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                 // Allows SimpleNames to be returned.
  55                 // This is used by MemberAccess to construct long names that can not be
  56                 // partially resolved (namespace-qualified names for example).
  57                 SimpleName              = 8,
  58
  59                 // Mask of all the expression class flags.
  60                 MaskExprClass           = 15,
  61
  62                 // Disable control flow analysis while resolving the expression.
  63                 // This is used when resolving the instance expression of a field expression.
  64                 DisableFlowAnalysis     = 16
  65         }
  66
  67         //
  68         // This is just as a hint to AddressOf of what will be done with the
  69         // address.
  70         [Flags]
  71         public enum AddressOp {
  72                 Store = 1,
  73                 Load  = 2,
  74                 LoadStore = 3
  75         };
  76
  77         /// <summary>
  78         ///   This interface is implemented by variables
  79         /// </summary>
  80         public interface IMemoryLocation {
  81                 /// <summary>
  82                 ///   The AddressOf method should generate code that loads
  83                 ///   the address of the object and leaves it on the stack.
  84                 ///
  85                 ///   The `mode' argument is used to notify the expression
  86                 ///   of whether this will be used to read from the address or
  87                 ///   write to the address.
  88                 ///
  89                 ///   This is just a hint that can be used to provide good error
  90                 ///   reporting, and should have no other side effects.
  91                 /// </summary>
  92                 void AddressOf (EmitContext ec, AddressOp mode);
  93         }
  94
  95         /// <summary>
  96         ///   We are either a namespace or a type.
  97         ///   If we're a type, `IsType' is true and we may use `Type' to get
  98         ///   a TypeExpr representing that type.
  99         /// </summary>
 100         public interface IAlias {
 101                 bool IsType {
 102                         get;
 103                 }
 104
 105                 string Name {
 106                         get;
 107                 }
 108
 109                 TypeExpr Type {
 110                         get;
 111                 }
 112         }
 113
 114         /// <summary>
 115         ///   This interface is implemented by variables
 116         /// </summary>
 117         public interface IVariable {
 118                 VariableInfo VariableInfo {
 119                         get;
 120                 }
 121
 122                 bool VerifyFixed (bool is_expression);
 123         }
 124
 125         /// <summary>
 126         ///   This interface denotes an expression which evaluates to a member
 127         ///   of a struct or a class.
 128         /// </summary>
 129         public interface IMemberExpr
 130         {
 131                 /// <summary>
 132                 ///   The name of this member.
 133                 /// </summary>
 134                 string Name {
 135                         get;
 136                 }
 137
 138                 /// <summary>
 139                 ///   Whether this is an instance member.
 140                 /// </summary>
 141                 bool IsInstance {
 142                         get;
 143                 }
 144
 145                 /// <summary>
 146                 ///   Whether this is a static member.
 147                 /// </summary>
 148                 bool IsStatic {
 149                         get;
 150                 }
 151
 152                 /// <summary>
 153                 ///   The type which declares this member.
 154                 /// </summary>
 155                 Type DeclaringType {
 156                         get;
 157                 }
 158
 159                 /// <summary>
 160                 ///   The instance expression associated with this member, if it's a
 161                 ///   non-static member.
 162                 /// </summary>
 163                 Expression InstanceExpression {
 164                         get; set;
 165                 }
 166         }
 167
 168         /// <remarks>
 169         ///   Base class for expressions
 170         /// </remarks>
 171         public abstract class Expression {
 172                 public ExprClass eclass;
 173                 protected Type type;
 174                 protected Location loc;
 175
 176                 public Type Type {
 177                         get {
 178                                 return type;
 179                         }
 180
 181                         set {
 182                                 type = value;
 183                         }
 184                 }
 185
 186                 public Location Location {
 187                         get {
 188                                 return loc;
 189                         }
 190                 }
 191
 192                 /// <summary>
 193                 ///   Utility wrapper routine for Error, just to beautify the code
 194                 /// </summary>
 195                 public void Error (int error, string s)
 196                 {
 197                         if (!Location.IsNull (loc))
 198                                 Report.Error (error, loc, s);
 199                         else
 200                                 Report.Error (error, s);
 201                 }
 202
 203                 /// <summary>
 204                 ///   Utility wrapper routine for Warning, just to beautify the code
 205                 /// </summary>
 206                 public void Warning (int warning, string s)
 207                 {
 208                         if (!Location.IsNull (loc))
 209                                 Report.Warning (warning, loc, s);
 210                         else
 211                                 Report.Warning (warning, s);
 212                 }
 213
 214                 /// <summary>
 215                 ///   Utility wrapper routine for Warning, only prints the warning if
 216                 ///   warnings of level `level' are enabled.
 217                 /// </summary>
 218                 public void Warning (int warning, int level, string s)
 219                 {
 220                         if (level <= RootContext.WarningLevel)
 221                                 Warning (warning, s);
 222                 }
 223
 224                 /// <summary>
 225                 ///   Performs semantic analysis on the Expression
 226                 /// </summary>
 227                 ///
 228                 /// <remarks>
 229                 ///   The Resolve method is invoked to perform the semantic analysis
 230                 ///   on the node.
 231                 ///
 232                 ///   The return value is an expression (it can be the
 233                 ///   same expression in some cases) or a new
 234                 ///   expression that better represents this node.
 235                 ///
 236                 ///   For example, optimizations of Unary (LiteralInt)
 237                 ///   would return a new LiteralInt with a negated
 238                 ///   value.
 239                 ///
 240                 ///   If there is an error during semantic analysis,
 241                 ///   then an error should be reported (using Report)
 242                 ///   and a null value should be returned.
 243                 ///
 244                 ///   There are two side effects expected from calling
 245                 ///   Resolve(): the the field variable "eclass" should
 246                 ///   be set to any value of the enumeration
 247                 ///   `ExprClass' and the type variable should be set
 248                 ///   to a valid type (this is the type of the
 249                 ///   expression).
 250                 /// </remarks>
 251                 public abstract Expression DoResolve (EmitContext ec);
 252
 253                 public virtual Expression DoResolveLValue (EmitContext ec, Expression right_side)
 254                 {
 255                         return DoResolve (ec);
 256                 }
 257
 258                 //
 259                 // This is used if the expression should be resolved as a type.
 260                 // the default implementation fails.   Use this method in
 261                 // those participants in the SimpleName chain system.
 262                 //
 263                 public virtual Expression ResolveAsTypeStep (EmitContext ec)
 264                 {
 265                         return null;
 266                 }
 267
 268                 //
 269                 // This is used to resolve the expression as a type, a null
 270                 // value will be returned if the expression is not a type
 271                 // reference
 272                 //
 273                 public TypeExpr ResolveAsTypeTerminal (EmitContext ec)
 274                 {
 275                         return ResolveAsTypeStep (ec) as TypeExpr;
 276                 }
 277
 278                 /// <summary>
 279                 ///   Resolves an expression and performs semantic analysis on it.
 280                 /// </summary>
 281                 ///
 282                 /// <remarks>
 283                 ///   Currently Resolve wraps DoResolve to perform sanity
 284                 ///   checking and assertion checking on what we expect from Resolve.
 285                 /// </remarks>
 286                 public Expression Resolve (EmitContext ec, ResolveFlags flags)
 287                 {
 288                         if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
 289                                 return ResolveAsTypeStep (ec);
 290
 291                         bool old_do_flow_analysis = ec.DoFlowAnalysis;
 292                         if ((flags & ResolveFlags.DisableFlowAnalysis) != 0)
 293                                 ec.DoFlowAnalysis = false;
 294
 295                         Expression e;
 296                         if (this is SimpleName)
 297                                 e = ((SimpleName) this).DoResolveAllowStatic (ec);
 298                         else
 299                                 e = DoResolve (ec);
 300
 301                         ec.DoFlowAnalysis = old_do_flow_analysis;
 302
 303                         if (e == null)
 304                                 return null;
 305
 306                         if (e is SimpleName){
 307                                 SimpleName s = (SimpleName) e;
 308
 309                                 if ((flags & ResolveFlags.SimpleName) == 0) {
 310                                         MemberLookupFailed (ec, null, ec.ContainerType, s.Name,
 311                                                             ec.DeclSpace.Name, loc);
 312                                         return null;
 313                                 }
 314
 315                                 return s;
 316                         }
 317
 318                         if ((e is TypeExpr) || (e is ComposedCast)) {
 319                                 if ((flags & ResolveFlags.Type) == 0) {
 320                                         e.Error_UnexpectedKind (flags);
 321                                         return null;
 322                                 }
 323
 324                                 return e;
 325                         }
 326
 327                         switch (e.eclass) {
 328                         case ExprClass.Type:
 329                                 if ((flags & ResolveFlags.VariableOrValue) == 0) {
 330                                         e.Error_UnexpectedKind (flags);
 331                                         return null;
 332                                 }
 333                                 break;
 334
 335                         case ExprClass.MethodGroup:
 336                                 if (!RootContext.V2){
 337                                 if ((flags & ResolveFlags.MethodGroup) == 0) {
 338                                         ((MethodGroupExpr) e).ReportUsageError ();
 339                                         return null;
 340                                 }
 341                                 }
 342                                 break;
 343
 344                         case ExprClass.Value:
 345                         case ExprClass.Variable:
 346                         case ExprClass.PropertyAccess:
 347                         case ExprClass.EventAccess:
 348                         case ExprClass.IndexerAccess:
 349                                 if ((flags & ResolveFlags.VariableOrValue) == 0) {
 350                                         Console.WriteLine ("I got: {0} and {1}", e.GetType (), e);
 351                                         Console.WriteLine ("I am {0} and {1}", this.GetType (), this);
 352                                         FieldInfo fi = ((FieldExpr) e).FieldInfo;
 353
 354                                         Console.WriteLine ("{0} and {1}", fi.DeclaringType, fi.Name);
 355                                         e.Error_UnexpectedKind (flags);
 356                                         return null;
 357                                 }
 358                                 break;
 359
 360                         default:
 361                                 throw new Exception ("Expression " + e.GetType () +
 362                                                      " ExprClass is Invalid after resolve");
 363                         }
 364
 365                         if (e.type == null)
 366                                 throw new Exception (
 367                                         "Expression " + e.GetType () +
 368                                         " did not set its type after Resolve\n" +
 369                                         "called from: " + this.GetType ());
 370
 371                         return e;
 372                 }
 373
 374                 /// <summary>
 375                 ///   Resolves an expression and performs semantic analysis on it.
 376                 /// </summary>
 377                 public Expression Resolve (EmitContext ec)
 378                 {
 379                         return Resolve (ec, ResolveFlags.VariableOrValue);
 380                 }
 381
 382                 /// <summary>
 383                 ///   Resolves an expression for LValue assignment
 384                 /// </summary>
 385                 ///
 386                 /// <remarks>
 387                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 388                 ///   checking and assertion checking on what we expect from Resolve
 389                 /// </remarks>
 390                 public Expression ResolveLValue (EmitContext ec, Expression right_side)
 391                 {
 392                         Expression e = DoResolveLValue (ec, right_side);
 393
 394                         if (e != null){
 395                                 if (e is SimpleName){
 396                                         SimpleName s = (SimpleName) e;
 397                                         MemberLookupFailed (ec, null, ec.ContainerType, s.Name,
 398                                                             ec.DeclSpace.Name, loc);
 399                                         return null;
 400                                 }
 401
 402                                 if (e.eclass == ExprClass.Invalid)
 403                                         throw new Exception ("Expression " + e +
 404                                                              " ExprClass is Invalid after resolve");
 405
 406                                 if (e.eclass == ExprClass.MethodGroup) {
 407                                         ((MethodGroupExpr) e).ReportUsageError ();
 408                                         return null;
 409                                 }
 410
 411                                 if ((e.type == null) && !(e is ConstructedType))
 412                                         throw new Exception ("Expression " + e +
 413                                                              " did not set its type after Resolve");
 414                         }
 415
 416                         return e;
 417                 }
 418
 419                 /// <summary>
 420                 ///   Emits the code for the expression
 421                 /// </summary>
 422                 ///
 423                 /// <remarks>
 424                 ///   The Emit method is invoked to generate the code
 425                 ///   for the expression.
 426                 /// </remarks>
 427                 public abstract void Emit (EmitContext ec);
 428
 429                 public virtual void EmitBranchable (EmitContext ec, Label target, bool onTrue)
 430                 {
 431                         Emit (ec);
 432                         ec.ig.Emit (onTrue ? OpCodes.Brtrue : OpCodes.Brfalse, target);
 433                 }
 434
 435                 /// <summary>
 436                 ///   Protected constructor.  Only derivate types should
 437                 ///   be able to be created
 438                 /// </summary>
 439
 440                 protected Expression ()
 441                 {
 442                         eclass = ExprClass.Invalid;
 443                         type = null;
 444                 }
 445
 446                 /// <summary>
 447                 ///   Returns a literalized version of a literal FieldInfo
 448                 /// </summary>
 449                 ///
 450                 /// <remarks>
 451                 ///   The possible return values are:
 452                 ///      IntConstant, UIntConstant
 453                 ///      LongLiteral, ULongConstant
 454                 ///      FloatConstant, DoubleConstant
 455                 ///      StringConstant
 456                 ///
 457                 ///   The value returned is already resolved.
