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                 // Mask of all the expression class flags.
  55                 MaskExprClass           = 7,
  56
  57                 // Disable control flow analysis while resolving the expression.
  58                 // This is used when resolving the instance expression of a field expression.
  59                 DisableFlowAnalysis     = 8,
  60
  61                 // Set if this is resolving the first part of a MemberAccess.
  62                 Intermediate            = 16
  63         }
  64
  65         //
  66         // This is just as a hint to AddressOf of what will be done with the
  67         // address.
  68         [Flags]
  69         public enum AddressOp {
  70                 Store = 1,
  71                 Load  = 2,
  72                 LoadStore = 3
  73         };
  74
  75         /// <summary>
  76         ///   This interface is implemented by variables
  77         /// </summary>
  78         public interface IMemoryLocation {
  79                 /// <summary>
  80                 ///   The AddressOf method should generate code that loads
  81                 ///   the address of the object and leaves it on the stack.
  82                 ///
  83                 ///   The `mode' argument is used to notify the expression
  84                 ///   of whether this will be used to read from the address or
  85                 ///   write to the address.
  86                 ///
  87                 ///   This is just a hint that can be used to provide good error
  88                 ///   reporting, and should have no other side effects.
  89                 /// </summary>
  90                 void AddressOf (EmitContext ec, AddressOp mode);
  91         }
  92
  93         /// <summary>
  94         ///   We are either a namespace or a type.
  95         ///   If we're a type, `IsType' is true and we may use `Type' to get
  96         ///   a TypeExpr representing that type.
  97         /// </summary>
  98         public interface IAlias {
  99                 bool IsType {
 100                         get;
 101                 }
 102
 103                 string Name {
 104                         get;
 105                 }
 106
 107                 TypeExpr ResolveAsType (EmitContext ec);
 108         }
 109
 110         /// <summary>
 111         ///   This interface is implemented by variables
 112         /// </summary>
 113         public interface IVariable {
 114                 VariableInfo VariableInfo {
 115                         get;
 116                 }
 117
 118                 bool VerifyFixed (bool is_expression);
 119         }
 120
 121         /// <summary>
 122         ///   This interface denotes an expression which evaluates to a member
 123         ///   of a struct or a class.
 124         /// </summary>
 125         public interface IMemberExpr
 126         {
 127                 /// <summary>
 128                 ///   The name of this member.
 129                 /// </summary>
 130                 string Name {
 131                         get;
 132                 }
 133
 134                 /// <summary>
 135                 ///   Whether this is an instance member.
 136                 /// </summary>
 137                 bool IsInstance {
 138                         get;
 139                 }
 140
 141                 /// <summary>
 142                 ///   Whether this is a static member.
 143                 /// </summary>
 144                 bool IsStatic {
 145                         get;
 146                 }
 147
 148                 /// <summary>
 149                 ///   The type which declares this member.
 150                 /// </summary>
 151                 Type DeclaringType {
 152                         get;
 153                 }
 154
 155                 /// <summary>
 156                 ///   The instance expression associated with this member, if it's a
 157                 ///   non-static member.
 158                 /// </summary>
 159                 Expression InstanceExpression {
 160                         get; set;
 161                 }
 162         }
 163
 164         /// <remarks>
 165         ///   Base class for expressions
 166         /// </remarks>
 167         public abstract class Expression {
 168                 public ExprClass eclass;
 169                 protected Type type;
 170                 protected Location loc;
 171
 172                 public Type Type {
 173                         get {
 174                                 return type;
 175                         }
 176
 177                         set {
 178                                 type = value;
 179                         }
 180                 }
 181
 182                 public Location Location {
 183                         get {
 184                                 return loc;
 185                         }
 186                 }
 187
 188                 /// <summary>
 189                 ///   Utility wrapper routine for Error, just to beautify the code
 190                 /// </summary>
 191                 public void Error (int error, string s)
 192                 {
 193                         if (!Location.IsNull (loc))
 194                                 Report.Error (error, loc, s);
 195                         else
 196                                 Report.Error (error, s);
 197                 }
 198
 199                 /// <summary>
 200                 ///   Utility wrapper routine for Warning, just to beautify the code
 201                 /// </summary>
 202                 public void Warning (int code, string format, params object[] args)
 203                 {
 204                         Report.Warning (code, loc, format, args);
 205                 }
 206
 207                 // Not nice but we have broken hierarchy
 208                 public virtual void CheckMarshallByRefAccess (Type container) {}
 209
 210                 /// <summary>
 211                 /// Tests presence of ObsoleteAttribute and report proper error
 212                 /// </summary>
 213                 protected void CheckObsoleteAttribute (Type type)
 214                 {
 215                         ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (type);
 216                         if (obsolete_attr == null)
 217                                 return;
 218
 219                         AttributeTester.Report_ObsoleteMessage (obsolete_attr, type.FullName, loc);
 220                 }
 221
 222                 public static bool IsAccessorAccessible (Type invocation_type, MethodInfo mi, out bool must_do_cs1540_check)
 223                 {
 224                         MethodAttributes ma = mi.Attributes & MethodAttributes.MemberAccessMask;
 225
 226                         must_do_cs1540_check = false; // by default we do not check for this
 227
 228                         //
 229                         // If only accessible to the current class or children
 230                         //
 231                         if (ma == MethodAttributes.Private) {
 232                                 Type declaring_type = mi.DeclaringType;
 233
 234                                 if (invocation_type != declaring_type)
 235                                         return TypeManager.IsNestedChildOf (invocation_type, declaring_type);
 236
 237                                 return true;
 238                         }
 239                         //
 240                         // FamAndAssem requires that we not only derivate, but we are on the
 241                         // same assembly.
 242                         //
 243                         if (ma == MethodAttributes.FamANDAssem){
 244                                 return (mi.DeclaringType.Assembly != invocation_type.Assembly);
 245                         }
 246
 247                         // Assembly and FamORAssem succeed if we're in the same assembly.
 248                         if ((ma == MethodAttributes.Assembly) || (ma == MethodAttributes.FamORAssem)){
 249                                 if (mi.DeclaringType.Assembly == invocation_type.Assembly)
 250                                         return true;
 251                         }
 252
 253                         // We already know that we aren't in the same assembly.
 254                         if (ma == MethodAttributes.Assembly)
 255                                 return false;
 256
 257                         // Family and FamANDAssem require that we derive.
 258                         if ((ma == MethodAttributes.Family) || (ma == MethodAttributes.FamANDAssem) || (ma == MethodAttributes.FamORAssem)){
 259                                 if (!TypeManager.IsNestedFamilyAccessible (invocation_type, mi.DeclaringType))
 260                                         return false;
 261
 262                                 if (!TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType))
 263                                         must_do_cs1540_check = true;
 264
 265                                 return true;
 266                         }
 267
 268                         return true;
 269                 }
 270
 271                 /// <summary>
 272                 ///   Performs semantic analysis on the Expression
 273                 /// </summary>
 274                 ///
 275                 /// <remarks>
 276                 ///   The Resolve method is invoked to perform the semantic analysis
 277                 ///   on the node.
 278                 ///
 279                 ///   The return value is an expression (it can be the
 280                 ///   same expression in some cases) or a new
 281                 ///   expression that better represents this node.
 282                 ///
 283                 ///   For example, optimizations of Unary (LiteralInt)
 284                 ///   would return a new LiteralInt with a negated
 285                 ///   value.
 286                 ///
 287                 ///   If there is an error during semantic analysis,
 288                 ///   then an error should be reported (using Report)
 289                 ///   and a null value should be returned.
 290                 ///
 291                 ///   There are two side effects expected from calling
 292                 ///   Resolve(): the the field variable "eclass" should
 293                 ///   be set to any value of the enumeration
 294                 ///   `ExprClass' and the type variable should be set
 295                 ///   to a valid type (this is the type of the
 296                 ///   expression).
 297                 /// </remarks>
 298                 public abstract Expression DoResolve (EmitContext ec);
 299
 300                 public virtual Expression DoResolveLValue (EmitContext ec, Expression right_side)
 301                 {
 302                         return DoResolve (ec);
 303                 }
 304
 305                 //
 306                 // This is used if the expression should be resolved as a type or namespace name.
 307                 // the default implementation fails.
 308                 //
 309                 public virtual FullNamedExpression ResolveAsTypeStep (EmitContext ec)
 310                 {
 311                         return null;
 312                 }
 313
 314                 //
 315                 // This is used to resolve the expression as a type, a null
 316                 // value will be returned if the expression is not a type
 317                 // reference
 318                 //
 319                 public TypeExpr ResolveAsTypeTerminal (EmitContext ec, bool silent)
 320                 {
 321                         int errors = Report.Errors;
 322
 323                         FullNamedExpression fne = ResolveAsTypeStep (ec);
 324
 325                         if (fne == null) {
 326                                 if (!silent && errors == Report.Errors)
 327                                         Report.Error (246, Location, "Cannot find type '{0}'", ToString ());
 328                                 return null;
 329                         }
 330
 331                         if (fne.eclass != ExprClass.Type) {
 332                                 if (!silent && errors == Report.Errors)
 333                                         Report.Error (118, Location, "'{0}' denotes a '{1}', where a type was expected",
 334                                                       fne.FullName, fne.ExprClassName ());
 335                                 return null;
 336                         }
 337
 338                         TypeExpr te = fne as TypeExpr;
 339
 340                         if (!te.CheckAccessLevel (ec.DeclSpace)) {
 341                                 Report.Error (122, Location, "'{0}' is inaccessible due to its protection level", te.Name);
 342                                 return null;
 343                         }
 344
 345                         return te;
 346                 }
 347
 348                 /// <summary>
 349                 ///   Resolves an expression and performs semantic analysis on it.
 350                 /// </summary>
 351                 ///
 352                 /// <remarks>
 353                 ///   Currently Resolve wraps DoResolve to perform sanity
 354                 ///   checking and assertion checking on what we expect from Resolve.
 355                 /// </remarks>
 356                 public Expression Resolve (EmitContext ec, ResolveFlags flags)
 357                 {
 358                         if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
 359                                 return ResolveAsTypeStep (ec);
 360
 361                         bool old_do_flow_analysis = ec.DoFlowAnalysis;
 362                         if ((flags & ResolveFlags.DisableFlowAnalysis) != 0)
 363                                 ec.DoFlowAnalysis = false;
 364
 365                         Expression e;
 366                         bool intermediate = (flags & ResolveFlags.Intermediate) == ResolveFlags.Intermediate;
 367                         if (this is SimpleName)
 368                                 e = ((SimpleName) this).DoResolveAllowStatic (ec, intermediate);
 369
 370                         else
 371                                 e = DoResolve (ec);
 372
 373                         ec.DoFlowAnalysis = old_do_flow_analysis;
 374
 375                         if (e == null)
 376                                 return null;
 377
 378                         if ((e is TypeExpr) || (e is ComposedCast) || (e is Namespace)) {
 379                                 if ((flags & ResolveFlags.Type) == 0) {
 380                                         e.Error_UnexpectedKind (flags, loc);
 381                                         return null;
 382                                 }
 383
 384                                 return e;
 385                         }
 386
 387                         switch (e.eclass) {
 388                         case ExprClass.Type:
 389                         case ExprClass.Namespace:
 390                                 if ((flags & ResolveFlags.VariableOrValue) == 0) {
 391                                         e.Error_UnexpectedKind (flags, loc);
 392                                         return null;
 393                                 }
 394                                 break;
 395
 396                         case ExprClass.MethodGroup:
 397                                 if (RootContext.Version == LanguageVersion.ISO_1){
 398                                         if ((flags & ResolveFlags.MethodGroup) == 0) {
 399                                                 ((MethodGroupExpr) e).ReportUsageError ();
 400                                                 return null;
 401                                         }
 402                                 }
 403                                 break;
 404
 405                         case ExprClass.Value:
 406                         case ExprClass.Variable:
 407                         case ExprClass.PropertyAccess:
 408                         case ExprClass.EventAccess:
 409                         case ExprClass.IndexerAccess:
 410                                 if ((flags & ResolveFlags.VariableOrValue) == 0) {
 411                                         Console.WriteLine ("I got: {0} and {1}", e.GetType (), e);
 412                                         Console.WriteLine ("I am {0} and {1}", this.GetType (), this);
 413                                         FieldInfo fi = ((FieldExpr) e).FieldInfo;
 414
 415                                         Console.WriteLine ("{0} and {1}", fi.DeclaringType, fi.Name);
 416                                         e.Error_UnexpectedKind (flags, loc);
 417                                         return null;
 418                                 }
 419                                 break;
 420
 421                         default:
 422                                 throw new Exception ("Expression " + e.GetType () +
 423                                                      " ExprClass is Invalid after resolve");
 424                         }
 425
 426                         if (e.type == null && !(e is Namespace)) {
 427                                 throw new Exception (
 428                                         "Expression " + e.GetType () +
 429                                         " did not set its type after Resolve\n" +
 430                                         "called from: " + this.GetType ());
 431                         }
 432
 433                         return e;
 434                 }
 435
 436                 /// <summary>
 437                 ///   Resolves an expression and performs semantic analysis on it.
 438                 /// </summary>
 439                 public Expression Resolve (EmitContext ec)
 440                 {
 441                         return Resolve (ec, ResolveFlags.VariableOrValue);
 442                 }
 443
 444                 /// <summary>
 445                 ///   Resolves an expression for LValue assignment
 446                 /// </summary>
 447                 ///
 448                 /// <remarks>
 449                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 450                 ///   checking and assertion checking on what we expect from Resolve
 451                 /// </remarks>
 452                 public Expression ResolveLValue (EmitContext ec, Expression right_side)
 453                 {
 454                         Expression e = DoResolveLValue (ec, right_side);
 455
 456                         if (e != null){
 457                                 if (e is SimpleName){
 458                                         SimpleName s = (SimpleName) e;
 459                                         MemberLookupFailed (ec, null, ec.ContainerType, s.Name,
 460                                                             ec.DeclSpace.Name, loc);
 461                                         return null;
 462                                 }
 463
 464                                 if (e.eclass == ExprClass.Invalid)
 465                                         throw new Exception ("Expression " + e +
 466                                                              " ExprClass is Invalid after resolve");
 467
 468                                 if (e.eclass == ExprClass.MethodGroup) {
 469                                         ((MethodGroupExpr) e).ReportUsageError ();
 470                                         return null;
 471                                 }
 472
 473                                 if (e.type == null)
 474                                         throw new Exception ("Expression " + e +
 475                                                              " did not set its type after Resolve");
 476                         }
 477
 478                         return e;
 479                 }
 480
 481                 /// <summary>
 482                 ///   Emits the code for the expression
 483                 /// </summary>
 484                 ///
 485                 /// <remarks>
 486                 ///   The Emit method is invoked to generate the code
 487                 ///   for the expression.
