mcs/gmcs/ecore.cs

   1 //
   2 // ecore.cs: Core of the Expression representation for the intermediate tree.
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //
   7 // (C) 2001, 2002, 2003 Ximian, Inc.
   8 //
   9 //
  10
  11 namespace Mono.CSharp {
  12         using System;
  13         using System.Collections;
  14         using System.Diagnostics;
  15         using System.Reflection;
  16         using System.Reflection.Emit;
  17         using System.Text;
  18
  19         /// <remarks>
  20         ///   The ExprClass class contains the is used to pass the
  21         ///   classification of an expression (value, variable, namespace,
  22         ///   type, method group, property access, event access, indexer access,
  23         ///   nothing).
  24         /// </remarks>
  25         public enum ExprClass : byte {
  26                 Invalid,
  27
  28                 Value,
  29                 Variable,
  30                 Namespace,
  31                 Type,
  32                 MethodGroup,
  33                 PropertyAccess,
  34                 EventAccess,
  35                 IndexerAccess,
  36                 Nothing,
  37         }
  38
  39         /// <remarks>
  40         ///   This is used to tell Resolve in which types of expressions we're
  41         ///   interested.
  42         /// </remarks>
  43         [Flags]
  44         public enum ResolveFlags {
  45                 // Returns Value, Variable, PropertyAccess, EventAccess or IndexerAccess.
  46                 VariableOrValue         = 1,
  47
  48                 // Returns a type expression.
  49                 Type                    = 2,
  50
  51                 // Returns a method group.
  52                 MethodGroup             = 4,
  53
  54                 // Mask of all the expression class flags.
  55                 MaskExprClass           = 7,
  56
  57                 // Disable control flow analysis while resolving the expression.
  58                 // This is used when resolving the instance expression of a field expression.
  59                 DisableFlowAnalysis     = 8,
  60
  61                 // Set if this is resolving the first part of a MemberAccess.
  62                 Intermediate            = 16
  63         }
  64
  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 null;
 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 virtual TypeExpr ResolveAsTypeTerminal (EmitContext ec)
 320                 {
 321                         int errors = Report.Errors;
 322
 323                         FullNamedExpression fne = ResolveAsTypeStep (ec);
 324
 325                         if (fne == null) {
 326                                 if (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 (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).DoResolve (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                         int errors = Report.Errors;
 455                         Expression e = DoResolveLValue (ec, right_side);
 456
 457                         if (e == null) {
 458                                 if (errors == Report.Errors)
 459                                         Report.Error (131, Location, "The left-hand side of an assignment or mutating operation must be a variable, property or indexer");
 460                                 return null;
 461                         }
 462
 463                         if (e != null){
 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) && !(e is ConstructedType))
 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 (
 633                                 container_type, qualifier_type,queried_type, mt, bf, name,
 634                                 almostMatchedMembers);
 635
 636                         if (mi == null)
 637                                 return null;
 638
 639                         int count = mi.Length;
 640
 641                         if (mi [0] is MethodBase)
 642                                 return new MethodGroupExpr (mi, loc);
 643
 644                         if (count > 1)
 645                                 return null;
 646
 647                         return ExprClassFromMemberInfo (ec, mi [0], loc);
 648                 }
 649
 650                 public const MemberTypes AllMemberTypes =
 651                         MemberTypes.Constructor |
 652                         MemberTypes.Event       |
 653                         MemberTypes.Field       |
 654                         MemberTypes.Method      |
 655                         MemberTypes.NestedType  |
 656                         MemberTypes.Property;
 657
 658                 public const BindingFlags AllBindingFlags =
 659                         BindingFlags.Public |
 660                         BindingFlags.Static |
 661                         BindingFlags.Instance;
 662
 663                 public static Expression MemberLookup (EmitContext ec, Type queried_type,
 664                                                        string name, Location loc)
 665                 {
 666                         return MemberLookup (ec, ec.ContainerType, null, queried_type, name,
 667                                              AllMemberTypes, AllBindingFlags, loc);
 668                 }
 669
 670                 public static Expression MemberLookup (EmitContext ec, Type qualifier_type,
 671                                                        Type queried_type, string name, Location loc)
 672                 {
 673                         return MemberLookup (ec, ec.ContainerType, qualifier_type, queried_type,
 674                                              name, AllMemberTypes, AllBindingFlags, loc);
 675                 }
 676
 677                 public static Expression MethodLookup (EmitContext ec, Type queried_type,
 678                                                        string name, Location loc)
 679                 {
 680                         return MemberLookup (ec, ec.ContainerType, null, queried_type, name,
 681                                              MemberTypes.Method, AllBindingFlags, loc);
 682                 }
 683
 684                 /// <summary>
 685                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 686                 ///   to find a final definition.  If the final definition is not found, we
 687                 ///   look for private members and display a useful debugging message if we
 688                 ///   find it.
 689                 /// </summary>
 690                 public static Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 691                                                             Type queried_type, string name,
 692                                                             Location loc)
 693                 {
 694                         return MemberLookupFinal (ec, qualifier_type, queried_type, name,
 695                                                   AllMemberTypes, AllBindingFlags, loc);
 696                 }
 697
 698                 public static Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 699                                                             Type queried_type, string name,
 700                                                             MemberTypes mt, BindingFlags bf,
 701                                                             Location loc)
 702                 {
 703                         Expression e;
 704
 705                         int errors = Report.Errors;
 706
 707                         e = MemberLookup (ec, ec.ContainerType, qualifier_type, queried_type,
 708                                           name, mt, bf, loc);
 709
 710                         if (e == null && errors == Report.Errors)
 711                                 // No errors were reported by MemberLookup, but there was an error.
 712                                 MemberLookupFailed (ec, qualifier_type, queried_type, name, null, true, loc);
 713
 714                         return e;
 715                 }
 716
 717                 public static void MemberLookupFailed (EmitContext ec, Type qualifier_type,
 718                                                        Type queried_type, string name,
 719                                                        string class_name, bool complain_if_none_found,
 720                                                        Location loc)
 721                 {
 722                         if (almostMatchedMembers.Count != 0) {
 723                                 if (qualifier_type == null) {
 724                                         foreach (MemberInfo m in almostMatchedMembers)
 725                                                 Report.Error (38, loc,
 726                                                               "Cannot access non-static member `{0}' via nested type `{1}'",
 727                                                               TypeManager.GetFullNameSignature (m),
 728                                                               TypeManager.CSharpName (ec.ContainerType));
 729                                         return;
 730                                 }
 731
 732
 733                                 if (qualifier_type != ec.ContainerType) {
 734                                         // Although a derived class can access protected members of
 735                                         // its base class it cannot do so through an instance of the
 736                                         // base class (CS1540).  If the qualifier_type is a base of the
 737                                         // ec.ContainerType and the lookup succeeds with the latter one,
 738                                         // then we are in this situation.
 739                                         for (int i = 0; i < almostMatchedMembers.Count; ++i) {
 740                                                 MemberInfo m = (MemberInfo) almostMatchedMembers [i];
 741                                                 for (int j = 0; j < i; ++j) {
 742                                                         if (m == almostMatchedMembers [j]) {
 743                                                                 m = null;
 744                                                                 break;
 745                                                         }
 746                                                 }
 747                                                 if (m == null)
 748                                                         continue;
 749
 750                                                 Report.SymbolRelatedToPreviousError (m);
 751                                                 Report.Error (1540, loc,
 752                                                               "Cannot access protected member `{0}' via a qualifier of type `{1}';"
 753                                                               + " the qualifier must be of type `{2}' (or derived from it)",
 754                                                               TypeManager.GetFullNameSignature (m),
 755                                                               TypeManager.CSharpName (qualifier_type),
 756                                                               TypeManager.CSharpName (ec.ContainerType));
 757                                         }
 758                                         return;
 759                                 }
 760                                 almostMatchedMembers.Clear ();
 761                         }
 762
 763                         MemberInfo[] mi = TypeManager.MemberLookup (queried_type, null, queried_type,
 764                                                                     AllMemberTypes, AllBindingFlags |
 765                                                                     BindingFlags.NonPublic, name, null);
 766
 767                         if (mi == null) {
 768                                 if (!complain_if_none_found)
 769                                         return;
 770
 771                                 if (class_name != null)
 772                                         Report.Error (103, loc, "The name `" + name + "' could not be " +
 773                                                       "found in `" + class_name + "'");
 774                                 else
 775                                         Report.Error (
 776                                                 117, loc, "`" + queried_type + "' does not contain a " +
 777                                                 "definition for `" + name + "'");
 778                                 return;
 779                         }
 780
 781                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 782                                                       AllMemberTypes, AllBindingFlags |
 783                                                       BindingFlags.NonPublic, name, null) == null) {
 784                                 if ((mi.Length == 1) && (mi [0] is Type)) {
 785                                         Type t = (Type) mi [0];
 786
 787                                         Report.Error (305, loc,
 788                                                       "Using the generic type `{0}' " +
 789                                                       "requires {1} type arguments",
 790                                                       TypeManager.GetFullName (t),
 791                                                       TypeManager.GetNumberOfTypeArguments (t));
 792                                         return;
 793                                 }
 794                         }
 795
 796                         if (name == ".ctor" && TypeManager.FindMembers (qualifier_type, MemberTypes.Constructor,
 797                                 BindingFlags.Static | BindingFlags.Instance | BindingFlags.Public | BindingFlags.DeclaredOnly, null, null).Count == 0)
 798                         {
 799                                 Report.Error (143, loc, String.Format ("The type '{0}' has no constructors defined", TypeManager.CSharpName (queried_type)));
 800                                 return;
 801                         }
 802
 803                         if (qualifier_type != null) {
 804                                 Report.Error (122, loc, "'{0}' is inaccessible due to its protection level", TypeManager.CSharpName (qualifier_type) + "." + name);
 805                         } else {
 806                                 Report.Error (122, loc, "'{0}' is inaccessible due to its protection level", name);
 807                 }
 808                 }
 809
 810                 static public MemberInfo GetFieldFromEvent (EventExpr event_expr)
 811                 {
 812                         EventInfo ei = event_expr.EventInfo;
 813
 814                         return TypeManager.GetPrivateFieldOfEvent (ei);
 815                 }
 816
 817                 /// <summary>
 818                 ///   Returns an expression that can be used to invoke operator true
 819                 ///   on the expression if it exists.
 820                 /// </summary>
 821                 static public Expression GetOperatorTrue (EmitContext ec, Expression e, Location loc)
 822                 {
 823                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 824                 }
 825
 826                 /// <summary>
 827                 ///   Returns an expression that can be used to invoke operator false
 828                 ///   on the expression if it exists.
