mcs/gmcs/ecore.cs

   1 //
   2 // ecore.cs: Core of the Expression representation for the intermediate tree.
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //   Marek Safar (marek.safar@seznam.cz)
   7 //
   8 // (C) 2001, 2002, 2003 Ximian, Inc.
   9 //
  10 //
  11
  12 namespace Mono.CSharp {
  13         using System;
  14         using System.Collections;
  15         using System.Diagnostics;
  16         using System.Reflection;
  17         using System.Reflection.Emit;
  18         using System.Text;
  19
  20         /// <remarks>
  21         ///   The ExprClass class contains the is used to pass the
  22         ///   classification of an expression (value, variable, namespace,
  23         ///   type, method group, property access, event access, indexer access,
  24         ///   nothing).
  25         /// </remarks>
  26         public enum ExprClass : byte {
  27                 Invalid,
  28
  29                 Value,
  30                 Variable,
  31                 Namespace,
  32                 Type,
  33                 MethodGroup,
  34                 PropertyAccess,
  35                 EventAccess,
  36                 IndexerAccess,
  37                 Nothing,
  38         }
  39
  40         /// <remarks>
  41         ///   This is used to tell Resolve in which types of expressions we're
  42         ///   interested.
  43         /// </remarks>
  44         [Flags]
  45         public enum ResolveFlags {
  46                 // Returns Value, Variable, PropertyAccess, EventAccess or IndexerAccess.
  47                 VariableOrValue         = 1,
  48
  49                 // Returns a type expression.
  50                 Type                    = 2,
  51
  52                 // Returns a method group.
  53                 MethodGroup             = 4,
  54
  55                 // Mask of all the expression class flags.
  56                 MaskExprClass           = 7,
  57
  58                 // Disable control flow analysis while resolving the expression.
  59                 // This is used when resolving the instance expression of a field expression.
  60                 DisableFlowAnalysis     = 8,
  61
  62                 // Set if this is resolving the first part of a MemberAccess.
  63                 Intermediate            = 16,
  64
  65                 // Disable control flow analysis _of struct_ while resolving the expression.
  66                 // This is used when resolving the instance expression of a field expression.
  67                 DisableStructFlowAnalysis       = 32,
  68
  69         }
  70
  71         //
  72         // This is just as a hint to AddressOf of what will be done with the
  73         // address.
  74         [Flags]
  75         public enum AddressOp {
  76                 Store = 1,
  77                 Load  = 2,
  78                 LoadStore = 3
  79         };
  80
  81         /// <summary>
  82         ///   This interface is implemented by variables
  83         /// </summary>
  84         public interface IMemoryLocation {
  85                 /// <summary>
  86                 ///   The AddressOf method should generate code that loads
  87                 ///   the address of the object and leaves it on the stack.
  88                 ///
  89                 ///   The `mode' argument is used to notify the expression
  90                 ///   of whether this will be used to read from the address or
  91                 ///   write to the address.
  92                 ///
  93                 ///   This is just a hint that can be used to provide good error
  94                 ///   reporting, and should have no other side effects.
  95                 /// </summary>
  96                 void AddressOf (EmitContext ec, AddressOp mode);
  97         }
  98
  99         /// <summary>
 100         ///   This interface is implemented by variables
 101         /// </summary>
 102         public interface IVariable {
 103                 VariableInfo VariableInfo {
 104                         get;
 105                 }
 106
 107                 bool VerifyFixed ();
 108         }
 109
 110         /// <remarks>
 111         ///   Base class for expressions
 112         /// </remarks>
 113         public abstract class Expression {
 114                 public ExprClass eclass;
 115                 protected Type type;
 116                 protected Location loc;
 117
 118                 public Type Type {
 119                         get { return type; }
 120                         set { type = value; }
 121                 }
 122
 123                 public virtual Location Location {
 124                         get { return loc; }
 125                 }
 126
 127                 /// <summary>
 128                 ///   Utility wrapper routine for Error, just to beautify the code
 129                 /// </summary>
 130                 public void Error (int error, string s)
 131                 {
 132                         if (loc.IsNull)
 133                                 Report.Error (error, s);
 134                         else
 135                                 Report.Error (error, loc, s);
 136                 }
 137
 138                 // Not nice but we have broken hierarchy
 139                 public virtual void CheckMarshallByRefAccess (Type container) {}
 140
 141                 public virtual bool GetAttributableValue (Type valueType, out object value)
 142                 {
 143                         Attribute.Error_AttributeArgumentNotValid (loc);
 144                         value = null;
 145                         return false;
 146                 }
 147
 148                 public virtual string GetSignatureForError ()
 149                 {
 150                         return TypeManager.CSharpName (type);
 151                 }
 152
 153                 public static bool IsAccessorAccessible (Type invocation_type, MethodInfo mi, out bool must_do_cs1540_check)
 154                 {
 155                         MethodAttributes ma = mi.Attributes & MethodAttributes.MemberAccessMask;
 156
 157                         must_do_cs1540_check = false; // by default we do not check for this
 158
 159                         if (ma == MethodAttributes.Public)
 160                                 return true;
 161
 162                         //
 163                         // If only accessible to the current class or children
 164                         //
 165                         if (ma == MethodAttributes.Private)
 166                                 return TypeManager.IsPrivateAccessible (invocation_type, mi.DeclaringType) ||
 167                                         TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType);
 168
 169                         if (mi.DeclaringType.Assembly == invocation_type.Assembly ||
 170                                         TypeManager.IsFriendAssembly (mi.DeclaringType.Assembly)) {
 171                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamORAssem)
 172                                         return true;
 173                         } else {
 174                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamANDAssem)
 175                                         return false;
 176                         }
 177
 178                         // Family and FamANDAssem require that we derive.
 179                         // FamORAssem requires that we derive if in different assemblies.
 180                         if (!TypeManager.IsNestedFamilyAccessible (invocation_type, mi.DeclaringType))
 181                                 return false;
 182
 183                         if (!TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType))
 184                                 must_do_cs1540_check = true;
 185
 186                         return true;
 187                 }
 188
 189                 /// <summary>
 190                 ///   Performs semantic analysis on the Expression
 191                 /// </summary>
 192                 ///
 193                 /// <remarks>
 194                 ///   The Resolve method is invoked to perform the semantic analysis
 195                 ///   on the node.
 196                 ///
 197                 ///   The return value is an expression (it can be the
 198                 ///   same expression in some cases) or a new
 199                 ///   expression that better represents this node.
 200                 ///
 201                 ///   For example, optimizations of Unary (LiteralInt)
 202                 ///   would return a new LiteralInt with a negated
 203                 ///   value.
 204                 ///
 205                 ///   If there is an error during semantic analysis,
 206                 ///   then an error should be reported (using Report)
 207                 ///   and a null value should be returned.
 208                 ///
 209                 ///   There are two side effects expected from calling
 210                 ///   Resolve(): the the field variable "eclass" should
 211                 ///   be set to any value of the enumeration
 212                 ///   `ExprClass' and the type variable should be set
 213                 ///   to a valid type (this is the type of the
 214                 ///   expression).
 215                 /// </remarks>
 216                 public abstract Expression DoResolve (EmitContext ec);
 217
 218                 public virtual Expression DoResolveLValue (EmitContext ec, Expression right_side)
 219                 {
 220                         return null;
 221                 }
 222
 223                 //
 224                 // This is used if the expression should be resolved as a type or namespace name.
 225                 // the default implementation fails.
 226                 //
 227                 public virtual FullNamedExpression ResolveAsTypeStep (IResolveContext ec,  bool silent)
 228                 {
 229                         return null;
 230                 }
 231
 232                 //
 233                 // This is used to resolve the expression as a type, a null
 234                 // value will be returned if the expression is not a type
 235                 // reference
 236                 //
 237                 public virtual TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
 238                 {
 239                         TypeExpr te = ResolveAsBaseTerminal (ec, silent);
 240                         if (te == null)
 241                                 return null;
 242
 243                         ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (te.Type);
 244                         if (obsolete_attr != null && !ec.IsInObsoleteScope) {
 245                                 AttributeTester.Report_ObsoleteMessage (obsolete_attr, GetSignatureForError (), Location);
 246                         }
 247                         return te;
 248                 }
 249
 250                 public TypeExpr ResolveAsBaseTerminal (IResolveContext ec, bool silent)
 251                 {
 252                         int errors = Report.Errors;
 253
 254                         FullNamedExpression fne = ResolveAsTypeStep (ec, silent);
 255
 256                         if (fne == null){
 257                                 if (!silent && errors == Report.Errors)
 258                                         Report.Error (118, loc, "Expecting a type.");
 259                                 return null;
 260                         }
 261
 262                         if (fne.eclass != ExprClass.Type) {
 263                                 if (!silent && errors == Report.Errors)
 264                                         fne.Error_UnexpectedKind (null, "type", loc);
 265                                 return null;
 266                         }
 267
 268                         TypeExpr te = fne as TypeExpr;
 269
 270                         if (!te.CheckAccessLevel (ec.DeclContainer)) {
 271                                 ErrorIsInaccesible (loc, TypeManager.CSharpName (te.Type));
 272                                 return null;
 273                         }
 274
 275                         // Constrains don't need to be checked for overrides
 276                         GenericMethod gm = ec.DeclContainer as GenericMethod;
 277                         if (gm != null && (gm.ModFlags & Modifiers.OVERRIDE) != 0) {
 278                                 te.loc = loc;
 279                                 return te;
 280                         }
 281
 282                         ConstructedType ct = te as ConstructedType;
 283                         if ((ct != null) && !ct.CheckConstraints (ec))
 284                                 return null;
 285
 286                         te.loc = loc;
 287                         return te;
 288                 }
 289
 290                 public static void ErrorIsInaccesible (Location loc, string name)
 291                 {
 292                         Report.Error (122, loc, "`{0}' is inaccessible due to its protection level", name);
 293                 }
 294
 295                 protected static void Error_CannotAccessProtected (Location loc, MemberInfo m, Type qualifier, Type container)
 296                 {
 297                         Report.Error (1540, loc, "Cannot access protected member `{0}' via a qualifier of type `{1}';"
 298                                 + " the qualifier must be of type `{2}' (or derived from it)",
 299                                 TypeManager.GetFullNameSignature (m),
 300                                 TypeManager.CSharpName (qualifier),
 301                                 TypeManager.CSharpName (container));
 302
 303                 }
 304
 305                 public virtual void Error_ValueCannotBeConverted (Location loc, Type target, bool expl)
 306                 {
 307                         if (Type.Name == target.Name){
 308                                 Report.ExtraInformation (loc,
 309                                         String.Format (
 310                                         "The type {0} has two conflicting definitions, one comes from {1} and the other from {2}",
 311                                         Type.Name, Type.Assembly.FullName, target.Assembly.FullName));
 312
 313                         }
 314
 315                         if (expl) {
 316                                 Report.Error (30, loc, "Cannot convert type `{0}' to `{1}'",
 317                                         GetSignatureForError (), TypeManager.CSharpName (target));
 318                                 return;
 319                         }
 320
 321                         Expression e = (this is EnumConstant) ? ((EnumConstant)this).Child : this;
 322                         bool b = Convert.ExplicitNumericConversion (e, target) != null;
 323
 324                         if (b || Convert.ExplicitReferenceConversionExists (Type, target) || Convert.ExplicitUnsafe (e, target) != null) {
 325                                 Report.Error (266, loc, "Cannot implicitly convert type `{0}' to `{1}'. An explicit conversion exists (are you missing a cast?)",
 326                                         TypeManager.CSharpName (Type), TypeManager.CSharpName (target));
 327                                 return;
 328                         }
 329
 330                         if (Type != TypeManager.string_type && this is Constant && !(this is NullCast)) {
 331                                 Report.Error (31, loc, "Constant value `{0}' cannot be converted to a `{1}'",
 332                                         GetSignatureForError (), TypeManager.CSharpName (target));
 333                                 return;
 334                         }
 335
 336                         Report.Error (29, loc, "Cannot implicitly convert type {0} to `{1}'",
 337                                 Type == TypeManager.anonymous_method_type ?
 338                                 "anonymous method" : "`" + GetSignatureForError () + "'",
 339                                 TypeManager.CSharpName (target));
 340                 }
 341
 342                 protected static void Error_TypeDoesNotContainDefinition (Location loc, Type type, string name)
 343                 {
 344                         Report.Error (117, loc, "`{0}' does not contain a definition for `{1}'",
 345                                 TypeManager.CSharpName (type), name);
 346                 }
 347
 348                 ResolveFlags ExprClassToResolveFlags
 349                 {
 350                         get {
 351                                 switch (eclass) {
 352                                         case ExprClass.Type:
 353                                         case ExprClass.Namespace:
 354                                                 return ResolveFlags.Type;
 355
 356                                         case ExprClass.MethodGroup:
 357                                                 return ResolveFlags.MethodGroup;
 358
 359                                         case ExprClass.Value:
 360                                         case ExprClass.Variable:
 361                                         case ExprClass.PropertyAccess:
 362                                         case ExprClass.EventAccess:
 363                                         case ExprClass.IndexerAccess:
 364                                                 return ResolveFlags.VariableOrValue;
 365
 366                                         default:
 367                                                 throw new Exception ("Expression " + GetType () +
 368                                                         " ExprClass is Invalid after resolve");
 369                                 }
 370                         }
 371                 }
 372
 373                 /// <summary>
 374                 ///   Resolves an expression and performs semantic analysis on it.
 375                 /// </summary>
 376                 ///
 377                 /// <remarks>
 378                 ///   Currently Resolve wraps DoResolve to perform sanity
 379                 ///   checking and assertion checking on what we expect from Resolve.
 380                 /// </remarks>
 381                 public Expression Resolve (EmitContext ec, ResolveFlags flags)
 382                 {
 383                         if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
 384                                 return ResolveAsTypeStep (ec, false);
 385
 386                         bool old_do_flow_analysis = ec.DoFlowAnalysis;
 387                         bool old_omit_struct_analysis = ec.OmitStructFlowAnalysis;
 388                         if ((flags & ResolveFlags.DisableFlowAnalysis) != 0)
 389                                 ec.DoFlowAnalysis = false;
 390                         if ((flags & ResolveFlags.DisableStructFlowAnalysis) != 0)
 391                                 ec.OmitStructFlowAnalysis = true;
 392
 393                         Expression e;
 394                         if (this is SimpleName) {
 395                                 bool intermediate = (flags & ResolveFlags.Intermediate) == ResolveFlags.Intermediate;
 396                                 e = ((SimpleName) this).DoResolve (ec, intermediate);
 397                         }
 398                         else
 399                                 e = DoResolve (ec);
 400
 401                         ec.DoFlowAnalysis = old_do_flow_analysis;
 402                         ec.OmitStructFlowAnalysis = old_omit_struct_analysis;
 403
 404                         if (e == null)
 405                                 return null;
 406
 407                         if ((flags & e.ExprClassToResolveFlags) == 0) {
 408                                 e.Error_UnexpectedKind (flags, loc);
 409                                 return null;
 410                         }
 411
 412                         if (e.type == null && !(e is Namespace)) {
 413                                 throw new Exception (
 414                                         "Expression " + e.GetType () +
 415                                         " did not set its type after Resolve\n" +
 416                                         "called from: " + this.GetType ());
 417                         }
 418
 419                         return e;
 420                 }
 421
 422                 /// <summary>
 423                 ///   Resolves an expression and performs semantic analysis on it.