 488                 /// </remarks>
 489                 public abstract void Emit (EmitContext ec);
 490
 491                 public virtual void EmitBranchable (EmitContext ec, Label target, bool onTrue)
 492                 {
 493                         Emit (ec);
 494                         ec.ig.Emit (onTrue ? OpCodes.Brtrue : OpCodes.Brfalse, target);
 495                 }
 496
 497                 /// <summary>
 498                 ///   Protected constructor.  Only derivate types should
 499                 ///   be able to be created
 500                 /// </summary>
 501
 502                 protected Expression ()
 503                 {
 504                         eclass = ExprClass.Invalid;
 505                         type = null;
 506                 }
 507
 508                 /// <summary>
 509                 ///   Returns a literalized version of a literal FieldInfo
 510                 /// </summary>
 511                 ///
 512                 /// <remarks>
 513                 ///   The possible return values are:
 514                 ///      IntConstant, UIntConstant
 515                 ///      LongLiteral, ULongConstant
 516                 ///      FloatConstant, DoubleConstant
 517                 ///      StringConstant
 518                 ///
 519                 ///   The value returned is already resolved.
 520                 /// </remarks>
 521                 public static Constant Constantify (object v, Type t)
 522                 {
 523                         if (t == TypeManager.int32_type)
 524                                 return new IntConstant ((int) v);
 525                         else if (t == TypeManager.uint32_type)
 526                                 return new UIntConstant ((uint) v);
 527                         else if (t == TypeManager.int64_type)
 528                                 return new LongConstant ((long) v);
 529                         else if (t == TypeManager.uint64_type)
 530                                 return new ULongConstant ((ulong) v);
 531                         else if (t == TypeManager.float_type)
 532                                 return new FloatConstant ((float) v);
 533                         else if (t == TypeManager.double_type)
 534                                 return new DoubleConstant ((double) v);
 535                         else if (t == TypeManager.string_type)
 536                                 return new StringConstant ((string) v);
 537                         else if (t == TypeManager.short_type)
 538                                 return new ShortConstant ((short)v);
 539                         else if (t == TypeManager.ushort_type)
 540                                 return new UShortConstant ((ushort)v);
 541                         else if (t == TypeManager.sbyte_type)
 542                                 return new SByteConstant (((sbyte)v));
 543                         else if (t == TypeManager.byte_type)
 544                                 return new ByteConstant ((byte)v);
 545                         else if (t == TypeManager.char_type)
 546                                 return new CharConstant ((char)v);
 547                         else if (t == TypeManager.bool_type)
 548                                 return new BoolConstant ((bool) v);
 549                         else if (t == TypeManager.decimal_type)
 550                                 return new DecimalConstant ((decimal) v);
 551                         else if (TypeManager.IsEnumType (t)){
 552                                 Type real_type = TypeManager.TypeToCoreType (v.GetType ());
 553                                 if (real_type == t)
 554                                         real_type = System.Enum.GetUnderlyingType (real_type);
 555
 556                                 Constant e = Constantify (v, real_type);
 557
 558                                 return new EnumConstant (e, t);
 559                         } else if (v == null && !TypeManager.IsValueType (t))
 560                                 return NullLiteral.Null;
 561                         else
 562                                 throw new Exception ("Unknown type for constant (" + t +
 563                                                      "), details: " + v);
 564                 }
 565
 566                 /// <summary>
 567                 ///   Returns a fully formed expression after a MemberLookup
 568                 /// </summary>
 569                 public static Expression ExprClassFromMemberInfo (EmitContext ec, MemberInfo mi, Location loc)
 570                 {
 571                         if (mi is EventInfo)
 572                                 return new EventExpr ((EventInfo) mi, loc);
 573                         else if (mi is FieldInfo)
 574                                 return new FieldExpr ((FieldInfo) mi, loc);
 575                         else if (mi is PropertyInfo)
 576                                 return new PropertyExpr (ec, (PropertyInfo) mi, loc);
 577                         else if (mi is Type){
 578                                 return new TypeExpression ((System.Type) mi, loc);
 579                         }
 580
 581                         return null;
 582                 }
 583
 584                 protected static ArrayList almostMatchedMembers = new ArrayList (4);
 585
 586                 //
 587                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 588                 //
 589                 // This code could use some optimizations, but we need to do some
 590                 // measurements.  For example, we could use a delegate to `flag' when
 591                 // something can not any longer be a method-group (because it is something
 592                 // else).
 593                 //
 594                 // Return values:
 595                 //     If the return value is an Array, then it is an array of
 596                 //     MethodBases
 597                 //
 598                 //     If the return value is an MemberInfo, it is anything, but a Method
 599                 //
 600                 //     null on error.
 601                 //
 602                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 603                 // the arguments here and have MemberLookup return only the methods that
 604                 // match the argument count/type, unlike we are doing now (we delay this
 605                 // decision).
 606                 //
 607                 // This is so we can catch correctly attempts to invoke instance methods
 608                 // from a static body (scan for error 120 in ResolveSimpleName).
 609                 //
 610                 //
 611                 // FIXME: Potential optimization, have a static ArrayList
 612                 //
 613
 614                 public static Expression MemberLookup (EmitContext ec, Type queried_type, string name,
 615                                                        MemberTypes mt, BindingFlags bf, Location loc)
 616                 {
 617                         return MemberLookup (ec, ec.ContainerType, null, queried_type, name, mt, bf, loc);
 618                 }
 619
 620                 //
 621                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 622                 // `qualifier_type' or null to lookup members in the current class.
 623                 //
 624
 625                 public static Expression MemberLookup (EmitContext ec, Type container_type,
 626                                                        Type qualifier_type, Type queried_type,
 627                                                        string name, MemberTypes mt,
 628                                                        BindingFlags bf, Location loc)
 629                 {
 630                         almostMatchedMembers.Clear ();
 631
 632                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 633                                                                      queried_type, mt, bf, name, almostMatchedMembers);
 634
 635                         if (mi == null)
 636                                 return null;
 637
 638                         int count = mi.Length;
 639
 640                         if (mi [0] is MethodBase)
 641                                 return new MethodGroupExpr (mi, loc);
 642
 643                         if (count > 1)
 644                                 return null;
 645
 646                         return ExprClassFromMemberInfo (ec, mi [0], loc);
 647                 }
 648
 649                 public const MemberTypes AllMemberTypes =
 650                         MemberTypes.Constructor |
 651                         MemberTypes.Event       |
 652                         MemberTypes.Field       |
 653                         MemberTypes.Method      |
 654                         MemberTypes.NestedType  |
 655                         MemberTypes.Property;
 656
 657                 public const BindingFlags AllBindingFlags =
 658                         BindingFlags.Public |
 659                         BindingFlags.Static |
 660                         BindingFlags.Instance;
 661
 662                 public static Expression MemberLookup (EmitContext ec, Type queried_type,
 663                                                        string name, Location loc)
 664                 {
 665                         return MemberLookup (ec, ec.ContainerType, null, queried_type, name,
 666                                              AllMemberTypes, AllBindingFlags, loc);
 667                 }
 668
 669                 public static Expression MemberLookup (EmitContext ec, Type qualifier_type,
 670                                                        Type queried_type, string name, Location loc)
 671                 {
 672                         return MemberLookup (ec, ec.ContainerType, qualifier_type, queried_type,
 673                                              name, AllMemberTypes, AllBindingFlags, loc);
 674                 }
 675
 676                 public static Expression MethodLookup (EmitContext ec, Type queried_type,
 677                                                        string name, Location loc)
 678                 {
 679                         return MemberLookup (ec, ec.ContainerType, null, queried_type, name,
 680                                              MemberTypes.Method, AllBindingFlags, loc);
 681                 }
 682
 683                 /// <summary>
 684                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 685                 ///   to find a final definition.  If the final definition is not found, we
 686                 ///   look for private members and display a useful debugging message if we
 687                 ///   find it.
 688                 /// </summary>
 689                 public static Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 690                                                             Type queried_type, string name, Location loc)
 691                 {
 692                         return MemberLookupFinal (ec, qualifier_type, queried_type, name,
 693                                                   AllMemberTypes, AllBindingFlags, loc);
 694                 }
 695
 696                 public static Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 697                                                             Type queried_type, string name,
 698                                                             MemberTypes mt, BindingFlags bf,
 699                                                             Location loc)
 700                 {
 701                         Expression e;
 702
 703                         int errors = Report.Errors;
 704
 705                         e = MemberLookup (ec, ec.ContainerType, qualifier_type, queried_type, name, mt, bf, loc);
 706
 707                         if (e == null && errors == Report.Errors)
 708                                 // No errors were reported by MemberLookup, but there was an error.
 709                                 MemberLookupFailed (ec, qualifier_type, queried_type, name, null, loc);
 710
 711                         return e;
 712                 }
 713
 714                 public static void MemberLookupFailed (EmitContext ec, Type qualifier_type,
 715                                                        Type queried_type, string name,
 716                                                        string class_name, Location loc)
 717                 {
 718                         if (almostMatchedMembers.Count != 0) {
 719                                 if (qualifier_type == null) {
 720                                         foreach (MemberInfo m in almostMatchedMembers)
 721                                                 Report.Error (38, loc,
 722                                                               "Cannot access non-static member `{0}' via nested type `{1}'",
 723                                                               TypeManager.GetFullNameSignature (m),
 724                                                               TypeManager.CSharpName (ec.ContainerType));
 725                                         return;
 726                                 }
 727
 728                                 if (qualifier_type != ec.ContainerType) {
 729                                         // Although a derived class can access protected members of
 730                                         // its base class it cannot do so through an instance of the
 731                                         // base class (CS1540).  If the qualifier_type is a base of the
 732                                         // ec.ContainerType and the lookup succeeds with the latter one,
 733                                         // then we are in this situation.
 734                                         for (int i = 0; i < almostMatchedMembers.Count; ++i) {
 735                                                 MemberInfo m = (MemberInfo) almostMatchedMembers [i];
 736                                                 for (int j = 0; j < i; ++j) {
 737                                                         if (m == almostMatchedMembers [j]) {
 738                                                                 m = null;
 739                                                                 break;
 740                                                         }
 741                                                 }
 742                                                 if (m == null)
 743                                                         continue;
 744
 745                                                 Report.SymbolRelatedToPreviousError (m);
 746                                                 Report.Error (1540, loc,
 747                                                               "Cannot access protected member `{0}' via a qualifier of type `{1}';"
 748                                                               + " the qualifier must be of type `{2}' (or derived from it)",
 749                                                               TypeManager.GetFullNameSignature (m),
 750                                                               TypeManager.CSharpName (qualifier_type),
 751                                                               TypeManager.CSharpName (ec.ContainerType));
 752                                         }
 753                                         return;
 754                                 }
 755                                 almostMatchedMembers.Clear ();
 756                         }
 757
 758                         object lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 759                                                                   AllMemberTypes, AllBindingFlags |
 760                                                                   BindingFlags.NonPublic, name, null);
 761
 762                         if (lookup == null) {
 763                                 if (class_name != null)
 764                                         Report.Error (103, loc, "The name `" + name + "' could not be " +
 765                                                       "found in `" + class_name + "'");
 766                                 else
 767                                         Report.Error (
 768                                                 117, loc, "`" + queried_type + "' does not contain a " +
 769                                                 "definition for `" + name + "'");
 770                                 return;
 771                         }
 772
 773                         if (name == ".ctor" && TypeManager.FindMembers (qualifier_type, MemberTypes.Constructor,
 774                                 BindingFlags.Static | BindingFlags.Instance | BindingFlags.Public | BindingFlags.DeclaredOnly, null, null).Count == 0)
 775                         {
 776                                 Report.Error (143, loc, String.Format ("The type '{0}' has no constructors defined", TypeManager.CSharpName (queried_type)));
 777                                 return;
 778                         }
 779
 780                         if (qualifier_type != null) {
 781                                 Report.Error (122, loc, "'{0}' is inaccessible due to its protection level", TypeManager.CSharpName (qualifier_type) + "." + name);
 782                         } else {
 783                                 Report.Error (122, loc, "'{0}' is inaccessible due to its protection level", name);
 784                         }
 785                 }
 786
 787                 static public MemberInfo GetFieldFromEvent (EventExpr event_expr)
 788                 {
 789                         EventInfo ei = event_expr.EventInfo;
 790
 791                         return TypeManager.GetPrivateFieldOfEvent (ei);
 792                 }
 793
 794                 /// <summary>
 795                 ///   Returns an expression that can be used to invoke operator true
 796                 ///   on the expression if it exists.
 797                 /// </summary>
 798                 static public StaticCallExpr GetOperatorTrue (EmitContext ec, Expression e, Location loc)
 799                 {
 800                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 801                 }
 802
 803                 /// <summary>
 804                 ///   Returns an expression that can be used to invoke operator false
 805                 ///   on the expression if it exists.