 829                 /// </summary>
 830                 static public Expression GetOperatorFalse (EmitContext ec, Expression e, Location loc)
 831                 {
 832                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 833                 }
 834
 835                 static Expression GetOperatorTrueOrFalse (EmitContext ec, Expression e, bool is_true, Location loc)
 836                 {
 837                         MethodBase method;
 838                         Expression operator_group;
 839
 840                         if (TypeManager.IsNullableType (e.Type))
 841                                 return new Nullable.OperatorTrueOrFalse (e, is_true, loc).Resolve (ec);
 842
 843                         operator_group = MethodLookup (ec, e.Type, is_true ? "op_True" : "op_False", loc);
 844                         if (operator_group == null)
 845                                 return null;
 846
 847                         ArrayList arguments = new ArrayList ();
 848                         arguments.Add (new Argument (e, Argument.AType.Expression));
 849                         method = Invocation.OverloadResolve (
 850                                 ec, (MethodGroupExpr) operator_group, arguments, false, loc);
 851
 852                         if (method == null)
 853                                 return null;
 854
 855                         return new StaticCallExpr ((MethodInfo) method, arguments, loc);
 856                 }
 857
 858                 /// <summary>
 859                 ///   Resolves the expression `e' into a boolean expression: either through
 860                 ///   an implicit conversion, or through an `operator true' invocation
 861                 /// </summary>
 862                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 863                 {
 864                         e = e.Resolve (ec);
 865                         if (e == null)
 866                                 return null;
 867
 868                         if (e.Type == TypeManager.bool_type)
 869                                 return e;
 870
 871                         Expression converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, Location.Null);
 872
 873                         if (converted != null)
 874                                 return converted;
 875
 876                         //
 877                         // If no implicit conversion to bool exists, try using `operator true'
 878                         //
 879                         Expression operator_true = Expression.GetOperatorTrue (ec, e, loc);
 880                         if (operator_true == null){
 881                                 Report.Error (31, loc, "Can not convert the expression to a boolean");
 882                                 return null;
 883                         }
 884                         return operator_true;
 885                 }
 886
 887                 public string ExprClassName ()
 888                 {
 889                         switch (eclass){
 890                         case ExprClass.Invalid:
 891                                 return "Invalid";
 892                         case ExprClass.Value:
 893                                 return "value";
 894                         case ExprClass.Variable:
 895                                 return "variable";
 896                         case ExprClass.Namespace:
 897                                 return "namespace";
 898                         case ExprClass.Type:
 899                                 return "type";
 900                         case ExprClass.MethodGroup:
 901                                 return "method group";
 902                         case ExprClass.PropertyAccess:
 903                                 return "property access";
 904                         case ExprClass.EventAccess:
 905                                 return "event access";
 906                         case ExprClass.IndexerAccess:
 907                                 return "indexer access";
 908                         case ExprClass.Nothing:
 909                                 return "null";
 910                         }
 911                         throw new Exception ("Should not happen");
 912                 }
 913
 914                 /// <summary>
 915                 ///   Reports that we were expecting `expr' to be of class `expected'
 916                 /// </summary>
 917                 public void Error_UnexpectedKind (string expected, Location loc)
 918                 {
 919                         Report.Error (118, loc, "Expression denotes a `" + ExprClassName () +
 920                                "' where a `" + expected + "' was expected");
 921                 }
 922
 923                 public void Error_UnexpectedKind (ResolveFlags flags, Location loc)
 924                 {
 925                         ArrayList valid = new ArrayList (10);
 926
 927                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
 928                                 valid.Add ("variable");
 929                                 valid.Add ("value");
 930                         }
 931
 932                         if ((flags & ResolveFlags.Type) != 0)
 933                                 valid.Add ("type");
 934
 935                         if ((flags & ResolveFlags.MethodGroup) != 0)
 936                                 valid.Add ("method group");
 937
 938                         if (valid.Count == 0)
 939                                 valid.Add ("unknown");
 940
 941                         StringBuilder sb = new StringBuilder ();
 942                         for (int i = 0; i < valid.Count; i++) {
 943                                 if (i > 0)
 944                                         sb.Append (", ");
 945                                 else if (i == valid.Count)
 946                                         sb.Append (" or ");
 947                                 sb.Append (valid [i]);
 948                         }
 949
 950                         Report.Error (119, loc, "Expression denotes a `" + ExprClassName () + "' where " +
 951                                "a `" + sb.ToString () + "' was expected");
 952                 }
 953
 954                 static public void Error_ConstantValueCannotBeConverted (Location l, string val, Type t)
 955                 {
 956                         Report.Error (31, l, "Constant value `" + val + "' cannot be converted to " +
 957                                       TypeManager.CSharpName (t));
 958                 }
 959
 960                 public static void UnsafeError (Location loc)
 961                 {
 962                         Report.Error (214, loc, "Pointers may only be used in an unsafe context");
 963                 }
 964
 965                 /// <summary>
 966                 ///   Converts the IntConstant, UIntConstant, LongConstant or
 967                 ///   ULongConstant into the integral target_type.   Notice
 968                 ///   that we do not return an `Expression' we do return
 969                 ///   a boxed integral type.
 970                 ///
 971                 ///   FIXME: Since I added the new constants, we need to
 972                 ///   also support conversions from CharConstant, ByteConstant,
 973                 ///   SByteConstant, UShortConstant, ShortConstant
 974                 ///
 975                 ///   This is used by the switch statement, so the domain
 976                 ///   of work is restricted to the literals above, and the
 977                 ///   targets are int32, uint32, char, byte, sbyte, ushort,
 978                 ///   short, uint64 and int64
 979                 /// </summary>
 980                 public static object ConvertIntLiteral (Constant c, Type target_type, Location loc)
 981                 {
 982                         if (!Convert.ImplicitStandardConversionExists (Convert.ConstantEC, c, target_type)){
 983                                 Convert.Error_CannotImplicitConversion (loc, c.Type, target_type);
 984                                 return null;
 985                         }
 986
 987                         string s = "";
 988
 989                         if (c.Type == target_type)
 990                                 return ((Constant) c).GetValue ();
 991
 992                         //
 993                         // Make into one of the literals we handle, we dont really care
 994                         // about this value as we will just return a few limited types
 995                         //
 996                         if (c is EnumConstant)
 997                                 c = ((EnumConstant)c).WidenToCompilerConstant ();
 998
 999                         if (c is IntConstant){
1000                                 int v = ((IntConstant) c).Value;
1001
1002                                 if (target_type == TypeManager.uint32_type){
1003                                         if (v >= 0)
1004                                                 return (uint) v;
1005                                 } else if (target_type == TypeManager.char_type){
1006                                         if (v >= Char.MinValue && v <= Char.MaxValue)
1007                                                 return (char) v;
1008                                 } else if (target_type == TypeManager.byte_type){
1009                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1010                                                 return (byte) v;
1011                                 } else if (target_type == TypeManager.sbyte_type){
1012                                         if (v >= SByte.MinValue && v <= SByte.MaxValue)
1013                                                 return (sbyte) v;
1014                                 } else if (target_type == TypeManager.short_type){
1015                                         if (v >= Int16.MinValue && v <= UInt16.MaxValue)
1016                                                 return (short) v;
1017                                 } else if (target_type == TypeManager.ushort_type){
1018                                         if (v >= UInt16.MinValue && v <= UInt16.MaxValue)
1019                                                 return (ushort) v;
1020                                 } else if (target_type == TypeManager.int64_type)
1021                                         return (long) v;
1022                                 else if (target_type == TypeManager.uint64_type){
1023                                         if (v > 0)
1024                                                 return (ulong) v;
1025                                 }
1026
1027                                 s = v.ToString ();
1028                         } else if (c is UIntConstant){
1029                                 uint v = ((UIntConstant) c).Value;
1030
1031                                 if (target_type == TypeManager.int32_type){
1032                                         if (v <= Int32.MaxValue)
1033                                                 return (int) v;
1034                                 } else if (target_type == TypeManager.char_type){
1035                                         if (v >= Char.MinValue && v <= Char.MaxValue)
1036                                                 return (char) v;
1037                                 } else if (target_type == TypeManager.byte_type){
1038                                         if (v <= Byte.MaxValue)
1039                                                 return (byte) v;
1040                                 } else if (target_type == TypeManager.sbyte_type){
1041                                         if (v <= SByte.MaxValue)
1042                                                 return (sbyte) v;
1043                                 } else if (target_type == TypeManager.short_type){
1044                                         if (v <= UInt16.MaxValue)
1045                                                 return (short) v;
1046                                 } else if (target_type == TypeManager.ushort_type){
1047                                         if (v <= UInt16.MaxValue)
1048                                                 return (ushort) v;
1049                                 } else if (target_type == TypeManager.int64_type)
1050                                         return (long) v;
1051                                 else if (target_type == TypeManager.uint64_type)
1052                                         return (ulong) v;
1053                                 s = v.ToString ();
1054                         } else if (c is LongConstant){
1055                                 long v = ((LongConstant) c).Value;
1056
1057                                 if (target_type == TypeManager.int32_type){
1058                                         if (v >= UInt32.MinValue && v <= UInt32.MaxValue)
1059                                                 return (int) v;
1060                                 } else if (target_type == TypeManager.uint32_type){
1061                                         if (v >= 0 && v <= UInt32.MaxValue)
1062                                                 return (uint) v;
1063                                 } else if (target_type == TypeManager.char_type){
1064                                         if (v >= Char.MinValue && v <= Char.MaxValue)
1065                                                 return (char) v;
1066                                 } else if (target_type == TypeManager.byte_type){
1067                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1068                                                 return (byte) v;
1069                                 } else if (target_type == TypeManager.sbyte_type){
1070                                         if (v >= SByte.MinValue && v <= SByte.MaxValue)
1071                                                 return (sbyte) v;
1072                                 } else if (target_type == TypeManager.short_type){
1073                                         if (v >= Int16.MinValue && v <= UInt16.MaxValue)
1074                                                 return (short) v;
1075                                 } else if (target_type == TypeManager.ushort_type){
1076                                         if (v >= UInt16.MinValue && v <= UInt16.MaxValue)
1077                                                 return (ushort) v;
1078                                 } else if (target_type == TypeManager.uint64_type){
1079                                         if (v > 0)
1080                                                 return (ulong) v;
1081                                 }
1082                                 s = v.ToString ();
1083                         } else if (c is ULongConstant){
1084                                 ulong v = ((ULongConstant) c).Value;
1085
1086                                 if (target_type == TypeManager.int32_type){
1087                                         if (v <= Int32.MaxValue)
1088                                                 return (int) v;
1089                                 } else if (target_type == TypeManager.uint32_type){
1090                                         if (v <= UInt32.MaxValue)
1091                                                 return (uint) v;
1092                                 } else if (target_type == TypeManager.char_type){
1093                                         if (v >= Char.MinValue && v <= Char.MaxValue)
1094                                                 return (char) v;
1095                                 } else if (target_type == TypeManager.byte_type){
1096                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1097                                                 return (byte) v;
1098                                 } else if (target_type == TypeManager.sbyte_type){
1099                                         if (v <= (int) SByte.MaxValue)
1100                                                 return (sbyte) v;
1101                                 } else if (target_type == TypeManager.short_type){
1102                                         if (v <= UInt16.MaxValue)
1103                                                 return (short) v;
1104                                 } else if (target_type == TypeManager.ushort_type){
1105                                         if (v <= UInt16.MaxValue)
1106                                                 return (ushort) v;
1107                                 } else if (target_type == TypeManager.int64_type){
1108                                         if (v <= Int64.MaxValue)
1109                                                 return (long) v;
1110                                 }
1111                                 s = v.ToString ();
1112                         } else if (c is ByteConstant){
1113                                 byte v = ((ByteConstant) c).Value;
1114
1115                                 if (target_type == TypeManager.int32_type)
1116                                         return (int) v;
1117                                 else if (target_type == TypeManager.uint32_type)
1118                                         return (uint) v;
1119                                 else if (target_type == TypeManager.char_type)
1120                                         return (char) v;
1121                                 else if (target_type == TypeManager.sbyte_type){
1122                                         if (v <= SByte.MaxValue)
1123                                                 return (sbyte) v;
1124                                 } else if (target_type == TypeManager.short_type)
1125                                         return (short) v;
1126                                 else if (target_type == TypeManager.ushort_type)
1127                                         return (ushort) v;
1128                                 else if (target_type == TypeManager.int64_type)
1129                                         return (long) v;
1130                                 else if (target_type == TypeManager.uint64_type)
1131                                         return (ulong) v;
1132                                 s = v.ToString ();
1133                         } else if (c is SByteConstant){
1134                                 sbyte v = ((SByteConstant) 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 >= 0)
1146                                                 return (byte) v;
1147                                 } else if (target_type == TypeManager.short_type)
1148                                         return (short) v;
1149                                 else if (target_type == TypeManager.ushort_type){
1150                                         if (v >= 0)
1151                                                 return (ushort) v;
1152                                 } else if (target_type == TypeManager.int64_type)
1153                                         return (long) v;
1154                                 else if (target_type == TypeManager.uint64_type){
1155                                         if (v >= 0)
1156                                                 return (ulong) v;
1157                                 }
1158                                 s = v.ToString ();
1159                         } else if (c is ShortConstant){
1160                                 short v = ((ShortConstant) c).Value;
1161
1162                                 if (target_type == TypeManager.int32_type){
1163                                         return (int) v;
1164                                 } else if (target_type == TypeManager.uint32_type){
1165                                         if (v >= 0)
1166                                                 return (uint) v;
1167                                 } else if (target_type == TypeManager.char_type){
1168                                         if (v >= 0)
1169                                                 return (char) v;
1170                                 } else if (target_type == TypeManager.byte_type){
1171                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1172                                                 return (byte) v;
1173                                 } else if (target_type == TypeManager.sbyte_type){
1174                                         if (v >= SByte.MinValue && v <= SByte.MaxValue)
1175                                                 return (sbyte) v;
1176                                 } else if (target_type == TypeManager.ushort_type){
1177                                         if (v >= 0)
1178                                                 return (ushort) v;
1179                                 } else if (target_type == TypeManager.int64_type)
1180                                         return (long) v;
1181                                 else if (target_type == TypeManager.uint64_type)
1182                                         return (ulong) v;
1183
1184                                 s = v.ToString ();
1185                         } else if (c is UShortConstant){
1186                                 ushort v = ((UShortConstant) c).Value;
1187
1188                                 if (target_type == TypeManager.int32_type)
1189                                         return (int) v;
1190                                 else if (target_type == TypeManager.uint32_type)
1191                                         return (uint) v;
1192                                 else if (target_type == TypeManager.char_type){
1193                                         if (v >= Char.MinValue && v <= Char.MaxValue)
1194                                                 return (char) v;
1195                                 } else if (target_type == TypeManager.byte_type){
1196                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1197                                                 return (byte) v;
1198                                 } else if (target_type == TypeManager.sbyte_type){
1199                                         if (v <= SByte.MaxValue)
1200                                                 return (byte) v;
1201                                 } else if (target_type == TypeManager.short_type){
1202                                         if (v <= Int16.MaxValue)
1203                                                 return (short) v;
1204                                 } else if (target_type == TypeManager.int64_type)
1205                                         return (long) v;
1206                                 else if (target_type == TypeManager.uint64_type)
1207                                         return (ulong) v;
1208
1209                                 s = v.ToString ();
1210                         } else if (c is CharConstant){
1211                                 char v = ((CharConstant) c).Value;
1212
1213                                 if (target_type == TypeManager.int32_type)
1214                                         return (int) v;
1215                                 else if (target_type == TypeManager.uint32_type)
1216                                         return (uint) v;
1217                                 else if (target_type == TypeManager.byte_type){
1218                                         if (v >= Byte.MinValue && v <= Byte.MaxValue)
1219                                                 return (byte) v;
1220                                 } else if (target_type == TypeManager.sbyte_type){
1221                                         if (v <= SByte.MaxValue)
1222                                                 return (sbyte) v;
1223                                 } else if (target_type == TypeManager.short_type){
1224                                         if (v <= Int16.MaxValue)
1225                                                 return (short) v;
1226                                 } else if (target_type == TypeManager.ushort_type)
1227                                         return (short) v;
1228                                 else if (target_type == TypeManager.int64_type)
1229                                         return (long) v;
1230                                 else if (target_type == TypeManager.uint64_type)
1231                                         return (ulong) v;
1232
1233                                 s = v.ToString ();
1234                         }
1235                         Error_ConstantValueCannotBeConverted (loc, s, target_type);
1236                         return null;
1237                 }
1238
1239                 //
1240                 // Load the object from the pointer.