 458                 /// </remarks>
 459                 public static Constant Constantify (object v, Type t)
 460                 {
 461                         if (t == TypeManager.int32_type)
 462                                 return new IntConstant ((int) v);
 463                         else if (t == TypeManager.uint32_type)
 464                                 return new UIntConstant ((uint) v);
 465                         else if (t == TypeManager.int64_type)
 466                                 return new LongConstant ((long) v);
 467                         else if (t == TypeManager.uint64_type)
 468                                 return new ULongConstant ((ulong) v);
 469                         else if (t == TypeManager.float_type)
 470                                 return new FloatConstant ((float) v);
 471                         else if (t == TypeManager.double_type)
 472                                 return new DoubleConstant ((double) v);
 473                         else if (t == TypeManager.string_type)
 474                                 return new StringConstant ((string) v);
 475                         else if (t == TypeManager.short_type)
 476                                 return new ShortConstant ((short)v);
 477                         else if (t == TypeManager.ushort_type)
 478                                 return new UShortConstant ((ushort)v);
 479                         else if (t == TypeManager.sbyte_type)
 480                                 return new SByteConstant (((sbyte)v));
 481                         else if (t == TypeManager.byte_type)
 482                                 return new ByteConstant ((byte)v);
 483                         else if (t == TypeManager.char_type)
 484                                 return new CharConstant ((char)v);
 485                         else if (t == TypeManager.bool_type)
 486                                 return new BoolConstant ((bool) v);
 487                         else if (TypeManager.IsEnumType (t)){
 488                                 Constant e = Constantify (v, TypeManager.TypeToCoreType (v.GetType ()));
 489
 490                                 return new EnumConstant (e, t);
 491                         } else
 492                                 throw new Exception ("Unknown type for constant (" + t +
 493                                                      "), details: " + v);
 494                 }
 495
 496                 /// <summary>
 497                 ///   Returns a fully formed expression after a MemberLookup
 498                 /// </summary>
 499                 public static Expression ExprClassFromMemberInfo (EmitContext ec, MemberInfo mi, Location loc)
 500                 {
 501                         if (mi is EventInfo)
 502                                 return new EventExpr ((EventInfo) mi, loc);
 503                         else if (mi is FieldInfo)
 504                                 return new FieldExpr ((FieldInfo) mi, loc);
 505                         else if (mi is PropertyInfo)
 506                                 return new PropertyExpr (ec, (PropertyInfo) mi, loc);
 507                         else if (mi is Type){
 508                                 return new TypeExpression ((System.Type) mi, loc);
 509                         }
 510
 511                         return null;
 512                 }
 513
 514                 //
 515                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 516                 //
 517                 // This code could use some optimizations, but we need to do some
 518                 // measurements.  For example, we could use a delegate to `flag' when
 519                 // something can not any longer be a method-group (because it is something
 520                 // else).
 521                 //
 522                 // Return values:
 523                 //     If the return value is an Array, then it is an array of
 524                 //     MethodBases
 525                 //
 526                 //     If the return value is an MemberInfo, it is anything, but a Method
 527                 //
 528                 //     null on error.
 529                 //
 530                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 531                 // the arguments here and have MemberLookup return only the methods that
 532                 // match the argument count/type, unlike we are doing now (we delay this
 533                 // decision).
 534                 //
 535                 // This is so we can catch correctly attempts to invoke instance methods
 536                 // from a static body (scan for error 120 in ResolveSimpleName).
 537                 //
 538                 //
 539                 // FIXME: Potential optimization, have a static ArrayList
 540                 //
 541
 542                 public static Expression MemberLookup (EmitContext ec, Type queried_type, string name,
 543                                                        MemberTypes mt, BindingFlags bf, Location loc)
 544                 {
 545                         return MemberLookup (ec, ec.ContainerType, null, queried_type, name, mt, bf, loc);
 546                 }
 547
 548                 //
 549                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 550                 // `qualifier_type' or null to lookup members in the current class.
 551                 //
 552
 553                 public static Expression MemberLookup (EmitContext ec, Type container_type,
 554                                                        Type qualifier_type, Type queried_type,
 555                                                        string name, MemberTypes mt,
 556                                                        BindingFlags bf, Location loc)
 557                 {
 558                         MemberInfo [] mi = TypeManager.MemberLookup (
 559                                 container_type, qualifier_type,queried_type, mt, bf, name);
 560
 561                         if (mi == null)
 562                                 return null;
 563
 564                         int count = mi.Length;
 565
 566                         if (mi [0] is MethodBase)
 567                                 return new MethodGroupExpr (mi, loc);
 568
 569                         if (count > 1)
 570                                 return null;
 571
 572                         return ExprClassFromMemberInfo (ec, mi [0], loc);
 573                 }
 574
 575                 public const MemberTypes AllMemberTypes =
 576                         MemberTypes.Constructor |
 577                         MemberTypes.Event       |
 578                         MemberTypes.Field       |
 579                         MemberTypes.Method      |
 580                         MemberTypes.NestedType  |
 581                         MemberTypes.Property;
 582
 583                 public const BindingFlags AllBindingFlags =
 584                         BindingFlags.Public |
 585                         BindingFlags.Static |
 586                         BindingFlags.Instance;
 587
 588                 public static Expression MemberLookup (EmitContext ec, Type queried_type,
 589                                                        string name, Location loc)
 590                 {
 591                         return MemberLookup (ec, ec.ContainerType, null, queried_type, name,
 592                                              AllMemberTypes, AllBindingFlags, loc);
 593                 }
 594
 595                 public static Expression MemberLookup (EmitContext ec, Type qualifier_type,
 596                                                        Type queried_type, string name, Location loc)
 597                 {
 598                         return MemberLookup (ec, ec.ContainerType, qualifier_type, queried_type,
 599                                              name, AllMemberTypes, AllBindingFlags, loc);
 600                 }
 601
 602                 public static Expression MethodLookup (EmitContext ec, Type queried_type,
 603                                                        string name, Location loc)
 604                 {
 605                         return MemberLookup (ec, ec.ContainerType, null, queried_type, name,
 606                                              MemberTypes.Method, AllBindingFlags, loc);
 607                 }
 608
 609                 /// <summary>
 610                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 611                 ///   to find a final definition.  If the final definition is not found, we
 612                 ///   look for private members and display a useful debugging message if we
 613                 ///   find it.
 614                 /// </summary>
 615                 public static Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 616                                                             Type queried_type, string name,
 617                                                             Location loc)
 618                 {
 619                         return MemberLookupFinal (ec, qualifier_type, queried_type, name,
 620                                                   AllMemberTypes, AllBindingFlags, loc);
 621                 }
 622
 623                 public static Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 624                                                             Type queried_type, string name,
 625                                                             MemberTypes mt, BindingFlags bf,
 626                                                             Location loc)
 627                 {
 628                         Expression e;
 629
 630                         int errors = Report.Errors;
 631
 632                         e = MemberLookup (ec, ec.ContainerType, qualifier_type, queried_type,
 633                                           name, mt, bf, loc);
 634
 635                         if (e != null)
 636                                 return e;
 637
 638                         // Error has already been reported.
 639                         if (errors < Report.Errors)
 640                                 return null;
 641
 642                         MemberLookupFailed (ec, qualifier_type, queried_type, name,
 643                                             null, loc);
 644                         return null;
 645                 }
 646
 647                 public static void MemberLookupFailed (EmitContext ec, Type qualifier_type,
 648                                                        Type queried_type, string name,
 649                                                        string class_name, Location loc)
 650                 {
 651                         MemberInfo[] mi = TypeManager.MemberLookup (queried_type, null, queried_type,
 652                                                                     AllMemberTypes, AllBindingFlags |
 653                                                                     BindingFlags.NonPublic, name);
 654
 655                         if (mi == null) {
 656                                 if (class_name != null)
 657                                         Report.Error (103, loc, "The name `" + name + "' could not be " +
 658                                                       "found in `" + class_name + "'");
 659                                 else
 660                                         Report.Error (
 661                                                 117, loc, "`" + queried_type + "' does not contain a " +
 662                                                 "definition for `" + name + "'");
 663                                 return;
 664                         }
 665
 666                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 667                                                       AllMemberTypes, AllBindingFlags |
 668                                                       BindingFlags.NonPublic, name) == null) {
 669                                 if ((mi.Length == 1) && (mi [0] is Type)) {
 670                                         Type t = (Type) mi [0];
 671
 672                                         Report.Error (305, loc,
 673                                                       "Using the generic type `{0}' " +
 674                                                       "requires {1} type arguments",
 675                                                       TypeManager.GetFullName (t),
 676                                                       TypeManager.GetNumberOfTypeArguments (t));
 677                                         return;
 678                                 }
 679                         }
 680
 681                         if ((qualifier_type != null) && (qualifier_type != ec.ContainerType) &&
 682                             ec.ContainerType.IsSubclassOf (qualifier_type)) {
 683                                 // Although a derived class can access protected members of
 684                                 // its base class it cannot do so through an instance of the
 685                                 // base class (CS1540).  If the qualifier_type is a parent of the
 686                                 // ec.ContainerType and the lookup succeeds with the latter one,
 687                                 // then we are in this situation.
 688
 689                                 mi = TypeManager.MemberLookup (
 690                                         ec.ContainerType, ec.ContainerType, ec.ContainerType,
 691                                         AllMemberTypes, AllBindingFlags, name);
 692
 693                                 if (mi != null) {
 694                                         Report.Error (
 695                                                 1540, loc, "Cannot access protected member `" +
 696                                                 TypeManager.CSharpName (qualifier_type) + "." +
 697                                                 name + "' " + "via a qualifier of type `" +
 698                                                 TypeManager.CSharpName (qualifier_type) + "'; the " +
 699                                                 "qualifier must be of type `" +
 700                                                 TypeManager.CSharpName (ec.ContainerType) + "' " +
 701                                                 "(or derived from it)");
 702                                         return;
 703                                 }
 704                         }
 705
 706                         if (qualifier_type != null)
 707                                 Report.Error (
 708                                         122, loc, "`" + TypeManager.CSharpName (qualifier_type) + "." +
 709                                         name + "' is inaccessible due to its protection level");
 710                         else if (name == ".ctor") {
 711                                 Report.Error (143, loc, String.Format ("The type {0} has no constructors defined",
 712                                                                        TypeManager.CSharpName (queried_type)));
 713                         } else {
 714                                 Report.Error (
 715                                         122, loc, "`" + name + "' is inaccessible due to its " +
 716                                         "protection level");
 717                 }
 718                 }
 719
 720                 static public MemberInfo GetFieldFromEvent (EventExpr event_expr)
 721                 {
 722                         EventInfo ei = event_expr.EventInfo;
 723
 724                         return TypeManager.GetPrivateFieldOfEvent (ei);
 725                 }
 726
 727                 /// <summary>
 728                 ///   Returns an expression that can be used to invoke operator true
 729                 ///   on the expression if it exists.
 730                 /// </summary>
 731                 static public StaticCallExpr GetOperatorTrue (EmitContext ec, Expression e, Location loc)
 732                 {
 733                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 734                 }
 735
 736                 /// <summary>
 737                 ///   Returns an expression that can be used to invoke operator false
 738                 ///   on the expression if it exists.
 739                 /// </summary>
 740                 static public StaticCallExpr GetOperatorFalse (EmitContext ec, Expression e, Location loc)
 741                 {
 742                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 743                 }
 744
 745                 static StaticCallExpr GetOperatorTrueOrFalse (EmitContext ec, Expression e, bool is_true, Location loc)
 746                 {
 747                         MethodBase method;
 748                         Expression operator_group;
 749
 750                         operator_group = MethodLookup (ec, e.Type, is_true ? "op_True" : "op_False", loc);
 751                         if (operator_group == null)
 752                                 return null;
 753
 754                         ArrayList arguments = new ArrayList ();
 755                         arguments.Add (new Argument (e, Argument.AType.Expression));
 756                         method = Invocation.OverloadResolve (
 757                                 ec, (MethodGroupExpr) operator_group, arguments, false, loc);
 758
 759                         if (method == null)
 760                                 return null;
 761
 762                         return new StaticCallExpr ((MethodInfo) method, arguments, loc);
 763                 }
 764
 765                 /// <summary>
 766                 ///   Resolves the expression `e' into a boolean expression: either through
 767                 ///   an implicit conversion, or through an `operator true' invocation
 768                 /// </summary>
 769                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 770                 {
 771                         e = e.Resolve (ec);
 772                         if (e == null)
 773                                 return null;
 774
 775                         Expression converted = e;
 776                         if (e.Type != TypeManager.bool_type)
 777                                 converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, new Location (-1));
 778
 779                         //
 780                         // If no implicit conversion to bool exists, try using `operator true'
 781                         //
 782                         if (converted == null){
 783                                 Expression operator_true = Expression.GetOperatorTrue (ec, e, loc);
 784                                 if (operator_true == null){
 785                                         Report.Error (
 786                                                 31, loc, "Can not convert the expression to a boolean");
 787                                         return null;
 788                                 }
 789                                 e = operator_true;
 790                         } else
 791                                 e = converted;
 792
 793                         return e;
 794                 }
 795
 796                 static string ExprClassName (ExprClass c)
 797                 {
 798                         switch (c){
 799                         case ExprClass.Invalid:
 800                                 return "Invalid";
 801                         case ExprClass.Value:
 802                                 return "value";
 803                         case ExprClass.Variable:
 804                                 return "variable";
 805                         case ExprClass.Namespace:
 806                                 return "namespace";
 807                         case ExprClass.Type:
 808                                 return "type";
 809                         case ExprClass.MethodGroup:
 810                                 return "method group";
 811                         case ExprClass.PropertyAccess:
 812                                 return "property access";
 813                         case ExprClass.EventAccess:
 814                                 return "event access";
 815                         case ExprClass.IndexerAccess:
 816                                 return "indexer access";
 817                         case ExprClass.Nothing:
 818                                 return "null";
 819                         }
 820                         throw new Exception ("Should not happen");
 821                 }
 822
 823                 /// <summary>
 824                 ///   Reports that we were expecting `expr' to be of class `expected'
 825                 /// </summary>
 826                 public void Error_UnexpectedKind (string expected)
 827                 {
 828                         string kind = "Unknown";
 829
 830                         kind = ExprClassName (eclass);
 831
 832                         Error (118, "Expression denotes a `" + kind +
 833                                "' where a `" + expected + "' was expected");
 834                 }
 835
 836                 public void Error_UnexpectedKind (ResolveFlags flags)
 837                 {
 838                         ArrayList valid = new ArrayList (10);
 839
 840                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
 841                                 valid.Add ("variable");
 842                                 valid.Add ("value");
 843                         }
 844
 845                         if ((flags & ResolveFlags.Type) != 0)
 846                                 valid.Add ("type");
 847
 848                         if ((flags & ResolveFlags.MethodGroup) != 0)
 849                                 valid.Add ("method group");
 850
 851                         if ((flags & ResolveFlags.SimpleName) != 0)
 852                                 valid.Add ("simple name");
 853
 854                         if (valid.Count == 0)
 855                                 valid.Add ("unknown");
 856
 857                         StringBuilder sb = new StringBuilder ();
 858                         for (int i = 0; i < valid.Count; i++) {
 859                                 if (i > 0)
 860                                         sb.Append (", ");
 861                                 else if (i == valid.Count)
 862                                         sb.Append (" or ");
 863                                 sb.Append (valid [i]);
 864                         }
 865
 866                         string kind = ExprClassName (eclass);
 867
 868                         Error (119, "Expression denotes a `" + kind + "' where " +
 869                                "a `" + sb.ToString () + "' was expected");
 870                 }
 871
 872                 static public void Error_ConstantValueCannotBeConverted (Location l, string val, Type t)
 873                 {
 874                         Report.Error (31, l, "Constant value `" + val + "' cannot be converted to " +
 875                                       TypeManager.CSharpName (t));
 876                 }
 877
 878                 public static void UnsafeError (Location loc)
 879                 {
 880                         Report.Error (214, loc, "Pointers may only be used in an unsafe context");
 881                 }
 882
 883                 /// <summary>
 884                 ///   Converts the IntConstant, UIntConstant, LongConstant or
 885                 ///   ULongConstant into the integral target_type.   Notice
 886                 ///   that we do not return an `Expression' we do return
 887                 ///   a boxed integral type.
