mcs/mcs/ecore.cs

   1 //
   2 // ecore.cs: Core of the Expression representation for the intermediate tree.
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   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                 // Set if this is resolving the first part of a MemberAccess.
  67                 Intermediate            = 32
  68         }
  69
  70         //
  71         // This is just as a hint to AddressOf of what will be done with the
  72         // address.
  73         [Flags]
  74         public enum AddressOp {
  75                 Store = 1,
  76                 Load  = 2,
  77                 LoadStore = 3
  78         };
  79
  80         /// <summary>
  81         ///   This interface is implemented by variables
  82         /// </summary>
  83         public interface IMemoryLocation {
  84                 /// <summary>
  85                 ///   The AddressOf method should generate code that loads
  86                 ///   the address of the object and leaves it on the stack.
  87                 ///
  88                 ///   The `mode' argument is used to notify the expression
  89                 ///   of whether this will be used to read from the address or
  90                 ///   write to the address.
  91                 ///
  92                 ///   This is just a hint that can be used to provide good error
  93                 ///   reporting, and should have no other side effects.
  94                 /// </summary>
  95                 void AddressOf (EmitContext ec, AddressOp mode);
  96         }
  97
  98         /// <summary>
  99         ///   This interface is implemented by variables
 100         /// </summary>
 101         public interface IVariable {
 102                 VariableInfo VariableInfo {
 103                         get;
 104                 }
 105
 106                 bool VerifyFixed (bool is_expression);
 107         }
 108
 109         /// <summary>
 110         ///   This interface denotes an expression which evaluates to a member
 111         ///   of a struct or a class.
 112         /// </summary>
 113         public interface IMemberExpr
 114         {
 115                 /// <summary>
 116                 ///   The name of this member.
 117                 /// </summary>
 118                 string Name {
 119                         get;
 120                 }
 121
 122                 /// <summary>
 123                 ///   Whether this is an instance member.
 124                 /// </summary>
 125                 bool IsInstance {
 126                         get;
 127                 }
 128
 129                 /// <summary>
 130                 ///   Whether this is a static member.
 131                 /// </summary>
 132                 bool IsStatic {
 133                         get;
 134                 }
 135
 136                 /// <summary>
 137                 ///   The type which declares this member.
 138                 /// </summary>
 139                 Type DeclaringType {
 140                         get;
 141                 }
 142
 143                 /// <summary>
 144                 ///   The instance expression associated with this member, if it's a
 145                 ///   non-static member.
 146                 /// </summary>
 147                 Expression InstanceExpression {
 148                         get; set;
 149                 }
 150         }
 151
 152         /// <remarks>
 153         ///   Base class for expressions
 154         /// </remarks>
 155         public abstract class Expression {
 156                 public ExprClass eclass;
 157                 protected Type type;
 158                 protected Location loc;
 159
 160                 public Type Type {
 161                         get {
 162                                 return type;
 163                         }
 164
 165                         set {
 166                                 type = value;
 167                         }
 168                 }
 169
 170                 public Location Location {
 171                         get {
 172                                 return loc;
 173                         }
 174                 }
 175
 176                 /// <summary>
 177                 ///   Utility wrapper routine for Error, just to beautify the code
 178                 /// </summary>
 179                 public void Error (int error, string s)
 180                 {
 181                         if (!Location.IsNull (loc))
 182                                 Report.Error (error, loc, s);
 183                         else
 184                                 Report.Error (error, s);
 185                 }
 186
 187                 /// <summary>
 188                 ///   Utility wrapper routine for Warning, just to beautify the code
 189                 /// </summary>
 190                 public void Warning (int code, string format, params object[] args)
 191                 {
 192                         Report.Warning (code, loc, format, args);
 193                 }
 194
 195                 /// <summary>
 196                 /// Tests presence of ObsoleteAttribute and report proper error
 197                 /// </summary>
 198                 protected void CheckObsoleteAttribute (Type type)
 199                 {
 200                         ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (type);
 201                         if (obsolete_attr == null)
 202                                 return;
 203
 204                         AttributeTester.Report_ObsoleteMessage (obsolete_attr, type.FullName, loc);
 205                 }
 206
 207                 /// <summary>
 208                 ///   Performs semantic analysis on the Expression
 209                 /// </summary>
 210                 ///
 211                 /// <remarks>
 212                 ///   The Resolve method is invoked to perform the semantic analysis
 213                 ///   on the node.
 214                 ///
 215                 ///   The return value is an expression (it can be the
 216                 ///   same expression in some cases) or a new
 217                 ///   expression that better represents this node.
 218                 ///
 219                 ///   For example, optimizations of Unary (LiteralInt)
 220                 ///   would return a new LiteralInt with a negated
 221                 ///   value.
 222                 ///
 223                 ///   If there is an error during semantic analysis,
 224                 ///   then an error should be reported (using Report)
 225                 ///   and a null value should be returned.
 226                 ///
 227                 ///   There are two side effects expected from calling
 228                 ///   Resolve(): the the field variable "eclass" should
 229                 ///   be set to any value of the enumeration
 230                 ///   `ExprClass' and the type variable should be set
 231                 ///   to a valid type (this is the type of the
 232                 ///   expression).
 233                 /// </remarks>
 234                 public abstract Expression DoResolve (EmitContext ec);
 235
 236                 public virtual Expression DoResolveLValue (EmitContext ec, Expression right_side)
 237                 {
 238                         return DoResolve (ec);
 239                 }
 240
 241                 //
 242                 // This is used if the expression should be resolved as a type.
 243                 // the default implementation fails.   Use this method in
 244                 // those participants in the SimpleName chain system.
 245                 //
 246                 public virtual Expression ResolveAsTypeStep (EmitContext ec)
 247                 {
 248                         return null;
 249                 }
 250
 251                 //
 252                 // This is used to resolve the expression as a type, a null
 253                 // value will be returned if the expression is not a type
 254                 // reference
 255                 //
 256                 public TypeExpr ResolveAsTypeTerminal (EmitContext ec, bool silent)
 257                 {
 258                         int errors = Report.Errors;
 259
 260                         TypeExpr te = ResolveAsTypeStep (ec) as TypeExpr;
 261
 262                         if (te == null || te.eclass != ExprClass.Type) {
 263                                 if (!silent && errors == Report.Errors)
 264                                         Report.Error (246, Location, "Cannot find type '{0}'", ToString ());
 265                                 return null;
 266                         }
 267
 268                         if (!te.CheckAccessLevel (ec.DeclSpace)) {
 269                                 Report.Error (122, Location, "'{0}' is inaccessible due to its protection level", te.Name);
 270                                 return null;
 271                         }
 272
 273                         return te;
 274                 }
 275
 276                 /// <summary>
 277                 ///   Resolves an expression and performs semantic analysis on it.
 278                 /// </summary>
 279                 ///
 280                 /// <remarks>
 281                 ///   Currently Resolve wraps DoResolve to perform sanity
 282                 ///   checking and assertion checking on what we expect from Resolve.
 283                 /// </remarks>
 284                 public Expression Resolve (EmitContext ec, ResolveFlags flags)
 285                 {
 286                         if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
 287                                 return ResolveAsTypeStep (ec);
 288
 289                         bool old_do_flow_analysis = ec.DoFlowAnalysis;
 290                         if ((flags & ResolveFlags.DisableFlowAnalysis) != 0)
 291                                 ec.DoFlowAnalysis = false;
 292
 293                         Expression e;
 294                         bool intermediate = (flags & ResolveFlags.Intermediate) == ResolveFlags.Intermediate;
 295                         if (this is SimpleName)
 296                                 e = ((SimpleName) this).DoResolveAllowStatic (ec, intermediate);
 297
 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, loc);
 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, loc);
 331                                         return null;
 332                                 }
 333                                 break;
 334
 335                         case ExprClass.MethodGroup:
 336                                 if (RootContext.Version == LanguageVersion.ISO_1){
 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, loc);
 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)
 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                                 Type real_type = TypeManager.TypeToCoreType (v.GetType ());
 489                                 if (real_type == t)
 490                                         real_type = System.Enum.GetUnderlyingType (real_type);
 491
 492                                 Constant e = Constantify (v, real_type);
 493
 494                                 return new EnumConstant (e, t);
 495                         } else if (v == null && !TypeManager.IsValueType (t))
 496                                 return NullLiteral.Null;
 497                         else
 498                                 throw new Exception ("Unknown type for constant (" + t +
 499                                                      "), details: " + v);
 500                 }
 501
 502                 /// <summary>
 503                 ///   Returns a fully formed expression after a MemberLookup
 504                 /// </summary>
 505                 public static Expression ExprClassFromMemberInfo (EmitContext ec, MemberInfo mi, Location loc)
 506                 {
 507                         if (mi is EventInfo)
 508                                 return new EventExpr ((EventInfo) mi, loc);
 509                         else if (mi is FieldInfo)
 510                                 return new FieldExpr ((FieldInfo) mi, loc);
 511                         else if (mi is PropertyInfo)
 512                                 return new PropertyExpr (ec, (PropertyInfo) mi, loc);
 513                         else if (mi is Type){
 514                                 return new TypeExpression ((System.Type) mi, loc);
 515                         }
 516
 517                         return null;
 518                 }
 519
 520
 521                 private static ArrayList almostMatchedMembers = new ArrayList (4);
 522
 523                 //
 524                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 525                 //
 526                 // This code could use some optimizations, but we need to do some
 527                 // measurements.  For example, we could use a delegate to `flag' when
 528                 // something can not any longer be a method-group (because it is something
 529                 // else).
 530                 //
 531                 // Return values:
 532                 //     If the return value is an Array, then it is an array of
 533                 //     MethodBases
 534                 //
 535                 //     If the return value is an MemberInfo, it is anything, but a Method
 536                 //
 537                 //     null on error.
 538                 //
 539                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 540                 // the arguments here and have MemberLookup return only the methods that
 541                 // match the argument count/type, unlike we are doing now (we delay this
 542                 // decision).
 543                 //
 544                 // This is so we can catch correctly attempts to invoke instance methods
 545                 // from a static body (scan for error 120 in ResolveSimpleName).
 546                 //
 547                 //
 548                 // FIXME: Potential optimization, have a static ArrayList
 549                 //
 550
 551                 public static Expression MemberLookup (EmitContext ec, Type queried_type, string name,
 552                                                        MemberTypes mt, BindingFlags bf, Location loc)
 553                 {
 554                         return MemberLookup (ec, ec.ContainerType, null, queried_type, name, mt, bf, loc);
 555                 }
 556
 557                 //
 558                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 559                 // `qualifier_type' or null to lookup members in the current class.
 560                 //
 561
 562                 public static Expression MemberLookup (EmitContext ec, Type container_type,
 563                                                        Type qualifier_type, Type queried_type,
 564                                                        string name, MemberTypes mt,
 565                                                        BindingFlags bf, Location loc)
 566                 {
 567                         almostMatchedMembers.Clear ();
 568
 569                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 570                                                                      queried_type, mt, bf, name, almostMatchedMembers);
 571
 572                         if (mi == null)
 573                                 return null;
 574
 575                         int count = mi.Length;
 576
 577                         if (mi [0] is MethodBase)
 578                                 return new MethodGroupExpr (mi, loc);
 579
 580                         if (count > 1)
 581                                 return null;
 582
 583                         return ExprClassFromMemberInfo (ec, mi [0], loc);
 584                 }
 585
 586                 public const MemberTypes AllMemberTypes =
 587                         MemberTypes.Constructor |
 588                         MemberTypes.Event       |
 589                         MemberTypes.Field       |
 590                         MemberTypes.Method      |
 591                         MemberTypes.NestedType  |
 592                         MemberTypes.Property;
 593
 594                 public const BindingFlags AllBindingFlags =
 595                         BindingFlags.Public |
 596                         BindingFlags.Static |
 597                         BindingFlags.Instance;
 598
 599                 public static Expression MemberLookup (EmitContext ec, Type queried_type,
 600                                                        string name, Location loc)
 601                 {
 602                         return MemberLookup (ec, ec.ContainerType, null, queried_type, name,
 603                                              AllMemberTypes, AllBindingFlags, loc);
 604                 }
 605
 606                 public static Expression MemberLookup (EmitContext ec, Type qualifier_type,
 607                                                        Type queried_type, string name, Location loc)
 608                 {
 609                         return MemberLookup (ec, ec.ContainerType, qualifier_type, queried_type,
 610                                              name, AllMemberTypes, AllBindingFlags, loc);
 611                 }
 612
 613                 public static Expression MethodLookup (EmitContext ec, Type queried_type,
 614                                                        string name, Location loc)
 615                 {
 616                         return MemberLookup (ec, ec.ContainerType, null, queried_type, name,
 617                                              MemberTypes.Method, AllBindingFlags, loc);
 618                 }
 619
 620                 /// <summary>
 621                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 622                 ///   to find a final definition.  If the final definition is not found, we
 623                 ///   look for private members and display a useful debugging message if we
 624                 ///   find it.
