventHandlerType;
5564                 }
5565
5566                 public override string Name {
5567                         get {
5568                                 return EventInfo.Name;
5569                         }
5570                 }
5571
5572                 public override bool IsInstance {
5573                         get {
5574                                 return !is_static;
5575                         }
5576                 }
5577
5578                 public override bool IsStatic {
5579                         get {
5580                                 return is_static;
5581                         }
5582                 }
5583
5584                 public override Type DeclaringType {
5585                         get {
5586                                 return EventInfo.DeclaringType;
5587                         }
5588                 }
5589
5590                 void Error_AssignmentEventOnly ()
5591                 {
5592                         Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of `+=' or `-=' operator",
5593                                 GetSignatureForError ());
5594                 }
5595
5596                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
5597                                                                 SimpleName original)
5598                 {
5599                         //
5600                         // If the event is local to this class, we transform ourselves into a FieldExpr
5601                         //
5602
5603                         if (EventInfo.DeclaringType == ec.ContainerType ||
5604                             TypeManager.IsNestedChildOf(ec.ContainerType, EventInfo.DeclaringType)) {
5605                                 EventField mi = TypeManager.GetEventField (EventInfo);
5606
5607                                 if (mi != null) {
5608                                         if (!ec.IsInObsoleteScope)
5609                                                 mi.CheckObsoleteness (loc);
5610
5611                                         if ((mi.ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0 && !ec.IsInCompoundAssignment)
5612                                                 Error_AssignmentEventOnly ();
5613
5614                                         FieldExpr ml = new FieldExpr (mi.BackingField.FieldBuilder, loc);
5615
5616                                         InstanceExpression = null;
5617
5618                                         return ml.ResolveMemberAccess (ec, left, loc, original);
5619                                 }
5620                         }
5621
5622                         if (left is This && !ec.IsInCompoundAssignment)
5623                                 Error_AssignmentEventOnly ();
5624
5625                         return base.ResolveMemberAccess (ec, left, loc, original);
5626                 }
5627
5628                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
5629                 {
5630                         if (is_static) {
5631                                 InstanceExpression = null;
5632                                 return true;
5633                         }
5634
5635                         if (InstanceExpression == null) {
5636                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5637                                 return false;
5638                         }
5639
5640                         InstanceExpression = InstanceExpression.DoResolve (ec);
5641                         if (InstanceExpression == null)
5642                                 return false;
5643
5644                         if (IsBase && add_accessor.IsAbstract) {
5645                                 Error_CannotCallAbstractBase(TypeManager.CSharpSignature(add_accessor));
5646                                 return false;
5647                         }
5648
5649                         //
5650                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
5651                         // However, in the Event case, we reported a CS0122 instead.
5652                         //
5653                         // TODO: Exact copy from PropertyExpr
5654                         //
5655                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
5656                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.ContainerType) &&
5657                             !TypeManager.IsNestedChildOf (ec.ContainerType, InstanceExpression.Type) &&
5658                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.ContainerType)) {
5659                                 Report.SymbolRelatedToPreviousError (EventInfo);
5660                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5661                                 return false;
5662                         }
5663
5664                         return true;
5665                 }
5666
5667                 public bool IsAccessibleFrom (Type invocation_type)
5668                 {
5669                         bool dummy;
5670                         return IsAccessorAccessible (invocation_type, add_accessor, out dummy) &&
5671                                 IsAccessorAccessible (invocation_type, remove_accessor, out dummy);
5672                 }
5673
5674                 public override Expression CreateExpressionTree (EmitContext ec)
5675                 {
5676                         throw new NotSupportedException ("ET");
5677                 }
5678
5679                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5680                 {
5681                         // contexts where an LValue is valid have already devolved to FieldExprs
5682                         Error_CannotAssign ();
5683                         return null;
5684                 }
5685
5686                 public override Expression DoResolve (EmitContext ec)
5687                 {
5688                         bool must_do_cs1540_check;
5689                         if (!(IsAccessorAccessible (ec.ContainerType, add_accessor, out must_do_cs1540_check) &&
5690                               IsAccessorAccessible (ec.ContainerType, remove_accessor, out must_do_cs1540_check))) {
5691                                 Report.SymbolRelatedToPreviousError (EventInfo);
5692                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5693                                 return null;
5694                         }
5695
5696                         if (!InstanceResolve (ec, must_do_cs1540_check))
5697                                 return null;
5698
5699                         if (!ec.IsInCompoundAssignment) {
5700                                 Error_CannotAssign ();
5701                                 return null;
5702                         }
5703
5704                         if (!ec.IsInObsoleteScope) {
5705                                 EventField ev = TypeManager.GetEventField (EventInfo);
5706                                 if (ev != null) {
5707                                         ev.CheckObsoleteness (loc);
5708                                 } else {
5709                                         ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (EventInfo);
5710                                         if (oa != null)
5711                                                 AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc);
5712                                 }
5713                         }
5714
5715                         return this;
5716                 }
5717
5718                 public override void Emit (EmitContext ec)
5719                 {
5720                         Error_CannotAssign ();
5721                 }