 806                 /// </summary>
 807                 static public StaticCallExpr GetOperatorFalse (EmitContext ec, Expression e, Location loc)
 808                 {
 809                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 810                 }
 811
 812                 static StaticCallExpr GetOperatorTrueOrFalse (EmitContext ec, Expression e, bool is_true, Location loc)
 813                 {
 814                         MethodBase method;
 815                         Expression operator_group;
 816
 817                         operator_group = MethodLookup (ec, e.Type, is_true ? "op_True" : "op_False", loc);
 818                         if (operator_group == null)
 819                                 return null;
 820
 821                         ArrayList arguments = new ArrayList ();
 822                         arguments.Add (new Argument (e, Argument.AType.Expression));
 823                         method = Invocation.OverloadResolve (
 824                                 ec, (MethodGroupExpr) operator_group, arguments, false, loc);
 825
 826                         if (method == null)
 827                                 return null;
 828
 829                         return new StaticCallExpr ((MethodInfo) method, arguments, loc);
 830                 }
 831
 832                 /// <summary>
 833                 ///   Resolves the expression `e' into a boolean expression: either through
 834                 ///   an implicit conversion, or through an `operator true' invocation
 835                 /// </summary>
 836                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 837                 {
 838                         e = e.Resolve (ec);
 839                         if (e == null)
 840                                 return null;
 841
 842                         if (e.Type == TypeManager.bool_type)
 843                                 return e;
 844
 845                         Expression converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, new Location (-1));
 846
 847                         if (converted != null)
 848                                 return converted;
 849
 850                         //
 851                         // If no implicit conversion to bool exists, try using `operator true'
 852                         //
 853                         Expression operator_true = Expression.GetOperatorTrue (ec, e, loc);
 854                         if (operator_true == null){
 855                                 Report.Error (31, loc, "Can not convert the expression to a boolean");
 856                                 return null;
 857                         }
 858                         return operator_true;
 859                 }
 860
 861                 public string ExprClassName ()
 862                 {
 863                         switch (eclass){
 864                         case ExprClass.Invalid:
 865                                 return "Invalid";
 866                         case ExprClass.Value:
 867                                 return "value";
 868                         case ExprClass.Variable:
 869                                 return "variable";
 870                         case ExprClass.Namespace:
 871                                 return "namespace";
 872                         case ExprClass.Type:
 873                                 return "type";
 874                         case ExprClass.MethodGroup:
 875                                 return "method group";
 876                         case ExprClass.PropertyAccess:
 877                                 return "property access";
 878                         case ExprClass.EventAccess:
 879                                 return "event access";
 880                         case ExprClass.IndexerAccess:
 881                                 return "indexer access";
 882                         case ExprClass.Nothing:
 883                                 return "null";
 884                         }
 885                         throw new Exception ("Should not happen");
 886                 }
 887
 888                 /// <summary>
 889                 ///   Reports that we were expecting `expr' to be of class `expected'
 890                 /// </summary>
 891                 public void Error_UnexpectedKind (string expected, Location loc)
 892                 {
 893                         Report.Error (118, loc, "Expression denotes a `" + ExprClassName () +
 894                                "' where a `" + expected + "' was expected");
 895                 }
 896
 897                 public void Error_UnexpectedKind (ResolveFlags flags, Location loc)
 898                 {
 899                         ArrayList valid = new ArrayList (10);
 900
 901                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
 902                                 valid.Add ("variable");
 903                                 valid.Add ("value");
 904                         }
 905
 906                         if ((flags & ResolveFlags.Type) != 0)
 907                                 valid.Add ("type");
 908
 909                         if ((flags & ResolveFlags.MethodGroup) != 0)
 910                                 valid.Add ("method group");
 911
 912                         if (valid.Count == 0)
 913                                 valid.Add ("unknown");
 914
 915                         StringBuilder sb = new StringBuilder ();
 916                         for (int i = 0; i < valid.Count; i++) {
 917                                 if (i > 0)
 918                                         sb.Append (", ");
 919                                 else if (i == valid.Count)
 920                                         sb.Append (" or ");
 921                                 sb.Append (valid [i]);
 922                         }
 923
 924                         Error (119, "Expression denotes a `" + ExprClassName () + "' where " +
 925                                "a `" + sb.ToString () + "' was expected");
 926                 }
 927
 928                 static public void Error_ConstantValueCannotBeConverted (Location l, string val, Type t)
 929                 {
 930                         Report.Error (31, l, "Constant value `" + val + "' cannot be converted to " +
 931                                       TypeManager.CSharpName (t));
 932                 }
 933
 934                 public static void UnsafeError (Location loc)
 935                 {
 936                         Report.Error (214, loc, "Pointers may only be used in an unsafe context");
 937                 }
 938
 939                 /// <summary>
 940                 ///   Converts the IntConstant, UIntConstant, LongConstant or
 941                 ///   ULongConstant into the integral target_type.   Notice
 942                 ///   that we do not return an `Expression' we do return
 943                 ///   a boxed integral type.
 944                 ///
 945                 ///   FIXME: Since I added the new constants, we need to
 946                 ///   also support conversions from CharConstant, ByteConstant,
 947                 ///   SByteConstant, UShortConstant, ShortConstant
 948                 ///
 949                 ///   This is used by the switch statement, so the domain
 950                 ///   of work is restricted to the literals above, and the
 951                 ///   targets are int32, uint32, char, byte, sbyte, ushort,
 952                 ///   short, uint64 and int64
 953                 /// </summary>
 954                 public static object ConvertIntLiteral (Constant c, Type target_type, Location loc)
 955                 {
 956                         if (!Convert.ImplicitStandardConversionExists (Convert.ConstantEC, c, target_type)){
 957                                 Convert.Error_CannotImplicitConversion (loc, c.Type, target_type);
 958                                 return null;
 959                         }
 960
 961                         string s = "";
 962
 963                         if (c.Type == target_type)
 964                                 return ((Constant) c).GetValue ();
 965
 966                         //
 967                         // Make into one of the literals we handle, we dont really care
 968                         // about this value as we will just return a few limited types
 969                         //
 970                         if (c is EnumConstant)
 971                                 c = ((EnumConstant)c).WidenToCompilerConstant ();
 972
 973                         if (c is IntConstant){
 974                                 int v = ((IntConstant) c).Value;
 975
 976                                 if (target_type == TypeManager.uint32_type){
 977                                         if (v >= 0)
 978                                                 return (uint) v;
 979                                 } else if (target_type == TypeManager.char_type){
 980                                         if (v >= Char.MinValue && v <= Char.MaxValue)
 981                                                 return (char) v;
 982                                 } else if (target_type == TypeManager.byte_type){
 983                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
 984                                                 return (byte) v;
 985                                 } else if (target_type == TypeManager.sbyte_type){
 986                                         if (v >= SByte.MinValue && v <= SByte.MaxValue)
 987                                                 return (sbyte) v;
 988                                 } else if (target_type == TypeManager.short_type){
 989                                         if (v >= Int16.MinValue && v <= UInt16.MaxValue)
 990                                                 return (short) v;
 991                                 } else if (target_type == TypeManager.ushort_type){
 992                                         if (v >= UInt16.MinValue && v <= UInt16.MaxValue)
 993                                                 return (ushort) v;
 994                                 } else if (target_type == TypeManager.int64_type)
 995                                         return (long) v;
 996                                 else if (target_type == TypeManager.uint64_type){
 997                                         if (v > 0)
 998                                                 return (ulong) v;
 999                                 }
1000
1001                                 s = v.ToString ();
1002                         } else if (c is UIntConstant){
1003                                 uint v = ((UIntConstant) c).Value;
1004
1005                                 if (target_type == TypeManager.int32_type){
1006                                         if (v <= Int32.MaxValue)
1007                                                 return (int) v;
1008                                 } else if (target_type == TypeManager.char_type){
1009                                         if (v >= Char.MinValue && v <= Char.MaxValue)
1010                                                 return (char) v;
1011                                 } else if (target_type == TypeManager.byte_type){
1012                                         if (v <= Byte.MaxValue)
1013                                                 return (byte) v;
1014                                 } else if (target_type == TypeManager.sbyte_type){
1015                                         if (v <= SByte.MaxValue)
1016                                                 return (sbyte) v;
1017                                 } else if (target_type == TypeManager.short_type){
1018                                         if (v <= UInt16.MaxValue)
1019                                                 return (short) v;
1020                                 } else if (target_type == TypeManager.ushort_type){
1021                                         if (v <= UInt16.MaxValue)
1022                                                 return (ushort) v;
1023                                 } else if (target_type == TypeManager.int64_type)
1024                                         return (long) v;
1025                                 else if (target_type == TypeManager.uint64_type)
1026                                         return (ulong) v;
1027                                 s = v.ToString ();
1028                         } else if (c is LongConstant){
1029                                 long v = ((LongConstant) c).Value;
1030
1031                                 if (target_type == TypeManager.int32_type){
1032                                         if (v >= UInt32.MinValue && v <= UInt32.MaxValue)
1033                                                 return (int) v;
1034                                 } else if (target_type == TypeManager.uint32_type){
1035                                         if (v >= 0 && v <= UInt32.MaxValue)
1036                                                 return (uint) v;
1037                                 } else if (target_type == TypeManager.char_type){
1038                                         if (v >= Char.MinValue && v <= Char.MaxValue)
1039                                                 return (char) v;
1040                                 } else if (target_type == TypeManager.byte_type){
1041                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1042                                                 return (byte) v;
1043                                 } else if (target_type == TypeManager.sbyte_type){
1044                                         if (v >= SByte.MinValue && v <= SByte.MaxValue)
1045                                                 return (sbyte) v;
1046                                 } else if (target_type == TypeManager.short_type){
1047                                         if (v >= Int16.MinValue && v <= UInt16.MaxValue)
1048                                                 return (short) v;
1049                                 } else if (target_type == TypeManager.ushort_type){
1050                                         if (v >= UInt16.MinValue && v <= UInt16.MaxValue)
1051                                                 return (ushort) v;
1052                                 } else if (target_type == TypeManager.uint64_type){
1053                                         if (v > 0)
1054                                                 return (ulong) v;
1055                                 }
1056                                 s = v.ToString ();
1057                         } else if (c is ULongConstant){
1058                                 ulong v = ((ULongConstant) c).Value;
1059
1060                                 if (target_type == TypeManager.int32_type){
1061                                         if (v <= Int32.MaxValue)
1062                                                 return (int) v;
1063                                 } else if (target_type == TypeManager.uint32_type){
1064                                         if (v <= UInt32.MaxValue)
1065                                                 return (uint) v;
1066                                 } else if (target_type == TypeManager.char_type){
1067                                         if (v >= Char.MinValue && v <= Char.MaxValue)
1068                                                 return (char) v;
1069                                 } else if (target_type == TypeManager.byte_type){
1070                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1071                                                 return (byte) v;
1072                                 } else if (target_type == TypeManager.sbyte_type){
1073                                         if (v <= (int) SByte.MaxValue)
1074                                                 return (sbyte) v;
1075                                 } else if (target_type == TypeManager.short_type){
1076                                         if (v <= UInt16.MaxValue)
1077                                                 return (short) v;
1078                                 } else if (target_type == TypeManager.ushort_type){
1079                                         if (v <= UInt16.MaxValue)
1080                                                 return (ushort) v;
1081                                 } else if (target_type == TypeManager.int64_type){
1082                                         if (v <= Int64.MaxValue)
1083                                                 return (long) v;
1084                                 }
1085                                 s = v.ToString ();
1086                         } else if (c is ByteConstant){
1087                                 byte v = ((ByteConstant) c).Value;
1088
1089                                 if (target_type == TypeManager.int32_type)
1090                                         return (int) v;
1091                                 else if (target_type == TypeManager.uint32_type)
1092                                         return (uint) v;
1093                                 else if (target_type == TypeManager.char_type)
1094                                         return (char) v;
1095                                 else if (target_type == TypeManager.sbyte_type){
1096                                         if (v <= SByte.MaxValue)
1097                                                 return (sbyte) v;
1098                                 } else if (target_type == TypeManager.short_type)
1099                                         return (short) v;
1100                                 else if (target_type == TypeManager.ushort_type)
1101                                         return (ushort) v;
1102                                 else if (target_type == TypeManager.int64_type)
1103                                         return (long) v;
1104                                 else if (target_type == TypeManager.uint64_type)
1105                                         return (ulong) v;
1106                                 s = v.ToString ();
1107                         } else if (c is SByteConstant){
1108                                 sbyte v = ((SByteConstant) c).Value;
1109
1110                                 if (target_type == TypeManager.int32_type)
1111                                         return (int) v;
1112                                 else if (target_type == TypeManager.uint32_type){
1113                                         if (v >= 0)
1114                                                 return (uint) v;
1115                                 } else if (target_type == TypeManager.char_type){
1116                                         if (v >= 0)
1117                                                 return (char) v;
1118                                 } else if (target_type == TypeManager.byte_type){
1119                                         if (v >= 0)
1120                                                 return (byte) v;
1121                                 } else if (target_type == TypeManager.short_type)
1122                                         return (short) v;
1123                                 else if (target_type == TypeManager.ushort_type){
1124                                         if (v >= 0)
1125                                                 return (ushort) v;
1126                                 } else if (target_type == TypeManager.int64_type)
1127                                         return (long) v;
1128                                 else if (target_type == TypeManager.uint64_type){
1129                                         if (v >= 0)
1130                                                 return (ulong) v;
1131                                 }
1132                                 s = v.ToString ();
1133                         } else if (c is ShortConstant){
1134                                 short v = ((ShortConstant) c).Value;
1135
1136                                 if (target_type == TypeManager.int32_type){
1137                                         return (int) v;
1138                                 } else if (target_type == TypeManager.uint32_type){
1139                                         if (v >= 0)
1140                                                 return (uint) v;
1141                                 } else if (target_type == TypeManager.char_type){
1142                                         if (v >= 0)
1143                                                 return (char) v;
1144                                 } else if (target_type == TypeManager.byte_type){
1145                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1146                                                 return (byte) v;
1147                                 } else if (target_type == TypeManager.sbyte_type){
1148                                         if (v >= SByte.MinValue && v <= SByte.MaxValue)
1149                                                 return (sbyte) v;
1150                                 } else if (target_type == TypeManager.ushort_type){
1151                                         if (v >= 0)
1152                                                 return (ushort) v;
1153                                 } else if (target_type == TypeManager.int64_type)
1154                                         return (long) v;
1155                                 else if (target_type == TypeManager.uint64_type)
1156                                         return (ulong) v;
1157
1158                                 s = v.ToString ();
1159                         } else if (c is UShortConstant){
1160                                 ushort v = ((UShortConstant) c).Value;
1161
1162                                 if (target_type == TypeManager.int32_type)
1163                                         return (int) v;
1164                                 else if (target_type == TypeManager.uint32_type)
1165                                         return (uint) v;
1166                                 else if (target_type == TypeManager.char_type){
1167                                         if (v >= Char.MinValue && v <= Char.MaxValue)
1168                                                 return (char) v;
1169                                 } else if (target_type == TypeManager.byte_type){
1170                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1171                                                 return (byte) v;
1172                                 } else if (target_type == TypeManager.sbyte_type){
1173                                         if (v <= SByte.MaxValue)
1174                                                 return (byte) v;
1175                                 } else if (target_type == TypeManager.short_type){
1176                                         if (v <= Int16.MaxValue)
1177                                                 return (short) v;
1178                                 } else if (target_type == TypeManager.int64_type)
1179                                         return (long) v;
1180                                 else if (target_type == TypeManager.uint64_type)
1181                                         return (ulong) v;
1182
1183                                 s = v.ToString ();
1184                         } else if (c is CharConstant){
1185                                 char v = ((CharConstant) c).Value;
1186
1187                                 if (target_type == TypeManager.int32_type)
1188                                         return (int) v;
1189                                 else if (target_type == TypeManager.uint32_type)
1190                                         return (uint) v;
1191                                 else if (target_type == TypeManager.byte_type){
1192                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1193                                                 return (byte) v;
1194                                 } else if (target_type == TypeManager.sbyte_type){
1195                                         if (v <= SByte.MaxValue)
1196                                                 return (sbyte) v;
1197                                 } else if (target_type == TypeManager.short_type){
1198                                         if (v <= Int16.MaxValue)
1199                                                 return (short) v;
1200                                 } else if (target_type == TypeManager.ushort_type)
1201                                         return (short) v;
1202                                 else if (target_type == TypeManager.int64_type)
1203                                         return (long) v;
1204                                 else if (target_type == TypeManager.uint64_type)
1205                                         return (ulong) v;
1206
1207                                 s = v.ToString ();
1208                         }
1209                         Error_ConstantValueCannotBeConverted (loc, s, target_type);
1210                         return null;
1211                 }
1212
1213                 //
1214                 // Load the object from the pointer.