 625                 /// </summary>
 626                 public static Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 627                                                             Type queried_type, string name, Location loc)
 628                 {
 629                         return MemberLookupFinal (ec, qualifier_type, queried_type, name,
 630                                                   AllMemberTypes, AllBindingFlags, loc);
 631                 }
 632
 633                 public static Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 634                                                             Type queried_type, string name,
 635                                                             MemberTypes mt, BindingFlags bf,
 636                                                             Location loc)
 637                 {
 638                         Expression e;
 639
 640                         int errors = Report.Errors;
 641
 642                         e = MemberLookup (ec, ec.ContainerType, qualifier_type, queried_type, name, mt, bf, loc);
 643
 644                         if (e == null && errors == Report.Errors)
 645                                 // No errors were reported by MemberLookup, but there was an error.
 646                                 MemberLookupFailed (ec, qualifier_type, queried_type, name, null, loc);
 647
 648                         return e;
 649                 }
 650
 651                 public static void MemberLookupFailed (EmitContext ec, Type qualifier_type,
 652                                                        Type queried_type, string name,
 653                                                        string class_name, Location loc)
 654                 {
 655                         if (almostMatchedMembers.Count != 0) {
 656                                 if (qualifier_type == null) {
 657                                         foreach (MemberInfo m in almostMatchedMembers)
 658                                                 Report.Error (38, loc,
 659                                                               "Cannot access non-static member `{0}' via nested type `{1}'",
 660                                                               TypeManager.GetFullNameSignature (m),
 661                                                               TypeManager.CSharpName (ec.ContainerType));
 662                                         return;
 663                                 }
 664
 665                                 if (qualifier_type != ec.ContainerType) {
 666                                         // Although a derived class can access protected members of
 667                                         // its base class it cannot do so through an instance of the
 668                                         // base class (CS1540).  If the qualifier_type is a parent of the
 669                                         // ec.ContainerType and the lookup succeeds with the latter one,
 670                                         // then we are in this situation.
 671                                         foreach (MemberInfo m in almostMatchedMembers)
 672                                                 Report.Error (1540, loc,
 673                                                               "Cannot access protected member `{0}' via a qualifier of type `{1}';"
 674                                                               + " the qualifier must be of type `{2}' (or derived from it)",
 675                                                               TypeManager.GetFullNameSignature (m),
 676                                                               TypeManager.CSharpName (qualifier_type),
 677                                                               TypeManager.CSharpName (ec.ContainerType));
 678                                         return;
 679                                 }
 680                                 almostMatchedMembers.Clear ();
 681                         }
 682
 683                         object lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 684                                                                   AllMemberTypes, AllBindingFlags |
 685                                                                   BindingFlags.NonPublic, name, null);
 686
 687                         if (lookup == null) {
 688                                 if (class_name != null)
 689                                         Report.Error (103, loc, "The name `" + name + "' could not be " +
 690                                                       "found in `" + class_name + "'");
 691                                 else
 692                                         Report.Error (
 693                                                 117, loc, "`" + queried_type + "' does not contain a " +
 694                                                 "definition for `" + name + "'");
 695                                 return;
 696                         }
 697
 698                         if (qualifier_type != null)
 699                                 Report.Error (122, loc, "'{0}' is inaccessible due to its protection level", TypeManager.CSharpName (qualifier_type) + "." + name);
 700                         else if (name == ".ctor") {
 701                                 Report.Error (143, loc, String.Format ("The type {0} has no constructors defined",
 702                                                                        TypeManager.CSharpName (queried_type)));
 703                         } else {
 704                                 Report.Error (122, loc, "'{0}' is inaccessible due to its protection level", name);
 705                         }
 706                 }
 707
 708                 static public MemberInfo GetFieldFromEvent (EventExpr event_expr)
 709                 {
 710                         EventInfo ei = event_expr.EventInfo;
 711
 712                         return TypeManager.GetPrivateFieldOfEvent (ei);
 713                 }
 714
 715                 /// <summary>
 716                 ///   Returns an expression that can be used to invoke operator true
 717                 ///   on the expression if it exists.
 718                 /// </summary>
 719                 static public StaticCallExpr GetOperatorTrue (EmitContext ec, Expression e, Location loc)
 720                 {
 721                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 722                 }
 723
 724                 /// <summary>
 725                 ///   Returns an expression that can be used to invoke operator false
 726                 ///   on the expression if it exists.
 727                 /// </summary>
 728                 static public StaticCallExpr GetOperatorFalse (EmitContext ec, Expression e, Location loc)
 729                 {
 730                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 731                 }
 732
 733                 static StaticCallExpr GetOperatorTrueOrFalse (EmitContext ec, Expression e, bool is_true, Location loc)
 734                 {
 735                         MethodBase method;
 736                         Expression operator_group;
 737
 738                         operator_group = MethodLookup (ec, e.Type, is_true ? "op_True" : "op_False", loc);
 739                         if (operator_group == null)
 740                                 return null;
 741
 742                         ArrayList arguments = new ArrayList ();
 743                         arguments.Add (new Argument (e, Argument.AType.Expression));
 744                         method = Invocation.OverloadResolve (
 745                                 ec, (MethodGroupExpr) operator_group, arguments, false, loc);
 746
 747                         if (method == null)
 748                                 return null;
 749
 750                         return new StaticCallExpr ((MethodInfo) method, arguments, loc);
 751                 }
 752
 753                 /// <summary>
 754                 ///   Resolves the expression `e' into a boolean expression: either through
 755                 ///   an implicit conversion, or through an `operator true' invocation
 756                 /// </summary>
 757                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 758                 {
 759                         e = e.Resolve (ec);
 760                         if (e == null)
 761                                 return null;
 762
 763                         Expression converted = e;
 764                         if (e.Type != TypeManager.bool_type)
 765                                 converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, new Location (-1));
 766
 767                         //
 768                         // If no implicit conversion to bool exists, try using `operator true'
 769                         //
 770                         if (converted == null){
 771                                 Expression operator_true = Expression.GetOperatorTrue (ec, e, loc);
 772                                 if (operator_true == null){
 773                                         Report.Error (
 774                                                 31, loc, "Can not convert the expression to a boolean");
 775                                         return null;
 776                                 }
 777                                 e = operator_true;
 778                         } else
 779                                 e = converted;
 780
 781                         return e;
 782                 }
 783
 784                 static string ExprClassName (ExprClass c)
 785                 {
 786                         switch (c){
 787                         case ExprClass.Invalid:
 788                                 return "Invalid";
 789                         case ExprClass.Value:
 790                                 return "value";
 791                         case ExprClass.Variable:
 792                                 return "variable";
 793                         case ExprClass.Namespace:
 794                                 return "namespace";
 795                         case ExprClass.Type:
 796                                 return "type";
 797                         case ExprClass.MethodGroup:
 798                                 return "method group";
 799                         case ExprClass.PropertyAccess:
 800                                 return "property access";
 801                         case ExprClass.EventAccess:
 802                                 return "event access";
 803                         case ExprClass.IndexerAccess:
 804                                 return "indexer access";
 805                         case ExprClass.Nothing:
 806                                 return "null";
 807                         }
 808                         throw new Exception ("Should not happen");
 809                 }
 810
 811                 /// <summary>
 812                 ///   Reports that we were expecting `expr' to be of class `expected'
 813                 /// </summary>
 814                 public void Error_UnexpectedKind (string expected, Location loc)
 815                 {
 816                         string kind = "Unknown";
 817
 818                         kind = ExprClassName (eclass);
 819
 820                         Report.Error (118, loc, "Expression denotes a `" + kind +
 821                                "' where a `" + expected + "' was expected");
 822                 }
 823
 824                 public void Error_UnexpectedKind (ResolveFlags flags, Location loc)
 825                 {
 826                         ArrayList valid = new ArrayList (10);
 827
 828                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
 829                                 valid.Add ("variable");
 830                                 valid.Add ("value");
 831                         }
 832
 833                         if ((flags & ResolveFlags.Type) != 0)
 834                                 valid.Add ("type");
 835
 836                         if ((flags & ResolveFlags.MethodGroup) != 0)
 837                                 valid.Add ("method group");
 838
 839                         if ((flags & ResolveFlags.SimpleName) != 0)
 840                                 valid.Add ("simple name");
 841
 842                         if (valid.Count == 0)
 843                                 valid.Add ("unknown");
 844
 845                         StringBuilder sb = new StringBuilder ();
 846                         for (int i = 0; i < valid.Count; i++) {
 847                                 if (i > 0)
 848                                         sb.Append (", ");
 849                                 else if (i == valid.Count)
 850                                         sb.Append (" or ");
 851                                 sb.Append (valid [i]);
 852                         }
 853
 854                         string kind = ExprClassName (eclass);
 855
 856                         Error (119, "Expression denotes a `" + kind + "' where " +
 857                                "a `" + sb.ToString () + "' was expected");
 858                 }
 859
 860                 static public void Error_ConstantValueCannotBeConverted (Location l, string val, Type t)
 861                 {
 862                         Report.Error (31, l, "Constant value `" + val + "' cannot be converted to " +
 863                                       TypeManager.CSharpName (t));
 864                 }
 865
 866                 public static void UnsafeError (Location loc)
 867                 {
 868                         Report.Error (214, loc, "Pointers may only be used in an unsafe context");
 869                 }
 870
 871                 /// <summary>
 872                 ///   Converts the IntConstant, UIntConstant, LongConstant or
 873                 ///   ULongConstant into the integral target_type.   Notice
 874                 ///   that we do not return an `Expression' we do return
 875                 ///   a boxed integral type.