 424                 /// </summary>
 425                 public Expression Resolve (EmitContext ec)
 426                 {
 427                         Expression e = Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
 428
 429                         if (e != null && e.eclass == ExprClass.MethodGroup && RootContext.Version == LanguageVersion.ISO_1) {
 430                                 ((MethodGroupExpr) e).ReportUsageError ();
 431                                 return null;
 432                         }
 433                         return e;
 434                 }
 435
 436                 public Constant ResolveAsConstant (EmitContext ec, MemberCore mc)
 437                 {
 438                         Expression e = Resolve (ec);
 439                         if (e == null)
 440                                 return null;
 441
 442                         Constant c = e as Constant;
 443                         if (c != null)
 444                                 return c;
 445
 446                         Const.Error_ExpressionMustBeConstant (loc, mc.GetSignatureForError ());
 447                         return null;
 448                 }
 449
 450                 /// <summary>
 451                 ///   Resolves an expression for LValue assignment
 452                 /// </summary>
 453                 ///
 454                 /// <remarks>
 455                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 456                 ///   checking and assertion checking on what we expect from Resolve
 457                 /// </remarks>
 458                 public Expression ResolveLValue (EmitContext ec, Expression right_side, Location loc)
 459                 {
 460                         int errors = Report.Errors;
 461                         Expression e = DoResolveLValue (ec, right_side);
 462
 463                         if (e == null) {
 464                                 if (errors == Report.Errors)
 465                                         Report.Error (131, loc, "The left-hand side of an assignment or mutating operation must be a variable, property or indexer");
 466                                 return null;
 467                         }
 468
 469                         if (e != null){
 470                                 if (e.eclass == ExprClass.Invalid)
 471                                         throw new Exception ("Expression " + e +
 472                                                              " ExprClass is Invalid after resolve");
 473
 474                                 if (e.eclass == ExprClass.MethodGroup) {
 475                                         ((MethodGroupExpr) e).ReportUsageError ();
 476                                         return null;
 477                                 }
 478
 479                                 if ((e.type == null) && !(e is ConstructedType))
 480                                         throw new Exception ("Expression " + e +
 481                                                              " did not set its type after Resolve");
 482                         }
 483
 484                         return e;
 485                 }
 486
 487                 /// <summary>
 488                 ///   Emits the code for the expression
 489                 /// </summary>
 490                 ///
 491                 /// <remarks>
 492                 ///   The Emit method is invoked to generate the code
 493                 ///   for the expression.
 494                 /// </remarks>
 495                 public abstract void Emit (EmitContext ec);
 496
 497                 public virtual void EmitBranchable (EmitContext ec, Label target, bool onTrue)
 498                 {
 499                         Emit (ec);
 500                         ec.ig.Emit (onTrue ? OpCodes.Brtrue : OpCodes.Brfalse, target);
 501                 }
 502
 503                 /// <summary>
 504                 ///   Protected constructor.  Only derivate types should
 505                 ///   be able to be created
 506                 /// </summary>
 507
 508                 protected Expression ()
 509                 {
 510                         eclass = ExprClass.Invalid;
 511                         type = null;
 512                 }
 513
 514                 /// <summary>
 515                 ///   Returns a literalized version of a literal FieldInfo
 516                 /// </summary>
 517                 ///
 518                 /// <remarks>
 519                 ///   The possible return values are:
 520                 ///      IntConstant, UIntConstant
 521                 ///      LongLiteral, ULongConstant
 522                 ///      FloatConstant, DoubleConstant
 523                 ///      StringConstant
 524                 ///
 525                 ///   The value returned is already resolved.
 526                 /// </remarks>
 527                 public static Constant Constantify (object v, Type t)
 528                 {
 529                         if (t == TypeManager.int32_type)
 530                                 return new IntConstant ((int) v, Location.Null);
 531                         else if (t == TypeManager.uint32_type)
 532                                 return new UIntConstant ((uint) v, Location.Null);
 533                         else if (t == TypeManager.int64_type)
 534                                 return new LongConstant ((long) v, Location.Null);
 535                         else if (t == TypeManager.uint64_type)
 536                                 return new ULongConstant ((ulong) v, Location.Null);
 537                         else if (t == TypeManager.float_type)
 538                                 return new FloatConstant ((float) v, Location.Null);
 539                         else if (t == TypeManager.double_type)
 540                                 return new DoubleConstant ((double) v, Location.Null);
 541                         else if (t == TypeManager.string_type)
 542                                 return new StringConstant ((string) v, Location.Null);
 543                         else if (t == TypeManager.short_type)
 544                                 return new ShortConstant ((short)v, Location.Null);
 545                         else if (t == TypeManager.ushort_type)
 546                                 return new UShortConstant ((ushort)v, Location.Null);
 547                         else if (t == TypeManager.sbyte_type)
 548                                 return new SByteConstant ((sbyte)v, Location.Null);
 549                         else if (t == TypeManager.byte_type)
 550                                 return new ByteConstant ((byte)v, Location.Null);
 551                         else if (t == TypeManager.char_type)
 552                                 return new CharConstant ((char)v, Location.Null);
 553                         else if (t == TypeManager.bool_type)
 554                                 return new BoolConstant ((bool) v, Location.Null);
 555                         else if (t == TypeManager.decimal_type)
 556                                 return new DecimalConstant ((decimal) v, Location.Null);
 557                         else if (TypeManager.IsEnumType (t)){
 558                                 Type real_type = TypeManager.TypeToCoreType (v.GetType ());
 559                                 if (real_type == t)
 560                                         real_type = System.Enum.GetUnderlyingType (real_type);
 561
 562                                 Constant e = Constantify (v, real_type);
 563
 564                                 return new EnumConstant (e, t);
 565                         } else if (v == null && !TypeManager.IsValueType (t))
 566                                 return new NullLiteral (Location.Null);
 567                         else
 568                                 throw new Exception ("Unknown type for constant (" + t +
 569                                                      "), details: " + v);
 570                 }
 571
 572                 /// <summary>
 573                 ///   Returns a fully formed expression after a MemberLookup
 574                 /// </summary>
 575                 ///
 576                 public static Expression ExprClassFromMemberInfo (Type containerType, MemberInfo mi, Location loc)
 577                 {
 578                         if (mi is EventInfo)
 579                                 return new EventExpr ((EventInfo) mi, loc);
 580                         else if (mi is FieldInfo)
 581                                 return new FieldExpr ((FieldInfo) mi, loc);
 582                         else if (mi is PropertyInfo)
 583                                 return new PropertyExpr (containerType, (PropertyInfo) mi, loc);
 584                         else if (mi is Type){
 585                                 return new TypeExpression ((System.Type) mi, loc);
 586                         }
 587
 588                         return null;
 589                 }
 590
 591                 protected static ArrayList almostMatchedMembers = new ArrayList (4);
 592
 593                 //
 594                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 595                 //
 596                 // This code could use some optimizations, but we need to do some
 597                 // measurements.  For example, we could use a delegate to `flag' when
 598                 // something can not any longer be a method-group (because it is something
 599                 // else).
 600                 //
 601                 // Return values:
 602                 //     If the return value is an Array, then it is an array of
 603                 //     MethodBases
 604                 //
 605                 //     If the return value is an MemberInfo, it is anything, but a Method
 606                 //
 607                 //     null on error.
 608                 //
 609                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 610                 // the arguments here and have MemberLookup return only the methods that
 611                 // match the argument count/type, unlike we are doing now (we delay this
 612                 // decision).
 613                 //
 614                 // This is so we can catch correctly attempts to invoke instance methods
 615                 // from a static body (scan for error 120 in ResolveSimpleName).
 616                 //
 617                 //
 618                 // FIXME: Potential optimization, have a static ArrayList
 619                 //
 620
 621                 public static Expression MemberLookup (Type container_type, Type queried_type, string name,
 622                                                        MemberTypes mt, BindingFlags bf, Location loc)
 623                 {
 624                         return MemberLookup (container_type, null, queried_type, name, mt, bf, loc);
 625                 }
 626
 627                 //
 628                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 629                 // `qualifier_type' or null to lookup members in the current class.
 630                 //
 631
 632                 public static Expression MemberLookup (Type container_type,
 633                                                        Type qualifier_type, Type queried_type,
 634                                                        string name, MemberTypes mt,
 635                                                        BindingFlags bf, Location loc)
 636                 {
 637                         almostMatchedMembers.Clear ();
 638
 639                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 640                                                                      queried_type, mt, bf, name, almostMatchedMembers);
 641
 642                         if (mi == null)
 643                                 return null;
 644
 645                         int count = mi.Length;
 646
 647                         if (mi [0] is MethodBase)
 648                                 return new MethodGroupExpr (mi, loc);
 649
 650                         if (count > 1)
 651                                 return null;
 652
 653                         return ExprClassFromMemberInfo (container_type, mi [0], loc);
 654                 }
 655
 656                 public const MemberTypes AllMemberTypes =
 657                         MemberTypes.Constructor |
 658                         MemberTypes.Event       |
 659                         MemberTypes.Field       |
 660                         MemberTypes.Method      |
 661                         MemberTypes.NestedType  |
 662                         MemberTypes.Property;
 663
 664                 public const BindingFlags AllBindingFlags =
 665                         BindingFlags.Public |
 666                         BindingFlags.Static |
 667                         BindingFlags.Instance;
 668
 669                 public static Expression MemberLookup (Type container_type, Type queried_type,
 670                                                        string name, Location loc)
 671                 {
 672                         return MemberLookup (container_type, null, queried_type, name,
 673                                              AllMemberTypes, AllBindingFlags, loc);
 674                 }
 675
 676                 public static Expression MemberLookup (Type container_type, Type qualifier_type,
 677                                                        Type queried_type, string name, Location loc)
 678                 {
 679                         return MemberLookup (container_type, qualifier_type, queried_type,
 680                                              name, AllMemberTypes, AllBindingFlags, loc);
 681                 }
 682
 683                 public static Expression MethodLookup (EmitContext ec, Type queried_type,
 684                                                        string name, Location loc)
 685                 {
 686                         return MemberLookup (ec.ContainerType, null, queried_type, name,
 687                                              MemberTypes.Method, AllBindingFlags, loc);
 688                 }
 689
 690                 /// <summary>
 691                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 692                 ///   to find a final definition.  If the final definition is not found, we
 693                 ///   look for private members and display a useful debugging message if we
 694                 ///   find it.
 695                 /// </summary>
 696                 public static Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 697                                                             Type queried_type, string name, Location loc)
 698                 {
 699                         return MemberLookupFinal (ec, qualifier_type, queried_type, name,
 700                                                   AllMemberTypes, AllBindingFlags, loc);
 701                 }
 702
 703                 public static Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 704                                                             Type queried_type, string name,
 705                                                             MemberTypes mt, BindingFlags bf,
 706                                                             Location loc)
 707                 {
 708                         Expression e;
 709
 710                         int errors = Report.Errors;
 711
 712                         e = MemberLookup (ec.ContainerType, qualifier_type, queried_type, name, mt, bf, loc);
 713
 714                         if (e == null && errors == Report.Errors)
 715                                 // No errors were reported by MemberLookup, but there was an error.
 716                                 MemberLookupFailed (ec.ContainerType, qualifier_type, queried_type, name, null, true, loc);
 717
 718                         return e;
 719                 }
 720
 721                 public static void MemberLookupFailed (Type container_type, Type qualifier_type,
 722                                                        Type queried_type, string name,
 723                                                        string class_name, bool complain_if_none_found,
 724                                                        Location loc)
 725                 {
 726                         if (almostMatchedMembers.Count != 0) {
 727                                 for (int i = 0; i < almostMatchedMembers.Count; ++i) {
 728                                         MemberInfo m = (MemberInfo) almostMatchedMembers [i];
 729                                         for (int j = 0; j < i; ++j) {
 730                                                 if (m == almostMatchedMembers [j]) {
 731                                                         m = null;
 732                                                         break;
 733                                                 }
 734                                         }
 735                                         if (m == null)
 736                                                 continue;
 737
 738                                         Type declaring_type = m.DeclaringType;
 739
 740                                         Report.SymbolRelatedToPreviousError (m);
 741                                         if (qualifier_type == null) {
 742                                                 Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
 743                                                               TypeManager.CSharpName (m.DeclaringType),
 744                                                               TypeManager.CSharpName (container_type));
 745
 746                                         } else if (qualifier_type != container_type &&
 747                                                    TypeManager.IsNestedFamilyAccessible (container_type, declaring_type)) {
 748                                                 // Although a derived class can access protected members of
 749                                                 // its base class it cannot do so through an instance of the
 750                                                 // base class (CS1540).  If the qualifier_type is a base of the
 751                                                 // ec.ContainerType and the lookup succeeds with the latter one,
 752                                                 // then we are in this situation.
 753                                                 Error_CannotAccessProtected (loc, m, qualifier_type, container_type);
 754                                         } else {
 755                                                 ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (m));
 756                                         }
 757                                 }
 758                                 almostMatchedMembers.Clear ();
 759                                 return;
 760                         }
 761
 762                         MemberInfo[] lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 763                                                                         AllMemberTypes, AllBindingFlags |
 764                                                                         BindingFlags.NonPublic, name, null);
 765
 766                         if (lookup == null) {
 767                                 if (!complain_if_none_found)
 768                                         return;
 769
 770                                 if (class_name != null)
 771                                         Report.Error (103, loc, "The name `{0}' does not exist in the context of `{1}'",
 772                                                 name, class_name);
 773                                 else
 774                                         Error_TypeDoesNotContainDefinition (loc, queried_type, name);
 775                                 return;
 776                         }
 777
 778                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 779                                                       AllMemberTypes, AllBindingFlags |
 780                                                       BindingFlags.NonPublic, name, null) == null) {
 781                                 if ((lookup.Length == 1) && (lookup [0] is Type)) {
 782                                         Type t = (Type) lookup [0];
 783
 784                                         Report.Error (305, loc,
 785                                                       "Using the generic type `{0}' " +
 786                                                       "requires {1} type arguments",
 787                                                       TypeManager.CSharpName (t),
 788                                                       TypeManager.GetNumberOfTypeArguments (t).ToString ());
 789                                         return;
 790                                 }
 791                         }
 792
 793                         MemberList ml = TypeManager.FindMembers (queried_type, MemberTypes.Constructor,
 794                                                                  BindingFlags.Static | BindingFlags.Instance | BindingFlags.Public | BindingFlags.DeclaredOnly, null, null);
 795                         if (name == ".ctor" && ml.Count == 0)
 796                         {
 797                                 Report.Error (143, loc, "The type `{0}' has no constructors defined", TypeManager.CSharpName (queried_type));
 798                                 return;
 799                         }
 800
 801                         ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (lookup [0]));
 802                 }
 803
 804                 /// <summary>
 805                 ///   Returns an expression that can be used to invoke operator true
 806                 ///   on the expression if it exists.
 807                 /// </summary>
 808                 static public Expression GetOperatorTrue (EmitContext ec, Expression e, Location loc)
 809                 {
 810                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 811                 }
 812
 813                 /// <summary>
 814                 ///   Returns an expression that can be used to invoke operator false
 815                 ///   on the expression if it exists.