1215                 //
1216                 public static void LoadFromPtr (ILGenerator ig, Type t)
1217                 {
1218                         if (t == TypeManager.int32_type)
1219                                 ig.Emit (OpCodes.Ldind_I4);
1220                         else if (t == TypeManager.uint32_type)
1221                                 ig.Emit (OpCodes.Ldind_U4);
1222                         else if (t == TypeManager.short_type)
1223                                 ig.Emit (OpCodes.Ldind_I2);
1224                         else if (t == TypeManager.ushort_type)
1225                                 ig.Emit (OpCodes.Ldind_U2);
1226                         else if (t == TypeManager.char_type)
1227                                 ig.Emit (OpCodes.Ldind_U2);
1228                         else if (t == TypeManager.byte_type)
1229                                 ig.Emit (OpCodes.Ldind_U1);
1230                         else if (t == TypeManager.sbyte_type)
1231                                 ig.Emit (OpCodes.Ldind_I1);
1232                         else if (t == TypeManager.uint64_type)
1233                                 ig.Emit (OpCodes.Ldind_I8);
1234                         else if (t == TypeManager.int64_type)
1235                                 ig.Emit (OpCodes.Ldind_I8);
1236                         else if (t == TypeManager.float_type)
1237                                 ig.Emit (OpCodes.Ldind_R4);
1238                         else if (t == TypeManager.double_type)
1239                                 ig.Emit (OpCodes.Ldind_R8);
1240                         else if (t == TypeManager.bool_type)
1241                                 ig.Emit (OpCodes.Ldind_I1);
1242                         else if (t == TypeManager.intptr_type)
1243                                 ig.Emit (OpCodes.Ldind_I);
1244                         else if (TypeManager.IsEnumType (t)) {
1245                                 if (t == TypeManager.enum_type)
1246                                         ig.Emit (OpCodes.Ldind_Ref);
1247                                 else
1248                                         LoadFromPtr (ig, TypeManager.EnumToUnderlying (t));
1249                         } else if (t.IsValueType)
1250                                 ig.Emit (OpCodes.Ldobj, t);
1251                         else if (t.IsPointer)
1252                                 ig.Emit (OpCodes.Ldind_I);
1253                         else
1254                                 ig.Emit (OpCodes.Ldind_Ref);
1255                 }
1256
1257                 //
1258                 // The stack contains the pointer and the value of type `type'
1259                 //
1260                 public static void StoreFromPtr (ILGenerator ig, Type type)
1261                 {
1262                         if (TypeManager.IsEnumType (type))
1263                                 type = TypeManager.EnumToUnderlying (type);
1264                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1265                                 ig.Emit (OpCodes.Stind_I4);
1266                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1267                                 ig.Emit (OpCodes.Stind_I8);
1268                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1269                                  type == TypeManager.ushort_type)
1270                                 ig.Emit (OpCodes.Stind_I2);
1271                         else if (type == TypeManager.float_type)
1272                                 ig.Emit (OpCodes.Stind_R4);
1273                         else if (type == TypeManager.double_type)
1274                                 ig.Emit (OpCodes.Stind_R8);
1275                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1276                                  type == TypeManager.bool_type)
1277                                 ig.Emit (OpCodes.Stind_I1);
1278                         else if (type == TypeManager.intptr_type)
1279                                 ig.Emit (OpCodes.Stind_I);
1280                         else if (type.IsValueType)
1281                                 ig.Emit (OpCodes.Stobj, type);
1282                         else
1283                                 ig.Emit (OpCodes.Stind_Ref);
1284                 }
1285
1286                 //
1287                 // Returns the size of type `t' if known, otherwise, 0
1288                 //
1289                 public static int GetTypeSize (Type t)
1290                 {
1291                         t = TypeManager.TypeToCoreType (t);
1292                         if (t == TypeManager.int32_type ||
1293                             t == TypeManager.uint32_type ||
1294                             t == TypeManager.float_type)
1295                                 return 4;
1296                         else if (t == TypeManager.int64_type ||
1297                                  t == TypeManager.uint64_type ||
1298                                  t == TypeManager.double_type)
1299                                 return 8;
1300                         else if (t == TypeManager.byte_type ||
1301                                  t == TypeManager.sbyte_type ||
1302                                  t == TypeManager.bool_type)
1303                                 return 1;
1304                         else if (t == TypeManager.short_type ||
1305                                  t == TypeManager.char_type ||
1306                                  t == TypeManager.ushort_type)
1307                                 return 2;
1308                         else if (t == TypeManager.decimal_type)
1309                                 return 16;
1310                         else
1311                                 return 0;
1312                 }
1313
1314                 public static void Error_NegativeArrayIndex (Location loc)
1315                 {
1316                         Report.Error (248, loc, "Cannot create an array with a negative size");
1317                 }
1318
1319                 //
1320                 // Converts `source' to an int, uint, long or ulong.
1321                 //
1322                 public Expression ExpressionToArrayArgument (EmitContext ec, Expression source, Location loc)
1323                 {
1324                         Expression target;
1325
1326                         bool old_checked = ec.CheckState;
1327                         ec.CheckState = true;
1328
1329                         target = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, loc);
1330                         if (target == null){
1331                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, loc);
1332                                 if (target == null){
1333                                         target = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, loc);
1334                                         if (target == null){
1335                                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, loc);
1336                                                 if (target == null)
1337                                                         Convert.Error_CannotImplicitConversion (loc, source.Type, TypeManager.int32_type);
1338                                         }
1339                                 }
1340                         }
1341                         ec.CheckState = old_checked;
1342
1343                         //
1344                         // Only positive constants are allowed at compile time
1345                         //
1346                         if (target is Constant){
1347                                 if (target is IntConstant){
1348                                         if (((IntConstant) target).Value < 0){
1349                                                 Error_NegativeArrayIndex (loc);
1350                                                 return null;
1351                                         }
1352                                 }
1353
1354                                 if (target is LongConstant){
1355                                         if (((LongConstant) target).Value < 0){
1356                                                 Error_NegativeArrayIndex (loc);
1357                                                 return null;
1358                                         }
1359                                 }
1360
1361                         }
1362
1363                         return target;
1364                 }
1365
1366         }
1367
1368         /// <summary>
1369         ///   This is just a base class for expressions that can
1370         ///   appear on statements (invocations, object creation,
1371         ///   assignments, post/pre increment and decrement).  The idea
1372         ///   being that they would support an extra Emition interface that
1373         ///   does not leave a result on the stack.
1374         /// </summary>
1375         public abstract class ExpressionStatement : Expression {
1376
1377                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1378                 {
1379                         Expression e = Resolve (ec);
1380                         if (e == null)
1381                                 return null;
1382
1383                         ExpressionStatement es = e as ExpressionStatement;
1384                         if (es == null)
1385                                 Error (201, "Only assignment, call, increment, decrement and new object " +
1386                                        "expressions can be used as a statement");
1387
1388                         return es;
1389                 }
1390
1391                 /// <summary>
1392                 ///   Requests the expression to be emitted in a `statement'
1393                 ///   context.  This means that no new value is left on the
1394                 ///   stack after invoking this method (constrasted with
1395                 ///   Emit that will always leave a value on the stack).
1396                 /// </summary>
1397                 public abstract void EmitStatement (EmitContext ec);
1398         }
1399
1400         /// <summary>
1401         ///   This kind of cast is used to encapsulate the child
1402         ///   whose type is child.Type into an expression that is
1403         ///   reported to return "return_type".  This is used to encapsulate
1404         ///   expressions which have compatible types, but need to be dealt
1405         ///   at higher levels with.
1406         ///
1407         ///   For example, a "byte" expression could be encapsulated in one
1408         ///   of these as an "unsigned int".  The type for the expression
1409         ///   would be "unsigned int".
1410         ///
1411         /// </summary>
1412         public class EmptyCast : Expression {
1413                 protected Expression child;
1414
1415                 public Expression Child {
1416                         get {
1417                                 return child;
1418                         }
1419                 }
1420
1421                 public EmptyCast (Expression child, Type return_type)
1422                 {
1423                         eclass = child.eclass;
1424                         type = return_type;
1425                         this.child = child;
1426                 }
1427
1428                 public override Expression DoResolve (EmitContext ec)
1429                 {
1430                         // This should never be invoked, we are born in fully
1431                         // initialized state.
1432
1433                         return this;
1434                 }
1435
1436                 public override void Emit (EmitContext ec)
1437                 {
1438                         child.Emit (ec);
1439                 }
1440         }
1441
1442         //
1443         // We need to special case this since an empty cast of
1444         // a NullLiteral is still a Constant
1445         //
1446         public class NullCast : Constant {
1447                 protected Expression child;
1448
1449                 public NullCast (Expression child, Type return_type)
1450                 {
1451                         eclass = child.eclass;
1452                         type = return_type;
1453                         this.child = child;
1454                 }
1455
1456                 override public string AsString ()
1457                 {
1458                         return "null";
1459                 }
1460
1461                 public override object GetValue ()
1462                 {
1463                         return null;
1464                 }
1465
1466                 public override Expression DoResolve (EmitContext ec)
1467                 {
1468                         // This should never be invoked, we are born in fully
1469                         // initialized state.
1470
1471                         return this;
1472                 }
1473
1474                 public override void Emit (EmitContext ec)
1475                 {
1476                         child.Emit (ec);
1477                 }
1478
1479                 public override bool IsNegative {
1480                         get {
1481                                 return false;
1482                         }
1483                 }
1484         }
1485
1486
1487         /// <summary>
1488         ///  This class is used to wrap literals which belong inside Enums
1489         /// </summary>
1490         public class EnumConstant : Constant {
1491                 public Constant Child;
1492
1493                 public EnumConstant (Constant child, Type enum_type)
1494                 {
1495                         eclass = child.eclass;
1496                         this.Child = child;
1497                         type = enum_type;
1498                 }
1499
1500                 public override Expression DoResolve (EmitContext ec)
1501                 {
1502                         // This should never be invoked, we are born in fully
1503                         // initialized state.
1504
1505                         return this;
1506                 }
1507
1508                 public override void Emit (EmitContext ec)
1509                 {
1510                         Child.Emit (ec);
1511                 }
1512
1513                 public override object GetValue ()
1514                 {
1515                         return Child.GetValue ();
1516                 }
1517
1518                 public object GetValueAsEnumType ()
1519                 {
1520                         return System.Enum.ToObject (type, Child.GetValue ());
1521                 }
1522
1523                 //
1524                 // Converts from one of the valid underlying types for an enumeration
1525                 // (int32, uint32, int64, uint64, short, ushort, byte, sbyte) to
1526                 // one of the internal compiler literals: Int/UInt/Long/ULong Literals.
1527                 //
1528                 public Constant WidenToCompilerConstant ()
1529                 {
1530                         Type t = TypeManager.EnumToUnderlying (Child.Type);
1531                         object v = ((Constant) Child).GetValue ();;
1532
1533                         if (t == TypeManager.int32_type)
1534                                 return new IntConstant ((int) v);
1535                         if (t == TypeManager.uint32_type)
1536                                 return new UIntConstant ((uint) v);
1537                         if (t == TypeManager.int64_type)
1538                                 return new LongConstant ((long) v);
1539                         if (t == TypeManager.uint64_type)
1540                                 return new ULongConstant ((ulong) v);
1541                         if (t == TypeManager.short_type)
1542                                 return new ShortConstant ((short) v);
1543                         if (t == TypeManager.ushort_type)
1544                                 return new UShortConstant ((ushort) v);
1545                         if (t == TypeManager.byte_type)
1546                                 return new ByteConstant ((byte) v);
1547                         if (t == TypeManager.sbyte_type)
1548                                 return new SByteConstant ((sbyte) v);
1549
1550                         throw new Exception ("Invalid enumeration underlying type: " + t);
1551                 }
1552
1553                 //
1554                 // Extracts the value in the enumeration on its native representation
1555                 //
1556                 public object GetPlainValue ()
1557                 {
1558                         Type t = TypeManager.EnumToUnderlying (Child.Type);
1559                         object v = ((Constant) Child).GetValue ();;
1560
1561                         if (t == TypeManager.int32_type)
1562                                 return (int) v;
1563                         if (t == TypeManager.uint32_type)
1564                                 return (uint) v;
1565                         if (t == TypeManager.int64_type)
1566                                 return (long) v;
1567                         if (t == TypeManager.uint64_type)
1568                                 return (ulong) v;
1569                         if (t == TypeManager.short_type)
1570                                 return (short) v;
1571                         if (t == TypeManager.ushort_type)
1572                                 return (ushort) v;
1573                         if (t == TypeManager.byte_type)
1574                                 return (byte) v;
1575                         if (t == TypeManager.sbyte_type)
1576                                 return (sbyte) v;
1577
1578                         return null;
1579                 }
1580
1581                 public override string AsString ()
1582                 {
1583                         return Child.AsString ();
1584                 }
1585
1586                 public override DoubleConstant ConvertToDouble ()
1587                 {
1588                         return Child.ConvertToDouble ();
1589                 }
1590
1591                 public override FloatConstant ConvertToFloat ()
1592                 {
1593                         return Child.ConvertToFloat ();
1594                 }
1595
1596                 public override ULongConstant ConvertToULong ()
1597                 {
1598                         return Child.ConvertToULong ();
1599                 }
1600
1601                 public override LongConstant ConvertToLong ()
1602                 {
1603                         return Child.ConvertToLong ();
1604                 }
1605
1606                 public override UIntConstant ConvertToUInt ()
1607                 {
1608                         return Child.ConvertToUInt ();
1609                 }
1610
1611                 public override IntConstant ConvertToInt ()
1612                 {
1613                         return Child.ConvertToInt ();
1614                 }
1615
1616                 public override bool IsZeroInteger {
1617                         get { return Child.IsZeroInteger; }
1618                 }
1619
1620                 public override bool IsNegative {
1621                         get {
1622                                 return Child.IsNegative;
1623                         }
1624                 }
1625         }
1626
1627         /// <summary>
1628         ///   This kind of cast is used to encapsulate Value Types in objects.