 876                 ///
 877                 ///   FIXME: Since I added the new constants, we need to
 878                 ///   also support conversions from CharConstant, ByteConstant,
 879                 ///   SByteConstant, UShortConstant, ShortConstant
 880                 ///
 881                 ///   This is used by the switch statement, so the domain
 882                 ///   of work is restricted to the literals above, and the
 883                 ///   targets are int32, uint32, char, byte, sbyte, ushort,
 884                 ///   short, uint64 and int64
 885                 /// </summary>
 886                 public static object ConvertIntLiteral (Constant c, Type target_type, Location loc)
 887                 {
 888                         if (!Convert.ImplicitStandardConversionExists (c, target_type)){
 889                                 Convert.Error_CannotImplicitConversion (loc, c.Type, target_type);
 890                                 return null;
 891                         }
 892
 893                         string s = "";
 894
 895                         if (c.Type == target_type)
 896                                 return ((Constant) c).GetValue ();
 897
 898                         //
 899                         // Make into one of the literals we handle, we dont really care
 900                         // about this value as we will just return a few limited types
 901                         //
 902                         if (c is EnumConstant)
 903                                 c = ((EnumConstant)c).WidenToCompilerConstant ();
 904
 905                         if (c is IntConstant){
 906                                 int v = ((IntConstant) c).Value;
 907
 908                                 if (target_type == TypeManager.uint32_type){
 909                                         if (v >= 0)
 910                                                 return (uint) v;
 911                                 } else if (target_type == TypeManager.char_type){
 912                                         if (v >= Char.MinValue && v <= Char.MaxValue)
 913                                                 return (char) v;
 914                                 } else if (target_type == TypeManager.byte_type){
 915                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
 916                                                 return (byte) v;
 917                                 } else if (target_type == TypeManager.sbyte_type){
 918                                         if (v >= SByte.MinValue && v <= SByte.MaxValue)
 919                                                 return (sbyte) v;
 920                                 } else if (target_type == TypeManager.short_type){
 921                                         if (v >= Int16.MinValue && v <= UInt16.MaxValue)
 922                                                 return (short) v;
 923                                 } else if (target_type == TypeManager.ushort_type){
 924                                         if (v >= UInt16.MinValue && v <= UInt16.MaxValue)
 925                                                 return (ushort) v;
 926                                 } else if (target_type == TypeManager.int64_type)
 927                                         return (long) v;
 928                                 else if (target_type == TypeManager.uint64_type){
 929                                         if (v > 0)
 930                                                 return (ulong) v;
 931                                 }
 932
 933                                 s = v.ToString ();
 934                         } else if (c is UIntConstant){
 935                                 uint v = ((UIntConstant) c).Value;
 936
 937                                 if (target_type == TypeManager.int32_type){
 938                                         if (v <= Int32.MaxValue)
 939                                                 return (int) v;
 940                                 } else if (target_type == TypeManager.char_type){
 941                                         if (v >= Char.MinValue && v <= Char.MaxValue)
 942                                                 return (char) v;
 943                                 } else if (target_type == TypeManager.byte_type){
 944                                         if (v <= Byte.MaxValue)
 945                                                 return (byte) v;
 946                                 } else if (target_type == TypeManager.sbyte_type){
 947                                         if (v <= SByte.MaxValue)
 948                                                 return (sbyte) v;
 949                                 } else if (target_type == TypeManager.short_type){
 950                                         if (v <= UInt16.MaxValue)
 951                                                 return (short) v;
 952                                 } else if (target_type == TypeManager.ushort_type){
 953                                         if (v <= UInt16.MaxValue)
 954                                                 return (ushort) v;
 955                                 } else if (target_type == TypeManager.int64_type)
 956                                         return (long) v;
 957                                 else if (target_type == TypeManager.uint64_type)
 958                                         return (ulong) v;
 959                                 s = v.ToString ();
 960                         } else if (c is LongConstant){
 961                                 long v = ((LongConstant) c).Value;
 962
 963                                 if (target_type == TypeManager.int32_type){
 964                                         if (v >= UInt32.MinValue && v <= UInt32.MaxValue)
 965                                                 return (int) v;
 966                                 } else if (target_type == TypeManager.uint32_type){
 967                                         if (v >= 0 && v <= UInt32.MaxValue)
 968                                                 return (uint) v;
 969                                 } else if (target_type == TypeManager.char_type){
 970                                         if (v >= Char.MinValue && v <= Char.MaxValue)
 971                                                 return (char) v;
 972                                 } else if (target_type == TypeManager.byte_type){
 973                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
 974                                                 return (byte) v;
 975                                 } else if (target_type == TypeManager.sbyte_type){
 976                                         if (v >= SByte.MinValue && v <= SByte.MaxValue)
 977                                                 return (sbyte) v;
 978                                 } else if (target_type == TypeManager.short_type){
 979                                         if (v >= Int16.MinValue && v <= UInt16.MaxValue)
 980                                                 return (short) v;
 981                                 } else if (target_type == TypeManager.ushort_type){
 982                                         if (v >= UInt16.MinValue && v <= UInt16.MaxValue)
 983                                                 return (ushort) v;
 984                                 } else if (target_type == TypeManager.uint64_type){
 985                                         if (v > 0)
 986                                                 return (ulong) v;
 987                                 }
 988                                 s = v.ToString ();
 989                         } else if (c is ULongConstant){
 990                                 ulong v = ((ULongConstant) c).Value;
 991
 992                                 if (target_type == TypeManager.int32_type){
 993                                         if (v <= Int32.MaxValue)
 994                                                 return (int) v;
 995                                 } else if (target_type == TypeManager.uint32_type){
 996                                         if (v <= UInt32.MaxValue)
 997                                                 return (uint) v;
 998                                 } else if (target_type == TypeManager.char_type){
 999                                         if (v >= Char.MinValue && v <= Char.MaxValue)
1000                                                 return (char) v;
1001                                 } else if (target_type == TypeManager.byte_type){
1002                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1003                                                 return (byte) v;
1004                                 } else if (target_type == TypeManager.sbyte_type){
1005                                         if (v <= (int) SByte.MaxValue)
1006                                                 return (sbyte) v;
1007                                 } else if (target_type == TypeManager.short_type){
1008                                         if (v <= UInt16.MaxValue)
1009                                                 return (short) v;
1010                                 } else if (target_type == TypeManager.ushort_type){
1011                                         if (v <= UInt16.MaxValue)
1012                                                 return (ushort) v;
1013                                 } else if (target_type == TypeManager.int64_type){
1014                                         if (v <= Int64.MaxValue)
1015                                                 return (long) v;
1016                                 }
1017                                 s = v.ToString ();
1018                         } else if (c is ByteConstant){
1019                                 byte v = ((ByteConstant) c).Value;
1020
1021                                 if (target_type == TypeManager.int32_type)
1022                                         return (int) v;
1023                                 else if (target_type == TypeManager.uint32_type)
1024                                         return (uint) v;
1025                                 else if (target_type == TypeManager.char_type)
1026                                         return (char) v;
1027                                 else if (target_type == TypeManager.sbyte_type){
1028                                         if (v <= SByte.MaxValue)
1029                                                 return (sbyte) v;
1030                                 } else if (target_type == TypeManager.short_type)
1031                                         return (short) v;
1032                                 else if (target_type == TypeManager.ushort_type)
1033                                         return (ushort) v;
1034                                 else if (target_type == TypeManager.int64_type)
1035                                         return (long) v;
1036                                 else if (target_type == TypeManager.uint64_type)
1037                                         return (ulong) v;
1038                                 s = v.ToString ();
1039                         } else if (c is SByteConstant){
1040                                 sbyte v = ((SByteConstant) c).Value;
1041
1042                                 if (target_type == TypeManager.int32_type)
1043                                         return (int) v;
1044                                 else if (target_type == TypeManager.uint32_type){
1045                                         if (v >= 0)
1046                                                 return (uint) v;
1047                                 } else if (target_type == TypeManager.char_type){
1048                                         if (v >= 0)
1049                                                 return (char) v;
1050                                 } else if (target_type == TypeManager.byte_type){
1051                                         if (v >= 0)
1052                                                 return (byte) v;
1053                                 } else if (target_type == TypeManager.short_type)
1054                                         return (short) v;
1055                                 else if (target_type == TypeManager.ushort_type){
1056                                         if (v >= 0)
1057                                                 return (ushort) v;
1058                                 } else if (target_type == TypeManager.int64_type)
1059                                         return (long) v;
1060                                 else if (target_type == TypeManager.uint64_type){
1061                                         if (v >= 0)
1062                                                 return (ulong) v;
1063                                 }
1064                                 s = v.ToString ();
1065                         } else if (c is ShortConstant){
1066                                 short v = ((ShortConstant) c).Value;
1067
1068                                 if (target_type == TypeManager.int32_type){
1069                                         return (int) v;
1070                                 } else if (target_type == TypeManager.uint32_type){
1071                                         if (v >= 0)
1072                                                 return (uint) v;
1073                                 } else if (target_type == TypeManager.char_type){
1074                                         if (v >= 0)
1075                                                 return (char) v;
1076                                 } else if (target_type == TypeManager.byte_type){
1077                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1078                                                 return (byte) v;
1079                                 } else if (target_type == TypeManager.sbyte_type){
1080                                         if (v >= SByte.MinValue && v <= SByte.MaxValue)
1081                                                 return (sbyte) v;
1082                                 } else if (target_type == TypeManager.ushort_type){
1083                                         if (v >= 0)
1084                                                 return (ushort) v;
1085                                 } else if (target_type == TypeManager.int64_type)
1086                                         return (long) v;
1087                                 else if (target_type == TypeManager.uint64_type)
1088                                         return (ulong) v;
1089
1090                                 s = v.ToString ();
1091                         } else if (c is UShortConstant){
1092                                 ushort v = ((UShortConstant) c).Value;
1093
1094                                 if (target_type == TypeManager.int32_type)
1095                                         return (int) v;
1096                                 else if (target_type == TypeManager.uint32_type)
1097                                         return (uint) v;
1098                                 else if (target_type == TypeManager.char_type){
1099                                         if (v >= Char.MinValue && v <= Char.MaxValue)
1100                                                 return (char) v;
1101                                 } else if (target_type == TypeManager.byte_type){
1102                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1103                                                 return (byte) v;
1104                                 } else if (target_type == TypeManager.sbyte_type){
1105                                         if (v <= SByte.MaxValue)
1106                                                 return (byte) v;
1107                                 } else if (target_type == TypeManager.short_type){
1108                                         if (v <= Int16.MaxValue)
1109                                                 return (short) v;
1110                                 } else if (target_type == TypeManager.int64_type)
1111                                         return (long) v;
1112                                 else if (target_type == TypeManager.uint64_type)
1113                                         return (ulong) v;
1114
1115                                 s = v.ToString ();
1116                         } else if (c is CharConstant){
1117                                 char v = ((CharConstant) c).Value;
1118
1119                                 if (target_type == TypeManager.int32_type)
1120                                         return (int) v;
1121                                 else if (target_type == TypeManager.uint32_type)
1122                                         return (uint) v;
1123                                 else if (target_type == TypeManager.byte_type){
1124                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1125                                                 return (byte) v;
1126                                 } else if (target_type == TypeManager.sbyte_type){
1127                                         if (v <= SByte.MaxValue)
1128                                                 return (sbyte) v;
1129                                 } else if (target_type == TypeManager.short_type){
1130                                         if (v <= Int16.MaxValue)
1131                                                 return (short) v;
1132                                 } else if (target_type == TypeManager.ushort_type)
1133                                         return (short) v;
1134                                 else if (target_type == TypeManager.int64_type)
1135                                         return (long) v;
1136                                 else if (target_type == TypeManager.uint64_type)
1137                                         return (ulong) v;
1138
1139                                 s = v.ToString ();
1140                         }
1141                         Error_ConstantValueCannotBeConverted (loc, s, target_type);
1142                         return null;
1143                 }
1144
1145                 //
1146                 // Load the object from the pointer.
1147                 //
1148                 public static void LoadFromPtr (ILGenerator ig, Type t)
1149                 {
1150                         if (t == TypeManager.int32_type)
1151                                 ig.Emit (OpCodes.Ldind_I4);
1152                         else if (t == TypeManager.uint32_type)
1153                                 ig.Emit (OpCodes.Ldind_U4);
1154                         else if (t == TypeManager.short_type)
1155                                 ig.Emit (OpCodes.Ldind_I2);
1156                         else if (t == TypeManager.ushort_type)
1157                                 ig.Emit (OpCodes.Ldind_U2);
1158                         else if (t == TypeManager.char_type)
1159                                 ig.Emit (OpCodes.Ldind_U2);
1160                         else if (t == TypeManager.byte_type)
1161                                 ig.Emit (OpCodes.Ldind_U1);
1162                         else if (t == TypeManager.sbyte_type)
1163                                 ig.Emit (OpCodes.Ldind_I1);
1164                         else if (t == TypeManager.uint64_type)
1165                                 ig.Emit (OpCodes.Ldind_I8);
1166                         else if (t == TypeManager.int64_type)
1167                                 ig.Emit (OpCodes.Ldind_I8);
1168                         else if (t == TypeManager.float_type)
1169                                 ig.Emit (OpCodes.Ldind_R4);
1170                         else if (t == TypeManager.double_type)
1171                                 ig.Emit (OpCodes.Ldind_R8);
1172                         else if (t == TypeManager.bool_type)
1173                                 ig.Emit (OpCodes.Ldind_I1);
1174                         else if (t == TypeManager.intptr_type)
1175                                 ig.Emit (OpCodes.Ldind_I);
1176                         else if (TypeManager.IsEnumType (t)) {
1177                                 if (t == TypeManager.enum_type)
1178                                         ig.Emit (OpCodes.Ldind_Ref);
1179                                 else
1180                                         LoadFromPtr (ig, TypeManager.EnumToUnderlying (t));
1181                         } else if (t.IsValueType)
1182                                 ig.Emit (OpCodes.Ldobj, t);
1183                         else if (t.IsPointer)
1184                                 ig.Emit (OpCodes.Ldind_I);
1185                         else
1186                                 ig.Emit (OpCodes.Ldind_Ref);
1187                 }
1188
1189                 //
1190                 // The stack contains the pointer and the value of type `type'
1191                 //
1192                 public static void StoreFromPtr (ILGenerator ig, Type type)
1193                 {
1194                         if (TypeManager.IsEnumType (type))
1195                                 type = TypeManager.EnumToUnderlying (type);
1196                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1197                                 ig.Emit (OpCodes.Stind_I4);
1198                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1199                                 ig.Emit (OpCodes.Stind_I8);
1200                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1201                                  type == TypeManager.ushort_type)
1202                                 ig.Emit (OpCodes.Stind_I2);
1203                         else if (type == TypeManager.float_type)
1204                                 ig.Emit (OpCodes.Stind_R4);
1205                         else if (type == TypeManager.double_type)
1206                                 ig.Emit (OpCodes.Stind_R8);
1207                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1208                                  type == TypeManager.bool_type)
1209                                 ig.Emit (OpCodes.Stind_I1);
1210                         else if (type == TypeManager.intptr_type)
1211                                 ig.Emit (OpCodes.Stind_I);
1212                         else if (type.IsValueType)
1213                                 ig.Emit (OpCodes.Stobj, type);
1214                         else
1215                                 ig.Emit (OpCodes.Stind_Ref);
1216                 }
1217
1218                 //
1219                 // Returns the size of type `t' if known, otherwise, 0
1220                 //
1221                 public static int GetTypeSize (Type t)
1222                 {
1223                         t = TypeManager.TypeToCoreType (t);
1224                         if (t == TypeManager.int32_type ||
1225                             t == TypeManager.uint32_type ||
1226                             t == TypeManager.float_type)
1227                                 return 4;
1228                         else if (t == TypeManager.int64_type ||
1229                                  t == TypeManager.uint64_type ||
1230                                  t == TypeManager.double_type)
1231                                 return 8;
1232                         else if (t == TypeManager.byte_type ||
1233                                  t == TypeManager.sbyte_type ||
1234                                  t == TypeManager.bool_type)
1235                                 return 1;
1236                         else if (t == TypeManager.short_type ||
1237                                  t == TypeManager.char_type ||
1238                                  t == TypeManager.ushort_type)
1239                                 return 2;
1240                         else if (t == TypeManager.decimal_type)
1241                                 return 16;
1242                         else
1243                                 return 0;
1244                 }
1245
1246                 public static void Error_NegativeArrayIndex (Location loc)
1247                 {
1248                         Report.Error (248, loc, "Cannot create an array with a negative size");
1249                 }
1250
1251                 //
1252                 // Converts `source' to an int, uint, long or ulong.