 888                 ///
 889                 ///   FIXME: Since I added the new constants, we need to
 890                 ///   also support conversions from CharConstant, ByteConstant,
 891                 ///   SByteConstant, UShortConstant, ShortConstant
 892                 ///
 893                 ///   This is used by the switch statement, so the domain
 894                 ///   of work is restricted to the literals above, and the
 895                 ///   targets are int32, uint32, char, byte, sbyte, ushort,
 896                 ///   short, uint64 and int64
 897                 /// </summary>
 898                 public static object ConvertIntLiteral (Constant c, Type target_type, Location loc)
 899                 {
 900                         if (!Convert.ImplicitStandardConversionExists (c, target_type)){
 901                                 Convert.Error_CannotImplicitConversion (loc, c.Type, target_type);
 902                                 return null;
 903                         }
 904
 905                         string s = "";
 906
 907                         if (c.Type == target_type)
 908                                 return ((Constant) c).GetValue ();
 909
 910                         //
 911                         // Make into one of the literals we handle, we dont really care
 912                         // about this value as we will just return a few limited types
 913                         //
 914                         if (c is EnumConstant)
 915                                 c = ((EnumConstant)c).WidenToCompilerConstant ();
 916
 917                         if (c is IntConstant){
 918                                 int v = ((IntConstant) c).Value;
 919
 920                                 if (target_type == TypeManager.uint32_type){
 921                                         if (v >= 0)
 922                                                 return (uint) v;
 923                                 } else if (target_type == TypeManager.char_type){
 924                                         if (v >= Char.MinValue && v <= Char.MaxValue)
 925                                                 return (char) v;
 926                                 } else if (target_type == TypeManager.byte_type){
 927                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
 928                                                 return (byte) v;
 929                                 } else if (target_type == TypeManager.sbyte_type){
 930                                         if (v >= SByte.MinValue && v <= SByte.MaxValue)
 931                                                 return (sbyte) v;
 932                                 } else if (target_type == TypeManager.short_type){
 933                                         if (v >= Int16.MinValue && v <= UInt16.MaxValue)
 934                                                 return (short) v;
 935                                 } else if (target_type == TypeManager.ushort_type){
 936                                         if (v >= UInt16.MinValue && v <= UInt16.MaxValue)
 937                                                 return (ushort) v;
 938                                 } else if (target_type == TypeManager.int64_type)
 939                                         return (long) v;
 940                                 else if (target_type == TypeManager.uint64_type){
 941                                         if (v > 0)
 942                                                 return (ulong) v;
 943                                 }
 944
 945                                 s = v.ToString ();
 946                         } else if (c is UIntConstant){
 947                                 uint v = ((UIntConstant) c).Value;
 948
 949                                 if (target_type == TypeManager.int32_type){
 950                                         if (v <= Int32.MaxValue)
 951                                                 return (int) v;
 952                                 } else if (target_type == TypeManager.char_type){
 953                                         if (v >= Char.MinValue && v <= Char.MaxValue)
 954                                                 return (char) v;
 955                                 } else if (target_type == TypeManager.byte_type){
 956                                         if (v <= Byte.MaxValue)
 957                                                 return (byte) v;
 958                                 } else if (target_type == TypeManager.sbyte_type){
 959                                         if (v <= SByte.MaxValue)
 960                                                 return (sbyte) v;
 961                                 } else if (target_type == TypeManager.short_type){
 962                                         if (v <= UInt16.MaxValue)
 963                                                 return (short) v;
 964                                 } else if (target_type == TypeManager.ushort_type){
 965                                         if (v <= UInt16.MaxValue)
 966                                                 return (ushort) v;
 967                                 } else if (target_type == TypeManager.int64_type)
 968                                         return (long) v;
 969                                 else if (target_type == TypeManager.uint64_type)
 970                                         return (ulong) v;
 971                                 s = v.ToString ();
 972                         } else if (c is LongConstant){
 973                                 long v = ((LongConstant) c).Value;
 974
 975                                 if (target_type == TypeManager.int32_type){
 976                                         if (v >= UInt32.MinValue && v <= UInt32.MaxValue)
 977                                                 return (int) v;
 978                                 } else if (target_type == TypeManager.uint32_type){
 979                                         if (v >= 0 && v <= UInt32.MaxValue)
 980                                                 return (uint) v;
 981                                 } else if (target_type == TypeManager.char_type){
 982                                         if (v >= Char.MinValue && v <= Char.MaxValue)
 983                                                 return (char) v;
 984                                 } else if (target_type == TypeManager.byte_type){
 985                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
 986                                                 return (byte) v;
 987                                 } else if (target_type == TypeManager.sbyte_type){
 988                                         if (v >= SByte.MinValue && v <= SByte.MaxValue)
 989                                                 return (sbyte) v;
 990                                 } else if (target_type == TypeManager.short_type){
 991                                         if (v >= Int16.MinValue && v <= UInt16.MaxValue)
 992                                                 return (short) v;
 993                                 } else if (target_type == TypeManager.ushort_type){
 994                                         if (v >= UInt16.MinValue && v <= UInt16.MaxValue)
 995                                                 return (ushort) v;
 996                                 } else if (target_type == TypeManager.uint64_type){
 997                                         if (v > 0)
 998                                                 return (ulong) v;
 999                                 }
1000                                 s = v.ToString ();
1001                         } else if (c is ULongConstant){
1002                                 ulong v = ((ULongConstant) c).Value;
1003
1004                                 if (target_type == TypeManager.int32_type){
1005                                         if (v <= Int32.MaxValue)
1006                                                 return (int) v;
1007                                 } else if (target_type == TypeManager.uint32_type){
1008                                         if (v <= UInt32.MaxValue)
1009                                                 return (uint) v;
1010                                 } else if (target_type == TypeManager.char_type){
1011                                         if (v >= Char.MinValue && v <= Char.MaxValue)
1012                                                 return (char) v;
1013                                 } else if (target_type == TypeManager.byte_type){
1014                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1015                                                 return (byte) v;
1016                                 } else if (target_type == TypeManager.sbyte_type){
1017                                         if (v <= (int) SByte.MaxValue)
1018                                                 return (sbyte) v;
1019                                 } else if (target_type == TypeManager.short_type){
1020                                         if (v <= UInt16.MaxValue)
1021                                                 return (short) v;
1022                                 } else if (target_type == TypeManager.ushort_type){
1023                                         if (v <= UInt16.MaxValue)
1024                                                 return (ushort) v;
1025                                 } else if (target_type == TypeManager.int64_type){
1026                                         if (v <= Int64.MaxValue)
1027                                                 return (long) v;
1028                                 }
1029                                 s = v.ToString ();
1030                         } else if (c is ByteConstant){
1031                                 byte v = ((ByteConstant) c).Value;
1032
1033                                 if (target_type == TypeManager.int32_type)
1034                                         return (int) v;
1035                                 else if (target_type == TypeManager.uint32_type)
1036                                         return (uint) v;
1037                                 else if (target_type == TypeManager.char_type)
1038                                         return (char) v;
1039                                 else if (target_type == TypeManager.sbyte_type){
1040                                         if (v <= SByte.MaxValue)
1041                                                 return (sbyte) v;
1042                                 } else if (target_type == TypeManager.short_type)
1043                                         return (short) v;
1044                                 else if (target_type == TypeManager.ushort_type)
1045                                         return (ushort) v;
1046                                 else if (target_type == TypeManager.int64_type)
1047                                         return (long) v;
1048                                 else if (target_type == TypeManager.uint64_type)
1049                                         return (ulong) v;
1050                                 s = v.ToString ();
1051                         } else if (c is SByteConstant){
1052                                 sbyte v = ((SByteConstant) c).Value;
1053
1054                                 if (target_type == TypeManager.int32_type)
1055                                         return (int) v;
1056                                 else if (target_type == TypeManager.uint32_type){
1057                                         if (v >= 0)
1058                                                 return (uint) v;
1059                                 } else if (target_type == TypeManager.char_type){
1060                                         if (v >= 0)
1061                                                 return (char) v;
1062                                 } else if (target_type == TypeManager.byte_type){
1063                                         if (v >= 0)
1064                                                 return (byte) v;
1065                                 } else if (target_type == TypeManager.short_type)
1066                                         return (short) v;
1067                                 else if (target_type == TypeManager.ushort_type){
1068                                         if (v >= 0)
1069                                                 return (ushort) v;
1070                                 } else if (target_type == TypeManager.int64_type)
1071                                         return (long) v;
1072                                 else if (target_type == TypeManager.uint64_type){
1073                                         if (v >= 0)
1074                                                 return (ulong) v;
1075                                 }
1076                                 s = v.ToString ();
1077                         } else if (c is ShortConstant){
1078                                 short v = ((ShortConstant) c).Value;
1079
1080                                 if (target_type == TypeManager.int32_type){
1081                                         return (int) v;
1082                                 } else if (target_type == TypeManager.uint32_type){
1083                                         if (v >= 0)
1084                                                 return (uint) v;
1085                                 } else if (target_type == TypeManager.char_type){
1086                                         if (v >= 0)
1087                                                 return (char) v;
1088                                 } else if (target_type == TypeManager.byte_type){
1089                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1090                                                 return (byte) v;
1091                                 } else if (target_type == TypeManager.sbyte_type){
1092                                         if (v >= SByte.MinValue && v <= SByte.MaxValue)
1093                                                 return (sbyte) v;
1094                                 } else if (target_type == TypeManager.ushort_type){
1095                                         if (v >= 0)
1096                                                 return (ushort) v;
1097                                 } else if (target_type == TypeManager.int64_type)
1098                                         return (long) v;
1099                                 else if (target_type == TypeManager.uint64_type)
1100                                         return (ulong) v;
1101
1102                                 s = v.ToString ();
1103                         } else if (c is UShortConstant){
1104                                 ushort v = ((UShortConstant) c).Value;
1105
1106                                 if (target_type == TypeManager.int32_type)
1107                                         return (int) v;
1108                                 else if (target_type == TypeManager.uint32_type)
1109                                         return (uint) v;
1110                                 else if (target_type == TypeManager.char_type){
1111                                         if (v >= Char.MinValue && v <= Char.MaxValue)
1112                                                 return (char) v;
1113                                 } else if (target_type == TypeManager.byte_type){
1114                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1115                                                 return (byte) v;
1116                                 } else if (target_type == TypeManager.sbyte_type){
1117                                         if (v <= SByte.MaxValue)
1118                                                 return (byte) v;
1119                                 } else if (target_type == TypeManager.short_type){
1120                                         if (v <= Int16.MaxValue)
1121                                                 return (short) v;
1122                                 } else if (target_type == TypeManager.int64_type)
1123                                         return (long) v;
1124                                 else if (target_type == TypeManager.uint64_type)
1125                                         return (ulong) v;
1126
1127                                 s = v.ToString ();
1128                         } else if (c is CharConstant){
1129                                 char v = ((CharConstant) c).Value;
1130
1131                                 if (target_type == TypeManager.int32_type)
1132                                         return (int) v;
1133                                 else if (target_type == TypeManager.uint32_type)
1134                                         return (uint) v;
1135                                 else if (target_type == TypeManager.byte_type){
1136                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1137                                                 return (byte) v;
1138                                 } else if (target_type == TypeManager.sbyte_type){
1139                                         if (v <= SByte.MaxValue)
1140                                                 return (sbyte) v;
1141                                 } else if (target_type == TypeManager.short_type){
1142                                         if (v <= Int16.MaxValue)
1143                                                 return (short) v;
1144                                 } else if (target_type == TypeManager.ushort_type)
1145                                         return (short) v;
1146                                 else if (target_type == TypeManager.int64_type)
1147                                         return (long) v;
1148                                 else if (target_type == TypeManager.uint64_type)
1149                                         return (ulong) v;
1150
1151                                 s = v.ToString ();
1152                         }
1153                         Error_ConstantValueCannotBeConverted (loc, s, target_type);
1154                         return null;
1155                 }
1156
1157                 //
1158                 // Load the object from the pointer.