5722
5723                 public void Error_CannotAssign ()
5724                 {
5725                         Report.Error (70, loc,
5726                                 "The event `{0}' can only appear on the left hand side of += or -= when used outside of the type `{1}'",
5727                                 GetSignatureForError (), TypeManager.CSharpName (EventInfo.DeclaringType));
5728                 }
5729
5730                 public override string GetSignatureForError ()
5731                 {
5732                         return TypeManager.CSharpSignature (EventInfo);
5733                 }
5734
5735                 public void EmitAddOrRemove (EmitContext ec, bool is_add, Expression source)
5736                 {
5737                         ArrayList args = new ArrayList (1);
5738                         args.Add (new Argument (source, Argument.AType.Expression));
5739                         Invocation.EmitCall (ec, IsBase, InstanceExpression, is_add ? add_accessor : remove_accessor, args, loc);
5740                 }
5741         }
5742
5743         public class TemporaryVariable : VariableReference
5744         {
5745                 LocalInfo li;
5746
5747                 public TemporaryVariable (Type type, Location loc)
5748                 {
5749                         this.type = type;
5750                         this.loc = loc;
5751                         eclass = ExprClass.Variable;
5752                 }
5753
5754                 public override Expression CreateExpressionTree (EmitContext ec)
5755                 {
5756                         throw new NotSupportedException ("ET");
5757                 }
5758
5759                 public override Expression DoResolve (EmitContext ec)
5760                 {
5761                         if (li != null)
5762                                 return this;
5763
5764                         TypeExpr te = new TypeExpression (type, loc);
5765                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
5766                         if (!li.Resolve (ec))
5767                                 return null;
5768
5769                         //
5770                         // Don't capture temporary variables except when using
5771                         // iterator redirection
5772                         //
5773                         if (ec.CurrentAnonymousMethod != null && ec.CurrentAnonymousMethod.IsIterator && ec.IsVariableCapturingRequired) {
5774                                 AnonymousMethodStorey storey = li.Block.Explicit.CreateAnonymousMethodStorey (ec);
5775                                 storey.CaptureLocalVariable (ec, li);
5776                         }
5777
5778                         return this;
5779                 }
5780
5781                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5782                 {
5783                         return DoResolve (ec);
5784                 }
5785
5786                 public override void Emit (EmitContext ec)
5787                 {
5788                         Emit (ec, false);
5789                 }
5790
5791                 public void EmitAssign (EmitContext ec, Expression source)
5792                 {
5793                         EmitAssign (ec, source, false, false);
5794                 }
5795
5796                 public override HoistedVariable GetHoistedVariable (EmitContext ec)
5797                 {
5798                         return li.HoistedVariableReference;
5799                 }
5800
5801                 public override bool IsFixed {
5802                         get { return true; }
5803                 }
5804
5805                 public override bool IsRef {
5806                         get { return false; }
5807                 }
5808
5809                 public override string Name {
5810                         get { throw new NotImplementedException (); }
5811                 }
5812
5813                 public override void SetHasAddressTaken ()
5814                 {
5815                         throw new NotImplementedException ();
5816                 }
5817
5818                 protected override ILocalVariable Variable {
5819                         get { return li; }
5820                 }
5821
5822                 public override VariableInfo VariableInfo {
5823                         get { throw new NotImplementedException (); }
5824                 }
5825         }
5826
5827         ///
5828         /// Handles `var' contextual keyword; var becomes a keyword only
5829         /// if no type called var exists in a variable scope
5830         ///
5831         public class VarExpr : SimpleName
5832         {
5833                 // Used for error reporting only
5834                 ArrayList initializer;
5835
5836                 public VarExpr (Location loc)
5837                         : base ("var", loc)
5838                 {
5839                 }
5840
5841                 public ArrayList VariableInitializer {
5842                         set {
5843                                 this.initializer = value;
5844                         }
5845                 }
5846
5847                 public bool InferType (EmitContext ec, Expression right_side)
5848                 {
5849                         if (type != null)
5850                                 throw new InternalErrorException ("An implicitly typed local variable could not be redefined");
5851
5852                         type = right_side.Type;
5853                         if (type == TypeManager.null_type || type == TypeManager.void_type || type == TypeManager.anonymous_method_type) {
5854                                 Report.Error (815, loc, "An implicitly typed local variable declaration cannot be initialized with `{0}'",
5855                                               right_side.GetSignatureForError ());
5856                                 return false;
5857                         }
5858
5859                         eclass = ExprClass.Variable;
5860                         return true;
5861                 }
5862
5863                 protected override void Error_TypeOrNamespaceNotFound (IResolveContext ec)
5864                 {
5865                         Report.Error (825, loc, "The contextual keyword `var' may only appear within a local variable declaration");
5866                 }
5867
5868                 public override TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
5869                 {
5870                         TypeExpr te = base.ResolveAsContextualType (rc, true);
5871                         if (te != null)
5872                                 return te;
5873
5874                         if (initializer == null)
5875                                 return null;
5876
5877                         if (initializer.Count > 1) {
5878                                 Location loc = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [1]).Location;
5879                                 Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
5880                                 initializer = null;
5881                                 return null;
5882                         }
5883
5884                         Expression variable_initializer = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [0]).expression_or_array_initializer;
5885                         if (variable_initializer == null) {
5886                                 Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
5887                                 return null;
5888                         }
5889
5890                         return null;
5891                 }
5892         }
5893 }