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