1241                 //
1242                 public static void LoadFromPtr (ILGenerator ig, Type t)
1243                 {
1244                         if (t == TypeManager.int32_type)
1245                                 ig.Emit (OpCodes.Ldind_I4);
1246                         else if (t == TypeManager.uint32_type)
1247                                 ig.Emit (OpCodes.Ldind_U4);
1248                         else if (t == TypeManager.short_type)
1249                                 ig.Emit (OpCodes.Ldind_I2);
1250                         else if (t == TypeManager.ushort_type)
1251                                 ig.Emit (OpCodes.Ldind_U2);
1252                         else if (t == TypeManager.char_type)
1253                                 ig.Emit (OpCodes.Ldind_U2);
1254                         else if (t == TypeManager.byte_type)
1255                                 ig.Emit (OpCodes.Ldind_U1);
1256                         else if (t == TypeManager.sbyte_type)
1257                                 ig.Emit (OpCodes.Ldind_I1);
1258                         else if (t == TypeManager.uint64_type)
1259                                 ig.Emit (OpCodes.Ldind_I8);
1260                         else if (t == TypeManager.int64_type)
1261                                 ig.Emit (OpCodes.Ldind_I8);
1262                         else if (t == TypeManager.float_type)
1263                                 ig.Emit (OpCodes.Ldind_R4);
1264                         else if (t == TypeManager.double_type)
1265                                 ig.Emit (OpCodes.Ldind_R8);
1266                         else if (t == TypeManager.bool_type)
1267                                 ig.Emit (OpCodes.Ldind_I1);
1268                         else if (t == TypeManager.intptr_type)
1269                                 ig.Emit (OpCodes.Ldind_I);
1270                         else if (TypeManager.IsEnumType (t)) {
1271                                 if (t == TypeManager.enum_type)
1272                                         ig.Emit (OpCodes.Ldind_Ref);
1273                                 else
1274                                         LoadFromPtr (ig, TypeManager.EnumToUnderlying (t));
1275                         } else if (t.IsValueType || t.IsGenericParameter)
1276                                 ig.Emit (OpCodes.Ldobj, t);
1277                         else if (t.IsPointer)
1278                                 ig.Emit (OpCodes.Ldind_I);
1279                         else
1280                                 ig.Emit (OpCodes.Ldind_Ref);
1281                 }
1282
1283                 //
1284                 // The stack contains the pointer and the value of type `type'
1285                 //
1286                 public static void StoreFromPtr (ILGenerator ig, Type type)
1287                 {
1288                         if (TypeManager.IsEnumType (type))
1289                                 type = TypeManager.EnumToUnderlying (type);
1290                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1291                                 ig.Emit (OpCodes.Stind_I4);
1292                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1293                                 ig.Emit (OpCodes.Stind_I8);
1294                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1295                                  type == TypeManager.ushort_type)
1296                                 ig.Emit (OpCodes.Stind_I2);
1297                         else if (type == TypeManager.float_type)
1298                                 ig.Emit (OpCodes.Stind_R4);
1299                         else if (type == TypeManager.double_type)
1300                                 ig.Emit (OpCodes.Stind_R8);
1301                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1302                                  type == TypeManager.bool_type)
1303                                 ig.Emit (OpCodes.Stind_I1);
1304                         else if (type == TypeManager.intptr_type)
1305                                 ig.Emit (OpCodes.Stind_I);
1306                         else if (type.IsValueType || type.IsGenericParameter)
1307                                 ig.Emit (OpCodes.Stobj, type);
1308                         else
1309                                 ig.Emit (OpCodes.Stind_Ref);
1310                 }
1311
1312                 //
1313                 // Returns the size of type `t' if known, otherwise, 0
1314                 //
1315                 public static int GetTypeSize (Type t)
1316                 {
1317                         t = TypeManager.TypeToCoreType (t);
1318                         if (t == TypeManager.int32_type ||
1319                             t == TypeManager.uint32_type ||
1320                             t == TypeManager.float_type)
1321                                 return 4;
1322                         else if (t == TypeManager.int64_type ||
1323                                  t == TypeManager.uint64_type ||
1324                                  t == TypeManager.double_type)
1325                                 return 8;
1326                         else if (t == TypeManager.byte_type ||
1327                                  t == TypeManager.sbyte_type ||
1328                                  t == TypeManager.bool_type)
1329                                 return 1;
1330                         else if (t == TypeManager.short_type ||
1331                                  t == TypeManager.char_type ||
1332                                  t == TypeManager.ushort_type)
1333                                 return 2;
1334                         else if (t == TypeManager.decimal_type)
1335                                 return 16;
1336                         else
1337                                 return 0;
1338                 }
1339
1340                 public static void Error_NegativeArrayIndex (Location loc)
1341                 {
1342                         Report.Error (248, loc, "Cannot create an array with a negative size");
1343                 }
1344
1345                 //
1346                 // Converts `source' to an int, uint, long or ulong.
1347                 //
1348                 public Expression ExpressionToArrayArgument (EmitContext ec, Expression source, Location loc)
1349                 {
1350                         Expression target;
1351
1352                         bool old_checked = ec.CheckState;
1353                         ec.CheckState = true;
1354
1355                         target = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, loc);
1356                         if (target == null){
1357                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, loc);
1358                                 if (target == null){
1359                                         target = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, loc);
1360                                         if (target == null){
1361                                                 target = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, loc);
1362                                                 if (target == null)
1363                                                         Convert.Error_CannotImplicitConversion (loc, source.Type, TypeManager.int32_type);
1364                                         }
1365                                 }
1366                         }
1367                         ec.CheckState = old_checked;
1368
1369                         //
1370                         // Only positive constants are allowed at compile time
1371                         //
1372                         if (target is Constant){
1373                                 if (target is IntConstant){
1374                                         if (((IntConstant) target).Value < 0){
1375                                                 Error_NegativeArrayIndex (loc);
1376                                                 return null;
1377                                         }
1378                                 }
1379
1380                                 if (target is LongConstant){
1381                                         if (((LongConstant) target).Value < 0){
1382                                                 Error_NegativeArrayIndex (loc);
1383                                                 return null;
1384                                         }
1385                                 }
1386
1387                         }
1388
1389                         return target;
1390                 }
1391
1392         }
1393
1394         /// <summary>
1395         ///   This is just a base class for expressions that can
1396         ///   appear on statements (invocations, object creation,
1397         ///   assignments, post/pre increment and decrement).  The idea
1398         ///   being that they would support an extra Emition interface that
1399         ///   does not leave a result on the stack.
1400         /// </summary>
1401         public abstract class ExpressionStatement : Expression {
1402
1403                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1404                 {
1405                         Expression e = Resolve (ec);
1406                         if (e == null)
1407                                 return null;
1408
1409                         ExpressionStatement es = e as ExpressionStatement;
1410                         if (es == null)
1411                                 Error (201, "Only assignment, call, increment, decrement and new object " +
1412                                        "expressions can be used as a statement");
1413
1414                         return es;
1415                 }
1416
1417                 /// <summary>
1418                 ///   Requests the expression to be emitted in a `statement'
1419                 ///   context.  This means that no new value is left on the
1420                 ///   stack after invoking this method (constrasted with
1421                 ///   Emit that will always leave a value on the stack).
1422                 /// </summary>
1423                 public abstract void EmitStatement (EmitContext ec);
1424         }
1425
1426         /// <summary>
1427         ///   This kind of cast is used to encapsulate the child
1428         ///   whose type is child.Type into an expression that is
1429         ///   reported to return "return_type".  This is used to encapsulate
1430         ///   expressions which have compatible types, but need to be dealt
1431         ///   at higher levels with.
1432         ///
1433         ///   For example, a "byte" expression could be encapsulated in one
1434         ///   of these as an "unsigned int".  The type for the expression
1435         ///   would be "unsigned int".
1436         ///
1437         /// </summary>
1438         public class EmptyCast : Expression {
1439                 protected Expression child;
1440
1441                 public Expression Child {
1442                         get {
1443                                 return child;
1444                         }
1445                 }
1446
1447                 public EmptyCast (Expression child, Type return_type)
1448                 {
1449                         eclass = child.eclass;
1450                         loc = child.Location;
1451                         type = return_type;
1452                         this.child = child;
1453                 }
1454
1455                 public override Expression DoResolve (EmitContext ec)
1456                 {
1457                         // This should never be invoked, we are born in fully
1458                         // initialized state.