 816                 /// </summary>
 817                 static public Expression GetOperatorFalse (EmitContext ec, Expression e, Location loc)
 818                 {
 819                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 820                 }
 821
 822                 static Expression GetOperatorTrueOrFalse (EmitContext ec, Expression e, bool is_true, Location loc)
 823                 {
 824                         MethodBase method;
 825                         Expression operator_group;
 826
 827                         if (TypeManager.IsNullableType (e.Type))
 828                                 return new Nullable.OperatorTrueOrFalse (e, is_true, loc).Resolve (ec);
 829
 830                         operator_group = MethodLookup (ec, e.Type, is_true ? "op_True" : "op_False", loc);
 831                         if (operator_group == null)
 832                                 return null;
 833
 834                         ArrayList arguments = new ArrayList ();
 835                         arguments.Add (new Argument (e, Argument.AType.Expression));
 836                         method = Invocation.OverloadResolve (
 837                                 ec, (MethodGroupExpr) operator_group, arguments, false, loc);
 838
 839                         if (method == null)
 840                                 return null;
 841
 842                         return new StaticCallExpr ((MethodInfo) method, arguments, loc);
 843                 }
 844
 845                 /// <summary>
 846                 ///   Resolves the expression `e' into a boolean expression: either through
 847                 ///   an implicit conversion, or through an `operator true' invocation
 848                 /// </summary>
 849                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 850                 {
 851                         e = e.Resolve (ec);
 852                         if (e == null)
 853                                 return null;
 854
 855                         if (e.Type == TypeManager.bool_type)
 856                                 return e;
 857
 858                         Expression converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, Location.Null);
 859
 860                         if (converted != null)
 861                                 return converted;
 862
 863                         //
 864                         // If no implicit conversion to bool exists, try using `operator true'
 865                         //
 866                         converted = Expression.GetOperatorTrue (ec, e, loc);
 867                         if (converted == null){
 868                                 e.Error_ValueCannotBeConverted (loc, TypeManager.bool_type, false);
 869                                 return null;
 870                         }
 871                         return converted;
 872                 }
 873
 874                 public virtual string ExprClassName
 875                 {
 876                         get {
 877                                 switch (eclass){
 878                                         case ExprClass.Invalid:
 879                                                 return "Invalid";
 880                                         case ExprClass.Value:
 881                                                 return "value";
 882                                         case ExprClass.Variable:
 883                                                 return "variable";
 884                                         case ExprClass.Namespace:
 885                                                 return "namespace";
 886                                         case ExprClass.Type:
 887                                                 return "type";
 888                                         case ExprClass.MethodGroup:
 889                                                 return "method group";
 890                                         case ExprClass.PropertyAccess:
 891                                                 return "property access";
 892                                         case ExprClass.EventAccess:
 893                                                 return "event access";
 894                                         case ExprClass.IndexerAccess:
 895                                                 return "indexer access";
 896                                         case ExprClass.Nothing:
 897                                                 return "null";
 898                                 }
 899                                 throw new Exception ("Should not happen");
 900                         }
 901                 }
 902
 903                 /// <summary>
 904                 ///   Reports that we were expecting `expr' to be of class `expected'
 905                 /// </summary>
 906                 public void Error_UnexpectedKind (DeclSpace ds, string expected, Location loc)
 907                 {
 908                         Error_UnexpectedKind (ds, expected, ExprClassName, loc);
 909                 }
 910
 911                 public void Error_UnexpectedKind (DeclSpace ds, string expected, string was, Location loc)
 912                 {
 913                         string name = GetSignatureForError ();
 914                         if (ds != null)
 915                                 name = ds.GetSignatureForError () + '.' + name;
 916
 917                         Report.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
 918                               name, was, expected);
 919                 }
 920
 921                 public void Error_UnexpectedKind (ResolveFlags flags, Location loc)
 922                 {
 923                         string [] valid = new string [4];
 924                         int count = 0;
 925
 926                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
 927                                 valid [count++] = "variable";
 928                                 valid [count++] = "value";
 929                         }
 930
 931                         if ((flags & ResolveFlags.Type) != 0)
 932                                 valid [count++] = "type";
 933
 934                         if ((flags & ResolveFlags.MethodGroup) != 0)
 935                                 valid [count++] = "method group";
 936
 937                         if (count == 0)
 938                                 valid [count++] = "unknown";
 939
 940                         StringBuilder sb = new StringBuilder (valid [0]);
 941                         for (int i = 1; i < count - 1; i++) {
 942                                 sb.Append ("', `");
 943                                 sb.Append (valid [i]);
 944                         }
 945                         if (count > 1) {
 946                                 sb.Append ("' or `");
 947                                 sb.Append (valid [count - 1]);
 948                         }
 949
 950                         Report.Error (119, loc,
 951                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
 952                 }
 953
 954                 public static void UnsafeError (Location loc)
 955                 {
 956                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
 957                 }
 958
 959                 //
 960                 // Load the object from the pointer.
 961                 //
 962                 public static void LoadFromPtr (ILGenerator ig, Type t)
 963                 {
 964                         if (t == TypeManager.int32_type)
 965                                 ig.Emit (OpCodes.Ldind_I4);
 966                         else if (t == TypeManager.uint32_type)
 967                                 ig.Emit (OpCodes.Ldind_U4);
 968                         else if (t == TypeManager.short_type)
 969                                 ig.Emit (OpCodes.Ldind_I2);
 970                         else if (t == TypeManager.ushort_type)
 971                                 ig.Emit (OpCodes.Ldind_U2);
 972                         else if (t == TypeManager.char_type)
 973                                 ig.Emit (OpCodes.Ldind_U2);
 974                         else if (t == TypeManager.byte_type)
 975                                 ig.Emit (OpCodes.Ldind_U1);
 976                         else if (t == TypeManager.sbyte_type)
 977                                 ig.Emit (OpCodes.Ldind_I1);
 978                         else if (t == TypeManager.uint64_type)
 979                                 ig.Emit (OpCodes.Ldind_I8);
 980                         else if (t == TypeManager.int64_type)
 981                                 ig.Emit (OpCodes.Ldind_I8);
 982                         else if (t == TypeManager.float_type)
 983                                 ig.Emit (OpCodes.Ldind_R4);
 984                         else if (t == TypeManager.double_type)
 985                                 ig.Emit (OpCodes.Ldind_R8);
 986                         else if (t == TypeManager.bool_type)
 987                                 ig.Emit (OpCodes.Ldind_I1);
 988                         else if (t == TypeManager.intptr_type)
 989                                 ig.Emit (OpCodes.Ldind_I);
 990                         else if (TypeManager.IsEnumType (t)) {
 991                                 if (t == TypeManager.enum_type)
 992                                         ig.Emit (OpCodes.Ldind_Ref);
 993                                 else
 994                                         LoadFromPtr (ig, TypeManager.EnumToUnderlying (t));
 995                         } else if (t.IsValueType || t.IsGenericParameter)
 996                                 ig.Emit (OpCodes.Ldobj, t);
 997                         else if (t.IsPointer)
 998                                 ig.Emit (OpCodes.Ldind_I);
 999                         else
1000                                 ig.Emit (OpCodes.Ldind_Ref);
1001                 }
1002
1003                 //
1004                 // The stack contains the pointer and the value of type `type'
1005                 //
1006                 public static void StoreFromPtr (ILGenerator ig, Type type)
1007                 {
1008                         if (TypeManager.IsEnumType (type))
1009                                 type = TypeManager.EnumToUnderlying (type);
1010                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1011                                 ig.Emit (OpCodes.Stind_I4);
1012                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1013                                 ig.Emit (OpCodes.Stind_I8);
1014                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1015                                  type == TypeManager.ushort_type)
1016                                 ig.Emit (OpCodes.Stind_I2);
1017                         else if (type == TypeManager.float_type)
1018                                 ig.Emit (OpCodes.Stind_R4);
1019                         else if (type == TypeManager.double_type)
1020                                 ig.Emit (OpCodes.Stind_R8);
1021                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1022                                  type == TypeManager.bool_type)
1023                                 ig.Emit (OpCodes.Stind_I1);
1024                         else if (type == TypeManager.intptr_type)
1025                                 ig.Emit (OpCodes.Stind_I);
1026                         else if (type.IsValueType || type.IsGenericParameter)
1027                                 ig.Emit (OpCodes.Stobj, type);
1028                         else
1029                                 ig.Emit (OpCodes.Stind_Ref);
1030                 }
1031
1032                 //
1033                 // Returns the size of type `t' if known, otherwise, 0
1034                 //
1035                 public static int GetTypeSize (Type t)
1036                 {
1037                         t = TypeManager.TypeToCoreType (t);
1038                         if (t == TypeManager.int32_type ||
1039                             t == TypeManager.uint32_type ||
1040                             t == TypeManager.float_type)
1041                                 return 4;
1042                         else if (t == TypeManager.int64_type ||
1043                                  t == TypeManager.uint64_type ||
1044                                  t == TypeManager.double_type)
1045                                 return 8;
1046                         else if (t == TypeManager.byte_type ||
1047                                  t == TypeManager.sbyte_type ||
1048                                  t == TypeManager.bool_type)
1049                                 return 1;
1050                         else if (t == TypeManager.short_type ||
1051                                  t == TypeManager.char_type ||
1052                                  t == TypeManager.ushort_type)
1053                                 return 2;
1054                         else if (t == TypeManager.decimal_type)
1055                                 return 16;
1056                         else
1057                                 return 0;
1058                 }
1059
1060                 public static void Error_NegativeArrayIndex (Location loc)
1061                 {
1062                         Report.Error (248, loc, "Cannot create an array with a negative size");
1063                 }
1064
1065                 protected void Error_CannotCallAbstractBase (string name)
1066                 {
1067                         Report.Error (205, loc, "Cannot call an abstract base member `{0}'", name);
1068                 }
1069
1070                 //
1071                 // Converts `source' to an int, uint, long or ulong.
1072                 //
1073                 public Expression ExpressionToArrayArgument (EmitContext ec, Expression source, Location loc)
1074                 {
1075                         Expression target;
1076
1077                         bool old_checked = ec.CheckState;
1078                         ec.CheckState = true;
1079
1080                         target = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, loc);
1081                         if (target == null){
1082                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, loc);
1083                                 if (target == null){
1084                                         target = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, loc);
1085                                         if (target == null){
1086                                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, loc);
1087                                                 if (target == null)
1088                                                         source.Error_ValueCannotBeConverted (loc, TypeManager.int32_type, false);
1089                                         }
1090                                 }
1091                         }
1092                         ec.CheckState = old_checked;
1093
1094                         //
1095                         // Only positive constants are allowed at compile time
1096                         //
1097                         if (target is Constant){
1098                                 if (target is IntConstant){
1099                                         if (((IntConstant) target).Value < 0){
1100                                                 Error_NegativeArrayIndex (loc);
1101                                                 return null;
1102                                         }
1103                                 }
1104
1105                                 if (target is LongConstant){
1106                                         if (((LongConstant) target).Value < 0){
1107                                                 Error_NegativeArrayIndex (loc);
1108                                                 return null;
1109                                         }
1110                                 }
1111
1112                         }
1113
1114                         return target;
1115                 }
1116
1117         }
1118
1119         /// <summary>
1120         ///   This is just a base class for expressions that can
1121         ///   appear on statements (invocations, object creation,
1122         ///   assignments, post/pre increment and decrement).  The idea
1123         ///   being that they would support an extra Emition interface that
1124         ///   does not leave a result on the stack.
1125         /// </summary>
1126         public abstract class ExpressionStatement : Expression {
1127
1128                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1129                 {
1130                         Expression e = Resolve (ec);
1131                         if (e == null)
1132                                 return null;
1133
1134                         ExpressionStatement es = e as ExpressionStatement;
1135                         if (es == null)
1136                                 Error (201, "Only assignment, call, increment, decrement and new object " +
1137                                        "expressions can be used as a statement");
1138
1139                         return es;
1140                 }
1141
1142                 /// <summary>
1143                 ///   Requests the expression to be emitted in a `statement'
1144                 ///   context.  This means that no new value is left on the
1145                 ///   stack after invoking this method (constrasted with
1146                 ///   Emit that will always leave a value on the stack).
1147                 /// </summary>
1148                 public abstract void EmitStatement (EmitContext ec);
1149         }
1150
1151         /// <summary>
1152         ///   This kind of cast is used to encapsulate the child
1153         ///   whose type is child.Type into an expression that is
1154         ///   reported to return "return_type".  This is used to encapsulate
1155         ///   expressions which have compatible types, but need to be dealt
1156         ///   at higher levels with.
1157         ///
1158         ///   For example, a "byte" expression could be encapsulated in one
1159         ///   of these as an "unsigned int".  The type for the expression
1160         ///   would be "unsigned int".
1161         ///
1162         /// </summary>
1163         public class EmptyCast : Expression {
1164                 protected readonly Expression child;
1165
1166                 public EmptyCast (Expression child, Type return_type)
1167                 {
1168                         eclass = child.eclass;
1169                         loc = child.Location;
1170                         type = return_type;
1171                         this.child = child;
1172                 }
1173
1174                 public override Expression DoResolve (EmitContext ec)
1175                 {
1176                         // This should never be invoked, we are born in fully
1177                         // initialized state.
1178
1179                         return this;
1180                 }
1181
1182                 public override void Emit (EmitContext ec)
1183                 {
1184                         child.Emit (ec);
1185                 }
1186
1187                 public override bool GetAttributableValue (Type valueType, out object value)
1188                 {
1189                         return child.GetAttributableValue (valueType, out value);
1190                 }
1191
1192         }
1193         /// <summary>
1194         ///     This is a numeric cast to a Decimal
1195         /// </summary>
1196         public class CastToDecimal : EmptyCast {
1197
1198                 MethodInfo conversion_operator;
1199
1200                 public CastToDecimal (Expression child)
1201                         : this (child, false)
1202                 {
1203                 }
1204
1205                 public CastToDecimal (Expression child, bool find_explicit)
1206                         : base (child, TypeManager.decimal_type)
1207                 {
1208                         conversion_operator = GetConversionOperator (find_explicit);
1209
1210                         if (conversion_operator == null)
1211                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1212                 }
1213
1214                 // Returns the implicit operator that converts from
1215                 // 'child.Type' to System.Decimal.
1216                 MethodInfo GetConversionOperator (bool find_explicit)
1217                 {
1218                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1219
1220                         MemberInfo [] mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1221                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1222
1223                         foreach (MethodInfo oper in mi) {
1224                                 ParameterData pd = TypeManager.GetParameterData (oper);
1225
1226                                 if (pd.ParameterType (0) == child.Type && oper.ReturnType == type)
1227                                         return oper;
1228                         }
1229
1230                         return null;
1231                 }
1232                 public override void Emit (EmitContext ec)
1233                 {
1234                         ILGenerator ig = ec.ig;
1235                         child.Emit (ec);
1236
1237                         ig.Emit (OpCodes.Call, conversion_operator);
1238                 }
1239         }
1240
1241         /// <summary>
1242         ///     This is an explicit numeric cast from a Decimal
1243         /// </summary>
1244         public class CastFromDecimal : EmptyCast
1245         {
1246                 static IDictionary operators;
1247
1248                 public CastFromDecimal (Expression child, Type return_type)
1249                         : base (child, return_type)
1250                 {
1251                         if (child.Type != TypeManager.decimal_type)
1252                                 throw new InternalErrorException (
1253                                         "The expected type is Decimal, instead it is " + child.Type.FullName);
1254                 }
1255
1256                 // Returns the explicit operator that converts from an
1257                 // express of type System.Decimal to 'type'.
1258                 public Expression Resolve ()
1259                 {
1260                         if (operators == null) {
1261                                  MemberInfo[] all_oper = TypeManager.MemberLookup (TypeManager.decimal_type,
1262                                         TypeManager.decimal_type, TypeManager.decimal_type, MemberTypes.Method,
1263                                         BindingFlags.Static | BindingFlags.Public, "op_Explicit", null);
1264
1265                                 operators = new System.Collections.Specialized.HybridDictionary ();
1266                                 foreach (MethodInfo oper in all_oper) {
1267                                         ParameterData pd = TypeManager.GetParameterData (oper);
1268                                         if (pd.ParameterType (0) == TypeManager.decimal_type)
1269                                                 operators.Add (oper.ReturnType, oper);
1270                                 }
1271                         }
1272
1273                         return operators.Contains (type) ? this : null;
1274                 }
1275
1276                 public override void Emit (EmitContext ec)
1277                 {
1278                         ILGenerator ig = ec.ig;
1279                         child.Emit (ec);
1280
1281                         ig.Emit (OpCodes.Call, (MethodInfo)operators [type]);
1282                 }
1283         }
1284
1285         //
1286         // We need to special case this since an empty cast of
1287         // a NullLiteral is still a Constant
1288         //
1289         public class NullCast : Constant {
1290                 public Constant child;
1291
1292                 public NullCast (Constant child, Type return_type):
1293                         base (Location.Null)
1294                 {
1295                         eclass = child.eclass;
1296                         type = return_type;
1297                         this.child = child;
1298                 }
1299
1300                 override public string AsString ()
1301                 {
1302                         return "null";
1303                 }
1304
1305                 public override object GetValue ()
1306                 {
1307                         return null;
1308                 }
1309
1310                 public override Expression DoResolve (EmitContext ec)
1311                 {
1312                         // This should never be invoked, we are born in fully
1313                         // initialized state.
1314
1315                         return this;
1316                 }
1317
1318                 public override void Emit (EmitContext ec)
1319                 {
1320                         child.Emit (ec);
1321                 }
1322
1323                 public override Constant Increment ()
1324                 {
1325                         throw new NotSupportedException ();
1326                 }
1327
1328                 public override bool IsDefaultValue {
1329                         get {
1330                                 return true;
1331                         }
1332                 }
1333
1334                 public override bool IsNegative {
1335                         get {
1336                                 return false;
1337                         }
1338                 }
1339
1340                 public override Constant Reduce (bool inCheckedContext, Type target_type)
1341                 {
1342                         if (type == target_type)
1343                                 return child.Reduce (inCheckedContext, target_type);
1344
1345                         return null;
1346                 }
1347
1348         }
1349
1350
1351         /// <summary>
1352         ///  This class is used to wrap literals which belong inside Enums
1353         /// </summary>
1354         public class EnumConstant : Constant {
1355                 public Constant Child;
1356
1357                 public EnumConstant (Constant child, Type enum_type):
1358                         base (child.Location)
1359                 {
1360                         eclass = child.eclass;
1361                         this.Child = child;
1362                         type = enum_type;
1363                 }
1364
1365                 public override Expression DoResolve (EmitContext ec)
1366                 {
1367                         // This should never be invoked, we are born in fully
1368                         // initialized state.