1629         ///
1630         ///   The effect of it is to box the value type emitted by the previous
1631         ///   operation.
1632         /// </summary>
1633         public class BoxedCast : EmptyCast {
1634
1635                 public BoxedCast (Expression expr)
1636                         : base (expr, TypeManager.object_type)
1637                 {
1638                         eclass = ExprClass.Value;
1639                 }
1640
1641                 public BoxedCast (Expression expr, Type target_type)
1642                         : base (expr, target_type)
1643                 {
1644                         eclass = ExprClass.Value;
1645                 }
1646
1647                 public override Expression DoResolve (EmitContext ec)
1648                 {
1649                         // This should never be invoked, we are born in fully
1650                         // initialized state.
1651
1652                         return this;
1653                 }
1654
1655                 public override void Emit (EmitContext ec)
1656                 {
1657                         base.Emit (ec);
1658
1659                         ec.ig.Emit (OpCodes.Box, child.Type);
1660                 }
1661         }
1662
1663         public class UnboxCast : EmptyCast {
1664                 public UnboxCast (Expression expr, Type return_type)
1665                         : base (expr, return_type)
1666                 {
1667                 }
1668
1669                 public override Expression DoResolve (EmitContext ec)
1670                 {
1671                         // This should never be invoked, we are born in fully
1672                         // initialized state.
1673
1674                         return this;
1675                 }
1676
1677                 public override void Emit (EmitContext ec)
1678                 {
1679                         Type t = type;
1680                         ILGenerator ig = ec.ig;
1681
1682                         base.Emit (ec);
1683                         ig.Emit (OpCodes.Unbox, t);
1684
1685                         LoadFromPtr (ig, t);
1686                 }
1687         }
1688
1689         /// <summary>
1690         ///   This is used to perform explicit numeric conversions.
1691         ///
1692         ///   Explicit numeric conversions might trigger exceptions in a checked
1693         ///   context, so they should generate the conv.ovf opcodes instead of
1694         ///   conv opcodes.
1695         /// </summary>
1696         public class ConvCast : EmptyCast {
1697                 public enum Mode : byte {
1698                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1699                         U1_I1, U1_CH,
1700                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1701                         U2_I1, U2_U1, U2_I2, U2_CH,
1702                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1703                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1704                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH,
1705                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH,
1706                         CH_I1, CH_U1, CH_I2,
1707                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1708                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4
1709                 }
1710
1711                 Mode mode;
1712                 bool checked_state;
1713
1714                 public ConvCast (EmitContext ec, Expression child, Type return_type, Mode m)
1715                         : base (child, return_type)
1716                 {
1717                         checked_state = ec.CheckState;
1718                         mode = m;
1719                 }
1720
1721                 public override Expression DoResolve (EmitContext ec)
1722                 {
1723                         // This should never be invoked, we are born in fully
1724                         // initialized state.
1725
1726                         return this;
1727                 }
1728
1729                 public override string ToString ()
1730                 {
1731                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1732                 }
1733
1734                 public override void Emit (EmitContext ec)
1735                 {
1736                         ILGenerator ig = ec.ig;
1737
1738                         base.Emit (ec);
1739
1740                         if (checked_state){
1741                                 switch (mode){
1742                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1743                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1744                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1745                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1746                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1747
1748                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1749                                 case Mode.U1_CH: /* nothing */ break;
1750
1751                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1752                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1753                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1754                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1755                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1756                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1757
1758                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1759                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1760                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1761                                 case Mode.U2_CH: /* nothing */ break;
1762
1763                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1764                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1765                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1766                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1767                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1768                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1769                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1770
1771                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1772                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1773                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1774                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1775                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1776                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1777
1778                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1779                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1780                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1781                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1782                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1783                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1784                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1785                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1786
1787                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1788                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1789                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1790                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1791                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1792                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1793                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1794                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1795
1796                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1797                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1798                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1799
1800                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1801                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1802                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1803                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1804                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1805                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1806                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1807                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1808                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1809
1810                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1811                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1812                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1813                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1814                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1815                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1816                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1817                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1818                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1819                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1820                                 }
1821                         } else {
1822                                 switch (mode){
1823                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1824                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1825                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1826                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
1827                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
1828
1829                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
1830                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
1831
1832                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
1833                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
1834                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
1835                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
1836                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
1837                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
1838
1839                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
1840                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
1841                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
1842                                 case Mode.U2_CH: /* nothing */ break;
1843
1844                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
1845                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
1846                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
1847                                 case Mode.I4_U4: /* nothing */ break;
1848                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
1849                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
1850                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
1851
1852                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
1853                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
1854                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
1855                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
1856                                 case Mode.U4_I4: /* nothing */ break;
1857                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
1858
1859                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
1860                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
1861                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
1862                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
1863                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
1864                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
1865                                 case Mode.I8_U8: /* nothing */ break;
1866                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
1867
1868                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
1869                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
1870                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
1871                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
1872                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
1873                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
1874                                 case Mode.U8_I8: /* nothing */ break;
1875                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
1876
1877                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
1878                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
1879                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
1880
1881                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
1882                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
1883                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
1884                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
1885                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
1886                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
1887                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
1888                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
1889                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
1890
1891                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
1892                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
1893                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
1894                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
1895                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
1896                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
1897                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
1898                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
1899                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
1900                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1901                                 }
1902                         }
1903                 }
1904         }
1905
1906         public class OpcodeCast : EmptyCast {
1907                 OpCode op, op2;
1908                 bool second_valid;
1909
1910                 public OpcodeCast (Expression child, Type return_type, OpCode op)
1911                         : base (child, return_type)
1912
1913                 {
1914                         this.op = op;
1915                         second_valid = false;
1916                 }
1917
1918                 public OpcodeCast (Expression child, Type return_type, OpCode op, OpCode op2)
1919                         : base (child, return_type)
1920
1921                 {
1922                         this.op = op;
1923                         this.op2 = op2;
1924                         second_valid = true;
1925                 }
1926
1927                 public override Expression DoResolve (EmitContext ec)
1928                 {
1929                         // This should never be invoked, we are born in fully
1930                         // initialized state.
1931
1932                         return this;
1933                 }
1934
1935                 public override void Emit (EmitContext ec)
1936                 {
1937                         base.Emit (ec);
1938                         ec.ig.Emit (op);
1939
1940                         if (second_valid)
1941                                 ec.ig.Emit (op2);
1942                 }
1943         }
1944
1945         /// <summary>
1946         ///   This kind of cast is used to encapsulate a child and cast it
1947         ///   to the class requested
1948         /// </summary>
1949         public class ClassCast : EmptyCast {
1950                 public ClassCast (Expression child, Type return_type)
1951                         : base (child, return_type)
1952
1953                 {
1954                 }
1955
1956                 public override Expression DoResolve (EmitContext ec)
1957                 {
1958                         // This should never be invoked, we are born in fully
1959                         // initialized state.
1960
1961                         return this;
1962                 }
1963
1964                 public override void Emit (EmitContext ec)
1965                 {
1966                         base.Emit (ec);
1967
1968                         ec.ig.Emit (OpCodes.Castclass, type);
1969                 }
1970
1971         }
1972
1973         /// <summary>
1974         ///   SimpleName expressions are formed of a single word and only happen at the beginning
1975         ///   of a dotted-name.
1976         /// </summary>
1977         public class SimpleName : Expression {
1978                 public string Name;
1979
1980                 public SimpleName (string name, Location l)
1981                 {
1982                         Name = name;
1983                         loc = l;
1984                 }
1985
1986                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
1987                 {
1988                         if (ec.IsFieldInitializer)
1989                                 Report.Error (
1990                                         236, l,
1991                                         "A field initializer cannot reference the non-static field, " +
1992                                         "method or property `"+name+"'");
1993                         else
1994                                 Report.Error (
1995                                         120, l,
1996                                         "An object reference is required " +
1997                                         "for the non-static field `"+name+"'");
1998                 }
1999
2000                 //
2001                 // Checks whether we are trying to access an instance
2002                 // property, method or field from a static body.
2003                 //
2004                 Expression MemberStaticCheck (EmitContext ec, Expression e)
2005                 {
2006                         if (e is IMemberExpr){
2007                                 IMemberExpr member = (IMemberExpr) e;
2008
2009                                 if (!member.IsStatic){
2010                                         Error_ObjectRefRequired (ec, loc, Name);
2011                                         return null;
2012                                 }
2013                         }
2014
2015                         return e;
2016                 }
2017
2018                 public override Expression DoResolve (EmitContext ec)
2019                 {
2020                         return SimpleNameResolve (ec, null, false, false);
2021                 }
2022
2023                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
2024                 {
2025                         return SimpleNameResolve (ec, right_side, false, false);
2026                 }
2027
2028
2029                 public Expression DoResolveAllowStatic (EmitContext ec, bool intermediate)
2030                 {
2031                         return SimpleNameResolve (ec, null, true, intermediate);
2032                 }
2033
2034                 public override FullNamedExpression ResolveAsTypeStep (EmitContext ec)
2035                 {
2036                         DeclSpace ds = ec.DeclSpace;
2037                         FullNamedExpression dt;
2038
2039                         int errors = Report.Errors;
2040                         dt = ec.ResolvingTypeTree
2041                                 ? ds.FindType (loc, Name)
2042                                 : ds.LookupType (Name, true, loc);
2043                         if (Report.Errors != errors)
2044                                 return null;
2045
2046                         return dt;
2047                 }
2048
2049                 Expression SimpleNameResolve (EmitContext ec, Expression right_side,
2050                                               bool allow_static, bool intermediate)
2051                 {
2052                         Expression e = DoSimpleNameResolve (ec, right_side, allow_static, intermediate);
2053                         if (e == null)
2054                                 return null;
2055
2056                         Block current_block = ec.CurrentBlock;
2057                         if (current_block != null){
2058                                 if (current_block.IsVariableNameUsedInChildBlock (Name)) {
2059                                         Report.Error (135, Location,
2060                                                       "'{0}' has a different meaning in a child block", Name);
2061                                         return null;
2062                                 }
2063                         }
2064
2065                         return e;
2066                 }
2067
2068                 /// <remarks>
2069                 ///   7.5.2: Simple Names.
2070                 ///
2071                 ///   Local Variables and Parameters are handled at
2072                 ///   parse time, so they never occur as SimpleNames.
2073                 ///
2074                 ///   The `allow_static' flag is used by MemberAccess only
2075                 ///   and it is used to inform us that it is ok for us to
2076                 ///   avoid the static check, because MemberAccess might end
2077                 ///   up resolving the Name as a Type name and the access as
2078                 ///   a static type access.
2079                 ///
2080                 ///   ie: Type Type; .... { Type.GetType (""); }
2081                 ///
2082                 ///   Type is both an instance variable and a Type;  Type.GetType
2083                 ///   is the static method not an instance method of type.
2084                 /// </remarks>
2085                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool allow_static, bool intermediate)
2086                 {
2087                         Expression e = null;
2088
2089                         //
2090                         // Stage 1: Performed by the parser (binding to locals or parameters).
2091                         //
2092                         Block current_block = ec.CurrentBlock;
2093                         if (current_block != null){
2094                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2095                                 if (vi != null){
2096                                         Expression var;
2097
2098                                         var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2099
2100                                         if (right_side != null)
2101                                                 return var.ResolveLValue (ec, right_side);
2102                                         else
2103                                                 return var.Resolve (ec);
2104                                 }
2105
2106                                 ParameterReference pref = current_block.GetParameterReference (Name, loc);
2107                                 if (pref != null) {
2108                                         if (right_side != null)
2109                                                 return pref.ResolveLValue (ec, right_side);
2110                                         else
2111                                                 return pref.Resolve (ec);
2112                                 }
2113                         }
2114
2115                         //
2116                         // Stage 2: Lookup members
2117                         //
2118
2119                         DeclSpace lookup_ds = ec.DeclSpace;
2120                         Type almost_matched_type = null;
2121                         ArrayList almost_matched = null;
2122                         do {
2123                                 if (lookup_ds.TypeBuilder == null)
2124                                         break;
2125
2126                                 e = MemberLookup (ec, lookup_ds.TypeBuilder, Name, loc);
2127                                 if (e != null)
2128                                         break;
2129
2130                                 if (almost_matched == null && almostMatchedMembers.Count > 0) {
2131                                         almost_matched_type = lookup_ds.TypeBuilder;
2132                                         almost_matched = (ArrayList) almostMatchedMembers.Clone ();
2133                                 }
2134
2135                                 lookup_ds =lookup_ds.Parent;
2136                         } while (lookup_ds != null);
2137
2138                         if (e == null && ec.ContainerType != null)
2139                                 e = MemberLookup (ec, ec.ContainerType, Name, loc);
2140
2141                         if (e == null) {
2142                                 if (almost_matched == null && almostMatchedMembers.Count > 0) {
2143                                         almost_matched_type = ec.ContainerType;
2144                                         almost_matched = (ArrayList) almostMatchedMembers.Clone ();
2145                                 }
2146                                 e = ResolveAsTypeStep (ec);
2147                         }
2148
2149                         if (e == null) {
2150                                 if (almost_matched != null)
2151                                         almostMatchedMembers = almost_matched;
2152                                 if (almost_matched_type == null)
2153                                         almost_matched_type = ec.ContainerType;
2154                                 MemberLookupFailed (ec, null, almost_matched_type, ((SimpleName) this).Name, ec.DeclSpace.Name, loc);
2155                                 return null;
2156                         }
2157
2158                         if (e is TypeExpr)
2159                                 return e;
2160
2161                         if (e is IMemberExpr) {
2162                                 e = MemberAccess.ResolveMemberAccess (ec, e, null, loc, this);
2163                                 if (e == null)
2164                                         return null;
2165
2166                                 IMemberExpr me = e as IMemberExpr;
2167                                 if (me == null)
2168                                         return e;
2169
2170                                 // This fails if ResolveMemberAccess() was unable to decide whether
2171                                 // it's a field or a type of the same name.