1159                 //
1160                 public static void LoadFromPtr (ILGenerator ig, Type t)
1161                 {
1162                         if (t == TypeManager.int32_type)
1163                                 ig.Emit (OpCodes.Ldind_I4);
1164                         else if (t == TypeManager.uint32_type)
1165                                 ig.Emit (OpCodes.Ldind_U4);
1166                         else if (t == TypeManager.short_type)
1167                                 ig.Emit (OpCodes.Ldind_I2);
1168                         else if (t == TypeManager.ushort_type)
1169                                 ig.Emit (OpCodes.Ldind_U2);
1170                         else if (t == TypeManager.char_type)
1171                                 ig.Emit (OpCodes.Ldind_U2);
1172                         else if (t == TypeManager.byte_type)
1173                                 ig.Emit (OpCodes.Ldind_U1);
1174                         else if (t == TypeManager.sbyte_type)
1175                                 ig.Emit (OpCodes.Ldind_I1);
1176                         else if (t == TypeManager.uint64_type)
1177                                 ig.Emit (OpCodes.Ldind_I8);
1178                         else if (t == TypeManager.int64_type)
1179                                 ig.Emit (OpCodes.Ldind_I8);
1180                         else if (t == TypeManager.float_type)
1181                                 ig.Emit (OpCodes.Ldind_R4);
1182                         else if (t == TypeManager.double_type)
1183                                 ig.Emit (OpCodes.Ldind_R8);
1184                         else if (t == TypeManager.bool_type)
1185                                 ig.Emit (OpCodes.Ldind_I1);
1186                         else if (t == TypeManager.intptr_type)
1187                                 ig.Emit (OpCodes.Ldind_I);
1188                         else if (TypeManager.IsEnumType (t)) {
1189                                 if (t == TypeManager.enum_type)
1190                                         ig.Emit (OpCodes.Ldind_Ref);
1191                                 else
1192                                         LoadFromPtr (ig, TypeManager.EnumToUnderlying (t));
1193                         } else if (t.IsValueType)
1194                                 ig.Emit (OpCodes.Ldobj, t);
1195                         else if (t.IsPointer)
1196                                 ig.Emit (OpCodes.Ldind_I);
1197                         else
1198                                 ig.Emit (OpCodes.Ldind_Ref);
1199                 }
1200
1201                 //
1202                 // The stack contains the pointer and the value of type `type'
1203                 //
1204                 public static void StoreFromPtr (ILGenerator ig, Type type)
1205                 {
1206                         if (TypeManager.IsEnumType (type))
1207                                 type = TypeManager.EnumToUnderlying (type);
1208                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1209                                 ig.Emit (OpCodes.Stind_I4);
1210                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1211                                 ig.Emit (OpCodes.Stind_I8);
1212                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1213                                  type == TypeManager.ushort_type)
1214                                 ig.Emit (OpCodes.Stind_I2);
1215                         else if (type == TypeManager.float_type)
1216                                 ig.Emit (OpCodes.Stind_R4);
1217                         else if (type == TypeManager.double_type)
1218                                 ig.Emit (OpCodes.Stind_R8);
1219                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1220                                  type == TypeManager.bool_type)
1221                                 ig.Emit (OpCodes.Stind_I1);
1222                         else if (type == TypeManager.intptr_type)
1223                                 ig.Emit (OpCodes.Stind_I);
1224                         else if (type.IsValueType)
1225                                 ig.Emit (OpCodes.Stobj, type);
1226                         else
1227                                 ig.Emit (OpCodes.Stind_Ref);
1228                 }
1229
1230                 //
1231                 // Returns the size of type `t' if known, otherwise, 0
1232                 //
1233                 public static int GetTypeSize (Type t)
1234                 {
1235                         t = TypeManager.TypeToCoreType (t);
1236                         if (t == TypeManager.int32_type ||
1237                             t == TypeManager.uint32_type ||
1238                             t == TypeManager.float_type)
1239                                 return 4;
1240                         else if (t == TypeManager.int64_type ||
1241                                  t == TypeManager.uint64_type ||
1242                                  t == TypeManager.double_type)
1243                                 return 8;
1244                         else if (t == TypeManager.byte_type ||
1245                                  t == TypeManager.sbyte_type ||
1246                                  t == TypeManager.bool_type)
1247                                 return 1;
1248                         else if (t == TypeManager.short_type ||
1249                                  t == TypeManager.char_type ||
1250                                  t == TypeManager.ushort_type)
1251                                 return 2;
1252                         else if (t == TypeManager.decimal_type)
1253                                 return 16;
1254                         else
1255                                 return 0;
1256                 }
1257
1258                 //
1259                 // Default implementation of IAssignMethod.CacheTemporaries
1260                 //
1261                 public void CacheTemporaries (EmitContext ec)
1262                 {
1263                 }
1264
1265                 static void Error_NegativeArrayIndex (Location loc)
1266                 {
1267                         Report.Error (284, loc, "Can not create array with a negative size");
1268                 }
1269
1270                 //
1271                 // Converts `source' to an int, uint, long or ulong.
1272                 //
1273                 public Expression ExpressionToArrayArgument (EmitContext ec, Expression source, Location loc)
1274                 {
1275                         Expression target;
1276
1277                         bool old_checked = ec.CheckState;
1278                         ec.CheckState = true;
1279
1280                         target = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, loc);
1281                         if (target == null){
1282                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, loc);
1283                                 if (target == null){
1284                                         target = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, loc);
1285                                         if (target == null){
1286                                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, loc);
1287                                                 if (target == null)
1288                                                         Convert.Error_CannotImplicitConversion (loc, source.Type, TypeManager.int32_type);
1289                                         }
1290                                 }
1291                         }
1292                         ec.CheckState = old_checked;
1293
1294                         //
1295                         // Only positive constants are allowed at compile time
1296                         //
1297                         if (target is Constant){
1298                                 if (target is IntConstant){
1299                                         if (((IntConstant) target).Value < 0){
1300                                                 Error_NegativeArrayIndex (loc);
1301                                                 return null;
1302                                         }
1303                                 }
1304
1305                                 if (target is LongConstant){
1306                                         if (((LongConstant) target).Value < 0){
1307                                                 Error_NegativeArrayIndex (loc);
1308                                                 return null;
1309                                         }
1310                                 }
1311
1312                         }
1313
1314                         return target;
1315                 }
1316
1317         }
1318
1319         /// <summary>
1320         ///   This is just a base class for expressions that can
1321         ///   appear on statements (invocations, object creation,
1322         ///   assignments, post/pre increment and decrement).  The idea
1323         ///   being that they would support an extra Emition interface that
1324         ///   does not leave a result on the stack.
1325         /// </summary>
1326         public abstract class ExpressionStatement : Expression {
1327
1328                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1329                 {
1330                         Expression e = Resolve (ec);
1331                         if (e == null)
1332                                 return null;
1333
1334                         ExpressionStatement es = e as ExpressionStatement;
1335                         if (es == null)
1336                                 Error (201, "Only assignment, call, increment, decrement and new object " +
1337                                        "expressions can be used as a statement");
1338
1339                         return es;
1340                 }
1341
1342                 /// <summary>
1343                 ///   Requests the expression to be emitted in a `statement'
1344                 ///   context.  This means that no new value is left on the
1345                 ///   stack after invoking this method (constrasted with
1346                 ///   Emit that will always leave a value on the stack).
1347                 /// </summary>
1348                 public abstract void EmitStatement (EmitContext ec);
1349         }
1350
1351         /// <summary>
1352         ///   This kind of cast is used to encapsulate the child
1353         ///   whose type is child.Type into an expression that is
1354         ///   reported to return "return_type".  This is used to encapsulate
1355         ///   expressions which have compatible types, but need to be dealt
1356         ///   at higher levels with.
1357         ///
1358         ///   For example, a "byte" expression could be encapsulated in one
1359         ///   of these as an "unsigned int".  The type for the expression
1360         ///   would be "unsigned int".
1361         ///
1362         /// </summary>
1363         public class EmptyCast : Expression {
1364                 protected Expression child;
1365
1366                 public Expression Child {
1367                         get {
1368                                 return child;
1369                         }
1370                 }
1371
1372                 public EmptyCast (Expression child, Type return_type)
1373                 {
1374                         eclass = child.eclass;
1375                         type = return_type;
1376                         this.child = child;
1377                 }
1378
1379                 public override Expression DoResolve (EmitContext ec)
1380                 {
1381                         // This should never be invoked, we are born in fully
1382                         // initialized state.
1383
1384                         return this;
1385                 }
1386
1387                 public override void Emit (EmitContext ec)
1388                 {
1389                         child.Emit (ec);
1390                 }
1391         }
1392
1393         //
1394         // We need to special case this since an empty cast of
1395         // a NullLiteral is still a Constant
1396         //
1397         public class NullCast : Constant {
1398                 protected Expression child;
1399
1400                 public NullCast (Expression child, Type return_type)
1401                 {
1402                         eclass = child.eclass;
1403                         type = return_type;
1404                         this.child = child;
1405                 }
1406
1407                 override public string AsString ()
1408                 {
1409                         return "null";
1410                 }
1411
1412                 public override object GetValue ()
1413                 {
1414                         return null;
1415                 }
1416
1417                 public override Expression DoResolve (EmitContext ec)
1418                 {
1419                         // This should never be invoked, we are born in fully
1420                         // initialized state.
1421
1422                         return this;
1423                 }
1424
1425                 public override void Emit (EmitContext ec)
1426                 {
1427                         child.Emit (ec);
1428                 }
1429         }
1430
1431
1432         /// <summary>
1433         ///  This class is used to wrap literals which belong inside Enums
1434         /// </summary>
1435         public class EnumConstant : Constant {
1436                 public Constant Child;
1437
1438                 public EnumConstant (Constant child, Type enum_type)
1439                 {
1440                         eclass = child.eclass;
1441                         this.Child = child;
1442                         type = enum_type;
1443                 }
1444
1445                 public override Expression DoResolve (EmitContext ec)
1446                 {
1447                         // This should never be invoked, we are born in fully
1448                         // initialized state.
1449
1450                         return this;
1451                 }
1452
1453                 public override void Emit (EmitContext ec)
1454                 {
1455                         Child.Emit (ec);
1456                 }
1457
1458                 public override object GetValue ()
1459                 {
1460                         return Child.GetValue ();
1461                 }
1462
1463                 //
1464                 // Converts from one of the valid underlying types for an enumeration
1465                 // (int32, uint32, int64, uint64, short, ushort, byte, sbyte) to
1466                 // one of the internal compiler literals: Int/UInt/Long/ULong Literals.
1467                 //
1468                 public Constant WidenToCompilerConstant ()
1469                 {
1470                         Type t = TypeManager.EnumToUnderlying (Child.Type);
1471                         object v = ((Constant) Child).GetValue ();;
1472
1473                         if (t == TypeManager.int32_type)
1474                                 return new IntConstant ((int) v);
1475                         if (t == TypeManager.uint32_type)
1476                                 return new UIntConstant ((uint) v);
1477                         if (t == TypeManager.int64_type)
1478                                 return new LongConstant ((long) v);
1479                         if (t == TypeManager.uint64_type)
1480                                 return new ULongConstant ((ulong) v);
1481                         if (t == TypeManager.short_type)
1482                                 return new ShortConstant ((short) v);
1483                         if (t == TypeManager.ushort_type)
1484                                 return new UShortConstant ((ushort) v);
1485                         if (t == TypeManager.byte_type)
1486                                 return new ByteConstant ((byte) v);
1487                         if (t == TypeManager.sbyte_type)
1488                                 return new SByteConstant ((sbyte) v);
1489
1490                         throw new Exception ("Invalid enumeration underlying type: " + t);
1491                 }
1492
1493                 //
1494                 // Extracts the value in the enumeration on its native representation
1495                 //
1496                 public object GetPlainValue ()
1497                 {
1498                         Type t = TypeManager.EnumToUnderlying (Child.Type);
1499                         object v = ((Constant) Child).GetValue ();;
1500
1501                         if (t == TypeManager.int32_type)
1502                                 return (int) v;
1503                         if (t == TypeManager.uint32_type)
1504                                 return (uint) v;
1505                         if (t == TypeManager.int64_type)
1506                                 return (long) v;
1507                         if (t == TypeManager.uint64_type)
1508                                 return (ulong) v;
1509                         if (t == TypeManager.short_type)
1510                                 return (short) v;
1511                         if (t == TypeManager.ushort_type)
1512                                 return (ushort) v;
1513                         if (t == TypeManager.byte_type)
1514                                 return (byte) v;
1515                         if (t == TypeManager.sbyte_type)
1516                                 return (sbyte) v;
1517
1518                         return null;
1519                 }
1520
1521                 public override string AsString ()
1522                 {
1523                         return Child.AsString ();
1524                 }
1525
1526                 public override DoubleConstant ConvertToDouble ()
1527                 {
1528                         return Child.ConvertToDouble ();
1529                 }
1530
1531                 public override FloatConstant ConvertToFloat ()
1532                 {
1533                         return Child.ConvertToFloat ();
1534                 }
1535
1536                 public override ULongConstant ConvertToULong ()
1537                 {
1538                         return Child.ConvertToULong ();
1539                 }
1540
1541                 public override LongConstant ConvertToLong ()
1542                 {
1543                         return Child.ConvertToLong ();
1544                 }
1545
1546                 public override UIntConstant ConvertToUInt ()
1547                 {
1548                         return Child.ConvertToUInt ();
1549                 }
1550
1551                 public override IntConstant ConvertToInt ()
1552                 {
1553                         return Child.ConvertToInt ();
1554                 }
1555         }
1556
1557         /// <summary>
1558         ///   This kind of cast is used to encapsulate Value Types in objects.
1559         ///
1560         ///   The effect of it is to box the value type emitted by the previous
1561         ///   operation.
1562         /// </summary>
1563         public class BoxedCast : EmptyCast {
1564
1565                 public BoxedCast (Expression expr)
1566                         : base (expr, TypeManager.object_type)
1567                 {
1568                 }
1569
1570                 public BoxedCast (Expression expr, Type target_type)
1571                         : base (expr, target_type)
1572                 {
1573                 }
1574
1575                 public override Expression DoResolve (EmitContext ec)
1576                 {
1577                         // This should never be invoked, we are born in fully
1578                         // initialized state.