1459
1460                         return this;
1461                 }
1462
1463                 public override void Emit (EmitContext ec)
1464                 {
1465                         child.Emit (ec);
1466                 }
1467         }
1468
1469         //
1470         // We need to special case this since an empty cast of
1471         // a NullLiteral is still a Constant
1472         //
1473         public class NullCast : Constant {
1474                 protected Expression child;
1475
1476                 public NullCast (Expression child, Type return_type)
1477                 {
1478                         eclass = child.eclass;
1479                         type = return_type;
1480                         this.child = child;
1481                 }
1482
1483                 override public string AsString ()
1484                 {
1485                         return "null";
1486                 }
1487
1488                 public override object GetValue ()
1489                 {
1490                         return null;
1491                 }
1492
1493                 public override Expression DoResolve (EmitContext ec)
1494                 {
1495                         // This should never be invoked, we are born in fully
1496                         // initialized state.
1497
1498                         return this;
1499                 }
1500
1501                 public override void Emit (EmitContext ec)
1502                 {
1503                         child.Emit (ec);
1504                 }
1505
1506                 public override bool IsDefaultValue {
1507                         get {
1508                                 throw new NotImplementedException ();
1509                         }
1510                 }
1511
1512                 public override bool IsNegative {
1513                         get {
1514                                 return false;
1515                         }
1516                 }
1517         }
1518
1519
1520         /// <summary>
1521         ///  This class is used to wrap literals which belong inside Enums
1522         /// </summary>
1523         public class EnumConstant : Constant {
1524                 public Constant Child;
1525
1526                 public EnumConstant (Constant child, Type enum_type)
1527                 {
1528                         eclass = child.eclass;
1529                         this.Child = child;
1530                         type = enum_type;
1531                 }
1532
1533                 public override Expression DoResolve (EmitContext ec)
1534                 {
1535                         // This should never be invoked, we are born in fully
1536                         // initialized state.
1537
1538                         return this;
1539                 }
1540
1541                 public override void Emit (EmitContext ec)
1542                 {
1543                         Child.Emit (ec);
1544                 }
1545
1546                 public override object GetValue ()
1547                 {
1548                         return Child.GetValue ();
1549                 }
1550
1551                 public object GetValueAsEnumType ()
1552                 {
1553                         return System.Enum.ToObject (type, Child.GetValue ());
1554                 }
1555
1556                 //
1557                 // Converts from one of the valid underlying types for an enumeration
1558                 // (int32, uint32, int64, uint64, short, ushort, byte, sbyte) to
1559                 // one of the internal compiler literals: Int/UInt/Long/ULong Literals.
1560                 //
1561                 public Constant WidenToCompilerConstant ()
1562                 {
1563                         Type t = TypeManager.EnumToUnderlying (Child.Type);
1564                         object v = ((Constant) Child).GetValue ();;
1565
1566                         if (t == TypeManager.int32_type)
1567                                 return new IntConstant ((int) v);
1568                         if (t == TypeManager.uint32_type)
1569                                 return new UIntConstant ((uint) v);
1570                         if (t == TypeManager.int64_type)
1571                                 return new LongConstant ((long) v);
1572                         if (t == TypeManager.uint64_type)
1573                                 return new ULongConstant ((ulong) v);
1574                         if (t == TypeManager.short_type)
1575                                 return new ShortConstant ((short) v);
1576                         if (t == TypeManager.ushort_type)
1577                                 return new UShortConstant ((ushort) v);
1578                         if (t == TypeManager.byte_type)
1579                                 return new ByteConstant ((byte) v);
1580                         if (t == TypeManager.sbyte_type)
1581                                 return new SByteConstant ((sbyte) v);
1582
1583                         throw new Exception ("Invalid enumeration underlying type: " + t);
1584                 }
1585
1586                 //
1587                 // Extracts the value in the enumeration on its native representation
1588                 //
1589                 public object GetPlainValue ()
1590                 {
1591                         Type t = TypeManager.EnumToUnderlying (Child.Type);
1592                         object v = ((Constant) Child).GetValue ();;
1593
1594                         if (t == TypeManager.int32_type)
1595                                 return (int) v;
1596                         if (t == TypeManager.uint32_type)
1597                                 return (uint) v;
1598                         if (t == TypeManager.int64_type)
1599                                 return (long) v;
1600                         if (t == TypeManager.uint64_type)
1601                                 return (ulong) v;
1602                         if (t == TypeManager.short_type)
1603                                 return (short) v;
1604                         if (t == TypeManager.ushort_type)
1605                                 return (ushort) v;
1606                         if (t == TypeManager.byte_type)
1607                                 return (byte) v;
1608                         if (t == TypeManager.sbyte_type)
1609                                 return (sbyte) v;
1610
1611                         return null;
1612                 }
1613
1614                 public override string AsString ()
1615                 {
1616                         return Child.AsString ();
1617                 }
1618
1619                 public override DoubleConstant ConvertToDouble ()
1620                 {
1621                         return Child.ConvertToDouble ();
1622                 }
1623
1624                 public override FloatConstant ConvertToFloat ()
1625                 {
1626                         return Child.ConvertToFloat ();
1627                 }
1628
1629                 public override ULongConstant ConvertToULong ()
1630                 {
1631                         return Child.ConvertToULong ();
1632                 }
1633
1634                 public override LongConstant ConvertToLong ()
1635                 {
1636                         return Child.ConvertToLong ();
1637                 }
1638
1639                 public override UIntConstant ConvertToUInt ()
1640                 {
1641                         return Child.ConvertToUInt ();
1642                 }
1643
1644                 public override IntConstant ConvertToInt ()
1645                 {
1646                         return Child.ConvertToInt ();
1647                 }
1648
1649                 public override bool IsDefaultValue {
1650                         get {
1651                                 return Child.IsDefaultValue;
1652                         }
1653                 }
1654
1655                 public override bool IsZeroInteger {
1656                         get { return Child.IsZeroInteger; }
1657                 }
1658
1659                 public override bool IsNegative {
1660                         get {
1661                                 return Child.IsNegative;
1662                         }
1663                 }
1664         }
1665
1666         /// <summary>
1667         ///   This kind of cast is used to encapsulate Value Types in objects.
1668         ///
1669         ///   The effect of it is to box the value type emitted by the previous
1670         ///   operation.
1671         /// </summary>
1672         public class BoxedCast : EmptyCast {
1673
1674                 public BoxedCast (Expression expr)
1675                         : base (expr, TypeManager.object_type)
1676                 {
1677                         eclass = ExprClass.Value;
1678                 }
1679
1680                 public BoxedCast (Expression expr, Type target_type)
1681                         : base (expr, target_type)
1682                 {
1683                         eclass = ExprClass.Value;
1684                 }
1685
1686                 public override Expression DoResolve (EmitContext ec)
1687                 {
1688                         // This should never be invoked, we are born in fully
1689                         // initialized state.
1690
1691                         return this;
1692                 }
1693
1694                 public override void Emit (EmitContext ec)
1695                 {
1696                         base.Emit (ec);
1697
1698                         ec.ig.Emit (OpCodes.Box, child.Type);
1699                 }
1700         }
1701
1702         public class UnboxCast : EmptyCast {
1703                 public UnboxCast (Expression expr, Type return_type)
1704                         : base (expr, return_type)
1705                 {
1706                 }
1707
1708                 public override Expression DoResolve (EmitContext ec)
1709                 {
1710                         // This should never be invoked, we are born in fully
1711                         // initialized state.
1712
1713                         return this;
1714                 }
1715
1716                 public override void Emit (EmitContext ec)
1717                 {
1718                         Type t = type;
1719                         ILGenerator ig = ec.ig;
1720
1721                         base.Emit (ec);
1722                         if (t.IsGenericParameter)
1723                                 ig.Emit (OpCodes.Unbox_Any, t);
1724                         else {
1725                                 ig.Emit (OpCodes.Unbox, t);
1726
1727                                 LoadFromPtr (ig, t);
1728                         }
1729                 }
1730         }
1731
1732         /// <summary>
1733         ///   This is used to perform explicit numeric conversions.
1734         ///
1735         ///   Explicit numeric conversions might trigger exceptions in a checked
1736         ///   context, so they should generate the conv.ovf opcodes instead of
1737         ///   conv opcodes.
1738         /// </summary>
1739         public class ConvCast : EmptyCast {
1740                 public enum Mode : byte {
1741                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1742                         U1_I1, U1_CH,
1743                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1744                         U2_I1, U2_U1, U2_I2, U2_CH,
1745                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1746                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1747                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH,
1748                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH,
1749                         CH_I1, CH_U1, CH_I2,
1750                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1751                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4
1752                 }
1753
1754                 Mode mode;
1755                 bool checked_state;
1756
1757                 public ConvCast (EmitContext ec, Expression child, Type return_type, Mode m)
1758                         : base (child, return_type)
1759                 {
1760                         checked_state = ec.CheckState;
1761                         mode = m;
1762                 }
1763
1764                 public override Expression DoResolve (EmitContext ec)
1765                 {
1766                         // This should never be invoked, we are born in fully
1767                         // initialized state.
1768
1769                         return this;
1770                 }
1771
1772                 public override string ToString ()
1773                 {
1774                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1775                 }
1776
1777                 public override void Emit (EmitContext ec)
1778                 {
1779                         ILGenerator ig = ec.ig;
1780
1781                         base.Emit (ec);
1782
1783                         if (checked_state){
1784                                 switch (mode){
1785                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1786                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1787                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1788                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1789                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1790
1791                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1792                                 case Mode.U1_CH: /* nothing */ break;
1793
1794                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1795                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1796                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1797                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1798                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1799                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1800
1801                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1802                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1803                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1804                                 case Mode.U2_CH: /* nothing */ break;
1805
1806                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1807                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1808                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1809                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1810                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1811                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1812                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1813
1814                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1815                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1816                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1817                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1818                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1819                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1820
1821                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1822                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1823                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1824                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1825                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1826                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1827                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1828                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1829
1830                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1831                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1832                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1833                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1834                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1835                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1836                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1837                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1838
1839                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1840                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1841                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1842
1843                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1844                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1845                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1846                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1847                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1848                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1849                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1850                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1851                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1852
1853                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1854                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1855                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1856                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1857                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1858                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1859                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1860                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1861                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1862                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1863                                 }
1864                         } else {
1865                                 switch (mode){
1866                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1867                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1868                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1869                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
1870                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
1871
1872                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
1873                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
1874
1875                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
1876                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
1877                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
1878                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
1879                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
1880                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
1881
1882                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
1883                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
1884                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
1885                                 case Mode.U2_CH: /* nothing */ break;
1886
1887                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
1888                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
1889                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
1890                                 case Mode.I4_U4: /* nothing */ break;
1891                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
1892                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
1893                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
1894
1895                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
1896                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
1897                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
1898                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
1899                                 case Mode.U4_I4: /* nothing */ break;
1900                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
1901
1902                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
1903                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
1904                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
1905                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
1906                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
1907                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
1908                                 case Mode.I8_U8: /* nothing */ break;
1909                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
1910
1911                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
1912                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
1913                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
1914                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
1915                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
1916                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
1917                                 case Mode.U8_I8: /* nothing */ break;
1918                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
1919
1920                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
1921                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
1922                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
1923
1924                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
1925                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
1926                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
1927                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
1928                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
1929                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
1930                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
1931                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
1932                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
1933
1934                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
1935                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
1936                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
1937                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
1938                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
1939                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
1940                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
1941                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
1942                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
1943                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1944                                 }
1945                         }
1946                 }
1947         }
1948
1949         public class OpcodeCast : EmptyCast {
1950                 OpCode op, op2;
1951                 bool second_valid;
1952
1953                 public OpcodeCast (Expression child, Type return_type, OpCode op)
1954                         : base (child, return_type)
1955
1956                 {
1957                         this.op = op;
1958                         second_valid = false;
1959                 }
1960
1961                 public OpcodeCast (Expression child, Type return_type, OpCode op, OpCode op2)
1962                         : base (child, return_type)
1963
1964                 {
1965                         this.op = op;
1966                         this.op2 = op2;
1967                         second_valid = true;
1968                 }
1969
1970                 public override Expression DoResolve (EmitContext ec)
1971                 {
1972                         // This should never be invoked, we are born in fully
1973                         // initialized state.