1253                 //
1254                 public Expression ExpressionToArrayArgument (EmitContext ec, Expression source, Location loc)
1255                 {
1256                         Expression target;
1257
1258                         bool old_checked = ec.CheckState;
1259                         ec.CheckState = true;
1260
1261                         target = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, loc);
1262                         if (target == null){
1263                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, loc);
1264                                 if (target == null){
1265                                         target = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, loc);
1266                                         if (target == null){
1267                                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, loc);
1268                                                 if (target == null)
1269                                                         Convert.Error_CannotImplicitConversion (loc, source.Type, TypeManager.int32_type);
1270                                         }
1271                                 }
1272                         }
1273                         ec.CheckState = old_checked;
1274
1275                         //
1276                         // Only positive constants are allowed at compile time
1277                         //
1278                         if (target is Constant){
1279                                 if (target is IntConstant){
1280                                         if (((IntConstant) target).Value < 0){
1281                                                 Error_NegativeArrayIndex (loc);
1282                                                 return null;
1283                                         }
1284                                 }
1285
1286                                 if (target is LongConstant){
1287                                         if (((LongConstant) target).Value < 0){
1288                                                 Error_NegativeArrayIndex (loc);
1289                                                 return null;
1290                                         }
1291                                 }
1292
1293                         }
1294
1295                         return target;
1296                 }
1297
1298         }
1299
1300         /// <summary>
1301         ///   This is just a base class for expressions that can
1302         ///   appear on statements (invocations, object creation,
1303         ///   assignments, post/pre increment and decrement).  The idea
1304         ///   being that they would support an extra Emition interface that
1305         ///   does not leave a result on the stack.
1306         /// </summary>
1307         public abstract class ExpressionStatement : Expression {
1308
1309                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1310                 {
1311                         Expression e = Resolve (ec);
1312                         if (e == null)
1313                                 return null;
1314
1315                         ExpressionStatement es = e as ExpressionStatement;
1316                         if (es == null)
1317                                 Error (201, "Only assignment, call, increment, decrement and new object " +
1318                                        "expressions can be used as a statement");
1319
1320                         return es;
1321                 }
1322
1323                 /// <summary>
1324                 ///   Requests the expression to be emitted in a `statement'
1325                 ///   context.  This means that no new value is left on the
1326                 ///   stack after invoking this method (constrasted with
1327                 ///   Emit that will always leave a value on the stack).
1328                 /// </summary>
1329                 public abstract void EmitStatement (EmitContext ec);
1330         }
1331
1332         /// <summary>
1333         ///   This kind of cast is used to encapsulate the child
1334         ///   whose type is child.Type into an expression that is
1335         ///   reported to return "return_type".  This is used to encapsulate
1336         ///   expressions which have compatible types, but need to be dealt
1337         ///   at higher levels with.
1338         ///
1339         ///   For example, a "byte" expression could be encapsulated in one
1340         ///   of these as an "unsigned int".  The type for the expression
1341         ///   would be "unsigned int".
1342         ///
1343         /// </summary>
1344         public class EmptyCast : Expression {
1345                 protected Expression child;
1346
1347                 public Expression Child {
1348                         get {
1349                                 return child;
1350                         }
1351                 }
1352
1353                 public EmptyCast (Expression child, Type return_type)
1354                 {
1355                         eclass = child.eclass;
1356                         type = return_type;
1357                         this.child = child;
1358                 }
1359
1360                 public override Expression DoResolve (EmitContext ec)
1361                 {
1362                         // This should never be invoked, we are born in fully
1363                         // initialized state.
1364
1365                         return this;
1366                 }
1367
1368                 public override void Emit (EmitContext ec)
1369                 {
1370                         child.Emit (ec);
1371                 }
1372         }
1373
1374         //
1375         // We need to special case this since an empty cast of
1376         // a NullLiteral is still a Constant
1377         //
1378         public class NullCast : Constant {
1379                 protected Expression child;
1380
1381                 public NullCast (Expression child, Type return_type)
1382                 {
1383                         eclass = child.eclass;
1384                         type = return_type;
1385                         this.child = child;
1386                 }
1387
1388                 override public string AsString ()
1389                 {
1390                         return "null";
1391                 }
1392
1393                 public override object GetValue ()
1394                 {
1395                         return null;
1396                 }
1397
1398                 public override Expression DoResolve (EmitContext ec)
1399                 {
1400                         // This should never be invoked, we are born in fully
1401                         // initialized state.
1402
1403                         return this;
1404                 }
1405
1406                 public override void Emit (EmitContext ec)
1407                 {
1408                         child.Emit (ec);
1409                 }
1410
1411                 public override bool IsNegative {
1412                         get {
1413                                 return false;
1414                         }
1415                 }
1416         }
1417
1418
1419         /// <summary>
1420         ///  This class is used to wrap literals which belong inside Enums
1421         /// </summary>
1422         public class EnumConstant : Constant {
1423                 public Constant Child;
1424
1425                 public EnumConstant (Constant child, Type enum_type)
1426                 {
1427                         eclass = child.eclass;
1428                         this.Child = child;
1429                         type = enum_type;
1430                 }
1431
1432                 public override Expression DoResolve (EmitContext ec)
1433                 {
1434                         // This should never be invoked, we are born in fully
1435                         // initialized state.
1436
1437                         return this;
1438                 }
1439
1440                 public override void Emit (EmitContext ec)
1441                 {
1442                         Child.Emit (ec);
1443                 }
1444
1445                 public override object GetValue ()
1446                 {
1447                         return Child.GetValue ();
1448                 }
1449
1450                 public object GetValueAsEnumType ()
1451                 {
1452                         return System.Enum.ToObject (type, Child.GetValue ());
1453                 }
1454
1455                 //
1456                 // Converts from one of the valid underlying types for an enumeration
1457                 // (int32, uint32, int64, uint64, short, ushort, byte, sbyte) to
1458                 // one of the internal compiler literals: Int/UInt/Long/ULong Literals.
1459                 //
1460                 public Constant WidenToCompilerConstant ()
1461                 {
1462                         Type t = TypeManager.EnumToUnderlying (Child.Type);
1463                         object v = ((Constant) Child).GetValue ();;
1464
1465                         if (t == TypeManager.int32_type)
1466                                 return new IntConstant ((int) v);
1467                         if (t == TypeManager.uint32_type)
1468                                 return new UIntConstant ((uint) v);
1469                         if (t == TypeManager.int64_type)
1470                                 return new LongConstant ((long) v);
1471                         if (t == TypeManager.uint64_type)
1472                                 return new ULongConstant ((ulong) v);
1473                         if (t == TypeManager.short_type)
1474                                 return new ShortConstant ((short) v);
1475                         if (t == TypeManager.ushort_type)
1476                                 return new UShortConstant ((ushort) v);
1477                         if (t == TypeManager.byte_type)
1478                                 return new ByteConstant ((byte) v);
1479                         if (t == TypeManager.sbyte_type)
1480                                 return new SByteConstant ((sbyte) v);
1481
1482                         throw new Exception ("Invalid enumeration underlying type: " + t);
1483                 }
1484
1485                 //
1486                 // Extracts the value in the enumeration on its native representation
1487                 //
1488                 public object GetPlainValue ()
1489                 {
1490                         Type t = TypeManager.EnumToUnderlying (Child.Type);
1491                         object v = ((Constant) Child).GetValue ();;
1492
1493                         if (t == TypeManager.int32_type)
1494                                 return (int) v;
1495                         if (t == TypeManager.uint32_type)
1496                                 return (uint) v;
1497                         if (t == TypeManager.int64_type)
1498                                 return (long) v;
1499                         if (t == TypeManager.uint64_type)
1500                                 return (ulong) v;
1501                         if (t == TypeManager.short_type)
1502                                 return (short) v;
1503                         if (t == TypeManager.ushort_type)
1504                                 return (ushort) v;
1505                         if (t == TypeManager.byte_type)
1506                                 return (byte) v;
1507                         if (t == TypeManager.sbyte_type)
1508                                 return (sbyte) v;
1509
1510                         return null;
1511                 }
1512
1513                 public override string AsString ()
1514                 {
1515                         return Child.AsString ();
1516                 }
1517
1518                 public override DoubleConstant ConvertToDouble ()
1519                 {
1520                         return Child.ConvertToDouble ();
1521                 }
1522
1523                 public override FloatConstant ConvertToFloat ()
1524                 {
1525                         return Child.ConvertToFloat ();
1526                 }
1527
1528                 public override ULongConstant ConvertToULong ()
1529                 {
1530                         return Child.ConvertToULong ();
1531                 }
1532
1533                 public override LongConstant ConvertToLong ()
1534                 {
1535                         return Child.ConvertToLong ();
1536                 }
1537
1538                 public override UIntConstant ConvertToUInt ()
1539                 {
1540                         return Child.ConvertToUInt ();
1541                 }
1542
1543                 public override IntConstant ConvertToInt ()
1544                 {
1545                         return Child.ConvertToInt ();
1546                 }
1547
1548                 public override bool IsZeroInteger {
1549                         get { return Child.IsZeroInteger; }
1550                 }
1551
1552                 public override bool IsNegative {
1553                         get {
1554                                 return Child.IsNegative;
1555                         }
1556                 }
1557         }
1558
1559         /// <summary>
1560         ///   This kind of cast is used to encapsulate Value Types in objects.
1561         ///
1562         ///   The effect of it is to box the value type emitted by the previous
1563         ///   operation.
1564         /// </summary>
1565         public class BoxedCast : EmptyCast {
1566
1567                 public BoxedCast (Expression expr)
1568                         : base (expr, TypeManager.object_type)
1569                 {
1570                         eclass = ExprClass.Value;
1571                 }
1572
1573                 public BoxedCast (Expression expr, Type target_type)
1574                         : base (expr, target_type)
1575                 {
1576                         eclass = ExprClass.Value;
1577                 }
1578
1579                 public override Expression DoResolve (EmitContext ec)
1580                 {
1581                         // This should never be invoked, we are born in fully
1582                         // initialized state.
1583
1584                         return this;
1585                 }
1586
1587                 public override void Emit (EmitContext ec)
1588                 {
1589                         base.Emit (ec);
1590
1591                         ec.ig.Emit (OpCodes.Box, child.Type);
1592                 }
1593         }
1594
1595         public class UnboxCast : EmptyCast {
1596                 public UnboxCast (Expression expr, Type return_type)
1597                         : base (expr, return_type)
1598                 {
1599                 }
1600
1601                 public override Expression DoResolve (EmitContext ec)
1602                 {
1603                         // This should never be invoked, we are born in fully
1604                         // initialized state.