1579
1580                         return this;
1581                 }
1582
1583                 public override void Emit (EmitContext ec)
1584                 {
1585                         base.Emit (ec);
1586
1587                         ec.ig.Emit (OpCodes.Box, child.Type);
1588                 }
1589         }
1590
1591         public class UnboxCast : EmptyCast {
1592                 public UnboxCast (Expression expr, Type return_type)
1593                         : base (expr, return_type)
1594                 {
1595                 }
1596
1597                 public override Expression DoResolve (EmitContext ec)
1598                 {
1599                         // This should never be invoked, we are born in fully
1600                         // initialized state.
1601
1602                         return this;
1603                 }
1604
1605                 public override void Emit (EmitContext ec)
1606                 {
1607                         Type t = type;
1608                         ILGenerator ig = ec.ig;
1609
1610                         base.Emit (ec);
1611                         if (t.IsGenericParameter)
1612                                 ig.Emit (OpCodes.Unbox_Any, t);
1613                         else {
1614                                 ig.Emit (OpCodes.Unbox, t);
1615
1616                                 LoadFromPtr (ig, t);
1617                         }
1618                 }
1619         }
1620
1621         /// <summary>
1622         ///   This is used to perform explicit numeric conversions.
1623         ///
1624         ///   Explicit numeric conversions might trigger exceptions in a checked
1625         ///   context, so they should generate the conv.ovf opcodes instead of
1626         ///   conv opcodes.
1627         /// </summary>
1628         public class ConvCast : EmptyCast {
1629                 public enum Mode : byte {
1630                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1631                         U1_I1, U1_CH,
1632                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1633                         U2_I1, U2_U1, U2_I2, U2_CH,
1634                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1635                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1636                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH,
1637                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH,
1638                         CH_I1, CH_U1, CH_I2,
1639                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1640                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4
1641                 }
1642
1643                 Mode mode;
1644                 bool checked_state;
1645
1646                 public ConvCast (EmitContext ec, Expression child, Type return_type, Mode m)
1647                         : base (child, return_type)
1648                 {
1649                         checked_state = ec.CheckState;
1650                         mode = m;
1651                 }
1652
1653                 public override Expression DoResolve (EmitContext ec)
1654                 {
1655                         // This should never be invoked, we are born in fully
1656                         // initialized state.
1657
1658                         return this;
1659                 }
1660
1661                 public override string ToString ()
1662                 {
1663                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1664                 }
1665
1666                 public override void Emit (EmitContext ec)
1667                 {
1668                         ILGenerator ig = ec.ig;
1669
1670                         base.Emit (ec);
1671
1672                         if (checked_state){
1673                                 switch (mode){
1674                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1675                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1676                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1677                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1678                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1679
1680                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1681                                 case Mode.U1_CH: /* nothing */ break;
1682
1683                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1684                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1685                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1686                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1687                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1688                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1689
1690                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1691                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1692                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1693                                 case Mode.U2_CH: /* nothing */ break;
1694
1695                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1696                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1697                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1698                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1699                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1700                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1701                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1702
1703                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1704                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1705                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1706                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1707                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1708                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1709
1710                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1711                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1712                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1713                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1714                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1715                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1716                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1717                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1718
1719                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1720                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1721                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1722                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1723                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1724                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1725                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1726                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1727
1728                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1729                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1730                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1731
1732                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1733                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1734                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1735                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1736                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1737                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1738                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1739                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1740                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1741
1742                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1743                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1744                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1745                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1746                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1747                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1748                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1749                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1750                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1751                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1752                                 }
1753                         } else {
1754                                 switch (mode){
1755                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1756                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1757                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1758                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
1759                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
1760
1761                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
1762                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
1763
1764                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
1765                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
1766                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
1767                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
1768                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
1769                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
1770
1771                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
1772                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
1773                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
1774                                 case Mode.U2_CH: /* nothing */ break;
1775
1776                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
1777                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
1778                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
1779                                 case Mode.I4_U4: /* nothing */ break;
1780                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
1781                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
1782                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
1783
1784                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
1785                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
1786                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
1787                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
1788                                 case Mode.U4_I4: /* nothing */ break;
1789                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
1790
1791                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
1792                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
1793                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
1794                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
1795                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
1796                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
1797                                 case Mode.I8_U8: /* nothing */ break;
1798                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
1799
1800                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
1801                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
1802                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
1803                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
1804                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
1805                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
1806                                 case Mode.U8_I8: /* nothing */ break;
1807                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
1808
1809                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
1810                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
1811                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
1812
1813                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
1814                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
1815                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
1816                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
1817                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
1818                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
1819                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
1820                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
1821                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
1822
1823                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
1824                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
1825                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
1826                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
1827                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
1828                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
1829                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
1830                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
1831                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
1832                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1833                                 }
1834                         }
1835                 }
1836         }
1837
1838         public class OpcodeCast : EmptyCast {
1839                 OpCode op, op2;
1840                 bool second_valid;
1841
1842                 public OpcodeCast (Expression child, Type return_type, OpCode op)
1843                         : base (child, return_type)
1844
1845                 {
1846                         this.op = op;
1847                         second_valid = false;
1848                 }
1849
1850                 public OpcodeCast (Expression child, Type return_type, OpCode op, OpCode op2)
1851                         : base (child, return_type)
1852
1853                 {
1854                         this.op = op;
1855                         this.op2 = op2;
1856                         second_valid = true;
1857                 }
1858
1859                 public override Expression DoResolve (EmitContext ec)
1860                 {
1861                         // This should never be invoked, we are born in fully
1862                         // initialized state.
1863
1864                         return this;
1865                 }
1866
1867                 public override void Emit (EmitContext ec)
1868                 {
1869                         base.Emit (ec);
1870                         ec.ig.Emit (op);
1871
1872                         if (second_valid)
1873                                 ec.ig.Emit (op2);
1874                 }
1875         }
1876
1877         /// <summary>
1878         ///   This kind of cast is used to encapsulate a child and cast it
1879         ///   to the class requested
1880         /// </summary>
1881         public class ClassCast : EmptyCast {
1882                 public ClassCast (Expression child, Type return_type)
1883                         : base (child, return_type)
1884
1885                 {
1886                 }
1887
1888                 public override Expression DoResolve (EmitContext ec)
1889                 {
1890                         // This should never be invoked, we are born in fully
1891                         // initialized state.
1892
1893                         return this;
1894                 }
1895
1896                 public override void Emit (EmitContext ec)
1897                 {
1898                         base.Emit (ec);
1899
1900                         if (child.Type.IsGenericParameter)
1901                                 ec.ig.Emit (OpCodes.Box, child.Type);
1902
1903                         if (type.IsGenericParameter)
1904                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
1905                         else
1906                                 ec.ig.Emit (OpCodes.Castclass, type);
1907                 }
1908         }
1909
1910         /// <summary>
1911         ///   SimpleName expressions are initially formed of a single
1912         ///   word and it only happens at the beginning of the expression.
1913         /// </summary>
1914         ///
1915         /// <remarks>
1916         ///   The expression will try to be bound to a Field, a Method
1917         ///   group or a Property.  If those fail we pass the name to our
1918         ///   caller and the SimpleName is compounded to perform a type
1919         ///   lookup.  The idea behind this process is that we want to avoid
1920         ///   creating a namespace map from the assemblies, as that requires
1921         ///   the GetExportedTypes function to be called and a hashtable to
1922         ///   be constructed which reduces startup time.  If later we find
1923         ///   that this is slower, we should create a `NamespaceExpr' expression
1924         ///   that fully participates in the resolution process.
1925         ///
1926         ///   For example `System.Console.WriteLine' is decomposed into
1927         ///   MemberAccess (MemberAccess (SimpleName ("System"), "Console"), "WriteLine")
1928         ///
1929         ///   The first SimpleName wont produce a match on its own, so it will
1930         ///   be turned into:
1931         ///   MemberAccess (SimpleName ("System.Console"), "WriteLine").
1932         ///
1933         ///   System.Console will produce a TypeExpr match.
1934         ///
1935         ///   The downside of this is that we might be hitting `LookupType' too many
1936         ///   times with this scheme.
1937         /// </remarks>
1938         public class SimpleName : Expression {
1939                 public string Name;
1940
1941                 //
1942                 // If true, then we are a simple name, not composed with a ".
1943                 //
1944                 bool is_base;
1945
1946                 public SimpleName (string a, string b, Location l)
1947                 {
1948                         Name = String.Concat (a, ".", b);
1949                         loc = l;
1950                         is_base = false;
1951                 }
1952
1953                 public SimpleName (string name, Location l)
1954                 {
1955                         Name = name;
1956                         loc = l;
1957                         is_base = true;
1958                 }
1959
1960                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
1961                 {
1962                         if (ec.IsFieldInitializer)
1963                                 Report.Error (
1964                                         236, l,
1965                                         "A field initializer cannot reference the non-static field, " +
1966                                         "method or property `"+name+"'");
1967                         else
1968                                 Report.Error (
1969                                         120, l,
1970                                         "An object reference is required " +
1971                                         "for the non-static field `"+name+"'");
1972                 }
1973
1974                 //
1975                 // Checks whether we are trying to access an instance
1976                 // property, method or field from a static body.
1977                 //
1978                 Expression MemberStaticCheck (EmitContext ec, Expression e)
1979                 {
1980                         if (e is IMemberExpr){
1981                                 IMemberExpr member = (IMemberExpr) e;
1982
1983                                 if (!member.IsStatic){
1984                                         Error_ObjectRefRequired (ec, loc, Name);
1985                                         return null;
1986                                 }
1987                         }
1988
1989                         return e;
1990                 }
1991
1992                 public override Expression DoResolve (EmitContext ec)
1993                 {
1994                         return SimpleNameResolve (ec, null, false);
1995                 }
1996
1997                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1998                 {
1999                         return SimpleNameResolve (ec, right_side, false);
2000                 }
2001
2002
2003                 public Expression DoResolveAllowStatic (EmitContext ec)
2004                 {
2005                         return SimpleNameResolve (ec, null, true);
2006                 }
2007
2008                 public override Expression ResolveAsTypeStep (EmitContext ec)
2009                 {
2010                         DeclSpace ds = ec.DeclSpace;
2011                         NamespaceEntry ns = ds.NamespaceEntry;
2012                         TypeExpr t;
2013                         IAlias alias_value;
2014
2015                         //
2016                         // Since we are cheating: we only do the Alias lookup for
2017                         // namespaces if the name does not include any dots in it
2018                         //
2019                         if (ns != null && is_base)
2020                                 alias_value = ns.LookupAlias (Name);
2021                         else
2022                                 alias_value = null;
2023
2024                         TypeParameterExpr generic_type = ds.LookupGeneric (Name, loc);
2025                         if (generic_type != null)
2026                                 return generic_type.ResolveAsTypeTerminal (ec);
2027
2028                         if (ec.ResolvingTypeTree){
2029                                 int errors = Report.Errors;
2030                                 Type dt = ds.FindType (loc, Name);
2031
2032                                 if (Report.Errors != errors)
2033                                         return null;
2034
2035                                 if (dt != null)
2036                                         return new TypeExpression (dt, loc);
2037
2038                                 if (alias_value != null){
2039                                         if (alias_value.IsType)
2040                                                 return alias_value.Type;
2041                                         if ((t = RootContext.LookupType (ds, alias_value.Name, true, loc)) != null)
2042                                                 return t;
2043                                 }
2044                         }
2045
2046                         //
2047                         // First, the using aliases
2048                         //
2049                         if (alias_value != null){
2050                                 if (alias_value.IsType)
2051                                         return alias_value.Type;
2052                                 if ((t = RootContext.LookupType (ds, alias_value.Name, true, loc)) != null)
2053                                         return t;
2054
2055                                 // we have alias value, but it isn't Type, so try if it's namespace
2056                                 return new SimpleName (alias_value.Name, loc);
2057                         }
2058
2059                         //
2060                         // Stage 2: Lookup up if we are an alias to a type
2061                         // or a namespace.
2062                         //
2063
2064                         if ((t = RootContext.LookupType (ds, Name, true, loc)) != null)
2065                                 return t;
2066
2067                         // No match, maybe our parent can compose us
2068                         // into something meaningful.
2069                         return this;
2070                 }
2071
2072                 /// <remarks>
2073                 ///   7.5.2: Simple Names.
2074                 ///
2075                 ///   Local Variables and Parameters are handled at
2076                 ///   parse time, so they never occur as SimpleNames.
2077                 ///
2078                 ///   The `allow_static' flag is used by MemberAccess only
2079                 ///   and it is used to inform us that it is ok for us to
2080                 ///   avoid the static check, because MemberAccess might end
2081                 ///   up resolving the Name as a Type name and the access as
2082                 ///   a static type access.
2083                 ///
2084                 ///   ie: Type Type; .... { Type.GetType (""); }
2085                 ///
2086                 ///   Type is both an instance variable and a Type;  Type.GetType
2087                 ///   is the static method not an instance method of type.
2088                 /// </remarks>
2089                 Expression SimpleNameResolve (EmitContext ec, Expression right_side, bool allow_static)
2090                 {
2091                         Expression e = null;
2092
2093                         //
2094                         // Stage 1: Performed by the parser (binding to locals or parameters).