1369
1370                         return this;
1371                 }
1372
1373                 public override void Emit (EmitContext ec)
1374                 {
1375                         Child.Emit (ec);
1376                 }
1377
1378                 public override bool GetAttributableValue (Type valueType, out object value)
1379                 {
1380                         value = GetTypedValue ();
1381                         return true;
1382                 }
1383
1384                 public override string GetSignatureForError()
1385                 {
1386                         return TypeManager.CSharpName (Type);
1387                 }
1388
1389                 public override object GetValue ()
1390                 {
1391                         return Child.GetValue ();
1392                 }
1393
1394                 public override object GetTypedValue ()
1395                 {
1396                         // FIXME: runtime is not ready to work with just emited enums
1397                         if (!RootContext.StdLib) {
1398                                 return Child.GetValue ();
1399                         }
1400
1401                         return System.Enum.ToObject (type, Child.GetValue ());
1402                 }
1403
1404                 public override string AsString ()
1405                 {
1406                         return Child.AsString ();
1407                 }
1408
1409                 public override DoubleConstant ConvertToDouble ()
1410                 {
1411                         return Child.ConvertToDouble ();
1412                 }
1413
1414                 public override FloatConstant ConvertToFloat ()
1415                 {
1416                         return Child.ConvertToFloat ();
1417                 }
1418
1419                 public override ULongConstant ConvertToULong ()
1420                 {
1421                         return Child.ConvertToULong ();
1422                 }
1423
1424                 public override LongConstant ConvertToLong ()
1425                 {
1426                         return Child.ConvertToLong ();
1427                 }
1428
1429                 public override UIntConstant ConvertToUInt ()
1430                 {
1431                         return Child.ConvertToUInt ();
1432                 }
1433
1434                 public override IntConstant ConvertToInt ()
1435                 {
1436                         return Child.ConvertToInt ();
1437                 }
1438
1439                 public override Constant Increment()
1440                 {
1441                         return new EnumConstant (Child.Increment (), type);
1442                 }
1443
1444                 public override bool IsDefaultValue {
1445                         get {
1446                                 return Child.IsDefaultValue;
1447                         }
1448                 }
1449
1450                 public override bool IsZeroInteger {
1451                         get { return Child.IsZeroInteger; }
1452                 }
1453
1454                 public override bool IsNegative {
1455                         get {
1456                                 return Child.IsNegative;
1457                         }
1458                 }
1459
1460                 public override Constant Reduce(bool inCheckedContext, Type target_type)
1461                 {
1462                         if (Child.Type == target_type)
1463                                 return Child;
1464
1465                         return Child.Reduce (inCheckedContext, target_type);
1466                 }
1467
1468                 public override Constant ToType (Type type, Location loc)
1469                 {
1470                         if (Type == type) {
1471                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1472                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1473                                         return this;
1474
1475                                 if (type.UnderlyingSystemType != Child.Type)
1476                                         Child = Child.ToType (type.UnderlyingSystemType, loc);
1477                                 return this;
1478                         }
1479
1480                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1481                                 Error_ValueCannotBeConverted (loc, type, false);
1482                                 return null;
1483                         }
1484
1485                         return Child.ToType (type, loc);
1486                 }
1487
1488         }
1489
1490         /// <summary>
1491         ///   This kind of cast is used to encapsulate Value Types in objects.
1492         ///
1493         ///   The effect of it is to box the value type emitted by the previous
1494         ///   operation.
1495         /// </summary>
1496         public class BoxedCast : EmptyCast {
1497
1498                 public BoxedCast (Expression expr, Type target_type)
1499                         : base (expr, target_type)
1500                 {
1501                         eclass = ExprClass.Value;
1502                 }
1503
1504                 public override Expression DoResolve (EmitContext ec)
1505                 {
1506                         // This should never be invoked, we are born in fully
1507                         // initialized state.
1508
1509                         return this;
1510                 }
1511
1512                 public override void Emit (EmitContext ec)
1513                 {
1514                         base.Emit (ec);
1515
1516                         ec.ig.Emit (OpCodes.Box, child.Type);
1517                 }
1518         }
1519
1520         public class UnboxCast : EmptyCast {
1521                 public UnboxCast (Expression expr, Type return_type)
1522                         : base (expr, return_type)
1523                 {
1524                 }
1525
1526                 public override Expression DoResolve (EmitContext ec)
1527                 {
1528                         // This should never be invoked, we are born in fully
1529                         // initialized state.
1530
1531                         return this;
1532                 }
1533
1534                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1535                 {
1536                         if (right_side == EmptyExpression.LValueMemberAccess)
1537                                 Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1538                         return base.DoResolveLValue (ec, right_side);
1539                 }
1540
1541                 public override void Emit (EmitContext ec)
1542                 {
1543                         Type t = type;
1544                         ILGenerator ig = ec.ig;
1545
1546                         base.Emit (ec);
1547                         if (t.IsGenericParameter)
1548                                 ig.Emit (OpCodes.Unbox_Any, t);
1549                         else {
1550                                 ig.Emit (OpCodes.Unbox, t);
1551
1552                                 LoadFromPtr (ig, t);
1553                         }
1554                 }
1555         }
1556
1557         /// <summary>
1558         ///   This is used to perform explicit numeric conversions.
1559         ///
1560         ///   Explicit numeric conversions might trigger exceptions in a checked
1561         ///   context, so they should generate the conv.ovf opcodes instead of
1562         ///   conv opcodes.
1563         /// </summary>
1564         public class ConvCast : EmptyCast {
1565                 public enum Mode : byte {
1566                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1567                         U1_I1, U1_CH,
1568                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1569                         U2_I1, U2_U1, U2_I2, U2_CH,
1570                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1571                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1572                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH,
1573                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH,
1574                         CH_I1, CH_U1, CH_I2,
1575                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1576                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4
1577                 }
1578
1579                 Mode mode;
1580
1581                 public ConvCast (Expression child, Type return_type, Mode m)
1582                         : base (child, return_type)
1583                 {
1584                         mode = m;
1585                 }
1586
1587                 public override Expression DoResolve (EmitContext ec)
1588                 {
1589                         // This should never be invoked, we are born in fully
1590                         // initialized state.
1591
1592                         return this;
1593                 }
1594
1595                 public override string ToString ()
1596                 {
1597                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1598                 }
1599
1600                 public override void Emit (EmitContext ec)
1601                 {
1602                         ILGenerator ig = ec.ig;
1603
1604                         base.Emit (ec);
1605
1606                         if (ec.CheckState){
1607                                 switch (mode){
1608                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1609                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1610                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1611                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1612                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1613
1614                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1615                                 case Mode.U1_CH: /* nothing */ break;
1616
1617                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1618                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1619                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1620                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1621                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1622                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1623
1624                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1625                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1626                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1627                                 case Mode.U2_CH: /* nothing */ break;
1628
1629                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1630                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1631                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1632                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1633                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1634                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1635                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1636
1637                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1638                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1639                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1640                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1641                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1642                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1643
1644                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1645                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1646                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1647                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1648                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1649                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1650                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1651                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1652
1653                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1654                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1655                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1656                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1657                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1658                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1659                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1660                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1661
1662                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1663                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1664                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1665
1666                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1667                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1668                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1669                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1670                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1671                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1672                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1673                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1674                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1675
1676                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1677                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1678                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1679                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1680                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1681                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1682                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1683                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1684                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1685                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1686                                 }
1687                         } else {
1688                                 switch (mode){
1689                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1690                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1691                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1692                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
1693                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
1694
1695                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
1696                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
1697
1698                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
1699                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
1700                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
1701                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
1702                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
1703                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
1704
1705                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
1706                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
1707                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
1708                                 case Mode.U2_CH: /* nothing */ break;
1709
1710                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
1711                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
1712                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
1713                                 case Mode.I4_U4: /* nothing */ break;
1714                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
1715                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
1716                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
1717
1718                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
1719                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
1720                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
1721                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
1722                                 case Mode.U4_I4: /* nothing */ break;
1723                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
1724
1725                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
1726                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
1727                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
1728                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
1729                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
1730                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
1731                                 case Mode.I8_U8: /* nothing */ break;
1732                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
1733
1734                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
1735                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
1736                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
1737                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
1738                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
1739                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
1740                                 case Mode.U8_I8: /* nothing */ break;
1741                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
1742
1743                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
1744                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
1745                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
1746
1747                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
1748                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
1749                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
1750                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
1751                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
1752                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
1753                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
1754                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
1755                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
1756
1757                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
1758                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
1759                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
1760                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
1761                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
1762                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
1763                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
1764                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
1765                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
1766                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1767                                 }
1768                         }
1769                 }
1770         }
1771
1772         public class OpcodeCast : EmptyCast {
1773                 OpCode op, op2;
1774                 bool second_valid;
1775
1776                 public OpcodeCast (Expression child, Type return_type, OpCode op)
1777                         : base (child, return_type)
1778
1779                 {
1780                         this.op = op;
1781                         second_valid = false;
1782                 }
1783
1784                 public OpcodeCast (Expression child, Type return_type, OpCode op, OpCode op2)
1785                         : base (child, return_type)
1786
1787                 {
1788                         this.op = op;
1789                         this.op2 = op2;
1790                         second_valid = true;
1791                 }
1792
1793                 public override Expression DoResolve (EmitContext ec)
1794                 {
1795                         // This should never be invoked, we are born in fully
1796                         // initialized state.
1797
1798                         return this;
1799                 }
1800
1801                 public override void Emit (EmitContext ec)
1802                 {
1803                         base.Emit (ec);
1804                         ec.ig.Emit (op);
1805
1806                         if (second_valid)
1807                                 ec.ig.Emit (op2);
1808                 }
1809         }
1810
1811         /// <summary>
1812         ///   This kind of cast is used to encapsulate a child and cast it
1813         ///   to the class requested
1814         /// </summary>
1815         public class ClassCast : EmptyCast {
1816                 public ClassCast (Expression child, Type return_type)
1817                         : base (child, return_type)
1818
1819                 {
1820                 }
1821
1822                 public override Expression DoResolve (EmitContext ec)
1823                 {
1824                         // This should never be invoked, we are born in fully
1825                         // initialized state.
1826
1827                         return this;
1828                 }
1829
1830                 public override void Emit (EmitContext ec)
1831                 {
1832                         base.Emit (ec);
1833
1834                         if (child.Type.IsGenericParameter)
1835                                 ec.ig.Emit (OpCodes.Box, child.Type);
1836
1837                         if (type.IsGenericParameter)
1838                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
1839                         else
1840                                 ec.ig.Emit (OpCodes.Castclass, type);
1841                 }
1842         }
1843
1844         /// <summary>
1845         ///   SimpleName expressions are formed of a single word and only happen at the beginning
1846         ///   of a dotted-name.
1847         /// </summary>
1848         public class SimpleName : Expression {
1849                 public string Name;
1850                 public readonly TypeArguments Arguments;
1851                 bool in_transit;
1852
1853                 public SimpleName (string name, Location l)
1854                 {
1855                         Name = name;
1856                         loc = l;
1857                 }
1858
1859                 public SimpleName (string name, TypeArguments args, Location l)
1860                 {
1861                         Name = name;
1862                         Arguments = args;
1863                         loc = l;
1864                 }
1865
1866                 public SimpleName (string name, TypeParameter[] type_params, Location l)
1867                 {
1868                         Name = name;
1869                         loc = l;
1870
1871                         Arguments = new TypeArguments (l);
1872                         foreach (TypeParameter type_param in type_params)
1873                                 Arguments.Add (new TypeParameterExpr (type_param, l));
1874                 }
1875
1876                 public static string RemoveGenericArity (string name)
1877                 {
1878                         int start = 0;
1879                         StringBuilder sb = new StringBuilder ();
1880                         while (start < name.Length) {
1881                                 int pos = name.IndexOf ('`', start);
1882                                 if (pos < 0) {
1883                                         sb.Append (name.Substring (start));
1884                                         break;
1885                                 }
1886
1887                                 sb.Append (name.Substring (start, pos-start));
1888
1889                                 pos++;
1890                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
1891                                         pos++;
1892
1893                                 start = pos;
1894                         }
1895
1896                         return sb.ToString ();
1897                 }
1898
1899                 public SimpleName GetMethodGroup ()
1900                 {
1901                         return new SimpleName (RemoveGenericArity (Name), Arguments, loc);
1902                 }
1903
1904                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
1905                 {
1906                         if (ec.IsFieldInitializer)
1907                                 Report.Error (236, l,
1908                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
1909                                         name);
1910                         else {
1911                                 if (name.LastIndexOf ('.') > 0)
1912                                         name = name.Substring (name.LastIndexOf ('.') + 1);
1913
1914                                 Report.Error (
1915                                         120, l, "`{0}': An object reference is required for the nonstatic field, method or property",
1916                                         name);
1917                         }
1918                 }
1919
1920                 public bool IdenticalNameAndTypeName (EmitContext ec, Expression resolved_to, Location loc)
1921                 {
1922                         return resolved_to != null && resolved_to.Type != null &&
1923                                 resolved_to.Type.Name == Name &&
1924                                 (ec.DeclContainer.LookupType (Name, loc, /* ignore_cs0104 = */ true) != null);
1925                 }
1926
1927                 public override Expression DoResolve (EmitContext ec)
1928                 {
1929                         return SimpleNameResolve (ec, null, false);
1930                 }
1931
1932                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1933                 {
1934                         return SimpleNameResolve (ec, right_side, false);
1935                 }
1936
1937
1938                 public Expression DoResolve (EmitContext ec, bool intermediate)
1939                 {
1940                         return SimpleNameResolve (ec, null, intermediate);
1941                 }
1942
1943                 private bool IsNestedChild (Type t, Type parent)
1944                 {
1945                         if (parent == null)
1946                                 return false;
1947
1948                         while (parent != null) {
1949                                 parent = TypeManager.DropGenericTypeArguments (parent);
1950                                 if (TypeManager.IsNestedChildOf (t, parent))
1951                                         return true;
1952
1953                                 parent = parent.BaseType;
1954                         }
1955
1956                         return false;
1957                 }
1958
1959                 FullNamedExpression ResolveNested (IResolveContext ec, Type t)
1960                 {
1961                         if (!t.IsGenericTypeDefinition)
1962                                 return null;
1963
1964                         DeclSpace ds = ec.DeclContainer;
1965                         while (ds != null) {
1966                                 if (IsNestedChild (t, ds.TypeBuilder))
1967                                         break;
1968
1969                                 ds = ds.Parent;
1970                         }
1971
1972                         if (ds == null)
1973                                 return null;
1974
1975                         Type[] gen_params = t.GetGenericArguments ();
1976
1977                         int arg_count = Arguments != null ? Arguments.Count : 0;
1978
1979                         for (; (ds != null) && ds.IsGeneric; ds = ds.Parent) {
1980                                 if (arg_count + ds.CountTypeParameters == gen_params.Length) {
1981                                         TypeArguments new_args = new TypeArguments (loc);
1982                                         foreach (TypeParameter param in ds.TypeParameters)
1983                                                 new_args.Add (new TypeParameterExpr (param, loc));
1984
1985                                         if (Arguments != null)
1986                                                 new_args.Add (Arguments);
1987
1988                                         return new ConstructedType (t, new_args, loc);
1989                                 }
1990                         }
1991
1992                         return null;
1993                 }
1994
1995                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
1996                 {
1997                         FullNamedExpression fne = ec.DeclContainer.LookupGeneric (Name, loc);
1998                         if (fne != null)
1999                                 return fne.ResolveAsTypeStep (ec, silent);
2000
2001                         int errors = Report.Errors;
2002                         fne = ec.DeclContainer.LookupType (Name, loc, /*ignore_cs0104=*/ false);
2003
2004                         if (fne != null) {
2005                                 if (fne.Type == null)
2006                                         return fne;
2007
2008                                 FullNamedExpression nested = ResolveNested (ec, fne.Type);
2009                                 if (nested != null)
2010                                         return nested.ResolveAsTypeStep (ec, false);
2011
2012                                 if (Arguments != null) {
2013                                         ConstructedType ct = new ConstructedType (fne, Arguments, loc);
2014                                         return ct.ResolveAsTypeStep (ec, false);
2015                                 }
2016
2017                                 return fne;
2018                         }
2019
2020                         if (silent || errors != Report.Errors)
2021                                 return null;
2022
2023                         MemberCore mc = ec.DeclContainer.GetDefinition (Name);
2024                         if (mc != null) {
2025                                 Error_UnexpectedKind (ec.DeclContainer, "type", GetMemberType (mc), loc);
2026                                 return null;
2027                         }
2028
2029                         string ns = ec.DeclContainer.NamespaceEntry.NS.Name;
2030                         string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2031                         foreach (Assembly a in RootNamespace.Global.Assemblies) {
2032                                 Type type = a.GetType (fullname);
2033                                 if (type != null) {
2034                                         Report.SymbolRelatedToPreviousError (type);
2035                                         Expression.ErrorIsInaccesible (loc, fullname);
2036                                         return null;
2037                                 }
2038                         }
2039
2040                         NamespaceEntry.Error_NamespaceNotFound (loc, Name);
2041                         return null;
2042                 }
2043
2044                 // TODO: I am still not convinced about this. If someone else will need it
2045                 // implement this as virtual property in MemberCore hierarchy
2046                 string GetMemberType (MemberCore mc)
2047                 {
2048                         if (mc is PropertyBase)
2049                                 return "property";
2050                         if (mc is Indexer)
2051                                 return "indexer";
2052                         if (mc is FieldBase)
2053                                 return "field";
2054                         if (mc is MethodCore)
2055                                 return "method";
2056                         if (mc is EnumMember)
2057                                 return "enum";
2058
2059                         return "type";
2060                 }
2061
2062                 Expression SimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2063                 {
2064                         if (in_transit)
2065                                 return null;
2066                         in_transit = true;
2067
2068                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2069                         if (e == null)
2070                                 return null;
2071
2072                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2073                                 return e;
2074
2075                         return null;
2076                 }
2077
2078                 /// <remarks>
2079                 ///   7.5.2: Simple Names.