1605
1606                         return this;
1607                 }
1608
1609                 public override void Emit (EmitContext ec)
1610                 {
1611                         Type t = type;
1612                         ILGenerator ig = ec.ig;
1613
1614                         base.Emit (ec);
1615                         ig.Emit (OpCodes.Unbox, t);
1616
1617                         LoadFromPtr (ig, t);
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                         ec.ig.Emit (OpCodes.Castclass, type);
1901                 }
1902
1903         }
1904
1905         /// <summary>
1906         ///   SimpleName expressions are initially formed of a single
1907         ///   word and it only happens at the beginning of the expression.
1908         /// </summary>
1909         ///
1910         /// <remarks>
1911         ///   The expression will try to be bound to a Field, a Method
1912         ///   group or a Property.  If those fail we pass the name to our
1913         ///   caller and the SimpleName is compounded to perform a type
1914         ///   lookup.  The idea behind this process is that we want to avoid
1915         ///   creating a namespace map from the assemblies, as that requires
1916         ///   the GetExportedTypes function to be called and a hashtable to
1917         ///   be constructed which reduces startup time.  If later we find
1918         ///   that this is slower, we should create a `NamespaceExpr' expression
1919         ///   that fully participates in the resolution process.
1920         ///
1921         ///   For example `System.Console.WriteLine' is decomposed into
1922         ///   MemberAccess (MemberAccess (SimpleName ("System"), "Console"), "WriteLine")
1923         ///
1924         ///   The first SimpleName wont produce a match on its own, so it will
1925         ///   be turned into:
1926         ///   MemberAccess (SimpleName ("System.Console"), "WriteLine").
1927         ///
1928         ///   System.Console will produce a TypeExpr match.
1929         ///
1930         ///   The downside of this is that we might be hitting `LookupType' too many
1931         ///   times with this scheme.
1932         /// </remarks>
1933         public class SimpleName : Expression {
1934                 public string Name;
1935
1936                 //
1937                 // If true, then we are a simple name, not composed with a ".
1938                 //
1939                 bool is_base;
1940
1941                 public SimpleName (string a, string b, Location l)
1942                 {
1943                         Name = String.Concat (a, ".", b);
1944                         loc = l;
1945                         is_base = false;
1946                 }
1947
1948                 public SimpleName (string name, Location l)
1949                 {
1950                         Name = name;
1951                         loc = l;
1952                         is_base = true;
1953                 }
1954
1955                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
1956                 {
1957                         if (ec.IsFieldInitializer)
1958                                 Report.Error (
1959                                         236, l,
1960                                         "A field initializer cannot reference the non-static field, " +
1961                                         "method or property `"+name+"'");
1962                         else
1963                                 Report.Error (
1964                                         120, l,
1965                                         "An object reference is required " +
1966                                         "for the non-static field `"+name+"'");
1967                 }
1968
1969                 //
1970                 // Checks whether we are trying to access an instance
1971                 // property, method or field from a static body.
1972                 //
1973                 Expression MemberStaticCheck (EmitContext ec, Expression e)
1974                 {
1975                         if (e is IMemberExpr){
1976                                 IMemberExpr member = (IMemberExpr) e;
1977
1978                                 if (!member.IsStatic){
1979                                         Error_ObjectRefRequired (ec, loc, Name);
1980                                         return null;
1981                                 }
1982                         }
1983
1984                         return e;
1985                 }
1986
1987                 public override Expression DoResolve (EmitContext ec)
1988                 {
1989                         return SimpleNameResolve (ec, null, false, false);
1990                 }
1991
1992                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1993                 {
1994                         return SimpleNameResolve (ec, right_side, false, false);
1995                 }
1996
1997
1998                 public Expression DoResolveAllowStatic (EmitContext ec, bool intermediate)
1999                 {
2000                         return SimpleNameResolve (ec, null, true, intermediate);
2001                 }
2002
2003                 public override Expression ResolveAsTypeStep (EmitContext ec)
2004                 {
2005                         DeclSpace ds = ec.DeclSpace;
2006                         NamespaceEntry ns = ds.NamespaceEntry;
2007                         Type t;
2008                         string alias_value;
2009
2010                         //
2011                         // Since we are cheating: we only do the Alias lookup for
2012                         // namespaces if the name does not include any dots in it
2013                         //
2014                         if (ns != null && is_base)
2015                                 alias_value = ns.LookupAlias (Name);
2016                         else
2017                                 alias_value = null;
2018
2019                         if (ec.ResolvingTypeTree){
2020                                 int errors = Report.Errors;
2021                                 Type dt = ds.FindType (loc, Name);
2022
2023                                 if (Report.Errors != errors)
2024                                         return null;
2025
2026                                 if (dt != null)
2027                                         return new TypeExpression (dt, loc);
2028
2029                                 if (alias_value != null){
2030                                         if ((t = RootContext.LookupType (ds, alias_value, true, loc)) != null)
2031                                                 return new TypeExpression (t, loc);
2032                                 }
2033                         }
2034
2035                         if ((t = RootContext.LookupType (ds, Name, true, loc)) != null)
2036                                 return new TypeExpression (t, loc);
2037
2038                         if (alias_value != null) {
2039                                 if ((t = RootContext.LookupType (ds, alias_value, true, loc)) != null)
2040                                         return new TypeExpression (t, loc);
2041
2042                                 // we have alias value, but it isn't Type, so try if it's namespace
2043                                 return new SimpleName (alias_value, loc);
2044                         }
2045
2046                         // No match, maybe our parent can compose us
2047                         // into something meaningful.
2048                         return this;
2049                 }
2050
2051                 Expression SimpleNameResolve (EmitContext ec, Expression right_side,
2052                                               bool allow_static, bool intermediate)
2053                 {
2054                         Expression e = DoSimpleNameResolve (ec, right_side, allow_static, intermediate);
2055                         if (e == null)
2056                                 return null;
2057
2058                         Block current_block = ec.CurrentBlock;
2059                         if (current_block != null){
2060                                 //LocalInfo vi = current_block.GetLocalInfo (Name);
2061                                 if (is_base &&
2062                                     current_block.IsVariableNameUsedInChildBlock(Name)) {
2063                                         Report.Error (135, Location,
2064                                                       "'{0}' has a different meaning in a " +
2065                                                       "child block", Name);
2066                                         return null;
2067                                 }
2068                         }
2069
2070                         return e;
2071                 }
2072
2073                 /// <remarks>
2074                 ///   7.5.2: Simple Names.
2075                 ///
2076                 ///   Local Variables and Parameters are handled at
2077                 ///   parse time, so they never occur as SimpleNames.
2078                 ///
2079                 ///   The `allow_static' flag is used by MemberAccess only
2080                 ///   and it is used to inform us that it is ok for us to
2081                 ///   avoid the static check, because MemberAccess might end
2082                 ///   up resolving the Name as a Type name and the access as
2083                 ///   a static type access.
2084                 ///
2085                 ///   ie: Type Type; .... { Type.GetType (""); }
2086                 ///
2087                 ///   Type is both an instance variable and a Type;  Type.GetType
2088                 ///   is the static method not an instance method of type.
2089                 /// </remarks>
2090                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool allow_static, bool intermediate)
2091                 {
2092                         Expression e = null;
2093
2094                         //
2095                         // Stage 1: Performed by the parser (binding to locals or parameters).
2096                         //
2097                         Block current_block = ec.CurrentBlock;
2098                         if (current_block != null){
2099                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2100                                 if (vi != null){
2101                                         Expression var;
2102
2103                                         var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2104
2105                                         if (right_side != null)
2106                                                 return var.ResolveLValue (ec, right_side);
2107                                         else
2108                                                 return var.Resolve (ec);
2109                                 }
2110
2111                                 int idx = -1;
2112                                 Parameter par = null;
2113                                 Parameters pars = current_block.Parameters;
2114                                 if (pars != null)
2115                                         par = pars.GetParameterByName (Name, out idx);
2116
2117                                 if (par != null) {
2118                                         ParameterReference param;
2119
2120                                         param = new ParameterReference (pars, current_block, idx, Name, loc);
2121
2122                                         if (right_side != null)
2123                                                 return param.ResolveLValue (ec, right_side);
2124                                         else
2125                                                 return param.Resolve (ec);
2126                                 }
2127                         }
2128
2129                         //
2130                         // Stage 2: Lookup members
2131                         //
2132
2133                         DeclSpace lookup_ds = ec.DeclSpace;
2134                         do {
2135                                 if (lookup_ds.TypeBuilder == null)
2136                                         break;
2137
2138                                 e = MemberLookup (ec, lookup_ds.TypeBuilder, Name, loc);
2139                                 if (e != null)
2140                                         break;
2141
2142                                 lookup_ds =lookup_ds.Parent;
2143                         } while (lookup_ds != null);
2144
2145                         if (e == null && ec.ContainerType != null)
2146                                 e = MemberLookup (ec, ec.ContainerType, Name, loc);
2147
2148                         if (e == null) {
2149                                 //
2150                                 // Since we are cheating (is_base is our hint
2151                                 // that we are the beginning of the name): we
2152                                 // only do the Alias lookup for namespaces if
2153                                 // the name does not include any dots in it
2154                                 //
2155                                 NamespaceEntry ns = ec.DeclSpace.NamespaceEntry;
2156                                 if (is_base && ns != null){
2157                                         string alias_value = ns.LookupAlias (Name);
2158                                         if (alias_value != null){
2159                                                 Name = alias_value;
2160                                                 Type t;
2161
2162                                                 if ((t = TypeManager.LookupType (Name)) != null)
2163                                                         return new TypeExpression (t, loc);
2164
2165                                                 // No match, maybe our parent can compose us
2166                                                 // into something meaningful.
2167                                                 return this;
2168                                         }
2169                                 }
2170
2171                                 return ResolveAsTypeStep (ec);
2172                         }
2173
2174                         if (e is TypeExpr)
2175                                 return e;
2176
2177                         if (e is IMemberExpr) {
2178                                 e = MemberAccess.ResolveMemberAccess (ec, e, null, loc, this);
2179                                 if (e == null)
2180                                         return null;
2181
2182                                 IMemberExpr me = e as IMemberExpr;
2183                                 if (me == null)
2184                                         return e;
2185
2186                                 // This fails if ResolveMemberAccess() was unable to decide whether
2187                                 // it's a field or a type of the same name.