1974
1975                         return this;
1976                 }
1977
1978                 public override void Emit (EmitContext ec)
1979                 {
1980                         base.Emit (ec);
1981                         ec.ig.Emit (op);
1982
1983                         if (second_valid)
1984                                 ec.ig.Emit (op2);
1985                 }
1986         }
1987
1988         /// <summary>
1989         ///   This kind of cast is used to encapsulate a child and cast it
1990         ///   to the class requested
1991         /// </summary>
1992         public class ClassCast : EmptyCast {
1993                 public ClassCast (Expression child, Type return_type)
1994                         : base (child, return_type)
1995
1996                 {
1997                 }
1998
1999                 public override Expression DoResolve (EmitContext ec)
2000                 {
2001                         // This should never be invoked, we are born in fully
2002                         // initialized state.
2003
2004                         return this;
2005                 }
2006
2007                 public override void Emit (EmitContext ec)
2008                 {
2009                         base.Emit (ec);
2010
2011                         if (child.Type.IsGenericParameter)
2012                                 ec.ig.Emit (OpCodes.Box, child.Type);
2013
2014                         if (type.IsGenericParameter)
2015                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2016                         else
2017                                 ec.ig.Emit (OpCodes.Castclass, type);
2018                 }
2019         }
2020
2021         /// <summary>
2022         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2023         ///   of a dotted-name.
2024         /// </summary>
2025         public class SimpleName : Expression {
2026                 public string Name;
2027                 public readonly TypeArguments Arguments;
2028
2029                 public SimpleName (string name, Location l)
2030                 {
2031                         Name = name;
2032                         loc = l;
2033                 }
2034
2035                 public SimpleName (string name, TypeArguments args, Location l)
2036                 {
2037                         Name = name;
2038                         Arguments = args;
2039                         loc = l;
2040                 }
2041
2042                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2043                 {
2044                         Name = name;
2045                         loc = l;
2046
2047                         Arguments = new TypeArguments (l);
2048                         foreach (TypeParameter type_param in type_params)
2049                                 Arguments.Add (new TypeParameterExpr (type_param, l));
2050                 }
2051
2052                 public static string RemoveGenericArity (string name)
2053                 {
2054                         int start = 0;
2055                         StringBuilder sb = new StringBuilder ();
2056                         while (start < name.Length) {
2057                                 int pos = name.IndexOf ('`', start);
2058                                 if (pos < 0) {
2059                                         sb.Append (name.Substring (start));
2060                                         break;
2061                                 }
2062
2063                                 sb.Append (name.Substring (start, pos-start));
2064
2065                                 pos++;
2066                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2067                                         pos++;
2068
2069                                 start = pos;
2070                         }
2071
2072                         return sb.ToString ();
2073                 }
2074
2075                 public SimpleName GetMethodGroup ()
2076                 {
2077                         return new SimpleName (RemoveGenericArity (Name), Arguments, loc);
2078                 }
2079
2080                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
2081                 {
2082                         if (ec.IsFieldInitializer)
2083                                 Report.Error (
2084                                         236, l,
2085                                         "A field initializer cannot reference the non-static field, " +
2086                                         "method or property `"+name+"'");
2087                         else
2088                                 Report.Error (
2089                                         120, l,
2090                                         "An object reference is required " +
2091                                         "for the non-static field `"+name+"'");
2092                 }
2093
2094                 public bool IdenticalNameAndTypeName (EmitContext ec, Expression resolved_to, Location loc)
2095                 {
2096                         return resolved_to != null && resolved_to.Type != null &&
2097                                 resolved_to.Type.Name == Name &&
2098                                 (ec.DeclSpace.LookupType (Name, loc, /* ignore_cs0104 = */ true) != null);
2099                 }
2100
2101                 //
2102                 // Checks whether we are trying to access an instance
2103                 // property, method or field from a static body.
2104                 //
2105                 Expression MemberStaticCheck (EmitContext ec, Expression e, bool intermediate)
2106                 {
2107                         if (e is IMemberExpr){
2108                                 IMemberExpr member = (IMemberExpr) e;
2109
2110                                 if (!member.IsStatic &&
2111                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2112                                         Error_ObjectRefRequired (ec, loc, Name);
2113                                         return null;
2114                                 }
2115                         }
2116
2117                         return e;
2118                 }
2119
2120                 public override Expression DoResolve (EmitContext ec)
2121                 {
2122                         return SimpleNameResolve (ec, null, false);
2123                 }
2124
2125                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
2126                 {
2127                         return SimpleNameResolve (ec, right_side, false);
2128                 }
2129
2130
2131                 public Expression DoResolve (EmitContext ec, bool intermediate)
2132                 {
2133                         return SimpleNameResolve (ec, null, intermediate);
2134                 }
2135
2136                 private bool IsNestedChild (Type t, Type parent)
2137                 {
2138                         if (parent == null)
2139                                 return false;
2140
2141                         while (parent != null) {
2142                                 if (parent.IsGenericInstance)
2143                                         parent = parent.GetGenericTypeDefinition ();
2144
2145                                 if (TypeManager.IsNestedChildOf (t, parent))
2146                                         return true;
2147
2148                                 parent = parent.BaseType;
2149                         }
2150
2151                         return false;
2152                 }
2153
2154                 FullNamedExpression ResolveNested (EmitContext ec, Type t)
2155                 {
2156                         if (!t.IsGenericTypeDefinition)
2157                                 return null;
2158
2159                         DeclSpace ds = ec.DeclSpace;
2160                         while (ds != null) {
2161                                 if (IsNestedChild (t, ds.TypeBuilder))
2162                                         break;
2163
2164                                 ds = ds.Parent;
2165                         }
2166
2167                         if (ds == null)
2168                                 return null;
2169
2170                         Type[] gen_params = t.GetGenericArguments ();
2171
2172                         int arg_count = Arguments != null ? Arguments.Count : 0;
2173
2174                         for (; (ds != null) && ds.IsGeneric; ds = ds.Parent) {
2175                                 if (arg_count + ds.CountTypeParameters == gen_params.Length) {
2176                                         TypeArguments new_args = new TypeArguments (loc);
2177                                         foreach (TypeParameter param in ds.TypeParameters)
2178                                                 new_args.Add (new TypeParameterExpr (param, loc));
2179
2180                                         if (Arguments != null)
2181                                                 new_args.Add (Arguments);
2182
2183                                         return new ConstructedType (t, new_args, loc);
2184                                 }
2185                         }
2186
2187                         return null;
2188                 }
2189
2190                 public override FullNamedExpression ResolveAsTypeStep (EmitContext ec)
2191                 {
2192                         FullNamedExpression dt = ec.DeclSpace.LookupGeneric (Name, loc);
2193                         if (dt != null)
2194                                 return dt.ResolveAsTypeStep (ec);
2195
2196                         int errors = Report.Errors;
2197                         dt = ec.DeclSpace.LookupType (Name, loc, /*ignore_cs0104=*/ false);
2198                         if (Report.Errors != errors)
2199                                 return null;
2200
2201                         if ((dt == null) || (dt.Type == null))
2202                                 return dt;
2203
2204                         FullNamedExpression nested = ResolveNested (ec, dt.Type);
2205                         if (nested != null)
2206                                 return nested.ResolveAsTypeStep (ec);
2207
2208                         if (Arguments != null) {
2209                                 ConstructedType ct = new ConstructedType (dt, Arguments, loc);
2210                                 return ct.ResolveAsTypeStep (ec);
2211                         }
2212
2213                         return dt;
2214                 }
2215
2216                 Expression SimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2217                 {
2218                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2219                         if (e == null)
2220                                 return null;
2221
2222                         Block current_block = ec.CurrentBlock;
2223                         if (current_block != null){
2224                                 if (current_block.IsVariableNameUsedInChildBlock (Name)) {
2225                                         Report.Error (135, Location,
2226                                                       "'{0}' has a different meaning in a child block", Name);
2227                                         return null;
2228                                 }
2229                         }
2230
2231                         if (e.Type != null && e.Type.IsPointer && !ec.InUnsafe) {
2232                                 UnsafeError (loc);
2233                                 return null;
2234                         }
2235
2236                         return e;
2237                 }
2238
2239                 /// <remarks>
2240                 ///   7.5.2: Simple Names.
2241                 ///
2242                 ///   Local Variables and Parameters are handled at
2243                 ///   parse time, so they never occur as SimpleNames.
2244                 ///
2245                 ///   The `intermediate' flag is used by MemberAccess only
2246                 ///   and it is used to inform us that it is ok for us to
2247                 ///   avoid the static check, because MemberAccess might end
2248                 ///   up resolving the Name as a Type name and the access as
2249                 ///   a static type access.
2250                 ///
2251                 ///   ie: Type Type; .... { Type.GetType (""); }
2252                 ///
2253                 ///   Type is both an instance variable and a Type;  Type.GetType
2254                 ///   is the static method not an instance method of type.
2255                 /// </remarks>
2256                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2257                 {
2258                         Expression e = null;
2259
2260                         //
2261                         // Stage 1: Performed by the parser (binding to locals or parameters).
2262                         //
2263                         Block current_block = ec.CurrentBlock;
2264                         if (current_block != null){
2265                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2266                                 if (vi != null){
2267                                         Expression var;
2268
2269                                         var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2270
2271                                         if (right_side != null)
2272                                                 return var.ResolveLValue (ec, right_side);
2273                                         else
2274                                                 return var.Resolve (ec);
2275                                 }
2276
2277                                 ParameterReference pref = current_block.GetParameterReference (Name, loc);
2278                                 if (pref != null) {
2279                                         if (right_side != null)
2280                                                 return pref.ResolveLValue (ec, right_side);
2281                                         else
2282                                                 return pref.Resolve (ec);
2283                                 }
2284                         }
2285
2286                         //
2287                         // Stage 2: Lookup members
2288                         //
2289
2290                         DeclSpace lookup_ds = ec.DeclSpace;
2291                         Type almost_matched_type = null;
2292                         ArrayList almost_matched = null;
2293                         do {
2294                                 if (lookup_ds.TypeBuilder == null)
2295                                         break;
2296
2297                                 e = MemberLookup (ec, lookup_ds.TypeBuilder, Name, loc);
2298                                 if (e != null)
2299                                         break;
2300
2301                                 if (almost_matched == null && almostMatchedMembers.Count > 0) {
2302                                         almost_matched_type = lookup_ds.TypeBuilder;
2303                                         almost_matched = (ArrayList) almostMatchedMembers.Clone ();
2304                                 }
2305
2306                                 lookup_ds =lookup_ds.Parent;
2307                         } while (lookup_ds != null);
2308
2309                         if (e == null && ec.ContainerType != null)
2310                                 e = MemberLookup (ec, ec.ContainerType, Name, loc);
2311
2312                         if (e == null) {
2313                                 if (almost_matched == null && almostMatchedMembers.Count > 0) {
2314                                         almost_matched_type = ec.ContainerType;
2315                                         almost_matched = (ArrayList) almostMatchedMembers.Clone ();
2316                                 }
2317                                 e = ResolveAsTypeStep (ec);
2318                         }
2319
2320                         if (e == null) {
2321                                 if (almost_matched != null)
2322                                         almostMatchedMembers = almost_matched;
2323                                 if (almost_matched_type == null)
2324                                         almost_matched_type = ec.ContainerType;
2325                                 MemberLookupFailed (ec, null, almost_matched_type, ((SimpleName) this).Name, ec.DeclSpace.Name, true, loc);
2326                                 return null;
2327                         }
2328
2329                         if (e is TypeExpr)
2330                                 return e;
2331
2332                         if (e is IMemberExpr) {
2333                                 e = MemberAccess.ResolveMemberAccess (ec, e, null, loc, this);
2334                                 if (e == null)
2335                                         return null;
2336
2337                                 IMemberExpr me = e as IMemberExpr;
2338                                 if (me == null)
2339                                         return e;
2340
2341                                 if (Arguments != null) {
2342                                         MethodGroupExpr mg = me as MethodGroupExpr;
2343                                         if (mg == null)
2344                                                 return null;
2345
2346                                         return mg.ResolveGeneric (ec, Arguments);
2347                                 }
2348
2349                                 // This fails if ResolveMemberAccess() was unable to decide whether
2350                                 // it's a field or a type of the same name.