2172
2173                                 if (!me.IsStatic && (me.InstanceExpression == null))
2174                                         return e;
2175
2176                                 if (!me.IsStatic &&
2177                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2178                                     me.InstanceExpression.Type != me.DeclaringType &&
2179                                     !me.InstanceExpression.Type.IsSubclassOf (me.DeclaringType) &&
2180                                     (!intermediate || !MemberAccess.IdenticalNameAndTypeName (ec, this, e, loc))) {
2181                                         Error (38, "Cannot access nonstatic member `" + me.Name + "' of " +
2182                                                "outer type `" + me.DeclaringType + "' via nested type `" +
2183                                                me.InstanceExpression.Type + "'");
2184                                         return null;
2185                                 }
2186
2187                                 return (right_side != null)
2188                                         ? e.DoResolveLValue (ec, right_side)
2189                                         : e.DoResolve (ec);
2190                         }
2191
2192                         if (ec.IsStatic || ec.IsFieldInitializer){
2193                                 if (allow_static)
2194                                         return e;
2195
2196                                 return MemberStaticCheck (ec, e);
2197                         } else
2198                                 return e;
2199                 }
2200
2201                 public override void Emit (EmitContext ec)
2202                 {
2203                         //
2204                         // If this is ever reached, then we failed to
2205                         // find the name as a namespace
2206                         //
2207
2208                         Error (103, "The name `" + Name +
2209                                "' does not exist in the class `" +
2210                                ec.DeclSpace.Name + "'");
2211                 }
2212
2213                 public override string ToString ()
2214                 {
2215                         return Name;
2216                 }
2217         }
2218
2219         /// <summary>
2220         ///   Represents a namespace or a type.  The name of the class was inspired by
2221         ///   section 10.8.1 (Fully Qualified Names).
2222         /// </summary>
2223         public abstract class FullNamedExpression : Expression {
2224                 public abstract string FullName {
2225                         get;
2226                 }
2227         }
2228
2229         /// <summary>
2230         ///   Fully resolved expression that evaluates to a type
2231         /// </summary>
2232         public abstract class TypeExpr : FullNamedExpression {
2233                 override public FullNamedExpression ResolveAsTypeStep (EmitContext ec)
2234                 {
2235                         TypeExpr t = DoResolveAsTypeStep (ec);
2236                         if (t == null)
2237                                 return null;
2238
2239                         eclass = ExprClass.Type;
2240                         return t;
2241                 }
2242
2243                 override public Expression DoResolve (EmitContext ec)
2244                 {
2245                         return ResolveAsTypeTerminal (ec, false);
2246                 }
2247
2248                 override public void Emit (EmitContext ec)
2249                 {
2250                         throw new Exception ("Should never be called");
2251                 }
2252
2253                 public virtual bool CheckAccessLevel (DeclSpace ds)
2254                 {
2255                         return ds.CheckAccessLevel (Type);
2256                 }
2257
2258                 public virtual bool AsAccessible (DeclSpace ds, int flags)
2259                 {
2260                         return ds.AsAccessible (Type, flags);
2261                 }
2262
2263                 public virtual bool IsClass {
2264                         get { return Type.IsClass; }
2265                 }
2266
2267                 public virtual bool IsValueType {
2268                         get { return Type.IsValueType; }
2269                 }
2270
2271                 public virtual bool IsInterface {
2272                         get { return Type.IsInterface; }
2273                 }
2274
2275                 public virtual bool IsSealed {
2276                         get { return Type.IsSealed; }
2277                 }
2278
2279                 public virtual bool CanInheritFrom ()
2280                 {
2281                         if (Type == TypeManager.enum_type ||
2282                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2283                             Type == TypeManager.multicast_delegate_type ||
2284                             Type == TypeManager.delegate_type ||
2285                             Type == TypeManager.array_type)
2286                                 return false;
2287
2288                         return true;
2289                 }
2290
2291                 public virtual bool IsAttribute {
2292                         get {
2293                                 return Type == TypeManager.attribute_type ||
2294                                         Type.IsSubclassOf (TypeManager.attribute_type);
2295                         }
2296                 }
2297
2298                 public abstract TypeExpr DoResolveAsTypeStep (EmitContext ec);
2299
2300                 public virtual Type ResolveType (EmitContext ec)
2301                 {
2302                         TypeExpr t = ResolveAsTypeTerminal (ec, false);
2303                         if (t == null)
2304                                 return null;
2305
2306                         return t.Type;
2307                 }
2308
2309                 public abstract string Name {
2310                         get;
2311                 }
2312
2313                 public override bool Equals (object obj)
2314                 {
2315                         TypeExpr tobj = obj as TypeExpr;
2316                         if (tobj == null)
2317                                 return false;
2318
2319                         return Type == tobj.Type;
2320                 }
2321
2322                 public override int GetHashCode ()
2323                 {
2324                         return Type.GetHashCode ();
2325                 }
2326
2327                 public override string ToString ()
2328                 {
2329                         return Name;
2330                 }
2331         }
2332
2333         public class TypeExpression : TypeExpr {
2334                 public TypeExpression (Type t, Location l)
2335                 {
2336                         Type = t;
2337                         eclass = ExprClass.Type;
2338                         loc = l;
2339                 }
2340
2341                 public override TypeExpr DoResolveAsTypeStep (EmitContext ec)
2342                 {
2343                         return this;
2344                 }
2345
2346                 public override string Name {
2347                         get {
2348                                 return Type.ToString ();
2349                         }
2350                 }
2351
2352                 public override string FullName {
2353                         get {
2354                                 return Type.FullName;
2355                         }
2356                 }
2357         }
2358
2359         /// <summary>
2360         ///   Used to create types from a fully qualified name.  These are just used
2361         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2362         ///   classified as a type.
2363         /// </summary>
2364         public class TypeLookupExpression : TypeExpr {
2365                 string name;
2366
2367                 public TypeLookupExpression (string name)
2368                 {
2369                         this.name = name;
2370                 }
2371
2372                 public override TypeExpr DoResolveAsTypeStep (EmitContext ec)
2373                 {
2374                         if (type == null) {
2375                                 FullNamedExpression t = ec.DeclSpace.LookupType (name, false, Location.Null);
2376                                 if (t == null)
2377                                         return null;
2378                                 if (!(t is TypeExpr))
2379                                         return null;
2380                                 type = ((TypeExpr) t).ResolveType (ec);
2381                         }
2382
2383                         return this;
2384                 }
2385
2386                 public override string Name {
2387                         get {
2388                                 return name;
2389                         }
2390                 }
2391
2392                 public override string FullName {
2393                         get {
2394                                 return name;
2395                         }
2396                 }
2397         }
2398
2399         public class TypeAliasExpression : TypeExpr {
2400                 TypeExpr texpr;
2401
2402                 public TypeAliasExpression (TypeExpr texpr, Location l)
2403                 {
2404                         this.texpr = texpr;
2405                         loc = texpr.Location;
2406
2407                         eclass = ExprClass.Type;
2408                 }
2409
2410                 public override string Name {
2411                         get { return texpr.Name; }
2412                 }
2413
2414                 public override string FullName {
2415                         get { return texpr.FullName; }
2416                 }
2417
2418                 public override TypeExpr DoResolveAsTypeStep (EmitContext ec)
2419                 {
2420                         Type type = texpr.ResolveType (ec);
2421                         if (type == null)
2422                                 return null;
2423
2424                         return new TypeExpression (type, loc);
2425                 }
2426
2427                 public override bool CheckAccessLevel (DeclSpace ds)
2428                 {
2429                         return texpr.CheckAccessLevel (ds);
2430                 }
2431
2432                 public override bool AsAccessible (DeclSpace ds, int flags)
2433                 {
2434                         return texpr.AsAccessible (ds, flags);
2435                 }
2436
2437                 public override bool IsClass {
2438                         get { return texpr.IsClass; }
2439                 }
2440
2441                 public override bool IsValueType {
2442                         get { return texpr.IsValueType; }
2443                 }
2444
2445                 public override bool IsInterface {
2446                         get { return texpr.IsInterface; }
2447                 }
2448
2449                 public override bool IsSealed {
2450                         get { return texpr.IsSealed; }
2451                 }
2452
2453                 public override bool IsAttribute {
2454                         get { return texpr.IsAttribute; }
2455                 }
2456         }
2457
2458         /// <summary>
2459         ///   MethodGroup Expression.
2460         ///
2461         ///   This is a fully resolved expression that evaluates to a type
2462         /// </summary>
2463         public class MethodGroupExpr : Expression, IMemberExpr {
2464                 public MethodBase [] Methods;
2465                 Expression instance_expression = null;
2466                 bool is_explicit_impl = false;
2467                 bool identical_type_name = false;
2468                 bool is_base;
2469
2470                 public MethodGroupExpr (MemberInfo [] mi, Location l)
2471                 {
2472                         Methods = new MethodBase [mi.Length];
2473                         mi.CopyTo (Methods, 0);
2474                         eclass = ExprClass.MethodGroup;
2475                         type = TypeManager.object_type;
2476                         loc = l;
2477                 }
2478
2479                 public MethodGroupExpr (ArrayList list, Location l)
2480                 {
2481                         Methods = new MethodBase [list.Count];
2482
2483                         try {
2484                                 list.CopyTo (Methods, 0);
2485                         } catch {
2486                                 foreach (MemberInfo m in list){
2487                                         if (!(m is MethodBase)){
2488                                                 Console.WriteLine ("Name " + m.Name);
2489                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
2490                                         }
2491                                 }
2492                                 throw;
2493                         }
2494
2495                         loc = l;
2496                         eclass = ExprClass.MethodGroup;
2497                         type = TypeManager.object_type;
2498                 }
2499
2500                 public Type DeclaringType {
2501                         get {
2502                                 //
2503                                 // The methods are arranged in this order:
2504                                 // derived type -> base type
2505                                 //
2506                                 return Methods [0].DeclaringType;
2507                         }
2508                 }
2509
2510                 //
2511                 // `A method group may have associated an instance expression'
2512                 //
2513                 public Expression InstanceExpression {
2514                         get {
2515                                 return instance_expression;
2516                         }
2517
2518                         set {
2519                                 instance_expression = value;
2520                         }
2521                 }
2522
2523                 public bool IsExplicitImpl {
2524                         get {
2525                                 return is_explicit_impl;
2526                         }
2527
2528                         set {
2529                                 is_explicit_impl = value;
2530                         }
2531                 }
2532
2533                 public bool IdenticalTypeName {
2534                         get {
2535                                 return identical_type_name;
2536                         }
2537
2538                         set {
2539                                 identical_type_name = value;
2540                         }
2541                 }
2542
2543                 public bool IsBase {
2544                         get {
2545                                 return is_base;
2546                         }
2547                         set {
2548                                 is_base = value;
2549                         }
2550                 }
2551
2552                 public string Name {
2553                         get {
2554                                 return Methods [0].Name;
2555                         }
2556                 }
2557
2558                 public bool IsInstance {
2559                         get {
2560                                 foreach (MethodBase mb in Methods)
2561                                         if (!mb.IsStatic)
2562                                                 return true;
2563
2564                                 return false;
2565                         }
2566                 }
2567
2568                 public bool IsStatic {
2569                         get {
2570                                 foreach (MethodBase mb in Methods)
2571                                         if (mb.IsStatic)
2572                                                 return true;
2573
2574                                 return false;
2575                         }
2576                 }
2577
2578                 override public Expression DoResolve (EmitContext ec)
2579                 {
2580                         if (!IsInstance)
2581                                 instance_expression = null;
2582
2583                         if (instance_expression != null) {
2584                                 instance_expression = instance_expression.DoResolve (ec);
2585                                 if (instance_expression == null)
2586                                         return null;
2587                         }
2588
2589                         return this;
2590                 }
2591
2592                 public void ReportUsageError ()
2593                 {
2594                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
2595                                       Name + "()' is referenced without parentheses");
2596                 }
2597
2598                 override public void Emit (EmitContext ec)
2599                 {
2600                         ReportUsageError ();
2601                 }
2602
2603                 bool RemoveMethods (bool keep_static)
2604                 {
2605                         ArrayList smethods = new ArrayList ();
2606
2607                         foreach (MethodBase mb in Methods){
2608                                 if (mb.IsStatic == keep_static)
2609                                         smethods.Add (mb);
2610                         }
2611
2612                         if (smethods.Count == 0)
2613                                 return false;
2614
2615                         Methods = new MethodBase [smethods.Count];
2616                         smethods.CopyTo (Methods, 0);
2617
2618                         return true;
2619                 }
2620
2621                 /// <summary>
2622                 ///   Removes any instance methods from the MethodGroup, returns
2623                 ///   false if the resulting set is empty.
2624                 /// </summary>
2625                 public bool RemoveInstanceMethods ()
2626                 {
2627                         return RemoveMethods (true);
2628                 }
2629
2630                 /// <summary>
2631                 ///   Removes any static methods from the MethodGroup, returns
2632                 ///   false if the resulting set is empty.