2188
2189                                 if (!me.IsStatic && (me.InstanceExpression == null))
2190                                         return e;
2191
2192                                 if (!me.IsStatic &&
2193                                     TypeManager.IsSubclassOrNestedChildOf (me.InstanceExpression.Type, me.DeclaringType) &&
2194                                     me.InstanceExpression.Type != me.DeclaringType &&
2195                                     !me.InstanceExpression.Type.IsSubclassOf (me.DeclaringType) &&
2196                                     (!intermediate || !MemberAccess.IdenticalNameAndTypeName (ec, this, e, loc))) {
2197                                         Error (38, "Cannot access nonstatic member `" + me.Name + "' of " +
2198                                                "outer type `" + me.DeclaringType + "' via nested type `" +
2199                                                me.InstanceExpression.Type + "'");
2200                                         return null;
2201                                 }
2202
2203                                 return (right_side != null)
2204                                         ? e.DoResolveLValue (ec, right_side)
2205                                         : e.DoResolve (ec);
2206                         }
2207
2208                         if (ec.IsStatic || ec.IsFieldInitializer){
2209                                 if (allow_static)
2210                                         return e;
2211
2212                                 return MemberStaticCheck (ec, e);
2213                         } else
2214                                 return e;
2215                 }
2216
2217                 public override void Emit (EmitContext ec)
2218                 {
2219                         //
2220                         // If this is ever reached, then we failed to
2221                         // find the name as a namespace
2222                         //
2223
2224                         Error (103, "The name `" + Name +
2225                                "' does not exist in the class `" +
2226                                ec.DeclSpace.Name + "'");
2227                 }
2228
2229                 public override string ToString ()
2230                 {
2231                         return Name;
2232                 }
2233         }
2234
2235         /// <summary>
2236         ///   Fully resolved expression that evaluates to a type
2237         /// </summary>
2238         public abstract class TypeExpr : Expression {
2239                 override public Expression ResolveAsTypeStep (EmitContext ec)
2240                 {
2241                         TypeExpr t = DoResolveAsTypeStep (ec);
2242                         if (t == null)
2243                                 return null;
2244
2245                         eclass = ExprClass.Type;
2246                         return t;
2247                 }
2248
2249                 override public Expression DoResolve (EmitContext ec)
2250                 {
2251                         return ResolveAsTypeTerminal (ec, false);
2252                 }
2253
2254                 override public void Emit (EmitContext ec)
2255                 {
2256                         throw new Exception ("Should never be called");
2257                 }
2258
2259                 public virtual bool CheckAccessLevel (DeclSpace ds)
2260                 {
2261                         return ds.CheckAccessLevel (Type);
2262                 }
2263
2264                 public virtual bool AsAccessible (DeclSpace ds, int flags)
2265                 {
2266                         return ds.AsAccessible (Type, flags);
2267                 }
2268
2269                 public virtual bool IsClass {
2270                         get { return Type.IsClass; }
2271                 }
2272
2273                 public virtual bool IsValueType {
2274                         get { return Type.IsValueType; }
2275                 }
2276
2277                 public virtual bool IsInterface {
2278                         get { return Type.IsInterface; }
2279                 }
2280
2281                 public virtual bool IsSealed {
2282                         get { return Type.IsSealed; }
2283                 }
2284
2285                 public virtual bool CanInheritFrom ()
2286                 {
2287                         if (Type == TypeManager.enum_type ||
2288                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2289                             Type == TypeManager.multicast_delegate_type ||
2290                             Type == TypeManager.delegate_type ||
2291                             Type == TypeManager.array_type)
2292                                 return false;
2293
2294                         return true;
2295                 }
2296
2297                 public virtual bool IsAttribute {
2298                         get {
2299                                 return Type == TypeManager.attribute_type ||
2300                                         Type.IsSubclassOf (TypeManager.attribute_type);
2301                         }
2302                 }
2303
2304                 public virtual TypeExpr[] GetInterfaces ()
2305                 {
2306                         return TypeManager.GetInterfaces (Type);
2307                 }
2308
2309                 public abstract TypeExpr DoResolveAsTypeStep (EmitContext ec);
2310
2311                 public virtual Type ResolveType (EmitContext ec)
2312                 {
2313                         TypeExpr t = ResolveAsTypeTerminal (ec, false);
2314                         if (t == null)
2315                                 return null;
2316
2317                         return t.Type;
2318                 }
2319
2320                 public abstract string Name {
2321                         get;
2322                 }
2323
2324                 public override bool Equals (object obj)
2325                 {
2326                         TypeExpr tobj = obj as TypeExpr;
2327                         if (tobj == null)
2328                                 return false;
2329
2330                         return Type == tobj.Type;
2331                 }
2332
2333                 public override int GetHashCode ()
2334                 {
2335                         return Type.GetHashCode ();
2336                 }
2337
2338                 public override string ToString ()
2339                 {
2340                         return Name;
2341                 }
2342         }
2343
2344         public class TypeExpression : TypeExpr {
2345                 public TypeExpression (Type t, Location l)
2346                 {
2347                         Type = t;
2348                         eclass = ExprClass.Type;
2349                         loc = l;
2350                 }
2351
2352                 public override TypeExpr DoResolveAsTypeStep (EmitContext ec)
2353                 {
2354                         return this;
2355                 }
2356
2357                 public override string Name {
2358                         get {
2359                                 return Type.ToString ();
2360                         }
2361                 }
2362         }
2363
2364         /// <summary>
2365         ///   Used to create types from a fully qualified name.  These are just used
2366         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2367         ///   classified as a type.
2368         /// </summary>
2369         public class TypeLookupExpression : TypeExpr {
2370                 string name;
2371
2372                 public TypeLookupExpression (string name)
2373                 {
2374                         this.name = name;
2375                 }
2376
2377                 public override TypeExpr DoResolveAsTypeStep (EmitContext ec)
2378                 {
2379                         if (type == null)
2380                                 type = RootContext.LookupType (ec.DeclSpace, name, false, Location.Null);
2381                         return this;
2382                 }
2383
2384                 public override string Name {
2385                         get {
2386                                 return name;
2387                         }
2388                 }
2389         }
2390
2391         /// <summary>
2392         ///   MethodGroup Expression.
2393         ///
2394         ///   This is a fully resolved expression that evaluates to a type
2395         /// </summary>
2396         public class MethodGroupExpr : Expression, IMemberExpr {
2397                 public MethodBase [] Methods;
2398                 Expression instance_expression = null;
2399                 bool is_explicit_impl = false;
2400                 bool identical_type_name = false;
2401                 bool is_base;
2402
2403                 public MethodGroupExpr (MemberInfo [] mi, Location l)
2404                 {
2405                         Methods = new MethodBase [mi.Length];
2406                         mi.CopyTo (Methods, 0);
2407                         eclass = ExprClass.MethodGroup;
2408                         type = TypeManager.object_type;
2409                         loc = l;
2410                 }
2411
2412                 public MethodGroupExpr (ArrayList list, Location l)
2413                 {
2414                         Methods = new MethodBase [list.Count];
2415
2416                         try {
2417                                 list.CopyTo (Methods, 0);
2418                         } catch {
2419                                 foreach (MemberInfo m in list){
2420                                         if (!(m is MethodBase)){
2421                                                 Console.WriteLine ("Name " + m.Name);
2422                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
2423                                         }
2424                                 }
2425                                 throw;
2426                         }
2427
2428                         loc = l;
2429                         eclass = ExprClass.MethodGroup;
2430                         type = TypeManager.object_type;
2431                 }
2432
2433                 public Type DeclaringType {
2434                         get {
2435                                 //
2436                                 // The methods are arranged in this order:
2437                                 // derived type -> base type
2438                                 //
2439                                 return Methods [0].DeclaringType;
2440                         }
2441                 }
2442
2443                 //
2444                 // `A method group may have associated an instance expression'
2445                 //
2446                 public Expression InstanceExpression {
2447                         get {
2448                                 return instance_expression;
2449                         }
2450
2451                         set {
2452                                 instance_expression = value;
2453                         }
2454                 }
2455
2456                 public bool IsExplicitImpl {
2457                         get {
2458                                 return is_explicit_impl;
2459                         }
2460
2461                         set {
2462                                 is_explicit_impl = value;
2463                         }
2464                 }
2465
2466                 public bool IdenticalTypeName {
2467                         get {
2468                                 return identical_type_name;
2469                         }
2470
2471                         set {
2472                                 identical_type_name = value;
2473                         }
2474                 }
2475
2476                 public bool IsBase {
2477                         get {
2478                                 return is_base;
2479                         }
2480                         set {
2481                                 is_base = value;
2482                         }
2483                 }
2484
2485                 public string Name {
2486                         get {
2487                                 return Methods [0].Name;
2488                         }
2489                 }
2490
2491                 public bool IsInstance {
2492                         get {
2493                                 foreach (MethodBase mb in Methods)
2494                                         if (!mb.IsStatic)
2495                                                 return true;
2496
2497                                 return false;
2498                         }
2499                 }
2500
2501                 public bool IsStatic {
2502                         get {
2503                                 foreach (MethodBase mb in Methods)
2504                                         if (mb.IsStatic)
2505                                                 return true;
2506
2507                                 return false;
2508                         }
2509                 }
2510
2511                 override public Expression DoResolve (EmitContext ec)
2512                 {
2513                         if (!IsInstance)
2514                                 instance_expression = null;
2515
2516                         if (instance_expression != null) {
2517                                 instance_expression = instance_expression.DoResolve (ec);
2518                                 if (instance_expression == null)
2519                                         return null;
2520                         }
2521
2522                         return this;
2523                 }
2524
2525                 public void ReportUsageError ()
2526                 {
2527                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
2528                                       Name + "()' is referenced without parentheses");
2529                 }
2530
2531                 override public void Emit (EmitContext ec)
2532                 {
2533                         ReportUsageError ();
2534                 }
2535
2536                 bool RemoveMethods (bool keep_static)
2537                 {
2538                         ArrayList smethods = new ArrayList ();
2539
2540                         foreach (MethodBase mb in Methods){
2541                                 if (mb.IsStatic == keep_static)
2542                                         smethods.Add (mb);
2543                         }
2544
2545                         if (smethods.Count == 0)
2546                                 return false;
2547
2548                         Methods = new MethodBase [smethods.Count];
2549                         smethods.CopyTo (Methods, 0);
2550
2551                         return true;
2552                 }
2553
2554                 /// <summary>
2555                 ///   Removes any instance methods from the MethodGroup, returns
2556                 ///   false if the resulting set is empty.
2557                 /// </summary>
2558                 public bool RemoveInstanceMethods ()
2559                 {
2560                         return RemoveMethods (true);
2561                 }
2562
2563                 /// <summary>
2564                 ///   Removes any static methods from the MethodGroup, returns
2565                 ///   false if the resulting set is empty.
2566                 /// </summary>
2567                 public bool RemoveStaticMethods ()
2568                 {
2569                         return RemoveMethods (false);
2570                 }
2571         }
2572
2573         /// <summary>
2574         ///   Fully resolved expression that evaluates to a Field
2575         /// </summary>
2576         public class FieldExpr : Expression, IAssignMethod, IMemoryLocation, IMemberExpr, IVariable {
2577                 public readonly FieldInfo FieldInfo;
2578                 Expression instance_expr;
2579                 VariableInfo variable_info;
2580
2581                 LocalTemporary temp;
2582                 bool prepared;
2583
2584                 public FieldExpr (FieldInfo fi, Location l)
2585                 {
2586                         FieldInfo = fi;
2587                         eclass = ExprClass.Variable;
2588                         type = fi.FieldType;
2589                         loc = l;
2590                 }
2591
2592                 public string Name {
2593                         get {
2594                                 return FieldInfo.Name;
2595                         }
2596                 }
2597
2598                 public bool IsInstance {
2599                         get {
2600                                 return !FieldInfo.IsStatic;
2601                         }
2602                 }
2603
2604                 public bool IsStatic {
2605                         get {
2606                                 return FieldInfo.IsStatic;
2607                         }
2608                 }
2609
2610                 public Type DeclaringType {
2611                         get {
2612                                 return FieldInfo.DeclaringType;
2613                         }
2614                 }
2615
2616                 public Expression InstanceExpression {
2617                         get {
2618                                 return instance_expr;
2619                         }
2620
2621                         set {
2622                                 instance_expr = value;
2623                         }
2624                 }
2625
2626                 public VariableInfo VariableInfo {
2627                         get {
2628                                 return variable_info;
2629                         }
2630                 }
2631
2632                 override public Expression DoResolve (EmitContext ec)
2633                 {
2634                         if (!FieldInfo.IsStatic){
2635                                 if (instance_expr == null){
2636                                         //
2637                                         // This can happen when referencing an instance field using
2638                                         // a fully qualified type expression: TypeName.InstanceField = xxx
2639                                         //
2640                                         SimpleName.Error_ObjectRefRequired (ec, loc, FieldInfo.Name);
2641                                         return null;
2642                                 }
2643
2644                                 // Resolve the field's instance expression while flow analysis is turned
2645                                 // off: when accessing a field "a.b", we must check whether the field
2646                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
2647                                 instance_expr = instance_expr.Resolve (ec, ResolveFlags.VariableOrValue |
2648                                                                        ResolveFlags.DisableFlowAnalysis);
2649                                 if (instance_expr == null)
2650                                         return null;
2651                         }
2652
2653                         ObsoleteAttribute oa;
2654                         FieldBase f = TypeManager.GetField (FieldInfo);
2655                         if (f != null) {
2656                                 oa = f.GetObsoleteAttribute (f.Parent);
2657                                 if (oa != null)
2658                                         AttributeTester.Report_ObsoleteMessage (oa, f.GetSignatureForError (), loc);
2659
2660                         // To be sure that type is external because we do not register generated fields
2661                         } else if (!(FieldInfo.DeclaringType is TypeBuilder)) {
2662                                 oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
2663                                 if (oa != null)
2664                                         AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
2665                         }
2666
2667                         // If the instance expression is a local variable or parameter.