2095                         //
2096                         Block current_block = ec.CurrentBlock;
2097                         if (current_block != null){
2098                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2099                                 if (vi != null){
2100                                         Expression var;
2101
2102                                         var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2103
2104                                         if (right_side != null)
2105                                                 return var.ResolveLValue (ec, right_side);
2106                                         else
2107                                                 return var.Resolve (ec);
2108                                 }
2109
2110                                 int idx = -1;
2111                                 Parameter par = null;
2112                                 Parameters pars = current_block.Parameters;
2113                                 if (pars != null)
2114                                         par = pars.GetParameterByName (Name, out idx);
2115
2116                                 if (par != null) {
2117                                         ParameterReference param;
2118
2119                                         param = new ParameterReference (pars, current_block, idx, Name, loc);
2120
2121                                         if (right_side != null)
2122                                                 return param.ResolveLValue (ec, right_side);
2123                                         else
2124                                                 return param.Resolve (ec);
2125                                 }
2126                         }
2127
2128                         //
2129                         // Stage 2: Lookup members
2130                         //
2131
2132                         DeclSpace lookup_ds = ec.DeclSpace;
2133                         do {
2134                                 if (lookup_ds.TypeBuilder == null)
2135                                         break;
2136
2137                                 e = MemberLookup (ec, lookup_ds.TypeBuilder, Name, loc);
2138                                 if (e != null)
2139                                         break;
2140
2141                                 lookup_ds =lookup_ds.Parent;
2142                         } while (lookup_ds != null);
2143
2144                         if (e == null && ec.ContainerType != null)
2145                                 e = MemberLookup (ec, ec.ContainerType, Name, loc);
2146
2147                         if (e == null) {
2148                                 //
2149                                 // Since we are cheating (is_base is our hint
2150                                 // that we are the beginning of the name): we
2151                                 // only do the Alias lookup for namespaces if
2152                                 // the name does not include any dots in it
2153                                 //
2154                                 NamespaceEntry ns = ec.DeclSpace.NamespaceEntry;
2155                                 if (is_base && ns != null){
2156                                         IAlias alias_value = ns.LookupAlias (Name);
2157                                         if (alias_value != null){
2158                                                 if (alias_value.IsType)
2159                                                         return alias_value.Type;
2160
2161                                                 Name = alias_value.Name;
2162                                                 Type t;
2163
2164                                                 if ((t = TypeManager.LookupType (Name)) != null)
2165                                                         return new TypeExpression (t, loc);
2166
2167                                                 // No match, maybe our parent can compose us
2168                                                 // into something meaningful.
2169                                                 return this;
2170                                         }
2171                                 }
2172
2173                                 return ResolveAsTypeStep (ec);
2174                         }
2175
2176                         if (e is TypeExpr)
2177                                 return e;
2178
2179                         if (e is IMemberExpr) {
2180                                 e = MemberAccess.ResolveMemberAccess (ec, e, null, loc, this);
2181                                 if (e == null)
2182                                         return null;
2183
2184                                 IMemberExpr me = e as IMemberExpr;
2185                                 if (me == null)
2186                                         return e;
2187
2188                                 // This fails if ResolveMemberAccess() was unable to decide whether
2189                                 // it's a field or a type of the same name.
2190                                 if (!me.IsStatic && (me.InstanceExpression == null))
2191                                         return e;
2192
2193                                 if (!me.IsStatic &&
2194                                     TypeManager.IsNestedChildOf (me.InstanceExpression.Type, me.DeclaringType) &&
2195                                     !me.InstanceExpression.Type.IsSubclassOf (me.DeclaringType)) {
2196                                         Error (38, "Cannot access nonstatic member `" + me.Name + "' of " +
2197                                                "outer type `" + me.DeclaringType + "' via nested type `" +
2198                                                me.InstanceExpression.Type + "'");
2199                                         return null;
2200                                 }
2201
2202                                 if (right_side != null)
2203                                         e = e.DoResolveLValue (ec, right_side);
2204                                 else
2205                                         e = e.DoResolve (ec);
2206
2207                                 return e;
2208                         }
2209
2210                         if (ec.IsStatic || ec.IsFieldInitializer){
2211                                 if (allow_static)
2212                                         return e;
2213
2214                                 return MemberStaticCheck (ec, e);
2215                         } else
2216                                 return e;
2217                 }
2218
2219                 public override void Emit (EmitContext ec)
2220                 {
2221                         //
2222                         // If this is ever reached, then we failed to
2223                         // find the name as a namespace
2224                         //
2225
2226                         Error (103, "The name `" + Name +
2227                                "' does not exist in the class `" +
2228                                ec.DeclSpace.Name + "'");
2229                 }
2230
2231                 public override string ToString ()
2232                 {
2233                         return Name;
2234                 }
2235         }
2236
2237         /// <summary>
2238         ///   Fully resolved expression that evaluates to a type
2239         /// </summary>
2240         public abstract class TypeExpr : Expression, IAlias {
2241                 override public Expression ResolveAsTypeStep (EmitContext ec)
2242                 {
2243                         TypeExpr t = DoResolveAsTypeStep (ec);
2244                         if (t == null)
2245                                 return null;
2246
2247                         eclass = ExprClass.Type;
2248                         return t;
2249                 }
2250
2251                 override public Expression DoResolve (EmitContext ec)
2252                 {
2253                         return ResolveAsTypeTerminal (ec);
2254                 }
2255
2256                 override public void Emit (EmitContext ec)
2257                 {
2258                         throw new Exception ("Should never be called");
2259                 }
2260
2261                 public virtual bool CheckAccessLevel (DeclSpace ds)
2262                 {
2263                         return ds.CheckAccessLevel (Type);
2264                 }
2265
2266                 public virtual bool AsAccessible (DeclSpace ds, int flags)
2267                 {
2268                         return ds.AsAccessible (Type, flags);
2269                 }
2270
2271                 public virtual bool IsClass {
2272                         get { return Type.IsClass; }
2273                 }
2274
2275                 public virtual bool IsValueType {
2276                         get { return Type.IsValueType; }
2277                 }
2278
2279                 public virtual bool IsInterface {
2280                         get { return Type.IsInterface; }
2281                 }
2282
2283                 public virtual bool IsSealed {
2284                         get { return Type.IsSealed; }
2285                 }
2286
2287                 public virtual bool CanInheritFrom ()
2288                 {
2289                         if (Type == TypeManager.enum_type ||
2290                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2291                             Type == TypeManager.delegate_type ||
2292                             Type == TypeManager.array_type)
2293                                 return false;
2294
2295                         return true;
2296                 }
2297
2298                 public virtual bool IsAttribute {
2299                         get {
2300                                 return Type == TypeManager.attribute_type ||
2301                                         Type.IsSubclassOf (TypeManager.attribute_type);
2302                         }
2303                 }
2304
2305                 public virtual TypeExpr[] GetInterfaces ()
2306                 {
2307                         return TypeManager.GetInterfaces (Type);
2308                 }
2309
2310                 public abstract TypeExpr DoResolveAsTypeStep (EmitContext ec);
2311
2312                 public virtual Type ResolveType (EmitContext ec)
2313                 {
2314                         TypeExpr t = ResolveAsTypeTerminal (ec);
2315                         if (t == null)
2316                                 return null;
2317
2318                         return t.Type;
2319                 }
2320
2321                 public abstract string Name {
2322                         get;
2323                 }
2324
2325                 public override bool Equals (object obj)
2326                 {
2327                         TypeExpr tobj = obj as TypeExpr;
2328                         if (tobj == null)
2329                                 return false;
2330
2331                         return Type == tobj.Type;
2332                 }
2333
2334                 public override string ToString ()
2335                 {
2336                         return Name;
2337                 }
2338
2339                 bool IAlias.IsType {
2340                         get { return true; }
2341                 }
2342
2343                 TypeExpr IAlias.Type {
2344                         get {
2345                                 return this;
2346                         }
2347                 }
2348         }
2349
2350         public class TypeExpression : TypeExpr, IAlias {
2351                 public TypeExpression (Type t, Location l)
2352                 {
2353                         Type = t;
2354                         eclass = ExprClass.Type;
2355                         loc = l;
2356                 }
2357
2358                 public override TypeExpr DoResolveAsTypeStep (EmitContext ec)
2359                 {
2360                         return this;
2361                 }
2362
2363                 public override string Name {
2364                         get {
2365                                 return Type.ToString ();
2366                         }
2367                 }
2368
2369                 string IAlias.Name {
2370                         get {
2371                                 return Type.FullName != null ? Type.FullName : Type.Name;
2372                         }
2373                 }
2374         }
2375
2376         /// <summary>
2377         ///   Used to create types from a fully qualified name.  These are just used
2378         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2379         ///   classified as a type.
2380         /// </summary>
2381         public class TypeLookupExpression : TypeExpr {
2382                 string name;
2383
2384                 public TypeLookupExpression (string name)
2385                 {
2386                         this.name = name;
2387                 }
2388
2389                 public override TypeExpr DoResolveAsTypeStep (EmitContext ec)
2390                 {
2391                         if (type == null) {
2392                                 TypeExpr texpr = RootContext.LookupType (
2393                                         ec.DeclSpace, name, false, Location.Null);
2394                                 if (texpr == null)
2395                                         return null;
2396
2397                                 type = texpr.ResolveType (ec);
2398                                 if (type == null)
2399                                         return null;
2400                         }
2401
2402                         return this;
2403                 }
2404
2405                 public override string Name {
2406                         get {
2407                                 return name;
2408                         }
2409                 }
2410         }
2411
2412         public class TypeAliasExpression : TypeExpr, IAlias {
2413                 TypeExpr texpr;
2414                 TypeArguments args;
2415                 string name;
2416
2417                 public TypeAliasExpression (TypeExpr texpr, TypeArguments args, Location l)
2418                 {
2419                         this.texpr = texpr;
2420                         this.args = args;
2421                         loc = texpr.Location;
2422
2423                         eclass = ExprClass.Type;
2424                         if (args != null)
2425                                 name = texpr.Name + "<" + args.ToString () + ">";
2426                         else
2427                                 name = texpr.Name;
2428                 }
2429
2430                 public override string Name {
2431                         get { return name; }
2432                 }
2433
2434                 public override TypeExpr DoResolveAsTypeStep (EmitContext ec)
2435                 {
2436                         Type type = texpr.ResolveType (ec);
2437                         if (type == null)
2438                                 return null;
2439
2440                         int num_args = TypeManager.GetNumberOfTypeArguments (type);
2441
2442                         if (args != null) {
2443                                 if (num_args == 0) {
2444                                         Report.Error (308, loc,
2445                                                       "The non-generic type `{0}' cannot " +
2446                                                       "be used with type arguments.",
2447                                                       TypeManager.CSharpName (type));
2448                                         return null;
2449                                 }
2450
2451                                 ConstructedType ctype = new ConstructedType (type, args, loc);
2452                                 return ctype.ResolveAsTypeTerminal (ec);
2453                         } else if (num_args > 0) {
2454                                 Report.Error (305, loc,
2455                                               "Using the generic type `{0}' " +
2456                                               "requires {1} type arguments",
2457                                               TypeManager.GetFullName (type), num_args);
2458                                 return null;
2459                         }
2460
2461                         return new TypeExpression (type, loc);
2462                 }
2463
2464                 public override Type ResolveType (EmitContext ec)
2465                 {
2466                         TypeExpr t = ResolveAsTypeTerminal (ec);
2467                         if (t == null)
2468                                 return null;
2469
2470                         type = t.ResolveType (ec);
2471                         return type;
2472                 }
2473
2474                 public override bool CheckAccessLevel (DeclSpace ds)
2475                 {
2476                         return texpr.CheckAccessLevel (ds);
2477                 }
2478
2479                 public override bool AsAccessible (DeclSpace ds, int flags)
2480                 {
2481                         return texpr.AsAccessible (ds, flags);
2482                 }
2483
2484                 public override bool IsClass {
2485                         get { return texpr.IsClass; }
2486                 }
2487
2488                 public override bool IsValueType {
2489                         get { return texpr.IsValueType; }
2490                 }
2491
2492                 public override bool IsInterface {
2493                         get { return texpr.IsInterface; }
2494                 }
2495
2496                 public override bool IsSealed {
2497                         get { return texpr.IsSealed; }
2498                 }
2499
2500                 public override bool IsAttribute {
2501                         get { return texpr.IsAttribute; }
2502                 }
2503         }
2504
2505         /// <summary>
2506         ///   MethodGroup Expression.