2080                 ///
2081                 ///   Local Variables and Parameters are handled at
2082                 ///   parse time, so they never occur as SimpleNames.
2083                 ///
2084                 ///   The `intermediate' flag is used by MemberAccess only
2085                 ///   and it is used to inform us that it is ok for us to
2086                 ///   avoid the static check, because MemberAccess might end
2087                 ///   up resolving the Name as a Type name and the access as
2088                 ///   a static type access.
2089                 ///
2090                 ///   ie: Type Type; .... { Type.GetType (""); }
2091                 ///
2092                 ///   Type is both an instance variable and a Type;  Type.GetType
2093                 ///   is the static method not an instance method of type.
2094                 /// </remarks>
2095                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2096                 {
2097                         Expression e = null;
2098
2099                         //
2100                         // Stage 1: Performed by the parser (binding to locals or parameters).
2101                         //
2102                         Block current_block = ec.CurrentBlock;
2103                         if (current_block != null){
2104                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2105                                 if (vi != null){
2106                                         LocalVariableReference var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2107                                         if (right_side != null) {
2108                                                 return var.ResolveLValue (ec, right_side, loc);
2109                                         } else {
2110                                                 ResolveFlags rf = ResolveFlags.VariableOrValue;
2111                                                 if (intermediate)
2112                                                         rf |= ResolveFlags.DisableFlowAnalysis;
2113                                                 return var.Resolve (ec, rf);
2114                                         }
2115                                 }
2116
2117                                 ParameterReference pref = current_block.Toplevel.GetParameterReference (Name, loc);
2118                                 if (pref != null) {
2119                                         if (right_side != null)
2120                                                 return pref.ResolveLValue (ec, right_side, loc);
2121                                         else
2122                                                 return pref.Resolve (ec);
2123                                 }
2124                         }
2125
2126                         //
2127                         // Stage 2: Lookup members
2128                         //
2129
2130                         DeclSpace lookup_ds = ec.DeclContainer;
2131                         Type almost_matched_type = null;
2132                         ArrayList almost_matched = null;
2133                         do {
2134                                 if (lookup_ds.TypeBuilder == null)
2135                                         break;
2136
2137                                 e = MemberLookup (ec.ContainerType, lookup_ds.TypeBuilder, Name, loc);
2138                                 if (e != null)
2139                                         break;
2140
2141                                 if (almost_matched == null && almostMatchedMembers.Count > 0) {
2142                                         almost_matched_type = lookup_ds.TypeBuilder;
2143                                         almost_matched = (ArrayList) almostMatchedMembers.Clone ();
2144                                 }
2145
2146                                 lookup_ds =lookup_ds.Parent;
2147                         } while (lookup_ds != null);
2148
2149                         if (e == null && ec.ContainerType != null)
2150                                 e = MemberLookup (ec.ContainerType, ec.ContainerType, Name, loc);
2151
2152                         if (e == null) {
2153                                 if (almost_matched == null && almostMatchedMembers.Count > 0) {
2154                                         almost_matched_type = ec.ContainerType;
2155                                         almost_matched = (ArrayList) almostMatchedMembers.Clone ();
2156                                 }
2157                                 e = ResolveAsTypeStep (ec, true);
2158                         }
2159
2160                         if (e == null) {
2161                                 if (almost_matched != null)
2162                                         almostMatchedMembers = almost_matched;
2163                                 if (almost_matched_type == null)
2164                                         almost_matched_type = ec.ContainerType;
2165                                 MemberLookupFailed (ec.ContainerType, null, almost_matched_type, ((SimpleName) this).Name, ec.DeclContainer.Name, true, loc);
2166                                 return null;
2167                         }
2168
2169                         if (e is TypeExpr)
2170                                 return e;
2171
2172                         if (e is MemberExpr) {
2173                                 MemberExpr me = (MemberExpr) e;
2174
2175                                 Expression left;
2176                                 if (me.IsInstance) {
2177                                         if (ec.IsStatic || ec.IsFieldInitializer) {
2178                                                 //
2179                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2180                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2181                                                 // and each predicate is true if the MethodGroupExpr contains
2182                                                 // at least one of that kind of method.
2183                                                 //
2184
2185                                                 if (!me.IsStatic &&
2186                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2187                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2188                                                         return EmptyExpression.Null;
2189                                                 }
2190
2191                                                 //
2192                                                 // Pass the buck to MemberAccess and Invocation.
2193                                                 //
2194                                                 left = EmptyExpression.Null;
2195                                         } else {
2196                                                 left = ec.GetThis (loc);
2197                                         }
2198                                 } else {
2199                                         left = new TypeExpression (ec.ContainerType, loc);
2200                                 }
2201
2202                                 e = me.ResolveMemberAccess (ec, left, loc, null);
2203                                 if (e == null)
2204                                         return null;
2205
2206                                 me = e as MemberExpr;
2207                                 if (me == null)
2208                                         return e;
2209
2210                                 if (Arguments != null) {
2211                                         MethodGroupExpr mg = me as MethodGroupExpr;
2212                                         if (mg == null)
2213                                                 return null;
2214
2215                                         return mg.ResolveGeneric (ec, Arguments);
2216                                 }
2217
2218                                 if (!me.IsStatic &&
2219                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2220                                     me.InstanceExpression.Type != me.DeclaringType &&
2221                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2222                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2223                                         Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2224                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2225                                         return null;
2226                                 }
2227
2228                                 return (right_side != null)
2229                                         ? me.DoResolveLValue (ec, right_side)
2230                                         : me.DoResolve (ec);
2231                         }
2232
2233                         return e;
2234                 }
2235
2236                 public override void Emit (EmitContext ec)
2237                 {
2238                         //
2239                         // If this is ever reached, then we failed to
2240                         // find the name as a namespace
2241                         //
2242
2243                         Error (103, "The name `" + Name +
2244                                "' does not exist in the class `" +
2245                                ec.DeclContainer.Name + "'");
2246                 }
2247
2248                 public override string ToString ()
2249                 {
2250                         return Name;
2251                 }
2252
2253                 public override string GetSignatureForError ()
2254                 {
2255                         return Name;
2256                 }
2257         }
2258
2259         /// <summary>
2260         ///   Represents a namespace or a type.  The name of the class was inspired by
2261         ///   section 10.8.1 (Fully Qualified Names).
2262         /// </summary>
2263         public abstract class FullNamedExpression : Expression {
2264                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2265                 {
2266                         return this;
2267                 }
2268
2269                 public abstract string FullName {
2270                         get;
2271                 }
2272         }
2273
2274         /// <summary>
2275         ///   Expression that evaluates to a type
2276         /// </summary>
2277         public abstract class TypeExpr : FullNamedExpression {
2278                 override public FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2279                 {
2280                         TypeExpr t = DoResolveAsTypeStep (ec);
2281                         if (t == null)
2282                                 return null;
2283
2284                         eclass = ExprClass.Type;
2285                         return t;
2286                 }
2287
2288                 override public Expression DoResolve (EmitContext ec)
2289                 {
2290                         return ResolveAsTypeTerminal (ec, false);
2291                 }
2292
2293                 override public void Emit (EmitContext ec)
2294                 {
2295                         throw new Exception ("Should never be called");
2296                 }
2297
2298                 public virtual bool CheckAccessLevel (DeclSpace ds)
2299                 {
2300                         return ds.CheckAccessLevel (Type);
2301                 }
2302
2303                 public virtual bool AsAccessible (DeclSpace ds, int flags)
2304                 {
2305                         return ds.AsAccessible (Type, flags);
2306                 }
2307
2308                 public virtual bool IsClass {
2309                         get { return Type.IsClass; }
2310                 }
2311
2312                 public virtual bool IsValueType {
2313                         get { return Type.IsValueType; }
2314                 }
2315
2316                 public virtual bool IsInterface {
2317                         get { return Type.IsInterface; }
2318                 }
2319
2320                 public virtual bool IsSealed {
2321                         get { return Type.IsSealed; }
2322                 }
2323
2324                 public virtual bool CanInheritFrom ()
2325                 {
2326                         if (Type == TypeManager.enum_type ||
2327                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2328                             Type == TypeManager.multicast_delegate_type ||
2329                             Type == TypeManager.delegate_type ||
2330                             Type == TypeManager.array_type)
2331                                 return false;
2332
2333                         return true;
2334                 }
2335
2336                 protected abstract TypeExpr DoResolveAsTypeStep (IResolveContext ec);
2337
2338                 public abstract string Name {
2339                         get;
2340                 }
2341
2342                 public override bool Equals (object obj)
2343                 {
2344                         TypeExpr tobj = obj as TypeExpr;
2345                         if (tobj == null)
2346                                 return false;
2347
2348                         return Type == tobj.Type;
2349                 }
2350
2351                 public override int GetHashCode ()
2352                 {
2353                         return Type.GetHashCode ();
2354                 }
2355
2356                 public override string ToString ()
2357                 {
2358                         return Name;
2359                 }
2360         }
2361
2362         /// <summary>
2363         ///   Fully resolved Expression that already evaluated to a type
2364         /// </summary>
2365         public class TypeExpression : TypeExpr {
2366                 public TypeExpression (Type t, Location l)
2367                 {
2368                         Type = t;
2369                         eclass = ExprClass.Type;
2370                         loc = l;
2371                 }
2372
2373                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2374                 {
2375                         return this;
2376                 }
2377
2378                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2379                 {
2380                         return this;
2381                 }
2382
2383                 public override string Name {
2384                         get { return Type.ToString (); }
2385                 }
2386
2387                 public override string FullName {
2388                         get { return Type.FullName; }
2389                 }
2390         }
2391
2392         /// <summary>
2393         ///   Used to create types from a fully qualified name.  These are just used
2394         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2395         ///   classified as a type.
2396         /// </summary>
2397         public sealed class TypeLookupExpression : TypeExpr {
2398                 readonly string name;
2399
2400                 public TypeLookupExpression (string name)
2401                 {
2402                         this.name = name;
2403                         eclass = ExprClass.Type;
2404                 }
2405
2406                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2407                 {
2408                         // It's null for corlib compilation only
2409                         if (type == null)
2410                                 return DoResolveAsTypeStep (ec);
2411
2412                         return this;
2413                 }
2414
2415                 static readonly char [] dot_array = { '.' };
2416                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2417                 {
2418                         // If name is of the form `N.I', first lookup `N', then search a member `I' in it.
2419                         string rest = null;
2420                         string lookup_name = name;
2421                         int pos = name.IndexOf ('.');
2422                         if (pos >= 0) {
2423                                 rest = name.Substring (pos + 1);
2424                                 lookup_name = name.Substring (0, pos);
2425                         }
2426
2427                         FullNamedExpression resolved = RootNamespace.Global.Lookup (ec.DeclContainer, lookup_name, Location.Null);
2428
2429                         if (resolved != null && rest != null) {
2430                                 // Now handle the rest of the the name.
2431                                 string [] elements = rest.Split (dot_array);
2432                                 string element;
2433                                 int count = elements.Length;
2434                                 int i = 0;
2435                                 while (i < count && resolved != null && resolved is Namespace) {
2436                                         Namespace ns = resolved as Namespace;
2437                                         element = elements [i++];
2438                                         lookup_name += "." + element;
2439                                         resolved = ns.Lookup (ec.DeclContainer, element, Location.Null);
2440                                 }
2441
2442                                 if (resolved != null && resolved is TypeExpr) {
2443                                         Type t = ((TypeExpr) resolved).Type;
2444                                         while (t != null) {
2445                                                 if (!ec.DeclContainer.CheckAccessLevel (t)) {
2446                                                         resolved = null;
2447                                                         lookup_name = t.FullName;
2448                                                         break;
2449                                                 }
2450                                                 if (i == count) {
2451                                                         type = t;
2452                                                         return this;
2453                                                 }
2454                                                 t = TypeManager.GetNestedType (t, elements [i++]);
2455                                         }
2456                                 }
2457                         }
2458
2459                         if (resolved == null) {
2460                                 NamespaceEntry.Error_NamespaceNotFound (loc, lookup_name);
2461                                 return null;
2462                         }
2463
2464                         if (!(resolved is TypeExpr)) {
2465                                 resolved.Error_UnexpectedKind (ec.DeclContainer, "type", loc);
2466                                 return null;
2467                         }
2468
2469                         type = resolved.Type;
2470                         return this;
2471                 }
2472
2473                 public override string Name {
2474                         get { return name; }
2475                 }
2476
2477                 public override string FullName {
2478                         get { return name; }
2479                 }
2480         }
2481
2482         /// <summary>
2483         ///   Represents an "unbound generic type", ie. typeof (Foo<>).
2484         ///   See 14.5.11.
2485         /// </summary>
2486         public class UnboundTypeExpression : TypeExpr
2487         {
2488                 MemberName name;
2489
2490                 public UnboundTypeExpression (MemberName name, Location l)
2491                 {
2492                         this.name = name;
2493                         loc = l;
2494                 }
2495
2496                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2497                 {
2498                         Expression expr;
2499                         if (name.Left != null) {
2500                                 Expression lexpr = name.Left.GetTypeExpression ();
2501                                 expr = new MemberAccess (lexpr, name.Basename);
2502                         } else {
2503                                 expr = new SimpleName (name.Basename, loc);
2504                         }
2505
2506                         FullNamedExpression fne = expr.ResolveAsTypeStep (ec, false);
2507                         if (fne == null)
2508                                 return null;
2509
2510                         type = fne.Type;
2511                         return new TypeExpression (type, loc);
2512                 }
2513
2514                 public override string Name {
2515                         get { return name.FullName; }
2516                 }
2517
2518                 public override string FullName {
2519                         get { return name.FullName; }
2520                 }
2521         }
2522
2523         public class TypeAliasExpression : TypeExpr {
2524                 FullNamedExpression alias;
2525                 TypeExpr texpr;
2526                 TypeArguments args;
2527                 string name;
2528
2529                 public TypeAliasExpression (FullNamedExpression alias, TypeArguments args, Location l)
2530                 {
2531                         this.alias = alias;
2532                         this.args = args;
2533                         loc = l;
2534
2535                         eclass = ExprClass.Type;
2536                         if (args != null)
2537                                 name = alias.FullName + "<" + args.ToString () + ">";
2538                         else
2539                                 name = alias.FullName;
2540                 }
2541
2542                 public override string Name {
2543                         get { return alias.FullName; }
2544                 }
2545
2546                 public override string FullName {
2547                         get { return name; }
2548                 }
2549
2550                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2551                 {
2552                         texpr = alias.ResolveAsTypeTerminal (ec, false);
2553                         if (texpr == null)
2554                                 return null;
2555
2556                         Type type = texpr.Type;
2557                         int num_args = TypeManager.GetNumberOfTypeArguments (type);
2558
2559                         if (args != null) {
2560                                 if (num_args == 0) {
2561                                         Report.Error (308, loc,
2562                                                       "The non-generic type `{0}' cannot " +
2563                                                       "be used with type arguments.",
2564                                                       TypeManager.CSharpName (type));
2565                                         return null;
2566                                 }
2567
2568                                 ConstructedType ctype = new ConstructedType (type, args, loc);
2569                                 return ctype.ResolveAsTypeTerminal (ec, false);
2570                         } else if (num_args > 0) {
2571                                 Report.Error (305, loc,
2572                                               "Using the generic type `{0}' " +
2573                                               "requires {1} type arguments",
2574                                               TypeManager.CSharpName (type), num_args.ToString ());
2575                                 return null;
2576                         }
2577
2578                         return texpr;
2579                 }
2580
2581                 public override bool CheckAccessLevel (DeclSpace ds)
2582                 {
2583                         return texpr.CheckAccessLevel (ds);
2584                 }
2585
2586                 public override bool AsAccessible (DeclSpace ds, int flags)
2587                 {
2588                         return texpr.AsAccessible (ds, flags);
2589                 }
2590
2591                 public override bool IsClass {
2592                         get { return texpr.IsClass; }
2593                 }
2594
2595                 public override bool IsValueType {
2596                         get { return texpr.IsValueType; }
2597                 }
2598
2599                 public override bool IsInterface {
2600                         get { return texpr.IsInterface; }
2601                 }
2602
2603                 public override bool IsSealed {
2604                         get { return texpr.IsSealed; }
2605                 }
2606         }
2607
2608         /// <summary>
2609         ///   This class denotes an expression which evaluates to a member
2610         ///   of a struct or a class.