2351
2352                                 if (!me.IsStatic && (me.InstanceExpression == null))
2353                                         return e;
2354
2355                                 if (!me.IsStatic &&
2356                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2357                                     me.InstanceExpression.Type != me.DeclaringType &&
2358                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2359                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2360                                         Error (38, "Cannot access nonstatic member `" + me.Name + "' of " +
2361                                                "outer type `" + me.DeclaringType + "' via nested type `" +
2362                                                me.InstanceExpression.Type + "'");
2363                                         return null;
2364                                 }
2365
2366                                 return (right_side != null)
2367                                         ? e.DoResolveLValue (ec, right_side)
2368                                         : e.DoResolve (ec);
2369                         }
2370
2371                         if (ec.IsStatic || ec.IsFieldInitializer){
2372                                 return MemberStaticCheck (ec, e, intermediate);
2373                         } else
2374                                 return e;
2375                 }
2376
2377                 public override void Emit (EmitContext ec)
2378                 {
2379                         //
2380                         // If this is ever reached, then we failed to
2381                         // find the name as a namespace
2382                         //
2383
2384                         Error (103, "The name `" + Name +
2385                                "' does not exist in the class `" +
2386                                ec.DeclSpace.Name + "'");
2387                 }
2388
2389                 public override string ToString ()
2390                 {
2391                         return Name;
2392                 }
2393         }
2394
2395         /// <summary>
2396         ///   Represents a namespace or a type.  The name of the class was inspired by
2397         ///   section 10.8.1 (Fully Qualified Names).
2398         /// </summary>
2399         public abstract class FullNamedExpression : Expression {
2400                 public override FullNamedExpression ResolveAsTypeStep (EmitContext ec)
2401                 {
2402                         return this;
2403                 }
2404
2405                 public abstract string FullName {
2406                         get;
2407                 }
2408         }
2409
2410         /// <summary>
2411         ///   Fully resolved expression that evaluates to a type
2412         /// </summary>
2413         public abstract class TypeExpr : FullNamedExpression {
2414                 override public FullNamedExpression ResolveAsTypeStep (EmitContext ec)
2415                 {
2416                         TypeExpr t = DoResolveAsTypeStep (ec);
2417                         if (t == null)
2418                                 return null;
2419
2420                         eclass = ExprClass.Type;
2421                         return t;
2422                 }
2423
2424                 override public Expression DoResolve (EmitContext ec)
2425                 {
2426                         return ResolveAsTypeTerminal (ec);
2427                 }
2428
2429                 override public void Emit (EmitContext ec)
2430                 {
2431                         throw new Exception ("Should never be called");
2432                 }
2433
2434                 public virtual bool CheckAccessLevel (DeclSpace ds)
2435                 {
2436                         return ds.CheckAccessLevel (Type);
2437                 }
2438
2439                 public virtual bool AsAccessible (DeclSpace ds, int flags)
2440                 {
2441                         return ds.AsAccessible (Type, flags);
2442                 }
2443
2444                 public virtual bool IsClass {
2445                         get { return Type.IsClass; }
2446                 }
2447
2448                 public virtual bool IsValueType {
2449                         get { return Type.IsValueType; }
2450                 }
2451
2452                 public virtual bool IsInterface {
2453                         get { return Type.IsInterface; }
2454                 }
2455
2456                 public virtual bool IsSealed {
2457                         get { return Type.IsSealed; }
2458                 }
2459
2460                 public virtual bool CanInheritFrom ()
2461                 {
2462                         if (Type == TypeManager.enum_type ||
2463                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2464                             Type == TypeManager.multicast_delegate_type ||
2465                             Type == TypeManager.delegate_type ||
2466                             Type == TypeManager.array_type)
2467                                 return false;
2468
2469                         return true;
2470                 }
2471
2472                 protected abstract TypeExpr DoResolveAsTypeStep (EmitContext ec);
2473
2474                 public virtual Type ResolveType (EmitContext ec)
2475                 {
2476                         TypeExpr t = ResolveAsTypeTerminal (ec);
2477                         if (t == null)
2478                                 return null;
2479
2480                         return t.Type;
2481                 }
2482
2483                 public abstract string Name {
2484                         get;
2485                 }
2486
2487                 public override bool Equals (object obj)
2488                 {
2489                         TypeExpr tobj = obj as TypeExpr;
2490                         if (tobj == null)
2491                                 return false;
2492
2493                         return Type == tobj.Type;
2494                 }
2495
2496                 public override int GetHashCode ()
2497                 {
2498                         return Type.GetHashCode ();
2499                 }
2500
2501                 public override string ToString ()
2502                 {
2503                         return Name;
2504                 }
2505         }
2506
2507         public class TypeExpression : TypeExpr {
2508                 public TypeExpression (Type t, Location l)
2509                 {
2510                         Type = t;
2511                         eclass = ExprClass.Type;
2512                         loc = l;
2513                 }
2514
2515                 protected override TypeExpr DoResolveAsTypeStep (EmitContext ec)
2516                 {
2517                         return this;
2518                 }
2519
2520                 public override string Name {
2521                         get {
2522                                 return Type.ToString ();
2523                         }
2524                 }
2525
2526                 public override string FullName {
2527                         get {
2528                                 return Type.FullName != null ? Type.FullName : Type.Name;
2529                         }
2530                 }
2531         }
2532
2533         /// <summary>
2534         ///   Used to create types from a fully qualified name.  These are just used
2535         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2536         ///   classified as a type.
2537         /// </summary>
2538         public class TypeLookupExpression : TypeExpr {
2539                 string name;
2540
2541                 public TypeLookupExpression (string name)
2542                 {
2543                         this.name = name;
2544                 }
2545
2546                 protected override TypeExpr DoResolveAsTypeStep (EmitContext ec)
2547                 {
2548                         if (type == null) {
2549                                 FullNamedExpression t = ec.DeclSpace.LookupType (name, Location.Null, /*ignore_cs0104=*/ false);
2550                                 if (t == null) {
2551                                         Report.Error (246, loc, "Cannot find type `" + name + "'");
2552                                         return null;
2553                                 }
2554                                 if (!(t is TypeExpr)) {
2555                                         Report.Error (118, Location, "'{0}' denotes a '{1}', where a type was expected",
2556                                                       t.FullName, t.ExprClassName ());
2557
2558                                         return null;
2559                                 }
2560                                 type = ((TypeExpr) t).ResolveType (ec);
2561                         }
2562
2563                         return this;
2564                 }
2565
2566                 public override string Name {
2567                         get {
2568                                 return name;
2569                         }
2570                 }
2571
2572                 public override string FullName {
2573                         get {
2574                                 return name;
2575                         }
2576                 }
2577         }
2578
2579         /// <summary>
2580         ///   Represents an "unbound generic type", ie. typeof (Foo<>).
2581         ///   See 14.5.11.
2582         /// </summary>
2583         public class UnboundTypeExpression : TypeLookupExpression {
2584                 public UnboundTypeExpression (string name)
2585                         : base (name)
2586                 { }
2587         }
2588
2589         public class TypeAliasExpression : TypeExpr {
2590                 FullNamedExpression alias;
2591                 TypeExpr texpr;
2592                 TypeArguments args;
2593                 string name;
2594
2595                 public TypeAliasExpression (FullNamedExpression alias, TypeArguments args, Location l)
2596                 {
2597                         this.alias = alias;
2598                         this.args = args;
2599                         loc = l;
2600
2601                         eclass = ExprClass.Type;
2602                         if (args != null)
2603                                 name = alias.FullName + "<" + args.ToString () + ">";
2604                         else
2605                                 name = alias.FullName;
2606                 }
2607
2608                 public override string Name {
2609                         get { return alias.FullName; }
2610                 }
2611
2612                 public override string FullName {
2613                         get { return name; }
2614                 }
2615
2616                 protected override TypeExpr DoResolveAsTypeStep (EmitContext ec)
2617                 {
2618                         texpr = alias.ResolveAsTypeTerminal (ec);
2619                         if (texpr == null)
2620                                 return null;
2621
2622                         Type type = texpr.Type;
2623                         int num_args = TypeManager.GetNumberOfTypeArguments (type);
2624
2625                         if (args != null) {
2626                                 if (num_args == 0) {
2627                                         Report.Error (308, loc,
2628                                                       "The non-generic type `{0}' cannot " +
2629                                                       "be used with type arguments.",
2630                                                       TypeManager.CSharpName (type));
2631                                         return null;
2632                                 }
2633
2634                                 ConstructedType ctype = new ConstructedType (type, args, loc);
2635                                 return ctype.ResolveAsTypeTerminal (ec);
2636                         } else if (num_args > 0) {
2637                                 Report.Error (305, loc,
2638                                               "Using the generic type `{0}' " +
2639                                               "requires {1} type arguments",
2640                                               TypeManager.GetFullName (type), num_args);
2641                                 return null;
2642                         }
2643
2644                         return new TypeExpression (type, loc);
2645                 }
2646
2647                 public override bool CheckAccessLevel (DeclSpace ds)
2648                 {
2649                         return texpr.CheckAccessLevel (ds);
2650                 }
2651
2652                 public override bool AsAccessible (DeclSpace ds, int flags)
2653                 {
2654                         return texpr.AsAccessible (ds, flags);
2655                 }
2656
2657                 public override bool IsClass {
2658                         get { return texpr.IsClass; }
2659                 }
2660
2661                 public override bool IsValueType {
2662                         get { return texpr.IsValueType; }
2663                 }
2664
2665                 public override bool IsInterface {
2666                         get { return texpr.IsInterface; }
2667                 }
2668
2669                 public override bool IsSealed {
2670                         get { return texpr.IsSealed; }
2671                 }
2672         }
2673
2674         /// <summary>
2675         ///   MethodGroup Expression.