2507         ///
2508         ///   This is a fully resolved expression that evaluates to a type
2509         /// </summary>
2510         public class MethodGroupExpr : Expression, IMemberExpr {
2511                 public MethodBase [] Methods;
2512                 Expression instance_expression = null;
2513                 bool is_explicit_impl = false;
2514                 bool has_type_arguments = false;
2515
2516                 public MethodGroupExpr (MemberInfo [] mi, Location l)
2517                 {
2518                         Methods = new MethodBase [mi.Length];
2519                         mi.CopyTo (Methods, 0);
2520                         eclass = ExprClass.MethodGroup;
2521                         type = TypeManager.object_type;
2522                         loc = l;
2523                 }
2524
2525                 public MethodGroupExpr (ArrayList list, Location l)
2526                 {
2527                         Methods = new MethodBase [list.Count];
2528
2529                         try {
2530                                 list.CopyTo (Methods, 0);
2531                         } catch {
2532                                 foreach (MemberInfo m in list){
2533                                         if (!(m is MethodBase)){
2534                                                 Console.WriteLine ("Name " + m.Name);
2535                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
2536                                         }
2537                                 }
2538                                 throw;
2539                         }
2540
2541                         loc = l;
2542                         eclass = ExprClass.MethodGroup;
2543                         type = TypeManager.object_type;
2544                 }
2545
2546                 public Type DeclaringType {
2547                         get {
2548                                 //
2549                                 // We assume that the top-level type is in the end
2550                                 //
2551                                 return Methods [Methods.Length - 1].DeclaringType;
2552                                 //return Methods [0].DeclaringType;
2553                         }
2554                 }
2555
2556                 //
2557                 // `A method group may have associated an instance expression'
2558                 //
2559                 public Expression InstanceExpression {
2560                         get {
2561                                 return instance_expression;
2562                         }
2563
2564                         set {
2565                                 instance_expression = value;
2566                         }
2567                 }
2568
2569                 public bool IsExplicitImpl {
2570                         get {
2571                                 return is_explicit_impl;
2572                         }
2573
2574                         set {
2575                                 is_explicit_impl = value;
2576                         }
2577                 }
2578
2579                 public bool HasTypeArguments {
2580                         get {
2581                                 return has_type_arguments;
2582                         }
2583
2584                         set {
2585                                 has_type_arguments = value;
2586                         }
2587                 }
2588
2589                 public string Name {
2590                         get {
2591                                 return TypeManager.CSharpSignature (
2592                                         Methods [Methods.Length - 1]);
2593                         }
2594                 }
2595
2596                 public bool IsInstance {
2597                         get {
2598                                 foreach (MethodBase mb in Methods)
2599                                         if (!mb.IsStatic)
2600                                                 return true;
2601
2602                                 return false;
2603                         }
2604                 }
2605
2606                 public bool IsStatic {
2607                         get {
2608                                 foreach (MethodBase mb in Methods)
2609                                         if (mb.IsStatic)
2610                                                 return true;
2611
2612                                 return false;
2613                         }
2614                 }
2615
2616                 override public Expression DoResolve (EmitContext ec)
2617                 {
2618                         if (!IsInstance)
2619                                 instance_expression = null;
2620
2621                         if (instance_expression != null) {
2622                                 instance_expression = instance_expression.DoResolve (ec);
2623                                 if (instance_expression == null)
2624                                         return null;
2625                         }
2626
2627                         return this;
2628                 }
2629
2630                 public void ReportUsageError ()
2631                 {
2632                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
2633                                       Name + "()' is referenced without parentheses");
2634                 }
2635
2636                 override public void Emit (EmitContext ec)
2637                 {
2638                         ReportUsageError ();
2639                 }
2640
2641                 bool RemoveMethods (bool keep_static)
2642                 {
2643                         ArrayList smethods = new ArrayList ();
2644
2645                         foreach (MethodBase mb in Methods){
2646                                 if (mb.IsStatic == keep_static)
2647                                         smethods.Add (mb);
2648                         }
2649
2650                         if (smethods.Count == 0)
2651                                 return false;
2652
2653                         Methods = new MethodBase [smethods.Count];
2654                         smethods.CopyTo (Methods, 0);
2655
2656                         return true;
2657                 }
2658
2659                 /// <summary>
2660                 ///   Removes any instance methods from the MethodGroup, returns
2661                 ///   false if the resulting set is empty.
2662                 /// </summary>
2663                 public bool RemoveInstanceMethods ()
2664                 {
2665                         return RemoveMethods (true);
2666                 }
2667
2668                 /// <summary>
2669                 ///   Removes any static methods from the MethodGroup, returns
2670                 ///   false if the resulting set is empty.
2671                 /// </summary>
2672                 public bool RemoveStaticMethods ()
2673                 {
2674                         return RemoveMethods (false);
2675                 }
2676         }
2677
2678         /// <summary>
2679         ///   Fully resolved expression that evaluates to a Field
2680         /// </summary>
2681         public class FieldExpr : Expression, IAssignMethod, IMemoryLocation, IMemberExpr, IVariable {
2682                 public readonly FieldInfo FieldInfo;
2683                 Expression instance_expr;
2684                 VariableInfo variable_info;
2685
2686                 public FieldExpr (FieldInfo fi, Location l)
2687                 {
2688                         FieldInfo = fi;
2689                         eclass = ExprClass.Variable;
2690                         type = TypeManager.TypeToCoreType (fi.FieldType);
2691                         loc = l;
2692                 }
2693
2694                 public string Name {
2695                         get {
2696                                 return FieldInfo.Name;
2697                         }
2698                 }
2699
2700                 public bool IsInstance {
2701                         get {
2702                                 return !FieldInfo.IsStatic;
2703                         }
2704                 }
2705
2706                 public bool IsStatic {
2707                         get {
2708                                 return FieldInfo.IsStatic;
2709                         }
2710                 }
2711
2712                 public Type DeclaringType {
2713                         get {
2714                                 return FieldInfo.DeclaringType;
2715                         }
2716                 }
2717
2718                 public Expression InstanceExpression {
2719                         get {
2720                                 return instance_expr;
2721                         }
2722
2723                         set {
2724                                 instance_expr = value;
2725                         }
2726                 }
2727
2728                 public VariableInfo VariableInfo {
2729                         get {
2730                                 return variable_info;
2731                         }
2732                 }
2733
2734                 override public Expression DoResolve (EmitContext ec)
2735                 {
2736                         if (!FieldInfo.IsStatic){
2737                                 if (instance_expr == null){
2738                                         //
2739                                         // This can happen when referencing an instance field using
2740                                         // a fully qualified type expression: TypeName.InstanceField = xxx
2741                                         //
2742                                         SimpleName.Error_ObjectRefRequired (ec, loc, FieldInfo.Name);
2743                                         return null;
2744                                 }
2745
2746                                 // Resolve the field's instance expression while flow analysis is turned
2747                                 // off: when accessing a field "a.b", we must check whether the field
2748                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
2749                                 instance_expr = instance_expr.Resolve (ec, ResolveFlags.VariableOrValue |
2750                                                                        ResolveFlags.DisableFlowAnalysis);
2751                                 if (instance_expr == null)
2752                                         return null;
2753                         }
2754
2755                         // If the instance expression is a local variable or parameter.
2756                         IVariable var = instance_expr as IVariable;
2757                         if ((var == null) || (var.VariableInfo == null))
2758                                 return this;
2759
2760                         VariableInfo vi = var.VariableInfo;
2761                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
2762                                 return null;
2763
2764                         variable_info = vi.GetSubStruct (FieldInfo.Name);
2765                         return this;
2766                 }
2767
2768                 void Report_AssignToReadonly (bool is_instance)
2769                 {
2770                         string msg;
2771
2772                         if (is_instance)
2773                                 msg = "Readonly field can not be assigned outside " +
2774                                 "of constructor or variable initializer";
2775                         else
2776                                 msg = "A static readonly field can only be assigned in " +
2777                                 "a static constructor";
2778
2779                         Report.Error (is_instance ? 191 : 198, loc, msg);
2780                 }
2781
2782                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
2783                 {
2784                         IVariable var = instance_expr as IVariable;
2785                         if ((var != null) && (var.VariableInfo != null))
2786                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
2787
2788                         Expression e = DoResolve (ec);
2789
2790                         if (e == null)
2791                                 return null;
2792
2793                         if (!FieldInfo.IsStatic && (instance_expr.Type.IsValueType && !(instance_expr is IMemoryLocation))) {
2794                                 // FIXME: Provide better error reporting.
2795                                 Error (1612, "Cannot modify expression because it is not a variable.");
2796                                 return null;
2797                         }
2798
2799                         if (!FieldInfo.IsInitOnly)
2800                                 return this;
2801
2802                         FieldBase fb = TypeManager.GetField (FieldInfo);
2803                         if (fb != null)
2804                                 fb.SetAssigned ();
2805
2806                         //
2807                         // InitOnly fields can only be assigned in constructors
2808                         //
2809
2810                         if (ec.IsConstructor){
2811                                 if (IsStatic && !ec.IsStatic)
2812                                         Report_AssignToReadonly (false);
2813
2814                                 Type ctype;
2815                                 if (ec.TypeContainer.CurrentType != null)
2816                                         ctype = ec.TypeContainer.CurrentType.ResolveType (ec);
2817                                 else
2818                                         ctype = ec.ContainerType;
2819
2820                                 if (TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
2821                                         return this;
2822                         }
2823
2824                         Report_AssignToReadonly (true);
2825
2826                         return null;
2827                 }
2828
2829                 public bool VerifyFixed (bool is_expression)
2830                 {
2831                         IVariable variable = instance_expr as IVariable;
2832                         if ((variable == null) || !variable.VerifyFixed (true))
2833                                 return false;
2834
2835                         return true;
2836                 }
2837
2838                 override public void Emit (EmitContext ec)
2839                 {
2840                         ILGenerator ig = ec.ig;
2841                         bool is_volatile = false;
2842
2843                         if (FieldInfo is FieldBuilder){
2844                                 FieldBase f = TypeManager.GetField (FieldInfo);
2845                                 if (f != null){
2846                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0)
2847                                                 is_volatile = true;
2848
2849                                         f.status |= Field.Status.USED;
2850                                 }
2851                         }
2852
2853                         if (FieldInfo.IsStatic){
2854                                 if (is_volatile)
2855                                         ig.Emit (OpCodes.Volatile);
2856
2857                                 ig.Emit (OpCodes.Ldsfld, FieldInfo);
2858                                 return;
2859                         }
2860
2861                         if (instance_expr.Type.IsValueType){
2862                                 IMemoryLocation ml;
2863                                 LocalTemporary tempo = null;
2864
2865                                 if (!(instance_expr is IMemoryLocation)){
2866                                         tempo = new LocalTemporary (ec, instance_expr.Type);
2867
2868                                         if (ec.RemapToProxy)
2869                                                 ec.EmitThis ();
2870
2871                                         InstanceExpression.Emit (ec);
2872                                         tempo.Store (ec);
2873                                         ml = tempo;
2874                                 } else
2875                                         ml = (IMemoryLocation) instance_expr;
2876
2877                                 ml.AddressOf (ec, AddressOp.Load);
2878                         } else {
2879                                 if (ec.RemapToProxy)
2880                                         ec.EmitThis ();
2881                                 else
2882                                         instance_expr.Emit (ec);
2883                         }
2884                         if (is_volatile)
2885                                 ig.Emit (OpCodes.Volatile);
2886
2887                         ig.Emit (OpCodes.Ldfld, FieldInfo);
2888                 }
2889
2890                 public void EmitAssign (EmitContext ec, Expression source)
2891                 {
2892                         FieldAttributes fa = FieldInfo.Attributes;
2893                         bool is_static = (fa & FieldAttributes.Static) != 0;
2894                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
2895                         ILGenerator ig = ec.ig;
2896
2897                         if (is_readonly && !ec.IsConstructor){
2898                                 Report_AssignToReadonly (!is_static);
2899                                 return;
2900                         }
2901
2902                         if (!is_static){
2903                                 Expression instance = instance_expr;
2904
2905                                 if (instance.Type.IsValueType){
2906                                         IMemoryLocation ml = (IMemoryLocation) instance;
2907
2908                                         ml.AddressOf (ec, AddressOp.Store);
2909                                 } else {
2910                                         if (ec.RemapToProxy)
2911                                                 ec.EmitThis ();
2912                                         else
2913                                                 instance.Emit (ec);
2914                                 }
2915                         }
2916
2917                         source.Emit (ec);
2918
2919                         if (FieldInfo is FieldBuilder){
2920                                 FieldBase f = TypeManager.GetField (FieldInfo);
2921                                 if (f != null){
2922                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0)
2923                                                 ig.Emit (OpCodes.Volatile);
2924
2925                                         f.status |= Field.Status.ASSIGNED;
2926                                 }
2927                         }
2928
2929                         if (is_static)
2930                                 ig.Emit (OpCodes.Stsfld, FieldInfo);
2931                         else
2932                                 ig.Emit (OpCodes.Stfld, FieldInfo);
2933                 }
2934
2935                 public void AddressOf (EmitContext ec, AddressOp mode)
2936                 {
2937                         ILGenerator ig = ec.ig;
2938
2939                         if (FieldInfo is FieldBuilder){
2940                                 FieldBase f = TypeManager.GetField (FieldInfo);
2941                                 if (f != null){
2942                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0){
2943                                                 Error (676, "volatile variable: can not take its address, or pass as ref/out parameter");
2944                                                 return;
2945                                         }
2946
2947                                         if ((mode & AddressOp.Store) != 0)
2948                                                 f.status |= Field.Status.ASSIGNED;
2949                                         if ((mode & AddressOp.Load) != 0)
2950                                                 f.status |= Field.Status.USED;
2951                                 }
2952                         }
2953
2954                         //
2955                         // Handle initonly fields specially: make a copy and then
2956                         // get the address of the copy.
2957                         //
2958                         bool need_copy;
2959                         if (FieldInfo.IsInitOnly){
2960                                 need_copy = true;
2961                                 if (ec.IsConstructor){
2962                                         if (FieldInfo.IsStatic){
2963                                                 if (ec.IsStatic)
2964                                                         need_copy = false;
2965                                         } else
2966                                                 need_copy = false;
2967                                 }
2968                         } else
2969                                 need_copy = false;
2970
2971                         if (need_copy){
2972                                 LocalBuilder local;
2973                                 Emit (ec);
2974                                 local = ig.DeclareLocal (type);
2975                                 ig.Emit (OpCodes.Stloc, local);
2976                                 ig.Emit (OpCodes.Ldloca, local);
2977                                 return;
2978                         }
2979
2980
2981                         if (FieldInfo.IsStatic){
2982                                 ig.Emit (OpCodes.Ldsflda, FieldInfo);
2983                         } else {
2984                                 //
2985                                 // In the case of `This', we call the AddressOf method, which will
2986                                 // only load the pointer, and not perform an Ldobj immediately after
2987                                 // the value has been loaded into the stack.
2988                                 //
2989                                 if (instance_expr is This)
2990                                         ((This)instance_expr).AddressOf (ec, AddressOp.LoadStore);
2991                                 else if (instance_expr.Type.IsValueType && instance_expr is IMemoryLocation){
2992                                         IMemoryLocation ml = (IMemoryLocation) instance_expr;
2993
2994                                         ml.AddressOf (ec, AddressOp.LoadStore);
2995                                 } else
2996                                         instance_expr.Emit (ec);
2997                                 ig.Emit (OpCodes.Ldflda, FieldInfo);
2998                         }
2999                 }
3000         }
3001
3002         //
3003         // A FieldExpr whose address can not be taken
3004         //
3005         public class FieldExprNoAddress : FieldExpr, IMemoryLocation {
3006                 public FieldExprNoAddress (FieldInfo fi, Location loc) : base (fi, loc)
3007                 {
3008                 }
3009
3010                 public new void AddressOf (EmitContext ec, AddressOp mode)
3011                 {
3012                         Report.Error (-215, "Report this: Taking the address of a remapped parameter not supported");
3013                 }
3014         }
3015
3016         /// <summary>
3017         ///   Expression that evaluates to a Property.  The Assign class
3018         ///   might set the `Value' expression if we are in an assignment.