2611         /// </summary>
2612         public abstract class MemberExpr : Expression
2613         {
2614                 /// <summary>
2615                 ///   The name of this member.
2616                 /// </summary>
2617                 public abstract string Name {
2618                         get;
2619                 }
2620
2621                 /// <summary>
2622                 ///   Whether this is an instance member.
2623                 /// </summary>
2624                 public abstract bool IsInstance {
2625                         get;
2626                 }
2627
2628                 /// <summary>
2629                 ///   Whether this is a static member.
2630                 /// </summary>
2631                 public abstract bool IsStatic {
2632                         get;
2633                 }
2634
2635                 /// <summary>
2636                 ///   The type which declares this member.
2637                 /// </summary>
2638                 public abstract Type DeclaringType {
2639                         get;
2640                 }
2641
2642                 /// <summary>
2643                 ///   The instance expression associated with this member, if it's a
2644                 ///   non-static member.
2645                 /// </summary>
2646                 public Expression InstanceExpression;
2647
2648                 public static void error176 (Location loc, string name)
2649                 {
2650                         Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
2651                                       "with an instance reference, qualify it with a type name instead", name);
2652                 }
2653
2654                 // TODO: possible optimalization
2655                 // Cache resolved constant result in FieldBuilder <-> expression map
2656                 public virtual Expression ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
2657                                                                SimpleName original)
2658                 {
2659                         //
2660                         // Precondition:
2661                         //   original == null || original.Resolve (...) ==> left
2662                         //
2663
2664                         if (left is TypeExpr) {
2665                                 if (!IsStatic) {
2666                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
2667                                         return null;
2668                                 }
2669
2670                                 return this;
2671                         }
2672
2673                         if (!IsInstance) {
2674                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
2675                                         return this;
2676
2677                                 error176 (loc, GetSignatureForError ());
2678                                 return null;
2679                         }
2680
2681                         InstanceExpression = left;
2682
2683                         return this;
2684                 }
2685
2686                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
2687                 {
2688                         if (IsStatic)
2689                                 return;
2690
2691                         if (InstanceExpression == EmptyExpression.Null) {
2692                                 SimpleName.Error_ObjectRefRequired (ec, loc, Name);
2693                                 return;
2694                         }
2695
2696                         if (InstanceExpression.Type.IsValueType) {
2697                                 if (InstanceExpression is IMemoryLocation) {
2698                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
2699                                 } else {
2700                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
2701                                         InstanceExpression.Emit (ec);
2702                                         t.Store (ec);
2703                                         t.AddressOf (ec, AddressOp.Store);
2704                                 }
2705                         } else
2706                                 InstanceExpression.Emit (ec);
2707
2708                         if (prepare_for_load)
2709                                 ec.ig.Emit (OpCodes.Dup);
2710                 }
2711         }
2712
2713         /// <summary>
2714         ///   MethodGroup Expression.
2715         ///
2716         ///   This is a fully resolved expression that evaluates to a type
2717         /// </summary>
2718         public class MethodGroupExpr : MemberExpr {
2719                 public MethodBase [] Methods;
2720                 bool has_type_arguments = false;
2721                 bool identical_type_name = false;
2722                 bool is_base;
2723
2724                 public MethodGroupExpr (MemberInfo [] mi, Location l)
2725                 {
2726                         Methods = new MethodBase [mi.Length];
2727                         mi.CopyTo (Methods, 0);
2728                         eclass = ExprClass.MethodGroup;
2729                         type = TypeManager.object_type;
2730                         loc = l;
2731                 }
2732
2733                 public MethodGroupExpr (ArrayList list, Location l)
2734                 {
2735                         Methods = new MethodBase [list.Count];
2736
2737                         try {
2738                                 list.CopyTo (Methods, 0);
2739                         } catch {
2740                                 foreach (MemberInfo m in list){
2741                                         if (!(m is MethodBase)){
2742                                                 Console.WriteLine ("Name " + m.Name);
2743                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
2744                                         }
2745                                 }
2746                                 throw;
2747                         }
2748
2749                         loc = l;
2750                         eclass = ExprClass.MethodGroup;
2751                         type = TypeManager.object_type;
2752                 }
2753
2754                 public override Type DeclaringType {
2755                         get {
2756                                 //
2757                                 // We assume that the top-level type is in the end
2758                                 //
2759                                 return Methods [Methods.Length - 1].DeclaringType;
2760                                 //return Methods [0].DeclaringType;
2761                         }
2762                 }
2763
2764                 public bool HasTypeArguments {
2765                         get {
2766                                 return has_type_arguments;
2767                         }
2768
2769                         set {
2770                                 has_type_arguments = value;
2771                         }
2772                 }
2773
2774                 public bool IdenticalTypeName {
2775                         get {
2776                                 return identical_type_name;
2777                         }
2778
2779                         set {
2780                                 identical_type_name = value;
2781                         }
2782                 }
2783
2784                 public bool IsBase {
2785                         get {
2786                                 return is_base;
2787                         }
2788                         set {
2789                                 is_base = value;
2790                         }
2791                 }
2792
2793                 public override string GetSignatureForError ()
2794                 {
2795                         return TypeManager.CSharpSignature (Methods [0]);
2796                 }
2797
2798                 public override string Name {
2799                         get {
2800                                 return Methods [0].Name;
2801                         }
2802                 }
2803
2804                 public override bool IsInstance {
2805                         get {
2806                                 foreach (MethodBase mb in Methods)
2807                                         if (!mb.IsStatic)
2808                                                 return true;
2809
2810                                 return false;
2811                         }
2812                 }
2813
2814                 public override bool IsStatic {
2815                         get {
2816                                 foreach (MethodBase mb in Methods)
2817                                         if (mb.IsStatic)
2818                                                 return true;
2819
2820                                 return false;
2821                         }
2822                 }
2823
2824                 public override Expression ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
2825                                                                 SimpleName original)
2826                 {
2827                         if (!(left is TypeExpr) &&
2828                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
2829                                 IdenticalTypeName = true;
2830
2831                         return base.ResolveMemberAccess (ec, left, loc, original);
2832                 }
2833
2834                 override public Expression DoResolve (EmitContext ec)
2835                 {
2836                         if (!IsInstance)
2837                                 InstanceExpression = null;
2838
2839                         if (InstanceExpression != null) {
2840                                 InstanceExpression = InstanceExpression.DoResolve (ec);
2841                                 if (InstanceExpression == null)
2842                                         return null;
2843                         }
2844
2845                         return this;
2846                 }
2847
2848                 public void ReportUsageError ()
2849                 {
2850                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
2851                                       Name + "()' is referenced without parentheses");
2852                 }
2853
2854                 override public void Emit (EmitContext ec)
2855                 {
2856                         ReportUsageError ();
2857                 }
2858
2859                 bool RemoveMethods (bool keep_static)
2860                 {
2861                         ArrayList smethods = new ArrayList ();
2862
2863                         foreach (MethodBase mb in Methods){
2864                                 if (mb.IsStatic == keep_static)
2865                                         smethods.Add (mb);
2866                         }
2867
2868                         if (smethods.Count == 0)
2869                                 return false;
2870
2871                         Methods = new MethodBase [smethods.Count];
2872                         smethods.CopyTo (Methods, 0);
2873
2874                         return true;
2875                 }
2876
2877                 /// <summary>
2878                 ///   Removes any instance methods from the MethodGroup, returns
2879                 ///   false if the resulting set is empty.
2880                 /// </summary>
2881                 public bool RemoveInstanceMethods ()
2882                 {
2883                         return RemoveMethods (true);
2884                 }
2885
2886                 /// <summary>
2887                 ///   Removes any static methods from the MethodGroup, returns
2888                 ///   false if the resulting set is empty.
2889                 /// </summary>
2890                 public bool RemoveStaticMethods ()
2891                 {
2892                         return RemoveMethods (false);
2893                 }
2894
2895                 public Expression ResolveGeneric (EmitContext ec, TypeArguments args)
2896                 {
2897                         if (args.Resolve (ec) == false)
2898                                 return null;
2899
2900                         Type[] atypes = args.Arguments;
2901
2902                         int first_count = 0;
2903                         MethodInfo first = null;
2904
2905                         ArrayList list = new ArrayList ();
2906                         foreach (MethodBase mb in Methods) {
2907                                 MethodInfo mi = mb as MethodInfo;
2908                                 if ((mi == null) || !mi.IsGenericMethod)
2909                                         continue;
2910
2911                                 Type[] gen_params = mi.GetGenericArguments ();
2912
2913                                 if (first == null) {
2914                                         first = mi;
2915                                         first_count = gen_params.Length;
2916                                 }
2917
2918                                 if (gen_params.Length != atypes.Length)
2919                                         continue;
2920
2921                                 list.Add (mi.MakeGenericMethod (atypes));
2922                         }
2923
2924                         if (list.Count > 0) {
2925                                 MethodGroupExpr new_mg = new MethodGroupExpr (list, Location);
2926                                 new_mg.InstanceExpression = InstanceExpression;
2927                                 new_mg.HasTypeArguments = true;
2928                                 new_mg.IsBase = IsBase;
2929                                 return new_mg;
2930                         }
2931
2932                         if (first != null)
2933                                 Report.Error (
2934                                         305, loc, "Using the generic method `{0}' " +
2935                                         "requires {1} type arguments", Name,
2936                                         first_count.ToString ());
2937                         else
2938                                 Report.Error (
2939                                         308, loc, "The non-generic method `{0}' " +
2940                                         "cannot be used with type arguments", Name);
2941
2942                         return null;
2943                 }
2944         }
2945
2946         /// <summary>
2947         ///   Fully resolved expression that evaluates to a Field
2948         /// </summary>
2949         public class FieldExpr : MemberExpr, IAssignMethod, IMemoryLocation, IVariable {
2950                 public readonly FieldInfo FieldInfo;
2951                 VariableInfo variable_info;
2952
2953                 LocalTemporary temp;
2954                 bool prepared;
2955                 bool in_initializer;
2956
2957                 public FieldExpr (FieldInfo fi, Location l, bool in_initializer):
2958                         this (fi, l)
2959                 {
2960                         this.in_initializer = in_initializer;
2961                 }
2962
2963                 public FieldExpr (FieldInfo fi, Location l)
2964                 {
2965                         FieldInfo = fi;
2966                         eclass = ExprClass.Variable;
2967                         type = TypeManager.TypeToCoreType (fi.FieldType);
2968                         loc = l;
2969                 }
2970
2971                 public override string Name {
2972                         get {
2973                                 return FieldInfo.Name;
2974                         }
2975                 }
2976
2977                 public override bool IsInstance {
2978                         get {
2979                                 return !FieldInfo.IsStatic;
2980                         }
2981                 }
2982
2983                 public override bool IsStatic {
2984                         get {
2985                                 return FieldInfo.IsStatic;
2986                         }
2987                 }
2988
2989                 public override Type DeclaringType {
2990                         get {
2991                                 return FieldInfo.DeclaringType;
2992                         }
2993                 }
2994
2995                 public override string GetSignatureForError ()
2996                 {
2997                         return TypeManager.GetFullNameSignature (FieldInfo);
2998                 }
2999
3000                 public VariableInfo VariableInfo {
3001                         get {
3002                                 return variable_info;
3003                         }
3004                 }
3005
3006                 public override Expression ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3007                                                                 SimpleName original)
3008                 {
3009                         FieldInfo fi = TypeManager.GetGenericFieldDefinition (FieldInfo);
3010
3011                         Type t = fi.FieldType;
3012
3013                         if (fi.IsLiteral || (fi.IsInitOnly && t == TypeManager.decimal_type)) {
3014                                 IConstant ic = TypeManager.GetConstant (fi);
3015                                 if (ic == null) {
3016                                         if (fi.IsLiteral) {
3017                                                 ic = new ExternalConstant (fi);
3018                                         } else {
3019                                                 ic = ExternalConstant.CreateDecimal (fi);
3020                                                 if (ic == null) {
3021                                                         return base.ResolveMemberAccess (ec, left, loc, original);
3022                                                 }
3023                                         }
3024                                         TypeManager.RegisterConstant (fi, ic);
3025                                 }
3026
3027                                 bool left_is_type = left is TypeExpr;
3028                                 if (!left_is_type && (original == null || !original.IdenticalNameAndTypeName (ec, left, loc))) {
3029                                         Report.SymbolRelatedToPreviousError (FieldInfo);
3030                                         error176 (loc, TypeManager.GetFullNameSignature (FieldInfo));
3031                                         return null;
3032                                 }
3033
3034                                 if (ic.ResolveValue ()) {
3035                                         if (!ec.IsInObsoleteScope)
3036                                                 ic.CheckObsoleteness (loc);
3037                                 }
3038
3039                                 return ic.Value;
3040                         }
3041
3042                         if (t.IsPointer && !ec.InUnsafe) {
3043                                 UnsafeError (loc);
3044                                 return null;
3045                         }
3046
3047                         return base.ResolveMemberAccess (ec, left, loc, original);
3048                 }
3049
3050                 override public Expression DoResolve (EmitContext ec)
3051                 {
3052                         return DoResolve (ec, false);
3053                 }
3054
3055                 Expression DoResolve (EmitContext ec, bool lvalue_instance)
3056                 {
3057                         if (ec.InRefOutArgumentResolving && FieldInfo.IsInitOnly && !ec.IsConstructor && FieldInfo.FieldType.IsValueType) {
3058                                 if (FieldInfo.FieldType is TypeBuilder) {
3059                                         if (FieldInfo.IsStatic)
3060                                                 Report.Error (1651, loc, "Fields of static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
3061                                                         GetSignatureForError ());
3062                                         else
3063                                                 Report.Error (1649, loc, "Members of readonly field `{0}.{1}' cannot be passed ref or out (except in a constructor)",
3064                                                         TypeManager.CSharpName (DeclaringType), Name);
3065                                 } else {
3066                                         if (FieldInfo.IsStatic)
3067                                                 Report.Error (199, loc, "A static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
3068                                                         Name);
3069                                         else
3070                                                 Report.Error (192, loc, "A readonly field `{0}' cannot be passed ref or out (except in a constructor)",
3071                                                         Name);
3072                                 }
3073                                 return null;
3074                         }
3075
3076                         if (!FieldInfo.IsStatic){
3077                                 if (InstanceExpression == null){
3078                                         //
3079                                         // This can happen when referencing an instance field using
3080                                         // a fully qualified type expression: TypeName.InstanceField = xxx
3081                                         //
3082                                         SimpleName.Error_ObjectRefRequired (ec, loc, FieldInfo.Name);
3083                                         return null;
3084                                 }
3085
3086                                 // Resolve the field's instance expression while flow analysis is turned
3087                                 // off: when accessing a field "a.b", we must check whether the field
3088                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
3089
3090                                 if (lvalue_instance) {
3091                                         bool old_do_flow_analysis = ec.DoFlowAnalysis;
3092                                         ec.DoFlowAnalysis = false;
3093                                         InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess, loc);
3094                                         ec.DoFlowAnalysis = old_do_flow_analysis;
3095                                 } else {
3096                                         ResolveFlags rf = ResolveFlags.VariableOrValue | ResolveFlags.DisableFlowAnalysis;
3097                                         InstanceExpression = InstanceExpression.Resolve (ec, rf);
3098                                 }
3099
3100                                 if (InstanceExpression == null)
3101                                         return null;
3102                         }
3103
3104                         if (!in_initializer && !ec.IsFieldInitializer) {
3105                                 ObsoleteAttribute oa;
3106                                 FieldBase f = TypeManager.GetField (FieldInfo);
3107                                 if (f != null) {
3108                                         if (!ec.IsInObsoleteScope)
3109                                                 f.CheckObsoleteness (loc);
3110
3111                                         // To be sure that type is external because we do not register generated fields
3112                                 } else if (!(FieldInfo.DeclaringType is TypeBuilder)) {
3113                                         oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
3114                                         if (oa != null)
3115                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
3116                                 }
3117                         }
3118
3119                         AnonymousContainer am = ec.CurrentAnonymousMethod;
3120                         if (am != null){
3121                                 if (!FieldInfo.IsStatic){
3122                                         if (!am.IsIterator && (ec.TypeContainer is Struct)){
3123                                                 Report.Error (1673, loc,
3124                                                 "Anonymous methods inside structs cannot access instance members of `{0}'. Consider copying `{0}' to a local variable outside the anonymous method and using the local instead",
3125                                                         "this");
3126                                                 return null;
3127                                         }
3128                                         if ((am.ContainerAnonymousMethod == null) && (InstanceExpression is This))
3129                                                 ec.CaptureField (this);
3130                                 }
3131                         }
3132
3133                         // If the instance expression is a local variable or parameter.