2668                         IVariable var = instance_expr as IVariable;
2669                         if ((var == null) || (var.VariableInfo == null))
2670                                 return this;
2671
2672                         VariableInfo vi = var.VariableInfo;
2673                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
2674                                 return null;
2675
2676                         variable_info = vi.GetSubStruct (FieldInfo.Name);
2677                         return this;
2678                 }
2679
2680                 void Report_AssignToReadonly (bool is_instance)
2681                 {
2682                         string msg;
2683
2684                         if (is_instance)
2685                                 msg = "Readonly field can not be assigned outside " +
2686                                 "of constructor or variable initializer";
2687                         else
2688                                 msg = "A static readonly field can only be assigned in " +
2689                                 "a static constructor";
2690
2691                         Report.Error (is_instance ? 191 : 198, loc, msg);
2692                 }
2693
2694                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
2695                 {
2696                         IVariable var = instance_expr as IVariable;
2697                         if ((var != null) && (var.VariableInfo != null))
2698                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
2699
2700                         Expression e = DoResolve (ec);
2701
2702                         if (e == null)
2703                                 return null;
2704
2705                         if (!FieldInfo.IsStatic && (instance_expr.Type.IsValueType && !(instance_expr is IMemoryLocation))) {
2706                                 // FIXME: Provide better error reporting.
2707                                 Error (1612, "Cannot modify expression because it is not a variable.");
2708                                 return null;
2709                         }
2710
2711                         if (!FieldInfo.IsInitOnly)
2712                                 return this;
2713
2714                         FieldBase fb = TypeManager.GetField (FieldInfo);
2715                         if (fb != null)
2716                                 fb.SetAssigned ();
2717
2718                         //
2719                         // InitOnly fields can only be assigned in constructors
2720                         //
2721
2722                         if (ec.IsConstructor){
2723                                 if (IsStatic && !ec.IsStatic)
2724                                         Report_AssignToReadonly (false);
2725
2726                                 if (ec.ContainerType == FieldInfo.DeclaringType)
2727                                         return this;
2728                         }
2729
2730                         Report_AssignToReadonly (!IsStatic);
2731
2732                         return null;
2733                 }
2734
2735                 public bool VerifyFixed (bool is_expression)
2736                 {
2737                         IVariable variable = instance_expr as IVariable;
2738                         if ((variable == null) || !variable.VerifyFixed (true))
2739                                 return false;
2740
2741                         return true;
2742                 }
2743
2744                 public void Emit (EmitContext ec, bool leave_copy)
2745                 {
2746                         ILGenerator ig = ec.ig;
2747                         bool is_volatile = false;
2748
2749                         if (FieldInfo is FieldBuilder){
2750                                 FieldBase f = TypeManager.GetField (FieldInfo);
2751                                 if (f != null){
2752                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0)
2753                                                 is_volatile = true;
2754
2755                                         f.status |= Field.Status.USED;
2756                                 }
2757                         }
2758
2759                         if (FieldInfo.IsStatic){
2760                                 if (is_volatile)
2761                                         ig.Emit (OpCodes.Volatile);
2762
2763                                 ig.Emit (OpCodes.Ldsfld, FieldInfo);
2764                         } else {
2765                                 if (!prepared)
2766                                         EmitInstance (ec);
2767
2768                                 if (is_volatile)
2769                                         ig.Emit (OpCodes.Volatile);
2770
2771                                 ig.Emit (OpCodes.Ldfld, FieldInfo);
2772                         }
2773
2774                         if (leave_copy) {
2775                                 ec.ig.Emit (OpCodes.Dup);
2776                                 if (!FieldInfo.IsStatic) {
2777                                         temp = new LocalTemporary (ec, this.Type);
2778                                         temp.Store (ec);
2779                                 }
2780                         }
2781                 }
2782
2783                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
2784                 {
2785                         FieldAttributes fa = FieldInfo.Attributes;
2786                         bool is_static = (fa & FieldAttributes.Static) != 0;
2787                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
2788                         ILGenerator ig = ec.ig;
2789                         prepared = prepare_for_load;
2790
2791                         if (is_readonly && !ec.IsConstructor){
2792                                 Report_AssignToReadonly (!is_static);
2793                                 return;
2794                         }
2795
2796                         if (!is_static) {
2797                                 EmitInstance (ec);
2798                                 if (prepare_for_load)
2799                                         ig.Emit (OpCodes.Dup);
2800                         }
2801
2802                         source.Emit (ec);
2803                         if (leave_copy) {
2804                                 ec.ig.Emit (OpCodes.Dup);
2805                                 if (!FieldInfo.IsStatic) {
2806                                         temp = new LocalTemporary (ec, this.Type);
2807                                         temp.Store (ec);
2808                                 }
2809                         }
2810
2811                         if (FieldInfo is FieldBuilder){
2812                                 FieldBase f = TypeManager.GetField (FieldInfo);
2813                                 if (f != null){
2814                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0)
2815                                                 ig.Emit (OpCodes.Volatile);
2816
2817                                         f.status |= Field.Status.ASSIGNED;
2818                                 }
2819                         }
2820
2821                         if (is_static)
2822                                 ig.Emit (OpCodes.Stsfld, FieldInfo);
2823                         else
2824                                 ig.Emit (OpCodes.Stfld, FieldInfo);
2825
2826                         if (temp != null)
2827                                 temp.Emit (ec);
2828                 }
2829
2830                 void EmitInstance (EmitContext ec)
2831                 {
2832                         if (instance_expr.Type.IsValueType) {
2833                                 if (instance_expr is IMemoryLocation) {
2834                                         ((IMemoryLocation) instance_expr).AddressOf (ec, AddressOp.LoadStore);
2835                                 } else {
2836                                         LocalTemporary t = new LocalTemporary (ec, instance_expr.Type);
2837                                         instance_expr.Emit (ec);
2838                                         t.Store (ec);
2839                                         t.AddressOf (ec, AddressOp.Store);
2840                                 }
2841                         } else
2842                                 instance_expr.Emit (ec);
2843                 }
2844
2845                 public override void Emit (EmitContext ec)
2846                 {
2847                         Emit (ec, false);
2848                 }
2849
2850                 public void AddressOf (EmitContext ec, AddressOp mode)
2851                 {
2852                         ILGenerator ig = ec.ig;
2853
2854                         if (FieldInfo is FieldBuilder){
2855                                 FieldBase f = TypeManager.GetField (FieldInfo);
2856                                 if (f != null){
2857                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0){
2858                                                 Error (676, "volatile variable: can not take its address, or pass as ref/out parameter");
2859                                                 return;
2860                                         }
2861
2862                                         if ((mode & AddressOp.Store) != 0)
2863                                                 f.status |= Field.Status.ASSIGNED;
2864                                         if ((mode & AddressOp.Load) != 0)
2865                                                 f.status |= Field.Status.USED;
2866                                 }
2867                         }
2868
2869                         //
2870                         // Handle initonly fields specially: make a copy and then
2871                         // get the address of the copy.
2872                         //
2873                         bool need_copy;
2874                         if (FieldInfo.IsInitOnly){
2875                                 need_copy = true;
2876                                 if (ec.IsConstructor){
2877                                         if (FieldInfo.IsStatic){
2878                                                 if (ec.IsStatic)
2879                                                         need_copy = false;
2880                                         } else
2881                                                 need_copy = false;
2882                                 }
2883                         } else
2884                                 need_copy = false;
2885
2886                         if (need_copy){
2887                                 LocalBuilder local;
2888                                 Emit (ec);
2889                                 local = ig.DeclareLocal (type);
2890                                 ig.Emit (OpCodes.Stloc, local);
2891                                 ig.Emit (OpCodes.Ldloca, local);
2892                                 return;
2893                         }
2894
2895
2896                         if (FieldInfo.IsStatic){
2897                                 ig.Emit (OpCodes.Ldsflda, FieldInfo);
2898                         } else {
2899                                 EmitInstance (ec);
2900                                 ig.Emit (OpCodes.Ldflda, FieldInfo);
2901                         }
2902                 }
2903         }
2904
2905         //
2906         // A FieldExpr whose address can not be taken
2907         //
2908         public class FieldExprNoAddress : FieldExpr, IMemoryLocation {
2909                 public FieldExprNoAddress (FieldInfo fi, Location loc) : base (fi, loc)
2910                 {
2911                 }
2912
2913                 public new void AddressOf (EmitContext ec, AddressOp mode)
2914                 {
2915                         Report.Error (-215, "Report this: Taking the address of a remapped parameter not supported");
2916                 }
2917         }
2918
2919         /// <summary>
2920         ///   Expression that evaluates to a Property.  The Assign class
2921         ///   might set the `Value' expression if we are in an assignment.
2922         ///
2923         ///   This is not an LValue because we need to re-write the expression, we
2924         ///   can not take data from the stack and store it.
2925         /// </summary>
2926         public class PropertyExpr : ExpressionStatement, IAssignMethod, IMemberExpr {
2927                 public readonly PropertyInfo PropertyInfo;
2928
2929                 //
2930                 // This is set externally by the  `BaseAccess' class
2931                 //
2932                 public bool IsBase;
2933                 MethodInfo getter, setter;
2934                 bool is_static;
2935                 bool must_do_cs1540_check;
2936
2937                 Expression instance_expr;
2938                 LocalTemporary temp;
2939                 bool prepared;
2940
2941                 public PropertyExpr (EmitContext ec, PropertyInfo pi, Location l)
2942                 {
2943                         PropertyInfo = pi;
2944                         eclass = ExprClass.PropertyAccess;
2945                         is_static = false;
2946                         loc = l;
2947
2948                         type = TypeManager.TypeToCoreType (pi.PropertyType);
2949
2950                         ResolveAccessors (ec);
2951                 }
2952
2953                 public string Name {
2954                         get {
2955                                 return PropertyInfo.Name;
2956                         }
2957                 }
2958
2959                 public bool IsInstance {
2960                         get {
2961                                 return !is_static;
2962                         }
2963                 }
2964
2965                 public bool IsStatic {
2966                         get {
2967                                 return is_static;
2968                         }
2969                 }
2970
2971                 public Type DeclaringType {
2972                         get {
2973                                 return PropertyInfo.DeclaringType;
2974                         }
2975                 }
2976
2977                 //
2978                 // The instance expression associated with this expression
2979                 //
2980                 public Expression InstanceExpression {
2981                         set {
2982                                 instance_expr = value;
2983                         }
2984
2985                         get {
2986                                 return instance_expr;
2987                         }
2988                 }
2989
2990                 public bool VerifyAssignable ()
2991                 {
2992                         if (setter == null) {
2993                                 Report.Error (200, loc,
2994                                               "The property `" + PropertyInfo.Name +
2995                                               "' can not be assigned to, as it has not set accessor");
2996                                 return false;
2997                         }
2998
2999                         return true;
3000                 }
3001
3002                 void FindAccessors (Type invocation_type)
3003                 {
3004                         BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
3005                                 BindingFlags.Static | BindingFlags.Instance |
3006                                 BindingFlags.DeclaredOnly;
3007
3008                         Type current = PropertyInfo.DeclaringType;
3009                         for (; current != null; current = current.BaseType) {
3010                                 MemberInfo[] group = TypeManager.MemberLookup (
3011                                         invocation_type, invocation_type, current,
3012                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
3013
3014                                 if (group == null)
3015                                         continue;
3016
3017                                 if (group.Length != 1)
3018                                         // Oooops, can this ever happen ?
3019                                         return;
3020
3021                                 PropertyInfo pi = (PropertyInfo) group [0];
3022
3023                                 if (getter == null)
3024                                         getter = pi.GetGetMethod (true);;
3025
3026                                 if (setter == null)
3027                                         setter = pi.GetSetMethod (true);;
3028
3029                                 MethodInfo accessor = getter != null ? getter : setter;
3030
3031                                 if (!accessor.IsVirtual)
3032                                         return;
3033                         }
3034                 }
3035
3036                 bool IsAccessorAccessible (Type invocation_type, MethodInfo mi)
3037                 {
3038                         MethodAttributes ma = mi.Attributes & MethodAttributes.MemberAccessMask;
3039
3040                         //
3041                         // If only accessible to the current class or children
3042                         //
3043                         if (ma == MethodAttributes.Private) {
3044                                 Type declaring_type = mi.DeclaringType;
3045
3046                                 if (invocation_type != declaring_type)
3047                                         return TypeManager.IsSubclassOrNestedChildOf (invocation_type, declaring_type);
3048
3049                                 return true;
3050                         }
3051                         //
3052                         // FamAndAssem requires that we not only derivate, but we are on the
3053                         // same assembly.
3054                         //
3055                         if (ma == MethodAttributes.FamANDAssem){
3056                                 return (mi.DeclaringType.Assembly != invocation_type.Assembly);
3057                         }
3058
3059                         // Assembly and FamORAssem succeed if we're in the same assembly.