3019         ///
3020         ///   This is not an LValue because we need to re-write the expression, we
3021         ///   can not take data from the stack and store it.
3022         /// </summary>
3023         public class PropertyExpr : ExpressionStatement, IAssignMethod, IMemberExpr {
3024                 public readonly PropertyInfo PropertyInfo;
3025
3026                 //
3027                 // This is set externally by the  `BaseAccess' class
3028                 //
3029                 public bool IsBase;
3030                 MethodInfo getter, setter;
3031                 bool is_static;
3032                 bool must_do_cs1540_check;
3033
3034                 Expression instance_expr;
3035
3036                 public PropertyExpr (EmitContext ec, PropertyInfo pi, Location l)
3037                 {
3038                         PropertyInfo = pi;
3039                         eclass = ExprClass.PropertyAccess;
3040                         is_static = false;
3041                         loc = l;
3042
3043                         type = TypeManager.TypeToCoreType (pi.PropertyType);
3044
3045                         ResolveAccessors (ec);
3046                 }
3047
3048                 public string Name {
3049                         get {
3050                                 return PropertyInfo.Name;
3051                         }
3052                 }
3053
3054                 public bool IsInstance {
3055                         get {
3056                                 return !is_static;
3057                         }
3058                 }
3059
3060                 public bool IsStatic {
3061                         get {
3062                                 return is_static;
3063                         }
3064                 }
3065
3066                 public Type DeclaringType {
3067                         get {
3068                                 return PropertyInfo.DeclaringType;
3069                         }
3070                 }
3071
3072                 //
3073                 // The instance expression associated with this expression
3074                 //
3075                 public Expression InstanceExpression {
3076                         set {
3077                                 instance_expr = value;
3078                         }
3079
3080                         get {
3081                                 return instance_expr;
3082                         }
3083                 }
3084
3085                 public bool VerifyAssignable ()
3086                 {
3087                         if (setter == null) {
3088                                 Report.Error (200, loc,
3089                                               "The property `" + PropertyInfo.Name +
3090                                               "' can not be assigned to, as it has not set accessor");
3091                                 return false;
3092                         }
3093
3094                         return true;
3095                 }
3096
3097                 MethodInfo GetAccessor (Type invocation_type, string accessor_name)
3098                 {
3099                         BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
3100                                 BindingFlags.Static | BindingFlags.Instance;
3101                         MemberInfo[] group;
3102
3103                         group = TypeManager.MemberLookup (
3104                                 invocation_type, invocation_type, PropertyInfo.DeclaringType,
3105                                 MemberTypes.Method, flags, accessor_name + "_" + PropertyInfo.Name);
3106
3107                         //
3108                         // The first method is the closest to us
3109                         //
3110                         if (group == null)
3111                                 return null;
3112
3113                         foreach (MethodInfo mi in group) {
3114                                 MethodAttributes ma = mi.Attributes & MethodAttributes.MemberAccessMask;
3115
3116                                 //
3117                                 // If only accessible to the current class or children
3118                                 //
3119                                 if (ma == MethodAttributes.Private) {
3120                                         Type declaring_type = mi.DeclaringType;
3121
3122                                         if (invocation_type != declaring_type){
3123                                                 if (TypeManager.IsSubclassOrNestedChildOf (invocation_type, mi.DeclaringType))
3124                                                         return mi;
3125                                                 else
3126                                                         continue;
3127                                         } else
3128                                                 return mi;
3129                                 }
3130                                 //
3131                                 // FamAndAssem requires that we not only derivate, but we are on the
3132                                 // same assembly.
3133                                 //
3134                                 if (ma == MethodAttributes.FamANDAssem){
3135                                         if (mi.DeclaringType.Assembly != invocation_type.Assembly)
3136                                                 continue;
3137                                         else
3138                                                 return mi;
3139                                 }
3140
3141                                 // Assembly and FamORAssem succeed if we're in the same assembly.
3142                                 if ((ma == MethodAttributes.Assembly) || (ma == MethodAttributes.FamORAssem)){
3143                                         if (mi.DeclaringType.Assembly == invocation_type.Assembly)
3144                                                 return mi;
3145                                 }
3146
3147                                 // We already know that we aren't in the same assembly.
3148                                 if (ma == MethodAttributes.Assembly)
3149                                         continue;
3150
3151                                 // Family and FamANDAssem require that we derive.
3152                                 if ((ma == MethodAttributes.Family) || (ma == MethodAttributes.FamANDAssem) || (ma == MethodAttributes.FamORAssem)){
3153                                         if (!TypeManager.IsSubclassOrNestedChildOf (invocation_type, mi.DeclaringType))
3154                                                 continue;
3155                                         else {
3156                                                 must_do_cs1540_check = true;
3157
3158                                                 return mi;
3159                                         }
3160                                 }
3161
3162                                 return mi;
3163                         }
3164
3165                         return null;
3166                 }
3167
3168                 //
3169                 // We also perform the permission checking here, as the PropertyInfo does not
3170                 // hold the information for the accessibility of its setter/getter
3171                 //
3172                 void ResolveAccessors (EmitContext ec)
3173                 {
3174                         getter = GetAccessor (ec.ContainerType, "get");
3175                         if ((getter != null) && getter.IsStatic)
3176                                 is_static = true;
3177
3178                         setter = GetAccessor (ec.ContainerType, "set");
3179                         if ((setter != null) && setter.IsStatic)
3180                                 is_static = true;
3181
3182                         if (setter == null && getter == null){
3183                                 Error (122, "`" + PropertyInfo.Name + "' " +
3184                                        "is inaccessible because of its protection level");
3185
3186                         }
3187                 }
3188
3189                 bool InstanceResolve (EmitContext ec)
3190                 {
3191                         if ((instance_expr == null) && ec.IsStatic && !is_static) {
3192                                 SimpleName.Error_ObjectRefRequired (ec, loc, PropertyInfo.Name);
3193                                 return false;
3194                         }
3195
3196                         if (instance_expr != null) {
3197                                 instance_expr = instance_expr.DoResolve (ec);
3198                                 if (instance_expr == null)
3199                                         return false;
3200                         }
3201
3202                         if (must_do_cs1540_check && (instance_expr != null)) {
3203                                 if ((instance_expr.Type != ec.ContainerType) &&
3204                                     ec.ContainerType.IsSubclassOf (instance_expr.Type)) {
3205                                         Report.Error (1540, loc, "Cannot access protected member `" +
3206                                                       PropertyInfo.DeclaringType + "." + PropertyInfo.Name +
3207                                                       "' via a qualifier of type `" +
3208                                                       TypeManager.CSharpName (instance_expr.Type) +
3209                                                       "'; the qualifier must be of type `" +
3210                                                       TypeManager.CSharpName (ec.ContainerType) +
3211                                                       "' (or derived from it)");
3212                                         return false;
3213                                 }
3214                         }
3215
3216                         return true;
3217                 }
3218
3219                 override public Expression DoResolve (EmitContext ec)
3220                 {
3221                         if (getter == null){
3222                                 //
3223                                 // The following condition happens if the PropertyExpr was
3224                                 // created, but is invalid (ie, the property is inaccessible),
3225                                 // and we did not want to embed the knowledge about this in
3226                                 // the caller routine.  This only avoids double error reporting.
3227                                 //
3228                                 if (setter == null)
3229                                         return null;
3230
3231                                 Report.Error (154, loc,
3232                                               "The property `" + PropertyInfo.Name +
3233                                               "' can not be used in " +
3234                                               "this context because it lacks a get accessor");
3235                                 return null;
3236                         }
3237
3238                         if (!InstanceResolve (ec))
3239                                 return null;
3240
3241                         //
3242                         // Only base will allow this invocation to happen.
3243                         //
3244                         if (IsBase && getter.IsAbstract){
3245                                 Report.Error (205, loc, "Cannot call an abstract base property: " +
3246                                               PropertyInfo.DeclaringType + "." +PropertyInfo.Name);
3247                                 return null;
3248                         }
3249
3250                         return this;
3251                 }
3252
3253                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3254                 {
3255                         if (setter == null){
3256                                 //
3257                                 // The following condition happens if the PropertyExpr was
3258                                 // created, but is invalid (ie, the property is inaccessible),
3259                                 // and we did not want to embed the knowledge about this in
3260                                 // the caller routine.  This only avoids double error reporting.
3261                                 //
3262                                 if (getter == null)
3263                                         return null;
3264
3265                                 Report.Error (154, loc,
3266                                               "The property `" + PropertyInfo.Name +
3267                                               "' can not be used in " +
3268                                               "this context because it lacks a set accessor");
3269                                 return null;
3270                         }
3271
3272                         if (!InstanceResolve (ec))
3273                                 return null;
3274
3275                         //
3276                         // Only base will allow this invocation to happen.
3277                         //
3278                         if (IsBase && setter.IsAbstract){
3279                                 Report.Error (205, loc, "Cannot call an abstract base property: " +
3280                                               PropertyInfo.DeclaringType + "." +PropertyInfo.Name);
3281                                 return null;
3282                         }
3283                         return this;
3284                 }
3285
3286                 override public void Emit (EmitContext ec)
3287                 {
3288                         //
3289                         // Special case: length of single dimension array property is turned into ldlen
3290                         //
3291                         if ((getter == TypeManager.system_int_array_get_length) ||
3292                             (getter == TypeManager.int_array_get_length)){
3293                                 Type iet = instance_expr.Type;
3294
3295                                 //
3296                                 // System.Array.Length can be called, but the Type does not
3297                                 // support invoking GetArrayRank, so test for that case first
3298                                 //
3299                                 if (iet != TypeManager.array_type && (iet.GetArrayRank () == 1)){
3300                                         instance_expr.Emit (ec);
3301                                         ec.ig.Emit (OpCodes.Ldlen);
3302                                         ec.ig.Emit (OpCodes.Conv_I4);
3303                                         return;
3304                                 }
3305                         }
3306
3307                         Invocation.EmitCall (ec, IsBase, IsStatic, instance_expr, getter, null, loc);
3308
3309                 }
3310
3311                 //
3312                 // Implements the IAssignMethod interface for assignments
3313                 //
3314                 public void EmitAssign (EmitContext ec, Expression source)
3315                 {
3316                         Argument arg = new Argument (source, Argument.AType.Expression);
3317                         ArrayList args = new ArrayList ();
3318
3319                         args.Add (arg);
3320                         Invocation.EmitCall (ec, IsBase, IsStatic, instance_expr, setter, args, loc);
3321                 }
3322
3323                 override public void EmitStatement (EmitContext ec)
3324                 {
3325                         Emit (ec);
3326                         ec.ig.Emit (OpCodes.Pop);
3327                 }
3328         }
3329
3330         /// <summary>
3331         ///   Fully resolved expression that evaluates to an Event
3332         /// </summary>
3333         public class EventExpr : Expression, IMemberExpr {
3334                 public readonly EventInfo EventInfo;
3335                 public Expression instance_expr;
3336
3337                 bool is_static;
3338                 MethodInfo add_accessor, remove_accessor;
3339
3340                 public EventExpr (EventInfo ei, Location loc)
3341                 {
3342                         EventInfo = ei;
3343                         this.loc = loc;
3344                         eclass = ExprClass.EventAccess;
3345
3346                         add_accessor = TypeManager.GetAddMethod (ei);
3347                         remove_accessor = TypeManager.GetRemoveMethod (ei);
3348
3349                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
3350                                 is_static = true;
3351
3352                         if (EventInfo is MyEventBuilder){
3353                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
3354                                 type = eb.EventType;
3355                                 eb.SetUsed ();
3356                         } else
3357                                 type = EventInfo.EventHandlerType;
3358                 }
3359
3360                 public string Name {
3361                         get {
3362                                 return EventInfo.Name;
3363                         }
3364                 }
3365
3366                 public bool IsInstance {
3367                         get {
3368                                 return !is_static;
3369                         }
3370                 }
3371
3372                 public bool IsStatic {
3373                         get {
3374                                 return is_static;
3375                         }
3376                 }
3377
3378                 public Type DeclaringType {
3379                         get {
3380                                 return EventInfo.DeclaringType;
3381                         }
3382                 }
3383
3384                 public Expression InstanceExpression {
3385                         get {
3386                                 return instance_expr;
3387                         }
3388
3389                         set {
3390                                 instance_expr = value;
3391                         }
3392                 }
3393
3394                 public override Expression DoResolve (EmitContext ec)
3395                 {
3396                         if (instance_expr != null) {
3397                                 instance_expr = instance_expr.DoResolve (ec);
3398                                 if (instance_expr == null)
3399                                         return null;
3400                         }
3401
3402
3403                         return this;
3404                 }
3405
3406                 public override void Emit (EmitContext ec)
3407                 {
3408                         Report.Error (70, loc, "The event `" + Name + "' can only appear on the left hand side of += or -= (except on the defining type)");
3409                 }
3410
3411                 public void EmitAddOrRemove (EmitContext ec, Expression source)
3412                 {
3413                         BinaryDelegate source_del = (BinaryDelegate) source;
3414                         Expression handler = source_del.Right;
3415
3416                         Argument arg = new Argument (handler, Argument.AType.Expression);
3417                         ArrayList args = new ArrayList ();
3418
3419                         args.Add (arg);
3420
3421                         if (source_del.IsAddition)
3422                                 Invocation.EmitCall (
3423                                         ec, false, IsStatic, instance_expr, add_accessor, args, loc);
3424                         else
3425                                 Invocation.EmitCall (
3426                                         ec, false, IsStatic, instance_expr, remove_accessor, args, loc);
3427                 }
3428         }
3429 }