2676         ///
2677         ///   This is a fully resolved expression that evaluates to a type
2678         /// </summary>
2679         public class MethodGroupExpr : Expression, IMemberExpr {
2680                 public MethodBase [] Methods;
2681                 Expression instance_expression = null;
2682                 bool is_explicit_impl = false;
2683                 bool has_type_arguments = false;
2684                 bool identical_type_name = false;
2685                 bool is_base;
2686
2687                 public MethodGroupExpr (MemberInfo [] mi, Location l)
2688                 {
2689                         Methods = new MethodBase [mi.Length];
2690                         mi.CopyTo (Methods, 0);
2691                         eclass = ExprClass.MethodGroup;
2692                         type = TypeManager.object_type;
2693                         loc = l;
2694                 }
2695
2696                 public MethodGroupExpr (ArrayList list, Location l)
2697                 {
2698                         Methods = new MethodBase [list.Count];
2699
2700                         try {
2701                                 list.CopyTo (Methods, 0);
2702                         } catch {
2703                                 foreach (MemberInfo m in list){
2704                                         if (!(m is MethodBase)){
2705                                                 Console.WriteLine ("Name " + m.Name);
2706                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
2707                                         }
2708                                 }
2709                                 throw;
2710                         }
2711
2712                         loc = l;
2713                         eclass = ExprClass.MethodGroup;
2714                         type = TypeManager.object_type;
2715                 }
2716
2717                 public Type DeclaringType {
2718                         get {
2719                                 //
2720                                 // We assume that the top-level type is in the end
2721                                 //
2722                                 return Methods [Methods.Length - 1].DeclaringType;
2723                                 //return Methods [0].DeclaringType;
2724                         }
2725                 }
2726
2727                 //
2728                 // `A method group may have associated an instance expression'
2729                 //
2730                 public Expression InstanceExpression {
2731                         get {
2732                                 return instance_expression;
2733                         }
2734
2735                         set {
2736                                 instance_expression = value;
2737                         }
2738                 }
2739
2740                 public bool IsExplicitImpl {
2741                         get {
2742                                 return is_explicit_impl;
2743                         }
2744
2745                         set {
2746                                 is_explicit_impl = value;
2747                         }
2748                 }
2749
2750                 public bool HasTypeArguments {
2751                         get {
2752                                 return has_type_arguments;
2753                         }
2754
2755                         set {
2756                                 has_type_arguments = value;
2757                         }
2758                 }
2759
2760                 public bool IdenticalTypeName {
2761                         get {
2762                                 return identical_type_name;
2763                         }
2764
2765                         set {
2766                                 identical_type_name = value;
2767                         }
2768                 }
2769
2770                 public bool IsBase {
2771                         get {
2772                                 return is_base;
2773                         }
2774                         set {
2775                                 is_base = value;
2776                         }
2777                 }
2778
2779                 public string Name {
2780                         get {
2781                                 //return Methods [0].Name;
2782                                 return Methods [Methods.Length - 1].Name;
2783                         }
2784                 }
2785
2786                 public bool IsInstance {
2787                         get {
2788                                 foreach (MethodBase mb in Methods)
2789                                         if (!mb.IsStatic)
2790                                                 return true;
2791
2792                                 return false;
2793                         }
2794                 }
2795
2796                 public bool IsStatic {
2797                         get {
2798                                 foreach (MethodBase mb in Methods)
2799                                         if (mb.IsStatic)
2800                                                 return true;
2801
2802                                 return false;
2803                         }
2804                 }
2805
2806                 override public Expression DoResolve (EmitContext ec)
2807                 {
2808                         if (!IsInstance)
2809                                 instance_expression = null;
2810
2811                         if (instance_expression != null) {
2812                                 instance_expression = instance_expression.DoResolve (ec);
2813                                 if (instance_expression == null)
2814                                         return null;
2815                         }
2816
2817                         return this;
2818                 }
2819
2820                 public void ReportUsageError ()
2821                 {
2822                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
2823                                       Name + "()' is referenced without parentheses");
2824                 }
2825
2826                 override public void Emit (EmitContext ec)
2827                 {
2828                         ReportUsageError ();
2829                 }
2830
2831                 bool RemoveMethods (bool keep_static)
2832                 {
2833                         ArrayList smethods = new ArrayList ();
2834
2835                         foreach (MethodBase mb in Methods){
2836                                 if (mb.IsStatic == keep_static)
2837                                         smethods.Add (mb);
2838                         }
2839
2840                         if (smethods.Count == 0)
2841                                 return false;
2842
2843                         Methods = new MethodBase [smethods.Count];
2844                         smethods.CopyTo (Methods, 0);
2845
2846                         return true;
2847                 }
2848
2849                 /// <summary>
2850                 ///   Removes any instance methods from the MethodGroup, returns
2851                 ///   false if the resulting set is empty.
2852                 /// </summary>
2853                 public bool RemoveInstanceMethods ()
2854                 {
2855                         return RemoveMethods (true);
2856                 }
2857
2858                 /// <summary>
2859                 ///   Removes any static methods from the MethodGroup, returns
2860                 ///   false if the resulting set is empty.
2861                 /// </summary>
2862                 public bool RemoveStaticMethods ()
2863                 {
2864                         return RemoveMethods (false);
2865                 }
2866
2867                 public Expression ResolveGeneric (EmitContext ec, TypeArguments args)
2868                 {
2869                         if (args.Resolve (ec) == false)
2870                                 return null;
2871
2872                         Type[] atypes = args.Arguments;
2873
2874                         int first_count = 0;
2875                         MethodInfo first = null;
2876
2877                         ArrayList list = new ArrayList ();
2878                         foreach (MethodBase mb in Methods) {
2879                                 MethodInfo mi = mb as MethodInfo;
2880                                 if ((mi == null) || !mi.HasGenericParameters)
2881                                         continue;
2882
2883                                 Type[] gen_params = mi.GetGenericArguments ();
2884
2885                                 if (first == null) {
2886                                         first = mi;
2887                                         first_count = gen_params.Length;
2888                                 }
2889
2890                                 if (gen_params.Length != atypes.Length)
2891                                         continue;
2892
2893                                 list.Add (mi.BindGenericParameters (atypes));
2894                         }
2895
2896                         if (list.Count > 0) {
2897                                 MethodGroupExpr new_mg = new MethodGroupExpr (list, Location);
2898                                 new_mg.InstanceExpression = InstanceExpression;
2899                                 new_mg.HasTypeArguments = true;
2900                                 return new_mg;
2901                         }
2902
2903                         if (first != null)
2904                                 Report.Error (
2905                                         305, loc, "Using the generic method `{0}' " +
2906                                         "requires {1} type arguments", Name,
2907                                         first_count);
2908                         else
2909                                 Report.Error (
2910                                         308, loc, "The non-generic method `{0}' " +
2911                                         "cannot be used with type arguments", Name);
2912
2913                         return null;
2914                 }
2915         }
2916
2917         /// <summary>
2918         ///   Fully resolved expression that evaluates to a Field
2919         /// </summary>
2920         public class FieldExpr : Expression, IAssignMethod, IMemoryLocation, IMemberExpr, IVariable {
2921                 public readonly FieldInfo FieldInfo;
2922                 Expression instance_expr;
2923                 VariableInfo variable_info;
2924
2925                 LocalTemporary temp;
2926                 bool prepared;
2927                 bool is_field_initializer;
2928
2929                 public FieldExpr (FieldInfo fi, Location l)
2930                 {
2931                         FieldInfo = fi;
2932                         eclass = ExprClass.Variable;
2933                         type = TypeManager.TypeToCoreType (fi.FieldType);
2934                         loc = l;
2935                 }
2936
2937                 public string Name {
2938                         get {
2939                                 return FieldInfo.Name;
2940                         }
2941                 }
2942
2943                 public bool IsInstance {
2944                         get {
2945                                 return !FieldInfo.IsStatic;
2946                         }
2947                 }
2948
2949                 public bool IsStatic {
2950                         get {
2951                                 return FieldInfo.IsStatic;
2952                         }
2953                 }
2954
2955                 public Type DeclaringType {
2956                         get {
2957                                 return FieldInfo.DeclaringType;
2958                         }
2959                 }
2960
2961                 public Expression InstanceExpression {
2962                         get {
2963                                 return instance_expr;
2964                         }
2965
2966                         set {
2967                                 instance_expr = value;
2968                         }
2969                 }
2970
2971                 public bool IsFieldInitializer {
2972                         get {
2973                                 return is_field_initializer;
2974                         }
2975
2976                         set {
2977                                 is_field_initializer = value;
2978                         }
2979                 }
2980
2981                 public VariableInfo VariableInfo {
2982                         get {
2983                                 return variable_info;
2984                         }
2985                 }
2986
2987                 override public Expression DoResolve (EmitContext ec)
2988                 {
2989                         if (!FieldInfo.IsStatic){
2990                                 if (instance_expr == null){
2991                                         //
2992                                         // This can happen when referencing an instance field using
2993                                         // a fully qualified type expression: TypeName.InstanceField = xxx
2994                                         //
2995                                         SimpleName.Error_ObjectRefRequired (ec, loc, FieldInfo.Name);
2996                                         return null;
2997                                 }
2998
2999                                 // Resolve the field's instance expression while flow analysis is turned
3000                                 // off: when accessing a field "a.b", we must check whether the field
3001                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
3002                                 instance_expr = instance_expr.Resolve (ec, ResolveFlags.VariableOrValue |
3003                                                                        ResolveFlags.DisableFlowAnalysis);
3004                                 if (instance_expr == null)
3005                                         return null;
3006                         }
3007
3008                         ObsoleteAttribute oa;
3009                         FieldBase f = TypeManager.GetField (FieldInfo);
3010                         if (f != null) {
3011                                 oa = f.GetObsoleteAttribute (f.Parent);
3012                                 if (oa != null)
3013                                         AttributeTester.Report_ObsoleteMessage (oa, f.GetSignatureForError (), loc);
3014                                 // To be sure that type is external because we do not register generated fields
3015                         } else if (!(FieldInfo.DeclaringType is TypeBuilder)) {
3016                                 oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
3017                                 if (oa != null)
3018                                         AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
3019                         }
3020
3021                         if (ec.CurrentAnonymousMethod != null){
3022                                 if (!FieldInfo.IsStatic){
3023                                         if (ec.TypeContainer is Struct){
3024                                                 Report.Error (1673, loc, "Can not reference instance variables in anonymous methods hosted in structs");
3025                                                 return null;
3026                                         }
3027                                         ec.CaptureField (this);
3028                                 }
3029                         }
3030
3031                         // If the instance expression is a local variable or parameter.
3032                         IVariable var = instance_expr as IVariable;
3033                         if ((var == null) || (var.VariableInfo == null))
3034                                 return this;
3035
3036                         VariableInfo vi = var.VariableInfo;
3037                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
3038                                 return null;
3039
3040                         variable_info = vi.GetSubStruct (FieldInfo.Name);
3041                         return this;
3042                 }
3043
3044                 void Report_AssignToReadonly (bool is_instance)
3045                 {
3046                         string msg;
3047
3048                         if (is_instance)
3049                                 msg = "Readonly field can not be assigned outside " +
3050                                 "of constructor or variable initializer";
3051                         else
3052                                 msg = "A static readonly field can only be assigned in " +
3053                                 "a static constructor";
3054
3055                         Report.Error (is_instance ? 191 : 198, loc, msg);
3056                 }
3057
3058                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3059                 {
3060                         IVariable var = instance_expr as IVariable;
3061                         if ((var != null) && (var.VariableInfo != null))
3062                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
3063
3064                         Expression e = DoResolve (ec);
3065
3066                         if (e == null)
3067                                 return null;
3068
3069                         if (!FieldInfo.IsStatic && (instance_expr.Type.IsValueType && !(instance_expr is IMemoryLocation))) {
3070                                 // FIXME: Provide better error reporting.