3060                         if ((ma == MethodAttributes.Assembly) || (ma == MethodAttributes.FamORAssem)){
3061                                 if (mi.DeclaringType.Assembly == invocation_type.Assembly)
3062                                         return true;
3063                         }
3064
3065                         // We already know that we aren't in the same assembly.
3066                         if (ma == MethodAttributes.Assembly)
3067                                 return false;
3068
3069                         // Family and FamANDAssem require that we derive.
3070                         if ((ma == MethodAttributes.Family) || (ma == MethodAttributes.FamANDAssem) || (ma == MethodAttributes.FamORAssem)){
3071                                 if (!TypeManager.IsSubclassOrNestedChildOf (invocation_type, mi.DeclaringType))
3072                                         return false;
3073
3074                                 if (!TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType))
3075                                         must_do_cs1540_check = true;
3076
3077                                 return true;
3078                         }
3079
3080                         return true;
3081                 }
3082
3083                 //
3084                 // We also perform the permission checking here, as the PropertyInfo does not
3085                 // hold the information for the accessibility of its setter/getter
3086                 //
3087                 void ResolveAccessors (EmitContext ec)
3088                 {
3089                         FindAccessors (ec.ContainerType);
3090
3091                         if (setter != null && !IsAccessorAccessible (ec.ContainerType, setter) ||
3092                                 getter != null && !IsAccessorAccessible (ec.ContainerType, getter)) {
3093                                 Report.Error (122, loc, "'{0}' is inaccessible due to its protection level", PropertyInfo.Name);
3094                         }
3095
3096                         is_static = getter != null ? getter.IsStatic : setter.IsStatic;
3097                 }
3098
3099                 bool InstanceResolve (EmitContext ec)
3100                 {
3101                         if ((instance_expr == null) && ec.IsStatic && !is_static) {
3102                                 SimpleName.Error_ObjectRefRequired (ec, loc, PropertyInfo.Name);
3103                                 return false;
3104                         }
3105
3106                         if (instance_expr != null) {
3107                                 instance_expr = instance_expr.DoResolve (ec);
3108                                 if (instance_expr == null)
3109                                         return false;
3110                         }
3111
3112                         if (must_do_cs1540_check && (instance_expr != null)) {
3113                                 if ((instance_expr.Type != ec.ContainerType) &&
3114                                     ec.ContainerType.IsSubclassOf (instance_expr.Type)) {
3115                                         Report.Error (1540, loc, "Cannot access protected member `" +
3116                                                       PropertyInfo.DeclaringType + "." + PropertyInfo.Name +
3117                                                       "' via a qualifier of type `" +
3118                                                       TypeManager.CSharpName (instance_expr.Type) +
3119                                                       "'; the qualifier must be of type `" +
3120                                                       TypeManager.CSharpName (ec.ContainerType) +
3121                                                       "' (or derived from it)");
3122                                         return false;
3123                                 }
3124                         }
3125
3126                         return true;
3127                 }
3128
3129                 override public Expression DoResolve (EmitContext ec)
3130                 {
3131                         if (getter != null){
3132                                 if (TypeManager.GetArgumentTypes (getter).Length != 0){
3133                                         Report.Error (
3134                                                 117, loc, "`{0}' does not contain a " +
3135                                                 "definition for `{1}'.", getter.DeclaringType,
3136                                                 Name);
3137                                         return null;
3138                                 }
3139                         }
3140
3141                         if (getter == null){
3142                                 //
3143                                 // The following condition happens if the PropertyExpr was
3144                                 // created, but is invalid (ie, the property is inaccessible),
3145                                 // and we did not want to embed the knowledge about this in
3146                                 // the caller routine.  This only avoids double error reporting.
3147                                 //
3148                                 if (setter == null)
3149                                         return null;
3150
3151                                 Report.Error (154, loc,
3152                                               "The property `" + PropertyInfo.Name +
3153                                               "' can not be used in " +
3154                                               "this context because it lacks a get accessor");
3155                                 return null;
3156                         }
3157
3158                         if (!InstanceResolve (ec))
3159                                 return null;
3160
3161                         //
3162                         // Only base will allow this invocation to happen.
3163                         //
3164                         if (IsBase && getter.IsAbstract){
3165                                 Report.Error (205, loc, "Cannot call an abstract base property: " +
3166                                               PropertyInfo.DeclaringType + "." +PropertyInfo.Name);
3167                                 return null;
3168                         }
3169
3170                         return this;
3171                 }
3172
3173                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3174                 {
3175                         if (setter == null){
3176                                 //
3177                                 // The following condition happens if the PropertyExpr was
3178                                 // created, but is invalid (ie, the property is inaccessible),
3179                                 // and we did not want to embed the knowledge about this in
3180                                 // the caller routine.  This only avoids double error reporting.
3181                                 //
3182                                 if (getter == null)
3183                                         return null;
3184
3185                                 Report.Error (154, loc,
3186                                               "The property `" + PropertyInfo.Name +
3187                                               "' can not be used in " +
3188                                               "this context because it lacks a set accessor");
3189                                 return null;
3190                         }
3191
3192                         if (TypeManager.GetArgumentTypes (setter).Length != 1){
3193                                 Report.Error (
3194                                         117, loc, "`{0}' does not contain a " +
3195                                         "definition for `{1}'.", getter.DeclaringType,
3196                                         Name);
3197                                 return null;
3198                         }
3199
3200                         if (!InstanceResolve (ec))
3201                                 return null;
3202
3203                         //
3204                         // Only base will allow this invocation to happen.
3205                         //
3206                         if (IsBase && setter.IsAbstract){
3207                                 Report.Error (205, loc, "Cannot call an abstract base property: " +
3208                                               PropertyInfo.DeclaringType + "." +PropertyInfo.Name);
3209                                 return null;
3210                         }
3211
3212                         //
3213                         // Check that we are not making changes to a temporary memory location
3214                         //
3215                         if (instance_expr != null && instance_expr.Type.IsValueType && !(instance_expr is IMemoryLocation)) {
3216                                 // FIXME: Provide better error reporting.
3217                                 Error (1612, "Cannot modify expression because it is not a variable.");
3218                                 return null;
3219                         }
3220
3221                         return this;
3222                 }
3223
3224
3225
3226                 public override void Emit (EmitContext ec)
3227                 {
3228                         Emit (ec, false);
3229                 }
3230
3231                 void EmitInstance (EmitContext ec)
3232                 {
3233                         if (is_static)
3234                                 return;
3235
3236                         if (instance_expr.Type.IsValueType) {
3237                                 if (instance_expr is IMemoryLocation) {
3238                                         ((IMemoryLocation) instance_expr).AddressOf (ec, AddressOp.LoadStore);
3239                                 } else {
3240                                         LocalTemporary t = new LocalTemporary (ec, instance_expr.Type);
3241                                         instance_expr.Emit (ec);
3242                                         t.Store (ec);
3243                                         t.AddressOf (ec, AddressOp.Store);
3244                                 }
3245                         } else
3246                                 instance_expr.Emit (ec);
3247
3248                         if (prepared)
3249                                 ec.ig.Emit (OpCodes.Dup);
3250                 }
3251
3252
3253                 public void Emit (EmitContext ec, bool leave_copy)
3254                 {
3255                         if (!prepared)
3256                                 EmitInstance (ec);
3257
3258                         //
3259                         // Special case: length of single dimension array property is turned into ldlen
3260                         //
3261                         if ((getter == TypeManager.system_int_array_get_length) ||
3262                             (getter == TypeManager.int_array_get_length)){
3263                                 Type iet = instance_expr.Type;
3264
3265                                 //
3266                                 // System.Array.Length can be called, but the Type does not
3267                                 // support invoking GetArrayRank, so test for that case first
3268                                 //
3269                                 if (iet != TypeManager.array_type && (iet.GetArrayRank () == 1)) {
3270                                         ec.ig.Emit (OpCodes.Ldlen);
3271                                         ec.ig.Emit (OpCodes.Conv_I4);
3272                                         return;
3273                                 }
3274                         }
3275
3276                         Invocation.EmitCall (ec, IsBase, IsStatic, new EmptyAddressOf (), getter, null, loc);
3277
3278                         if (!leave_copy)
3279                                 return;
3280
3281                         ec.ig.Emit (OpCodes.Dup);
3282                         if (!is_static) {
3283                                 temp = new LocalTemporary (ec, this.Type);
3284                                 temp.Store (ec);
3285                         }
3286                 }
3287
3288                 //
3289                 // Implements the IAssignMethod interface for assignments
3290                 //
3291                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
3292                 {
3293                         prepared = prepare_for_load;
3294
3295                         EmitInstance (ec);
3296
3297                         source.Emit (ec);
3298                         if (leave_copy) {
3299                                 ec.ig.Emit (OpCodes.Dup);
3300                                 if (!is_static) {
3301                                         temp = new LocalTemporary (ec, this.Type);
3302                                         temp.Store (ec);
3303                                 }
3304                         }
3305
3306                         ArrayList args = new ArrayList (1);
3307                         args.Add (new Argument (new EmptyAddressOf (), Argument.AType.Expression));
3308
3309                         Invocation.EmitCall (ec, IsBase, IsStatic, new EmptyAddressOf (), setter, args, loc);
3310
3311                         if (temp != null)
3312                                 temp.Emit (ec);
3313                 }
3314
3315                 override public void EmitStatement (EmitContext ec)
3316                 {
3317                         Emit (ec);
3318                         ec.ig.Emit (OpCodes.Pop);
3319                 }
3320         }
3321
3322         /// <summary>
3323         ///   Fully resolved expression that evaluates to an Event
3324         /// </summary>
3325         public class EventExpr : Expression, IMemberExpr {
3326                 public readonly EventInfo EventInfo;
3327                 Expression instance_expr;
3328
3329                 bool is_static;
3330                 MethodInfo add_accessor, remove_accessor;
3331
3332                 public EventExpr (EventInfo ei, Location loc)
3333                 {
3334                         EventInfo = ei;
3335                         this.loc = loc;
3336                         eclass = ExprClass.EventAccess;
3337
3338                         add_accessor = TypeManager.GetAddMethod (ei);
3339                         remove_accessor = TypeManager.GetRemoveMethod (ei);
3340
3341                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
3342                                 is_static = true;
3343
3344                         if (EventInfo is MyEventBuilder){
3345                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
3346                                 type = eb.EventType;
3347                                 eb.SetUsed ();
3348                         } else
3349                                 type = EventInfo.EventHandlerType;
3350                 }
3351
3352                 public string Name {
3353                         get {
3354                                 return EventInfo.Name;
3355                         }
3356                 }
3357
3358                 public bool IsInstance {
3359                         get {
3360                                 return !is_static;
3361                         }
3362                 }
3363
3364                 public bool IsStatic {
3365                         get {
3366                                 return is_static;
3367                         }
3368                 }
3369
3370                 public Type DeclaringType {
3371                         get {
3372                                 return EventInfo.DeclaringType;
3373                         }
3374                 }
3375
3376                 public Expression InstanceExpression {
3377                         get {
3378                                 return instance_expr;
3379                         }
3380
3381                         set {
3382                                 instance_expr = value;
3383                         }
3384                 }
3385
3386                 public override Expression DoResolve (EmitContext ec)
3387                 {
3388                         if (instance_expr != null) {
3389                                 instance_expr = instance_expr.DoResolve (ec);
3390                                 if (instance_expr == null)
3391                                         return null;
3392                         }
3393
3394
3395                         return this;
3396                 }
3397
3398                 public override void Emit (EmitContext ec)
3399                 {
3400                         Report.Error (70, loc, "The event `" + Name + "' can only appear on the left hand side of += or -= (except on the defining type)");
3401                 }
3402
3403                 public void EmitAddOrRemove (EmitContext ec, Expression source)
3404                 {
3405                         BinaryDelegate source_del = (BinaryDelegate) source;
3406                         Expression handler = source_del.Right;
3407
3408                         Argument arg = new Argument (handler, Argument.AType.Expression);
3409                         ArrayList args = new ArrayList ();
3410
3411                         args.Add (arg);
3412
3413                         if (source_del.IsAddition)
3414                                 Invocation.EmitCall (
3415                                         ec, false, IsStatic, instance_expr, add_accessor, args, loc);
3416                         else
3417                                 Invocation.EmitCall (
3418                                         ec, false, IsStatic, instance_expr, remove_accessor, args, loc);
3419                 }
3420         }
3421 }