2633                 /// </summary>
2634                 public bool RemoveStaticMethods ()
2635                 {
2636                         return RemoveMethods (false);
2637                 }
2638         }
2639
2640         /// <summary>
2641         ///   Fully resolved expression that evaluates to a Field
2642         /// </summary>
2643         public class FieldExpr : Expression, IAssignMethod, IMemoryLocation, IMemberExpr, IVariable {
2644                 public readonly FieldInfo FieldInfo;
2645                 Expression instance_expr;
2646                 VariableInfo variable_info;
2647
2648                 LocalTemporary temp;
2649                 bool prepared;
2650
2651                 public FieldExpr (FieldInfo fi, Location l)
2652                 {
2653                         FieldInfo = fi;
2654                         eclass = ExprClass.Variable;
2655                         type = fi.FieldType;
2656                         loc = l;
2657                 }
2658
2659                 public string Name {
2660                         get {
2661                                 return FieldInfo.Name;
2662                         }
2663                 }
2664
2665                 public bool IsInstance {
2666                         get {
2667                                 return !FieldInfo.IsStatic;
2668                         }
2669                 }
2670
2671                 public bool IsStatic {
2672                         get {
2673                                 return FieldInfo.IsStatic;
2674                         }
2675                 }
2676
2677                 public Type DeclaringType {
2678                         get {
2679                                 return FieldInfo.DeclaringType;
2680                         }
2681                 }
2682
2683                 public Expression InstanceExpression {
2684                         get {
2685                                 return instance_expr;
2686                         }
2687
2688                         set {
2689                                 instance_expr = value;
2690                         }
2691                 }
2692
2693                 public VariableInfo VariableInfo {
2694                         get {
2695                                 return variable_info;
2696                         }
2697                 }
2698
2699                 override public Expression DoResolve (EmitContext ec)
2700                 {
2701                         if (!FieldInfo.IsStatic){
2702                                 if (instance_expr == null){
2703                                         //
2704                                         // This can happen when referencing an instance field using
2705                                         // a fully qualified type expression: TypeName.InstanceField = xxx
2706                                         //
2707                                         SimpleName.Error_ObjectRefRequired (ec, loc, FieldInfo.Name);
2708                                         return null;
2709                                 }
2710
2711                                 // Resolve the field's instance expression while flow analysis is turned
2712                                 // off: when accessing a field "a.b", we must check whether the field
2713                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
2714                                 instance_expr = instance_expr.Resolve (ec, ResolveFlags.VariableOrValue |
2715                                                                        ResolveFlags.DisableFlowAnalysis);
2716                                 if (instance_expr == null)
2717                                         return null;
2718                         }
2719
2720                         ObsoleteAttribute oa;
2721                         FieldBase f = TypeManager.GetField (FieldInfo);
2722                         if (f != null) {
2723                                 oa = f.GetObsoleteAttribute (f.Parent);
2724                                 if (oa != null)
2725                                         AttributeTester.Report_ObsoleteMessage (oa, f.GetSignatureForError (), loc);
2726
2727                         // To be sure that type is external because we do not register generated fields
2728                         } else if (!(FieldInfo.DeclaringType is TypeBuilder)) {
2729                                 oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
2730                                 if (oa != null)
2731                                         AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
2732                         }
2733
2734                         if (ec.CurrentAnonymousMethod != null){
2735                                 if (!FieldInfo.IsStatic){
2736                                         if (ec.TypeContainer is Struct){
2737                                                 Report.Error (1673, loc, "Can not reference instance variables in anonymous methods hosted in structs");
2738                                                 return null;
2739                                         }
2740                                         ec.CaptureField (this);
2741                                 }
2742                         }
2743
2744                         // If the instance expression is a local variable or parameter.
2745                         IVariable var = instance_expr as IVariable;
2746                         if ((var == null) || (var.VariableInfo == null))
2747                                 return this;
2748
2749                         VariableInfo vi = var.VariableInfo;
2750                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
2751                                 return null;
2752
2753                         variable_info = vi.GetSubStruct (FieldInfo.Name);
2754                         return this;
2755                 }
2756
2757                 void Report_AssignToReadonly (bool is_instance)
2758                 {
2759                         string msg;
2760
2761                         if (is_instance)
2762                                 msg = "Readonly field can not be assigned outside " +
2763                                 "of constructor or variable initializer";
2764                         else
2765                                 msg = "A static readonly field can only be assigned in " +
2766                                 "a static constructor";
2767
2768                         Report.Error (is_instance ? 191 : 198, loc, msg);
2769                 }
2770
2771                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
2772                 {
2773                         IVariable var = instance_expr as IVariable;
2774                         if ((var != null) && (var.VariableInfo != null))
2775                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
2776
2777                         Expression e = DoResolve (ec);
2778
2779                         if (e == null)
2780                                 return null;
2781
2782                         if (!FieldInfo.IsStatic && (instance_expr.Type.IsValueType && !(instance_expr is IMemoryLocation))) {
2783                                 // FIXME: Provide better error reporting.
2784                                 Error (1612, "Cannot modify expression because it is not a variable.");
2785                                 return null;
2786                         }
2787
2788                         if (!FieldInfo.IsInitOnly)
2789                                 return this;
2790
2791                         FieldBase fb = TypeManager.GetField (FieldInfo);
2792                         if (fb != null)
2793                                 fb.SetAssigned ();
2794
2795                         //
2796                         // InitOnly fields can only be assigned in constructors
2797                         //
2798
2799                         if (ec.IsConstructor){
2800                                 if (IsStatic && !ec.IsStatic)
2801                                         Report_AssignToReadonly (false);
2802
2803                                 if (ec.ContainerType == FieldInfo.DeclaringType)
2804                                         return this;
2805                         }
2806
2807                         Report_AssignToReadonly (!IsStatic);
2808
2809                         return null;
2810                 }
2811
2812                 public override void CheckMarshallByRefAccess (Type container)
2813                 {
2814                         if (!IsStatic && Type.IsValueType && !container.IsSubclassOf (TypeManager.mbr_type) && DeclaringType.IsSubclassOf (TypeManager.mbr_type)) {
2815                                 Report.SymbolRelatedToPreviousError (DeclaringType);
2816                                 Report.Error (1690, loc, "Cannot call '{0}' method, property, or indexer because it is a value type member of a marshal-by-reference class", Name);
2817                         }
2818                 }
2819
2820                 public bool VerifyFixed (bool is_expression)
2821                 {
2822                         IVariable variable = instance_expr as IVariable;
2823                         if ((variable == null) || !variable.VerifyFixed (true))
2824                                 return false;
2825
2826                         return true;
2827                 }
2828
2829                 public void Emit (EmitContext ec, bool leave_copy)
2830                 {
2831                         ILGenerator ig = ec.ig;
2832                         bool is_volatile = false;
2833
2834                         if (FieldInfo is FieldBuilder){
2835                                 FieldBase f = TypeManager.GetField (FieldInfo);
2836                                 if (f != null){
2837                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0)
2838                                                 is_volatile = true;
2839
2840                                         f.status |= Field.Status.USED;
2841                                 }
2842                         }
2843
2844                         if (FieldInfo.IsStatic){
2845                                 if (is_volatile)
2846                                         ig.Emit (OpCodes.Volatile);
2847
2848                                 ig.Emit (OpCodes.Ldsfld, FieldInfo);
2849                         } else {
2850                                 if (!prepared)
2851                                         EmitInstance (ec);
2852
2853                                 if (is_volatile)
2854                                         ig.Emit (OpCodes.Volatile);
2855
2856                                 ig.Emit (OpCodes.Ldfld, FieldInfo);
2857                         }
2858
2859                         if (leave_copy) {
2860                                 ec.ig.Emit (OpCodes.Dup);
2861                                 if (!FieldInfo.IsStatic) {
2862                                         temp = new LocalTemporary (ec, this.Type);
2863                                         temp.Store (ec);
2864                                 }
2865                         }
2866                 }
2867
2868                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
2869                 {
2870                         FieldAttributes fa = FieldInfo.Attributes;
2871                         bool is_static = (fa & FieldAttributes.Static) != 0;
2872                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
2873                         ILGenerator ig = ec.ig;
2874                         prepared = prepare_for_load;
2875
2876                         if (is_readonly && !ec.IsConstructor){
2877                                 Report_AssignToReadonly (!is_static);
2878                                 return;
2879                         }
2880
2881                         if (!is_static) {
2882                                 EmitInstance (ec);
2883                                 if (prepare_for_load)
2884                                         ig.Emit (OpCodes.Dup);
2885                         }
2886
2887                         source.Emit (ec);
2888                         if (leave_copy) {
2889                                 ec.ig.Emit (OpCodes.Dup);
2890                                 if (!FieldInfo.IsStatic) {
2891                                         temp = new LocalTemporary (ec, this.Type);
2892                                         temp.Store (ec);
2893                                 }
2894                         }
2895
2896                         if (FieldInfo is FieldBuilder){
2897                                 FieldBase f = TypeManager.GetField (FieldInfo);
2898                                 if (f != null){
2899                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0)
2900                                                 ig.Emit (OpCodes.Volatile);
2901
2902                                         f.status |= Field.Status.ASSIGNED;
2903                                 }
2904                         }
2905
2906                         if (is_static)
2907                                 ig.Emit (OpCodes.Stsfld, FieldInfo);
2908                         else
2909                                 ig.Emit (OpCodes.Stfld, FieldInfo);
2910
2911                         if (temp != null)
2912                                 temp.Emit (ec);
2913                 }
2914
2915                 void EmitInstance (EmitContext ec)
2916                 {
2917                         if (instance_expr.Type.IsValueType) {
2918                                 if (instance_expr is IMemoryLocation) {
2919                                         ((IMemoryLocation) instance_expr).AddressOf (ec, AddressOp.LoadStore);
2920                                 } else {
2921                                         LocalTemporary t = new LocalTemporary (ec, instance_expr.Type);
2922                                         instance_expr.Emit (ec);
2923                                         t.Store (ec);
2924                                         t.AddressOf (ec, AddressOp.Store);
2925                                 }
2926                         } else
2927                                 instance_expr.Emit (ec);
2928                 }
2929
2930                 public override void Emit (EmitContext ec)
2931                 {
2932                         Emit (ec, false);
2933                 }
2934
2935                 public void AddressOf (EmitContext ec, AddressOp mode)
2936                 {
2937                         ILGenerator ig = ec.ig;
2938
2939                         if (FieldInfo is FieldBuilder){
2940                                 FieldBase f = TypeManager.GetField (FieldInfo);
2941                                 if (f != null){
2942                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0){
2943                                                 Error (676, "volatile variable: can not take its address, or pass as ref/out parameter");
2944                                                 return;
2945                                         }
2946
2947                                         if ((mode & AddressOp.Store) != 0)
2948                                                 f.status |= Field.Status.ASSIGNED;
2949                                         if ((mode & AddressOp.Load) != 0)
2950                                                 f.status |= Field.Status.USED;
2951                                 }
2952                         }
2953
2954                         //
2955                         // Handle initonly fields specially: make a copy and then
2956                         // get the address of the copy.
2957                         //
2958                         bool need_copy;
2959                         if (FieldInfo.IsInitOnly){
2960                                 need_copy = true;
2961                                 if (ec.IsConstructor){
2962                                         if (FieldInfo.IsStatic){
2963                                                 if (ec.IsStatic)
2964                                                         need_copy = false;
2965                                         } else
2966                                                 need_copy = false;
2967                                 }
2968                         } else
2969                                 need_copy = false;
2970
2971                         if (need_copy){
2972                                 LocalBuilder local;
2973                                 Emit (ec);
2974                                 local = ig.DeclareLocal (type);
2975                                 ig.Emit (OpCodes.Stloc, local);
2976                                 ig.Emit (OpCodes.Ldloca, local);
2977                                 return;
2978                         }
2979
2980
2981                         if (FieldInfo.IsStatic){
2982                                 ig.Emit (OpCodes.Ldsflda, FieldInfo);
2983                         } else {
2984                                 EmitInstance (ec);
2985                                 ig.Emit (OpCodes.Ldflda, FieldInfo);
2986                         }
2987                 }
2988         }
2989
2990         //
2991         // A FieldExpr whose address can not be taken
2992         //
2993         public class FieldExprNoAddress : FieldExpr, IMemoryLocation {
2994                 public FieldExprNoAddress (FieldInfo fi, Location loc) : base (fi, loc)
2995                 {
2996                 }
2997
2998                 public new void AddressOf (EmitContext ec, AddressOp mode)
2999                 {
3000                         Report.Error (-215, "Report this: Taking the address of a remapped parameter not supported");
3001                 }
3002         }
3003
3004         /// <summary>
3005         ///   Expression that evaluates to a Property.  The Assign class
3006         ///   might set the `Value' expression if we are in an assignment.
3007         ///
3008         ///   This is not an LValue because we need to re-write the expression, we
3009         ///   can not take data from the stack and store it.
3010         /// </summary>
3011         public class PropertyExpr : ExpressionStatement, IAssignMethod, IMemberExpr {
3012                 public readonly PropertyInfo PropertyInfo;
3013
3014                 //
3015                 // This is set externally by the  `BaseAccess' class
3016                 //
3017                 public bool IsBase;
3018                 MethodInfo getter, setter;
3019                 bool is_static;
3020
3021                 Expression instance_expr;
3022                 LocalTemporary temp;
3023                 bool prepared;
3024
3025                 internal static PtrHashtable AccessorTable = new PtrHashtable ();
3026
3027                 public PropertyExpr (EmitContext ec, PropertyInfo pi, Location l)
3028                 {
3029                         PropertyInfo = pi;
3030                         eclass = ExprClass.PropertyAccess;
3031                         is_static = false;
3032                         loc = l;
3033
3034                         type = TypeManager.TypeToCoreType (pi.PropertyType);
3035
3036                         ResolveAccessors (ec);
3037                 }
3038
3039                 public string Name {
3040                         get {
3041                                 return PropertyInfo.Name;
3042                         }
3043                 }
3044
3045                 public bool IsInstance {
3046                         get {
3047                                 return !is_static;
3048                         }
3049                 }
3050
3051                 public bool IsStatic {
3052                         get {
3053                                 return is_static;
3054                         }
3055                 }
3056
3057                 public Type DeclaringType {
3058                         get {
3059                                 return PropertyInfo.DeclaringType;
3060                         }
3061                 }
3062
3063                 //
3064                 // The instance expression associated with this expression
3065                 //
3066                 public Expression InstanceExpression {
3067                         set {
3068                                 instance_expr = value;
3069                         }
3070
3071                         get {
3072                                 return instance_expr;
3073                         }
3074                 }
3075
3076                 public bool VerifyAssignable ()
3077                 {
3078                         if (setter == null) {
3079                                 Report.Error (200, loc,
3080                                               "The property `" + PropertyInfo.Name +
3081                                               "' can not be assigned to, as it has not set accessor");
3082                                 return false;
3083                         }
3084
3085                         return true;
3086                 }
3087
3088                 void FindAccessors (Type invocation_type)
3089                 {
3090                         BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
3091                                 BindingFlags.Static | BindingFlags.Instance |
3092                                 BindingFlags.DeclaredOnly;
3093
3094                         Type current = PropertyInfo.DeclaringType;
3095                         for (; current != null; current = current.BaseType) {
3096                                 MemberInfo[] group = TypeManager.MemberLookup (
3097                                         invocation_type, invocation_type, current,
3098                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
3099
3100                                 if (group == null)
3101                                         continue;
3102
3103                                 if (group.Length != 1)
3104                                         // Oooops, can this ever happen ?