3134                         IVariable var = InstanceExpression as IVariable;
3135                         if ((var == null) || (var.VariableInfo == null))
3136                                 return this;
3137
3138                         VariableInfo vi = var.VariableInfo;
3139                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
3140                                 return null;
3141
3142                         variable_info = vi.GetSubStruct (FieldInfo.Name);
3143                         return this;
3144                 }
3145
3146                 void Report_AssignToReadonly (Expression right_side)
3147                 {
3148                         int code;
3149                         string msg;
3150                         bool need_error_sig = false;
3151                         if (right_side == EmptyExpression.LValueMemberAccess) {
3152                                 if (IsStatic) {
3153                                         code = 1650;
3154                                         msg = "Fields of static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)";
3155                                 } else {
3156                                         code = 1648;
3157                                         msg = "Members of readonly field `{0}' cannot be modified (except in a constructor or a variable initializer)";
3158                                 }
3159                                 need_error_sig = true;
3160                         } else if (IsStatic) {
3161                                 code = 198;
3162                                 msg = "A static readonly field cannot be assigned to (except in a static constructor or a variable initializer)";
3163                         } else {
3164                                 code = 191;
3165                                 msg = "A readonly field cannot be assigned to (except in a constructor or a variable initializer)";
3166                         }
3167
3168                         if (need_error_sig)
3169                                 Report.Error (code, loc, msg, GetSignatureForError ());
3170                         else
3171                                 Report.Error (code, loc, msg);
3172                 }
3173
3174                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3175                 {
3176                         IVariable var = InstanceExpression as IVariable;
3177                         if ((var != null) && (var.VariableInfo != null))
3178                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
3179
3180                         bool lvalue_instance = !FieldInfo.IsStatic && FieldInfo.DeclaringType.IsValueType;
3181
3182                         Expression e = DoResolve (ec, lvalue_instance);
3183
3184                         if (e == null)
3185                                 return null;
3186
3187                         FieldBase fb = TypeManager.GetField (FieldInfo);
3188                         if (fb != null)
3189                                 fb.SetAssigned ();
3190
3191                         if (!FieldInfo.IsInitOnly)
3192                                 return this;
3193
3194                         //
3195                         // InitOnly fields can only be assigned in constructors or initializers
3196                         //
3197
3198                         if (ec.IsFieldInitializer)
3199                                 return this;
3200
3201                         if (ec.IsConstructor){
3202                                 if (IsStatic && !ec.IsStatic)
3203                                         Report_AssignToReadonly (right_side);
3204
3205                                 Type ctype;
3206                                 if (ec.TypeContainer.CurrentType != null)
3207                                         ctype = ec.TypeContainer.CurrentType;
3208                                 else
3209                                         ctype = ec.ContainerType;
3210
3211                                 if (TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
3212                                         return this;
3213                         }
3214
3215                         Report_AssignToReadonly (right_side);
3216
3217                         return null;
3218                 }
3219
3220                 public override void CheckMarshallByRefAccess (Type container)
3221                 {
3222                         if (!IsStatic && Type.IsValueType && !container.IsSubclassOf (TypeManager.mbr_type) && DeclaringType.IsSubclassOf (TypeManager.mbr_type)) {
3223                                 Report.SymbolRelatedToPreviousError (DeclaringType);
3224                                 Report.Error (1690, loc, "Cannot call methods, properties, or indexers on `{0}' because it is a value type member of a marshal-by-reference class",
3225                                         GetSignatureForError ());
3226                         }
3227                 }
3228
3229                 public bool VerifyFixed ()
3230                 {
3231                         IVariable variable = InstanceExpression as IVariable;
3232                         // A variable of the form V.I is fixed when V is a fixed variable of a struct type.
3233                         // We defer the InstanceExpression check after the variable check to avoid a
3234                         // separate null check on InstanceExpression.
3235                         return variable != null && InstanceExpression.Type.IsValueType && variable.VerifyFixed ();
3236                 }
3237
3238                 public override int GetHashCode()
3239                 {
3240                         return FieldInfo.GetHashCode ();
3241                 }
3242
3243                 public override bool Equals (object obj)
3244                 {
3245                         FieldExpr fe = obj as FieldExpr;
3246                         if (fe == null)
3247                                 return false;
3248
3249                         if (FieldInfo != fe.FieldInfo)
3250                                 return false;
3251
3252                         if (InstanceExpression == null || fe.InstanceExpression == null)
3253                                 return true;
3254
3255                         return InstanceExpression.Equals (fe.InstanceExpression);
3256                 }
3257
3258                 public void Emit (EmitContext ec, bool leave_copy)
3259                 {
3260                         ILGenerator ig = ec.ig;
3261                         bool is_volatile = false;
3262
3263                         FieldBase f = TypeManager.GetField (FieldInfo);
3264                         if (f != null){
3265                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
3266                                         is_volatile = true;
3267
3268                                 f.SetMemberIsUsed ();
3269                         }
3270
3271                         if (FieldInfo.IsStatic){
3272                                 if (is_volatile)
3273                                         ig.Emit (OpCodes.Volatile);
3274
3275                                 ig.Emit (OpCodes.Ldsfld, FieldInfo);
3276                         } else {
3277                                 if (!prepared)
3278                                         EmitInstance (ec, false);
3279
3280                                 if (is_volatile)
3281                                         ig.Emit (OpCodes.Volatile);
3282
3283                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
3284                                 if (ff != null)
3285                                 {
3286                                         ig.Emit (OpCodes.Ldflda, FieldInfo);
3287                                         ig.Emit (OpCodes.Ldflda, ff.Element);
3288                                 }
3289                                 else {
3290                                         ig.Emit (OpCodes.Ldfld, FieldInfo);
3291                                 }
3292                         }
3293
3294                         if (leave_copy) {
3295                                 ec.ig.Emit (OpCodes.Dup);
3296                                 if (!FieldInfo.IsStatic) {
3297                                         temp = new LocalTemporary (this.Type);
3298                                         temp.Store (ec);
3299                                 }
3300                         }
3301                 }
3302
3303                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
3304                 {
3305                         FieldAttributes fa = FieldInfo.Attributes;
3306                         bool is_static = (fa & FieldAttributes.Static) != 0;
3307                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
3308                         ILGenerator ig = ec.ig;
3309                         prepared = prepare_for_load;
3310
3311                         if (is_readonly && !ec.IsConstructor){
3312                                 Report_AssignToReadonly (source);
3313                                 return;
3314                         }
3315
3316                         EmitInstance (ec, prepare_for_load);
3317
3318                         source.Emit (ec);
3319                         if (leave_copy) {
3320                                 ec.ig.Emit (OpCodes.Dup);
3321                                 if (!FieldInfo.IsStatic) {
3322                                         temp = new LocalTemporary (this.Type);
3323                                         temp.Store (ec);
3324                                 }
3325                         }
3326
3327                         if (FieldInfo is FieldBuilder){
3328                                 FieldBase f = TypeManager.GetField (FieldInfo);
3329                                 if (f != null){
3330                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0)
3331                                                 ig.Emit (OpCodes.Volatile);
3332
3333                                         f.SetAssigned ();
3334                                 }
3335                         }
3336
3337                         if (is_static)
3338                                 ig.Emit (OpCodes.Stsfld, FieldInfo);
3339                         else
3340                                 ig.Emit (OpCodes.Stfld, FieldInfo);
3341
3342                         if (temp != null)
3343                                 temp.Emit (ec);
3344                 }
3345
3346                 public override void Emit (EmitContext ec)
3347                 {
3348                         Emit (ec, false);
3349                 }
3350
3351                 public void AddressOf (EmitContext ec, AddressOp mode)
3352                 {
3353                         ILGenerator ig = ec.ig;
3354
3355                         if (FieldInfo is FieldBuilder){
3356                                 FieldBase f = TypeManager.GetField (FieldInfo);
3357                                 if (f != null){
3358                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0){
3359                                                 Report.Warning (420, 1, loc, "`{0}': A volatile fields cannot be passed using a ref or out parameter",
3360                                                         f.GetSignatureForError ());
3361                                                 return;
3362                                         }
3363
3364                                         if ((mode & AddressOp.Store) != 0)
3365                                                 f.SetAssigned ();
3366                                         if ((mode & AddressOp.Load) != 0)
3367                                                 f.SetMemberIsUsed ();
3368                                 }
3369                         }
3370
3371                         //
3372                         // Handle initonly fields specially: make a copy and then
3373                         // get the address of the copy.
3374                         //
3375                         bool need_copy;
3376                         if (FieldInfo.IsInitOnly){
3377                                 need_copy = true;
3378                                 if (ec.IsConstructor){
3379                                         if (FieldInfo.IsStatic){
3380                                                 if (ec.IsStatic)
3381                                                         need_copy = false;
3382                                         } else
3383                                                 need_copy = false;
3384                                 }
3385                         } else
3386                                 need_copy = false;
3387
3388                         if (need_copy){
3389                                 LocalBuilder local;
3390                                 Emit (ec);
3391                                 local = ig.DeclareLocal (type);
3392                                 ig.Emit (OpCodes.Stloc, local);
3393                                 ig.Emit (OpCodes.Ldloca, local);
3394                                 return;
3395                         }
3396
3397
3398                         if (FieldInfo.IsStatic){
3399                                 ig.Emit (OpCodes.Ldsflda, FieldInfo);
3400                         } else {
3401                                 if (!prepared)
3402                                         EmitInstance (ec, false);
3403                                 ig.Emit (OpCodes.Ldflda, FieldInfo);
3404                         }
3405                 }
3406         }
3407
3408         //
3409         // A FieldExpr whose address can not be taken
3410         //
3411         public class FieldExprNoAddress : FieldExpr, IMemoryLocation {
3412                 public FieldExprNoAddress (FieldInfo fi, Location loc) : base (fi, loc)
3413                 {
3414                 }
3415
3416                 public new void AddressOf (EmitContext ec, AddressOp mode)
3417                 {
3418                         Report.Error (-215, "Report this: Taking the address of a remapped parameter not supported");
3419                 }
3420         }
3421
3422         /// <summary>
3423         ///   Expression that evaluates to a Property.  The Assign class
3424         ///   might set the `Value' expression if we are in an assignment.
3425         ///
3426         ///   This is not an LValue because we need to re-write the expression, we
3427         ///   can not take data from the stack and store it.
3428         /// </summary>
3429         public class PropertyExpr : MemberExpr, IAssignMethod {
3430                 public readonly PropertyInfo PropertyInfo;
3431
3432                 //
3433                 // This is set externally by the  `BaseAccess' class
3434                 //
3435                 public bool IsBase;
3436                 MethodInfo getter, setter;
3437                 bool is_static;
3438
3439                 bool resolved;
3440
3441                 LocalTemporary temp;
3442                 bool prepared;
3443
3444                 internal static PtrHashtable AccessorTable = new PtrHashtable ();
3445
3446                 public PropertyExpr (Type containerType, PropertyInfo pi, Location l)
3447                 {
3448                         PropertyInfo = pi;
3449                         eclass = ExprClass.PropertyAccess;
3450                         is_static = false;
3451                         loc = l;
3452
3453                         type = TypeManager.TypeToCoreType (pi.PropertyType);
3454
3455                         ResolveAccessors (containerType);
3456                 }
3457
3458                 public override string Name {
3459                         get {
3460                                 return PropertyInfo.Name;
3461                         }
3462                 }
3463
3464                 public override bool IsInstance {
3465                         get {
3466                                 return !is_static;
3467                         }
3468                 }
3469
3470                 public override bool IsStatic {
3471                         get {
3472                                 return is_static;
3473                         }
3474                 }
3475
3476                 public override Type DeclaringType {
3477                         get {
3478                                 return PropertyInfo.DeclaringType;
3479                         }
3480                 }
3481
3482                 public override string GetSignatureForError ()
3483                 {
3484                         return TypeManager.GetFullNameSignature (PropertyInfo);
3485                 }
3486
3487                 void FindAccessors (Type invocation_type)
3488                 {
3489                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
3490                                 BindingFlags.Static | BindingFlags.Instance |
3491                                 BindingFlags.DeclaredOnly;
3492
3493                         Type current = PropertyInfo.DeclaringType;
3494                         for (; current != null; current = current.BaseType) {
3495                                 MemberInfo[] group = TypeManager.MemberLookup (
3496                                         invocation_type, invocation_type, current,
3497                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
3498
3499                                 if (group == null)
3500                                         continue;
3501
3502                                 if (group.Length != 1)
3503                                         // Oooops, can this ever happen ?
3504                                         return;
3505
3506                                 PropertyInfo pi = (PropertyInfo) group [0];
3507
3508                                 if (getter == null)
3509                                         getter = pi.GetGetMethod (true);
3510
3511                                 if (setter == null)
3512                                         setter = pi.GetSetMethod (true);
3513
3514                                 MethodInfo accessor = getter != null ? getter : setter;
3515
3516                                 if (!accessor.IsVirtual)
3517                                         return;
3518                         }
3519                 }
3520
3521                 //
3522                 // We also perform the permission checking here, as the PropertyInfo does not
3523                 // hold the information for the accessibility of its setter/getter
3524                 //
3525                 // TODO: can use TypeManager.GetProperty to boost performance
3526                 void ResolveAccessors (Type containerType)
3527                 {
3528                         FindAccessors (containerType);
3529
3530                         if (getter != null) {
3531                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
3532                                 IMethodData md = TypeManager.GetMethod (the_getter);
3533                                 if (md != null)
3534                                         md.SetMemberIsUsed ();
3535
3536                                 AccessorTable [getter] = PropertyInfo;
3537                                 is_static = getter.IsStatic;
3538                         }
3539
3540                         if (setter != null) {
3541                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
3542                                 IMethodData md = TypeManager.GetMethod (the_setter);
3543                                 if (md != null)
3544                                         md.SetMemberIsUsed ();
3545
3546                                 AccessorTable [setter] = PropertyInfo;
3547                                 is_static = setter.IsStatic;
3548                         }
3549                 }
3550
3551                 bool InstanceResolve (EmitContext ec, bool lvalue_instance, bool must_do_cs1540_check)
3552                 {
3553                         if (is_static) {
3554                                 InstanceExpression = null;
3555                                 return true;
3556                         }
3557
3558                         if (InstanceExpression == null) {
3559                                 SimpleName.Error_ObjectRefRequired (ec, loc, PropertyInfo.Name);
3560                                 return false;
3561                         }
3562
3563                         if (lvalue_instance)
3564                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess, loc);
3565                         else
3566                                 InstanceExpression = InstanceExpression.DoResolve (ec);
3567                         if (InstanceExpression == null)
3568                                 return false;
3569
3570                         InstanceExpression.CheckMarshallByRefAccess (ec.ContainerType);
3571
3572                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
3573                             InstanceExpression.Type != ec.ContainerType &&
3574                             ec.ContainerType.IsSubclassOf (PropertyInfo.DeclaringType) &&
3575                             !InstanceExpression.Type.IsSubclassOf (ec.ContainerType)) {
3576                                 Error_CannotAccessProtected (loc, PropertyInfo, InstanceExpression.Type, ec.ContainerType);
3577                                 return false;
3578                         }
3579
3580                         return true;
3581                 }
3582
3583                 void Error_PropertyNotFound (MethodInfo mi, bool getter)
3584                 {
3585                         // TODO: correctly we should compare arguments but it will lead to bigger changes
3586                         if (mi is MethodBuilder) {
3587                                 Error_TypeDoesNotContainDefinition (loc, PropertyInfo.DeclaringType, Name);
3588                                 return;
3589                         }
3590
3591                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
3592                         sig.Append ('.');
3593                         ParameterData iparams = TypeManager.GetParameterData (mi);
3594                         sig.Append (getter ? "get_" : "set_");
3595                         sig.Append (Name);
3596                         sig.Append (iparams.GetSignatureForError ());
3597
3598                         Report.SymbolRelatedToPreviousError (mi);
3599                         Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
3600                                 Name, sig.ToString ());
3601                 }
3602
3603                 override public Expression DoResolve (EmitContext ec)
3604                 {
3605                         if (resolved)
3606                                 return this;
3607
3608                         if (getter != null){
3609                                 if (TypeManager.GetParameterData (getter).Count != 0){
3610                                         Error_PropertyNotFound (getter, true);
3611                                         return null;
3612                                 }
3613                         }
3614
3615                         if (getter == null){
3616                                 //
3617                                 // The following condition happens if the PropertyExpr was
3618                                 // created, but is invalid (ie, the property is inaccessible),
3619                                 // and we did not want to embed the knowledge about this in
3620                                 // the caller routine.  This only avoids double error reporting.
3621                                 //
3622                                 if (setter == null)
3623                                         return null;
3624
3625                                 if (InstanceExpression != EmptyExpression.Null) {
3626                                         Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
3627                                                 TypeManager.GetFullNameSignature (PropertyInfo));
3628                                         return null;
3629                                 }
3630                         }
3631
3632                         bool must_do_cs1540_check = false;
3633                         if (getter != null &&
3634                             !IsAccessorAccessible (ec.ContainerType, getter, out must_do_cs1540_check)) {
3635                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter) as PropertyBase.PropertyMethod;
3636                                 if (pm != null && pm.HasCustomAccessModifier) {
3637                                         Report.SymbolRelatedToPreviousError (pm);
3638                                         Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
3639                                                 TypeManager.CSharpSignature (getter));
3640                                 }
3641                                 else
3642                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter));
3643                                 return null;
3644                         }
3645
3646                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
3647                                 return null;
3648
3649                         //
3650                         // Only base will allow this invocation to happen.
3651                         //
3652                         if (IsBase && getter.IsAbstract) {
3653                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
3654                                 return null;
3655                         }
3656
3657                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe){
3658                                 UnsafeError (loc);
3659                                 return null;
3660                         }
3661
3662                         resolved = true;
3663
3664                         return this;
3665                 }
3666
3667                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3668                 {
3669                         if (right_side == EmptyExpression.OutAccess) {
3670                                 Report.Error (206, loc, "A property or indexer `{0}' may not be passed as an out or ref parameter",
3671                                               GetSignatureForError ());
3672                                 return null;
3673                         }
3674
3675                         if (right_side == EmptyExpression.LValueMemberAccess) {
3676                                 Report.Error (1612, loc, "Cannot modify the return value of `{0}' because it is not a variable",
3677                                               GetSignatureForError ());
3678                                 return null;
3679                         }
3680
3681                         if (setter == null){
3682                                 //
3683                                 // The following condition happens if the PropertyExpr was
3684                                 // created, but is invalid (ie, the property is inaccessible),
3685                                 // and we did not want to embed the knowledge about this in
3686                                 // the caller routine.  This only avoids double error reporting.
3687                                 //
3688                                 if (getter == null)
3689                                         return null;
3690                                 Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
3691                                               GetSignatureForError ());
3692                                 return null;
3693                         }
3694
3695                         if (TypeManager.GetParameterData (setter).Count != 1){
3696                                 Error_PropertyNotFound (setter, false);
3697                                 return null;
3698                         }
3699
3700                         bool must_do_cs1540_check;
3701                         if (!IsAccessorAccessible (ec.ContainerType, setter, out must_do_cs1540_check)) {
3702                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter) as PropertyBase.PropertyMethod;
3703                                 if (pm != null && pm.HasCustomAccessModifier) {
3704                                         Report.SymbolRelatedToPreviousError (pm);
3705                                         Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
3706                                                 TypeManager.CSharpSignature (setter));
3707                                 }
3708                                 else
3709                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter));
3710                                 return null;
3711                         }
3712
3713                         if (!InstanceResolve (ec, PropertyInfo.DeclaringType.IsValueType, must_do_cs1540_check))
3714                                 return null;
3715
3716                         //
3717                         // Only base will allow this invocation to happen.
3718                         //
3719                         if (IsBase && setter.IsAbstract){
3720                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
3721                                 return null;
3722                         }
3723
3724                         return this;
3725                 }
3726
3727                 public override void Emit (EmitContext ec)
3728                 {
3729                         Emit (ec, false);
3730                 }
3731
3732                 public void Emit (EmitContext ec, bool leave_copy)
3733                 {
3734                         //
3735                         // Special case: length of single dimension array property is turned into ldlen
3736                         //
3737                         if ((getter == TypeManager.system_int_array_get_length) ||
3738                             (getter == TypeManager.int_array_get_length)){
3739                                 Type iet = InstanceExpression.Type;
3740
3741                                 //
3742                                 // System.Array.Length can be called, but the Type does not
3743                                 // support invoking GetArrayRank, so test for that case first
3744                                 //
3745                                 if (iet != TypeManager.array_type && (iet.GetArrayRank () == 1)) {
3746                                         if (!prepared)
3747                                                 EmitInstance (ec, false);
3748                                         ec.ig.Emit (OpCodes.Ldlen);
3749                                         ec.ig.Emit (OpCodes.Conv_I4);
3750                                         return;
3751                                 }
3752                         }
3753
3754                         Invocation.EmitCall (ec, IsBase, IsStatic, InstanceExpression, getter, null, loc, prepared, false);
3755
3756                         if (leave_copy) {
3757                                 ec.ig.Emit (OpCodes.Dup);
3758                                 if (!is_static) {
3759                                         temp = new LocalTemporary (this.Type);
3760                                         temp.Store (ec);
3761                                 }
3762                         }
3763                 }
3764
3765                 //
3766                 // Implements the IAssignMethod interface for assignments
3767                 //
3768                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
3769                 {
3770                         Expression my_source = source;
3771
3772                         prepared = prepare_for_load;
3773
3774                         if (prepared) {
3775                                 source.Emit (ec);
3776                                 if (leave_copy) {
3777                                         ec.ig.Emit (OpCodes.Dup);
3778                                         if (!is_static) {
3779                                                 temp = new LocalTemporary (this.Type);
3780                                                 temp.Store (ec);
3781                                         }
3782                                 }
3783                         } else if (leave_copy) {
3784                                 source.Emit (ec);
3785                                 if (!is_static) {
3786                                         temp = new LocalTemporary (this.Type);
3787                                         temp.Store (ec);
3788                                 }
3789                                 my_source = temp;
3790                         }
3791
3792                         ArrayList args = new ArrayList (1);
3793                         args.Add (new Argument (my_source, Argument.AType.Expression));
3794
3795                         Invocation.EmitCall (ec, IsBase, IsStatic, InstanceExpression, setter, args, loc, false, prepared);
3796
3797                         if (temp != null)
3798                                 temp.Emit (ec);
3799                 }
3800         }
3801
3802         /// <summary>
3803         ///   Fully resolved expression that evaluates to an Event
3804         /// </summary>
3805         public class EventExpr : MemberExpr {
3806                 public readonly EventInfo EventInfo;
3807
3808                 bool is_static;
3809                 MethodInfo add_accessor, remove_accessor;
3810
3811                 public EventExpr (EventInfo ei, Location loc)
3812                 {
3813                         EventInfo = ei;
3814                         this.loc = loc;
3815                         eclass = ExprClass.EventAccess;
3816
3817                         add_accessor = TypeManager.GetAddMethod (ei);
3818                         remove_accessor = TypeManager.GetRemoveMethod (ei);
3819
3820                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
3821                                 is_static = true;
3822
3823                         if (EventInfo is MyEventBuilder){
3824                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
3825                                 type = eb.EventType;
3826                                 eb.SetUsed ();
3827                         } else
3828                                 type = EventInfo.EventHandlerType;
3829                 }
3830
3831                 public override string Name {
3832                         get {
3833                                 return EventInfo.Name;
3834                         }
3835                 }
3836
3837                 public override bool IsInstance {
3838                         get {
3839                                 return !is_static;
3840                         }
3841                 }
3842
3843                 public override bool IsStatic {
3844                         get {
3845                                 return is_static;
3846                         }
3847                 }
3848
3849                 public override Type DeclaringType {
3850                         get {
3851                                 return EventInfo.DeclaringType;
3852                         }
3853                 }
3854
3855                 public override Expression ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3856                                                                 SimpleName original)
3857                 {
3858                         //
3859                         // If the event is local to this class, we transform ourselves into a FieldExpr
3860                         //
3861
3862                         if (EventInfo.DeclaringType == ec.ContainerType ||
3863                             TypeManager.IsNestedChildOf(ec.ContainerType, EventInfo.DeclaringType)) {
3864                                 MemberInfo mi = TypeManager.GetPrivateFieldOfEvent (EventInfo);
3865
3866                                 if (mi != null) {
3867                                         MemberExpr ml = (MemberExpr) ExprClassFromMemberInfo (ec.ContainerType, mi, loc);
3868
3869                                         if (ml == null) {
3870                                                 Report.Error (-200, loc, "Internal error!!");
3871                                                 return null;
3872                                         }
3873
3874                                         InstanceExpression = null;
3875
3876                                         return ml.ResolveMemberAccess (ec, left, loc, original);
3877                                 }
3878                         }
3879
3880                         return base.ResolveMemberAccess (ec, left, loc, original);
3881                 }
3882
3883
3884                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
3885                 {
3886                         if (is_static) {
3887                                 InstanceExpression = null;
3888                                 return true;
3889                         }
3890
3891                         if (InstanceExpression == null) {
3892                                 SimpleName.Error_ObjectRefRequired (ec, loc, EventInfo.Name);
3893                                 return false;
3894                         }
3895
3896                         InstanceExpression = InstanceExpression.DoResolve (ec);
3897                         if (InstanceExpression == null)
3898                                 return false;
3899
3900                         //
3901                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
3902                         // However, in the Event case, we reported a CS0122 instead.
3903                         //
3904                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
3905                             InstanceExpression.Type != ec.ContainerType &&
3906                             ec.ContainerType.IsSubclassOf (InstanceExpression.Type)) {
3907                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
3908                                 return false;
3909                         }
3910
3911                         return true;
3912                 }
3913
3914                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
3915                 {
3916                         return DoResolve (ec);
3917                 }
3918
3919                 public override Expression DoResolve (EmitContext ec)
3920                 {
3921                         bool must_do_cs1540_check;
3922                         if (!(IsAccessorAccessible (ec.ContainerType, add_accessor, out must_do_cs1540_check) &&
3923                               IsAccessorAccessible (ec.ContainerType, remove_accessor, out must_do_cs1540_check))) {
3924                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
3925                                 return null;
3926                         }
3927
3928                         if (!InstanceResolve (ec, must_do_cs1540_check))
3929                                 return null;
3930
3931                         return this;
3932                 }
3933
3934                 public override void Emit (EmitContext ec)
3935                 {
3936                         if (InstanceExpression is This)
3937                                 Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of += or -=", GetSignatureForError ());
3938                         else
3939                                 Report.Error (70, loc, "The event `{0}' can only appear on the left hand side of += or -= "+
3940                                               "(except on the defining type)", Name);
3941                 }
3942
3943                 public override string GetSignatureForError ()
3944                 {
3945                         return TypeManager.CSharpSignature (EventInfo);
3946                 }
3947
3948                 public void EmitAddOrRemove (EmitContext ec, Expression source)
3949                 {
3950                         BinaryDelegate source_del = (BinaryDelegate) source;
3951                         Expression handler = source_del.Right;
3952
3953                         Argument arg = new Argument (handler, Argument.AType.Expression);
3954                         ArrayList args = new ArrayList ();
3955
3956                         args.Add (arg);
3957
3958                         if (source_del.IsAddition)
3959                                 Invocation.EmitCall (
3960                                         ec, false, IsStatic, InstanceExpression, add_accessor, args, loc);
3961                         else
3962                                 Invocation.EmitCall (
3963                                         ec, false, IsStatic, InstanceExpression, remove_accessor, args, loc);
3964                 }
3965         }
3966
3967
3968         public class TemporaryVariable : Expression, IMemoryLocation
3969         {
3970                 LocalInfo li;
3971
3972                 public TemporaryVariable (Type type, Location loc)
3973                 {
3974                         this.type = type;
3975                         this.loc = loc;
3976                         eclass = ExprClass.Value;
3977                 }
3978
3979                 public override Expression DoResolve (EmitContext ec)
3980                 {
3981                         if (li != null)
3982                                 return this;
3983
3984                         TypeExpr te = new TypeExpression (type, loc);
3985                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
3986                         if (!li.Resolve (ec))
3987                                 return null;
3988
3989                         AnonymousContainer am = ec.CurrentAnonymousMethod;
3990                         if ((am != null) && am.IsIterator)
3991                                 ec.CaptureVariable (li);
3992
3993                         return this;
3994                 }
3995
3996                 public override void Emit (EmitContext ec)
3997                 {
3998                         ILGenerator ig = ec.ig;
3999
4000                         if (li.FieldBuilder != null) {
4001                                 ig.Emit (OpCodes.Ldarg_0);
4002                                 ig.Emit (OpCodes.Ldfld, li.FieldBuilder);
4003                         } else {
4004                                 ig.Emit (OpCodes.Ldloc, li.LocalBuilder);
4005                         }
4006                 }
4007
4008                 public void EmitLoadAddress (EmitContext ec)
4009                 {
4010                         ILGenerator ig = ec.ig;
4011
4012                         if (li.FieldBuilder != null) {
4013                                 ig.Emit (OpCodes.Ldarg_0);
4014                                 ig.Emit (OpCodes.Ldflda, li.FieldBuilder);
4015                         } else {
4016                                 ig.Emit (OpCodes.Ldloca, li.LocalBuilder);
4017                         }
4018                 }
4019
4020                 public void Store (EmitContext ec, Expression right_side)
4021                 {
4022                         if (li.FieldBuilder != null)
4023                                 ec.ig.Emit (OpCodes.Ldarg_0);
4024
4025                         right_side.Emit (ec);
4026                         if (li.FieldBuilder != null) {
4027                                 ec.ig.Emit (OpCodes.Stfld, li.FieldBuilder);
4028                         } else {
4029                                 ec.ig.Emit (OpCodes.Stloc, li.LocalBuilder);
4030                         }
4031                 }
4032
4033                 public void EmitThis (EmitContext ec)
4034                 {
4035                         if (li.FieldBuilder != null) {
4036                                 ec.ig.Emit (OpCodes.Ldarg_0);
4037                         }
4038                 }
4039
4040                 public void EmitStore (ILGenerator ig)
4041                 {
4042                         if (li.FieldBuilder != null)
4043                                 ig.Emit (OpCodes.Stfld, li.FieldBuilder);
4044                         else
4045                                 ig.Emit (OpCodes.Stloc, li.LocalBuilder);
4046                 }
4047
4048                 public void AddressOf (EmitContext ec, AddressOp mode)
4049                 {
4050                         EmitLoadAddress (ec);
4051                 }
4052         }
4053
4054 }