3105                                         return;
3106
3107                                 PropertyInfo pi = (PropertyInfo) group [0];
3108
3109                                 if (getter == null)
3110                                         getter = pi.GetGetMethod (true);
3111
3112                                 if (setter == null)
3113                                         setter = pi.GetSetMethod (true);
3114
3115                                 MethodInfo accessor = getter != null ? getter : setter;
3116
3117                                 if (!accessor.IsVirtual)
3118                                         return;
3119                         }
3120                 }
3121
3122                 //
3123                 // We also perform the permission checking here, as the PropertyInfo does not
3124                 // hold the information for the accessibility of its setter/getter
3125                 //
3126                 void ResolveAccessors (EmitContext ec)
3127                 {
3128                         FindAccessors (ec.ContainerType);
3129
3130                         if (getter != null) {
3131                                 AccessorTable [getter] = PropertyInfo;
3132                                 is_static = getter.IsStatic;
3133                         }
3134
3135                         if (setter != null) {
3136                                 AccessorTable [setter] = PropertyInfo;
3137                                 is_static = setter.IsStatic;
3138                         }
3139                 }
3140
3141                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
3142                 {
3143                         if ((instance_expr == null) && ec.IsStatic && !is_static) {
3144                                 SimpleName.Error_ObjectRefRequired (ec, loc, PropertyInfo.Name);
3145                                 return false;
3146                         }
3147
3148                         if (instance_expr != null) {
3149                                 instance_expr = instance_expr.DoResolve (ec);
3150                                 if (instance_expr == null)
3151                                         return false;
3152
3153                                 instance_expr.CheckMarshallByRefAccess (ec.ContainerType);
3154                         }
3155
3156                         if (must_do_cs1540_check && (instance_expr != null)) {
3157                                 if ((instance_expr.Type != ec.ContainerType) &&
3158                                     ec.ContainerType.IsSubclassOf (instance_expr.Type)) {
3159                                         Report.Error (1540, loc, "Cannot access protected member `" +
3160                                                       PropertyInfo.DeclaringType + "." + PropertyInfo.Name +
3161                                                       "' via a qualifier of type `" +
3162                                                       TypeManager.CSharpName (instance_expr.Type) +
3163                                                       "'; the qualifier must be of type `" +
3164                                                       TypeManager.CSharpName (ec.ContainerType) +
3165                                                       "' (or derived from it)");
3166                                         return false;
3167                                 }
3168                         }
3169
3170                         return true;
3171                 }
3172
3173                 override public Expression DoResolve (EmitContext ec)
3174                 {
3175                         if (getter != null){
3176                                 if (TypeManager.GetArgumentTypes (getter).Length != 0){
3177                                         Report.Error (
3178                                                 117, loc, "`{0}' does not contain a " +
3179                                                 "definition for `{1}'.", getter.DeclaringType,
3180                                                 Name);
3181                                         return null;
3182                                 }
3183                         }
3184
3185                         if (getter == null){
3186                                 //
3187                                 // The following condition happens if the PropertyExpr was
3188                                 // created, but is invalid (ie, the property is inaccessible),
3189                                 // and we did not want to embed the knowledge about this in
3190                                 // the caller routine.  This only avoids double error reporting.
3191                                 //
3192                                 if (setter == null)
3193                                         return null;
3194
3195                                 Report.Error (154, loc,
3196                                               "The property `" + PropertyInfo.Name +
3197                                               "' can not be used in " +
3198                                               "this context because it lacks a get accessor");
3199                                 return null;
3200                         }
3201
3202                         bool must_do_cs1540_check;
3203                         if (!IsAccessorAccessible (ec.ContainerType, getter, out must_do_cs1540_check)) {
3204                                 Report.Error (122, loc, "'{0}.get' is inaccessible due to its protection level", PropertyInfo.Name);
3205                                 return null;
3206                         }
3207
3208                         if (!InstanceResolve (ec, must_do_cs1540_check))
3209                                 return null;
3210
3211                         //
3212                         // Only base will allow this invocation to happen.
3213                         //
3214                         if (IsBase && getter.IsAbstract){
3215                                 Report.Error (205, loc, "Cannot call an abstract base property: " +
3216                                               PropertyInfo.DeclaringType + "." +PropertyInfo.Name);
3217                                 return null;
3218                         }
3219
3220                         return this;
3221                 }
3222
3223                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3224                 {
3225                         if (setter == null){
3226                                 //
3227                                 // The following condition happens if the PropertyExpr was
3228                                 // created, but is invalid (ie, the property is inaccessible),
3229                                 // and we did not want to embed the knowledge about this in
3230                                 // the caller routine.  This only avoids double error reporting.
3231                                 //
3232                                 if (getter == null)
3233                                         return null;
3234
3235                                 Report.Error (154, loc,
3236                                               "The property `" + PropertyInfo.Name +
3237                                               "' can not be used in " +
3238                                               "this context because it lacks a set accessor");
3239                                 return null;
3240                         }
3241
3242                         if (TypeManager.GetArgumentTypes (setter).Length != 1){
3243                                 Report.Error (
3244                                         117, loc, "`{0}' does not contain a " +
3245                                         "definition for `{1}'.", getter.DeclaringType,
3246                                         Name);
3247                                 return null;
3248                         }
3249
3250                         bool must_do_cs1540_check;
3251                         if (!IsAccessorAccessible (ec.ContainerType, setter, out must_do_cs1540_check)) {
3252                                 Report.Error (122, loc, "'{0}.set' is inaccessible due to its protection level", PropertyInfo.Name);
3253                                 return null;
3254                         }
3255
3256                         if (!InstanceResolve (ec, must_do_cs1540_check))
3257                                 return null;
3258
3259                         //
3260                         // Only base will allow this invocation to happen.
3261                         //
3262                         if (IsBase && setter.IsAbstract){
3263                                 Report.Error (205, loc, "Cannot call an abstract base property: " +
3264                                               PropertyInfo.DeclaringType + "." +PropertyInfo.Name);
3265                                 return null;
3266                         }
3267
3268                         //
3269                         // Check that we are not making changes to a temporary memory location
3270                         //
3271                         if (instance_expr != null && instance_expr.Type.IsValueType && !(instance_expr is IMemoryLocation)) {
3272                                 // FIXME: Provide better error reporting.
3273                                 Error (1612, "Cannot modify expression because it is not a variable.");
3274                                 return null;
3275                         }
3276
3277                         return this;
3278                 }
3279
3280
3281
3282                 public override void Emit (EmitContext ec)
3283                 {
3284                         Emit (ec, false);
3285                 }
3286
3287                 void EmitInstance (EmitContext ec)
3288                 {
3289                         if (is_static)
3290                                 return;
3291
3292                         if (instance_expr.Type.IsValueType) {
3293                                 if (instance_expr is IMemoryLocation) {
3294                                         ((IMemoryLocation) instance_expr).AddressOf (ec, AddressOp.LoadStore);
3295                                 } else {
3296                                         LocalTemporary t = new LocalTemporary (ec, instance_expr.Type);
3297                                         instance_expr.Emit (ec);
3298                                         t.Store (ec);
3299                                         t.AddressOf (ec, AddressOp.Store);
3300                                 }
3301                         } else
3302                                 instance_expr.Emit (ec);
3303
3304                         if (prepared)
3305                                 ec.ig.Emit (OpCodes.Dup);
3306                 }
3307
3308
3309                 public void Emit (EmitContext ec, bool leave_copy)
3310                 {
3311                         if (!prepared)
3312                                 EmitInstance (ec);
3313
3314                         //
3315                         // Special case: length of single dimension array property is turned into ldlen
3316                         //
3317                         if ((getter == TypeManager.system_int_array_get_length) ||
3318                             (getter == TypeManager.int_array_get_length)){
3319                                 Type iet = instance_expr.Type;
3320
3321                                 //
3322                                 // System.Array.Length can be called, but the Type does not
3323                                 // support invoking GetArrayRank, so test for that case first
3324                                 //
3325                                 if (iet != TypeManager.array_type && (iet.GetArrayRank () == 1)) {
3326                                         ec.ig.Emit (OpCodes.Ldlen);
3327                                         ec.ig.Emit (OpCodes.Conv_I4);
3328                                         return;
3329                                 }
3330                         }
3331
3332                         Invocation.EmitCall (ec, IsBase, IsStatic, new EmptyAddressOf (), getter, null, loc);
3333
3334                         if (!leave_copy)
3335                                 return;
3336
3337                         ec.ig.Emit (OpCodes.Dup);
3338                         if (!is_static) {
3339                                 temp = new LocalTemporary (ec, this.Type);
3340                                 temp.Store (ec);
3341                         }
3342                 }
3343
3344                 //
3345                 // Implements the IAssignMethod interface for assignments
3346                 //
3347                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
3348                 {
3349                         prepared = prepare_for_load;
3350
3351                         EmitInstance (ec);
3352
3353                         source.Emit (ec);
3354                         if (leave_copy) {
3355                                 ec.ig.Emit (OpCodes.Dup);
3356                                 if (!is_static) {
3357                                         temp = new LocalTemporary (ec, this.Type);
3358                                         temp.Store (ec);
3359                                 }
3360                         }
3361
3362                         ArrayList args = new ArrayList (1);
3363                         args.Add (new Argument (new EmptyAddressOf (), Argument.AType.Expression));
3364
3365                         Invocation.EmitCall (ec, IsBase, IsStatic, new EmptyAddressOf (), setter, args, loc);
3366
3367                         if (temp != null)
3368                                 temp.Emit (ec);
3369                 }
3370
3371                 override public void EmitStatement (EmitContext ec)
3372                 {
3373                         Emit (ec);
3374                         ec.ig.Emit (OpCodes.Pop);
3375                 }
3376         }
3377
3378         /// <summary>
3379         ///   Fully resolved expression that evaluates to an Event
3380         /// </summary>
3381         public class EventExpr : Expression, IMemberExpr {
3382                 public readonly EventInfo EventInfo;
3383                 Expression instance_expr;
3384
3385                 bool is_static;
3386                 MethodInfo add_accessor, remove_accessor;
3387
3388                 public EventExpr (EventInfo ei, Location loc)
3389                 {
3390                         EventInfo = ei;
3391                         this.loc = loc;
3392                         eclass = ExprClass.EventAccess;
3393
3394                         add_accessor = TypeManager.GetAddMethod (ei);
3395                         remove_accessor = TypeManager.GetRemoveMethod (ei);
3396
3397                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
3398                                 is_static = true;
3399
3400                         if (EventInfo is MyEventBuilder){
3401                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
3402                                 type = eb.EventType;
3403                                 eb.SetUsed ();
3404                         } else
3405                                 type = EventInfo.EventHandlerType;
3406                 }
3407
3408                 public string Name {
3409                         get {
3410                                 return EventInfo.Name;
3411                         }
3412                 }
3413
3414                 public bool IsInstance {
3415                         get {
3416                                 return !is_static;
3417                         }
3418                 }
3419
3420                 public bool IsStatic {
3421                         get {
3422                                 return is_static;
3423                         }
3424                 }
3425
3426                 public Type DeclaringType {
3427                         get {
3428                                 return EventInfo.DeclaringType;
3429                         }
3430                 }
3431
3432                 public Expression InstanceExpression {
3433                         get {
3434                                 return instance_expr;
3435                         }
3436
3437                         set {
3438                                 instance_expr = value;
3439                         }
3440                 }
3441
3442                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
3443                 {
3444                         if ((instance_expr == null) && ec.IsStatic && !is_static) {
3445                                 SimpleName.Error_ObjectRefRequired (ec, loc, EventInfo.Name);
3446                                 return false;
3447                         }
3448
3449                         if (instance_expr != null) {
3450                                 instance_expr = instance_expr.DoResolve (ec);
3451                                 if (instance_expr == null)
3452                                         return false;
3453                         }
3454
3455                         //
3456                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
3457                         // However, in the Event case, we reported a CS0122 instead.
3458                         //
3459                         if (must_do_cs1540_check && (instance_expr != null)) {
3460                                 if ((instance_expr.Type != ec.ContainerType) &&
3461                                         ec.ContainerType.IsSubclassOf (instance_expr.Type)) {
3462                                         Report.Error (122, loc, "'{0}' is inaccessible due to its protection level",
3463                                                 DeclaringType.Name + "." + EventInfo.Name);
3464
3465                                         return false;
3466                                 }
3467                         }
3468
3469                         return true;
3470                 }
3471
3472                 public override Expression DoResolve (EmitContext ec)
3473                 {
3474                         if (instance_expr != null) {
3475                                 instance_expr = instance_expr.DoResolve (ec);
3476                                 if (instance_expr == null)
3477                                         return null;
3478                         }
3479
3480                         bool must_do_cs1540_check;
3481                         if (!(IsAccessorAccessible (ec.ContainerType, add_accessor, out must_do_cs1540_check)
3482                                     && IsAccessorAccessible (ec.ContainerType, remove_accessor, out must_do_cs1540_check))) {
3483
3484                                Report.Error (122, loc, "'{0}' is inaccessible due to its protection level",
3485                                                DeclaringType.Name + "." + EventInfo.Name);
3486                                return null;
3487                         }
3488
3489                         if (!InstanceResolve (ec, must_do_cs1540_check))
3490                                 return null;
3491
3492                         return this;
3493                 }
3494
3495                 public override void Emit (EmitContext ec)
3496                 {
3497                         if (instance_expr is This)
3498                                 Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of += or -=, try calling the actual delegate", Name);
3499                         else
3500                                 Report.Error (70, loc, "The event `{0}' can only appear on the left hand side of += or -= "+
3501                                               "(except on the defining type)", Name);
3502                 }
3503
3504                 public void EmitAddOrRemove (EmitContext ec, Expression source)
3505                 {
3506                         BinaryDelegate source_del = (BinaryDelegate) source;
3507                         Expression handler = source_del.Right;
3508
3509                         Argument arg = new Argument (handler, Argument.AType.Expression);
3510                         ArrayList args = new ArrayList ();
3511
3512                         args.Add (arg);
3513
3514                         if (source_del.IsAddition)
3515                                 Invocation.EmitCall (
3516                                         ec, false, IsStatic, instance_expr, add_accessor, args, loc);
3517                         else
3518                                 Invocation.EmitCall (
3519                                         ec, false, IsStatic, instance_expr, remove_accessor, args, loc);
3520                 }
3521         }
3522 }