3071                                 Error (1612, "Cannot modify expression because it is not a variable.");
3072                                 return null;
3073                         }
3074
3075                         if (!FieldInfo.IsInitOnly)
3076                                 return this;
3077
3078                         FieldBase fb = TypeManager.GetField (FieldInfo);
3079                         if (fb != null)
3080                                 fb.SetAssigned ();
3081
3082                         //
3083                         // InitOnly fields can only be assigned in constructors
3084                         //
3085
3086                         if (ec.IsConstructor){
3087                                 if (IsStatic && !ec.IsStatic)
3088                                         Report_AssignToReadonly (false);
3089
3090                                 Type ctype;
3091                                 if (!is_field_initializer &&
3092                                     (ec.TypeContainer.CurrentType != null))
3093                                         ctype = ec.TypeContainer.CurrentType;
3094                                 else
3095                                         ctype = ec.ContainerType;
3096
3097                                 if (TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
3098                                         return this;
3099                         }
3100
3101                         Report_AssignToReadonly (!IsStatic);
3102
3103                         return null;
3104                 }
3105
3106                 public override void CheckMarshallByRefAccess (Type container)
3107                 {
3108                         if (!IsStatic && Type.IsValueType && !container.IsSubclassOf (TypeManager.mbr_type) && DeclaringType.IsSubclassOf (TypeManager.mbr_type)) {
3109                                 Report.SymbolRelatedToPreviousError (DeclaringType);
3110                                 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);
3111                         }
3112                 }
3113
3114                 public bool VerifyFixed (bool is_expression)
3115                 {
3116                         IVariable variable = instance_expr as IVariable;
3117                         if ((variable == null) || !variable.VerifyFixed (true))
3118                                 return false;
3119
3120                         return true;
3121                 }
3122
3123                 public void Emit (EmitContext ec, bool leave_copy)
3124                 {
3125                         ILGenerator ig = ec.ig;
3126                         bool is_volatile = false;
3127
3128                         if (FieldInfo is FieldBuilder){
3129                                 FieldBase f = TypeManager.GetField (FieldInfo);
3130                                 if (f != null){
3131                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0)
3132                                                 is_volatile = true;
3133
3134                                         f.status |= Field.Status.USED;
3135                                 }
3136                         }
3137
3138                         if (FieldInfo.IsStatic){
3139                                 if (is_volatile)
3140                                         ig.Emit (OpCodes.Volatile);
3141
3142                                 ig.Emit (OpCodes.Ldsfld, FieldInfo);
3143                         } else {
3144                                 if (!prepared)
3145                                         EmitInstance (ec);
3146
3147                                 if (is_volatile)
3148                                         ig.Emit (OpCodes.Volatile);
3149
3150                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
3151                                 if (ff != null)
3152                                 {
3153                                         ig.Emit (OpCodes.Ldflda, FieldInfo);
3154                                         ig.Emit (OpCodes.Ldflda, ff.Element);
3155                                 }
3156                                 else {
3157                                         ig.Emit (OpCodes.Ldfld, FieldInfo);
3158                                 }
3159                         }
3160
3161                         if (leave_copy) {
3162                                 ec.ig.Emit (OpCodes.Dup);
3163                                 if (!FieldInfo.IsStatic) {
3164                                         temp = new LocalTemporary (ec, this.Type);
3165                                         temp.Store (ec);
3166                                 }
3167                         }
3168                 }
3169
3170                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
3171                 {
3172                         FieldAttributes fa = FieldInfo.Attributes;
3173                         bool is_static = (fa & FieldAttributes.Static) != 0;
3174                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
3175                         ILGenerator ig = ec.ig;
3176                         prepared = prepare_for_load;
3177
3178                         if (is_readonly && !ec.IsConstructor){
3179                                 Report_AssignToReadonly (!is_static);
3180                                 return;
3181                         }
3182
3183                         if (!is_static) {
3184                                 EmitInstance (ec);
3185                                 if (prepare_for_load)
3186                                         ig.Emit (OpCodes.Dup);
3187                         }
3188
3189                         source.Emit (ec);
3190                         if (leave_copy) {
3191                                 ec.ig.Emit (OpCodes.Dup);
3192                                 if (!FieldInfo.IsStatic) {
3193                                         temp = new LocalTemporary (ec, this.Type);
3194                                         temp.Store (ec);
3195                                 }
3196                         }
3197
3198                         if (FieldInfo is FieldBuilder){
3199                                 FieldBase f = TypeManager.GetField (FieldInfo);
3200                                 if (f != null){
3201                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0)
3202                                                 ig.Emit (OpCodes.Volatile);
3203
3204                                         f.status |= Field.Status.ASSIGNED;
3205                                 }
3206                         }
3207
3208                         if (is_static)
3209                                 ig.Emit (OpCodes.Stsfld, FieldInfo);
3210                         else
3211                                 ig.Emit (OpCodes.Stfld, FieldInfo);
3212
3213                         if (temp != null)
3214                                 temp.Emit (ec);
3215                 }
3216
3217                 void EmitInstance (EmitContext ec)
3218                 {
3219                         //
3220                         // In case it escapes StaticMemberCheck due to IdenticalTypeAndName.
3221                         // This happens in cases like 'string String', 'int Int32', etc.
3222                         // where the "IdenticalTypeAndName" mechanism is fooled.
3223                         //
3224                         if (instance_expr == null) {
3225                                 SimpleName.Error_ObjectRefRequired (ec, loc, FieldInfo.Name);
3226                                 return;
3227                         }
3228
3229                         if (instance_expr.Type.IsValueType) {
3230                                 if (instance_expr is IMemoryLocation) {
3231                                         ((IMemoryLocation) instance_expr).AddressOf (ec, AddressOp.LoadStore);
3232                                 } else {
3233                                         LocalTemporary t = new LocalTemporary (ec, instance_expr.Type);
3234                                         instance_expr.Emit (ec);
3235                                         t.Store (ec);
3236                                         t.AddressOf (ec, AddressOp.Store);
3237                                 }
3238                         } else
3239                                 instance_expr.Emit (ec);
3240                 }
3241
3242                 public override void Emit (EmitContext ec)
3243                 {
3244                         Emit (ec, false);
3245                 }
3246
3247                 public void AddressOf (EmitContext ec, AddressOp mode)
3248                 {
3249                         ILGenerator ig = ec.ig;
3250
3251                         if (FieldInfo is FieldBuilder){
3252                                 FieldBase f = TypeManager.GetField (FieldInfo);
3253                                 if (f != null){
3254                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0){
3255                                                 Error (676, "volatile variable: can not take its address, or pass as ref/out parameter");
3256                                                 return;
3257                                         }
3258
3259                                         if ((mode & AddressOp.Store) != 0)
3260                                                 f.status |= Field.Status.ASSIGNED;
3261                                         if ((mode & AddressOp.Load) != 0)
3262                                                 f.status |= Field.Status.USED;
3263                                 }
3264                         }
3265
3266                         //
3267                         // Handle initonly fields specially: make a copy and then
3268                         // get the address of the copy.
3269                         //
3270                         bool need_copy;
3271                         if (FieldInfo.IsInitOnly){
3272                                 need_copy = true;
3273                                 if (ec.IsConstructor){
3274                                         if (FieldInfo.IsStatic){
3275                                                 if (ec.IsStatic)
3276                                                         need_copy = false;
3277                                         } else
3278                                                 need_copy = false;
3279                                 }
3280                         } else
3281                                 need_copy = false;
3282
3283                         if (need_copy){
3284                                 LocalBuilder local;
3285                                 Emit (ec);
3286                                 local = ig.DeclareLocal (type);
3287                                 ig.Emit (OpCodes.Stloc, local);
3288                                 ig.Emit (OpCodes.Ldloca, local);
3289                                 return;
3290                         }
3291
3292
3293                         if (FieldInfo.IsStatic){
3294                                 ig.Emit (OpCodes.Ldsflda, FieldInfo);
3295                         } else {
3296                                 EmitInstance (ec);
3297                                 ig.Emit (OpCodes.Ldflda, FieldInfo);
3298                         }
3299                 }
3300         }
3301
3302         //
3303         // A FieldExpr whose address can not be taken
3304         //
3305         public class FieldExprNoAddress : FieldExpr, IMemoryLocation {
3306                 public FieldExprNoAddress (FieldInfo fi, Location loc) : base (fi, loc)
3307                 {
3308                 }
3309
3310                 public new void AddressOf (EmitContext ec, AddressOp mode)
3311                 {
3312                         Report.Error (-215, "Report this: Taking the address of a remapped parameter not supported");
3313                 }
3314         }
3315
3316         /// <summary>
3317         ///   Expression that evaluates to a Property.  The Assign class
3318         ///   might set the `Value' expression if we are in an assignment.
3319         ///
3320         ///   This is not an LValue because we need to re-write the expression, we
3321         ///   can not take data from the stack and store it.
3322         /// </summary>
3323         public class PropertyExpr : ExpressionStatement, IAssignMethod, IMemberExpr {
3324                 public readonly PropertyInfo PropertyInfo;
3325
3326                 //
3327                 // This is set externally by the  `BaseAccess' class
3328                 //
3329                 public bool IsBase;
3330                 MethodInfo getter, setter;
3331                 bool is_static;
3332
3333                 Expression instance_expr;
3334                 LocalTemporary temp;
3335                 bool prepared;
3336
3337                 internal static PtrHashtable AccessorTable = new PtrHashtable ();
3338
3339                 public PropertyExpr (EmitContext ec, PropertyInfo pi, Location l)
3340                 {
3341                         PropertyInfo = pi;
3342                         eclass = ExprClass.PropertyAccess;
3343                         is_static = false;
3344                         loc = l;
3345
3346                         type = TypeManager.TypeToCoreType (pi.PropertyType);
3347
3348                         ResolveAccessors (ec);
3349                 }
3350
3351                 public string Name {
3352                         get {
3353                                 return PropertyInfo.Name;
3354                         }
3355                 }
3356
3357                 public bool IsInstance {
3358                         get {
3359                                 return !is_static;
3360                         }
3361                 }
3362
3363                 public bool IsStatic {
3364                         get {
3365                                 return is_static;
3366                         }
3367                 }
3368
3369                 public Type DeclaringType {
3370                         get {
3371                                 return PropertyInfo.DeclaringType;
3372                         }
3373                 }
3374
3375                 //
3376                 // The instance expression associated with this expression
3377                 //
3378                 public Expression InstanceExpression {
3379                         set {
3380                                 instance_expr = value;
3381                         }
3382
3383                         get {
3384                                 return instance_expr;
3385                         }
3386                 }
3387
3388                 public bool VerifyAssignable ()
3389                 {
3390                         if (setter == null) {
3391                                 Report.Error (200, loc,
3392                                               "The property `" + PropertyInfo.Name +
3393                                               "' can not be assigned to, as it has not set accessor");
3394                                 return false;
3395                         }
3396
3397                         return true;
3398                 }
3399
3400                 void FindAccessors (Type invocation_type)
3401                 {
3402                         BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
3403                                 BindingFlags.Static | BindingFlags.Instance |
3404                                 BindingFlags.DeclaredOnly;
3405
3406                         Type current = PropertyInfo.DeclaringType;
3407                         for (; current != null; current = current.BaseType) {
3408                                 MemberInfo[] group = TypeManager.MemberLookup (
3409                                         invocation_type, invocation_type, current,
3410                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
3411
3412                                 if (group == null)
3413                                         continue;
3414
3415                                 if (group.Length != 1)
3416                                         // Oooops, can this ever happen ?
3417                                         return;
3418
3419                                 PropertyInfo pi = (PropertyInfo) group [0];
3420
3421                                 if (getter == null)
3422                                         getter = pi.GetGetMethod (true);
3423
3424                                 if (setter == null)
3425                                         setter = pi.GetSetMethod (true);
3426
3427                                 MethodInfo accessor = getter != null ? getter : setter;
3428
3429                                 if (!accessor.IsVirtual)
3430                                         return;
3431                         }
3432                 }
3433
3434                 //
3435                 // We also perform the permission checking here, as the PropertyInfo does not
3436                 // hold the information for the accessibility of its setter/getter
3437                 //
3438                 void ResolveAccessors (EmitContext ec)
3439                 {
3440                         FindAccessors (ec.ContainerType);
3441
3442                         if (getter != null) {
3443                                 AccessorTable [getter] = PropertyInfo;
3444                                 is_static = getter.IsStatic;
3445                         }
3446
3447                         if (setter != null) {
3448                                 AccessorTable [setter] = PropertyInfo;
3449                                 is_static = setter.IsStatic;
3450                         }
3451                 }
3452
3453                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
3454                 {
3455                         if ((instance_expr == null) && ec.IsStatic && !is_static) {
3456                                 SimpleName.Error_ObjectRefRequired (ec, loc, PropertyInfo.Name);
3457                                 return false;
3458                         }
3459
3460                         if (instance_expr != null) {
3461                                 instance_expr = instance_expr.DoResolve (ec);
3462                                 if (instance_expr == null)
3463                                         return false;
3464
3465                                 instance_expr.CheckMarshallByRefAccess (ec.ContainerType);
3466                         }
3467
3468                         if (must_do_cs1540_check && (instance_expr != null)) {
3469                                 if ((instance_expr.Type != ec.ContainerType) &&
3470                                     ec.ContainerType.IsSubclassOf (instance_expr.Type)) {
3471                                         Report.Error (1540, loc, "Cannot access protected member `" +
3472                                                       PropertyInfo.DeclaringType + "." + PropertyInfo.Name +
3473                                                       "' via a qualifier of type `" +
3474                                                       TypeManager.CSharpName (instance_expr.Type) +
3475                                                       "'; the qualifier must be of type `" +
3476                                                       TypeManager.CSharpName (ec.ContainerType) +
3477                                                       "' (or derived from it)");
3478                                         return false;
3479                                 }
3480                         }
3481
3482                         return true;
3483                 }
3484
3485                 override public Expression DoResolve (EmitContext ec)
3486                 {
3487                         if (getter != null){
3488                                 if (TypeManager.GetArgumentTypes (getter).Length != 0){
3489                                         Report.Error (
3490                                                 117, loc, "`{0}' does not contain a " +
3491                                                 "definition for `{1}'.", getter.DeclaringType,
3492                                                 Name);
3493                                         return null;
3494                                 }
3495                         }
3496
3497                         if (getter == null){
3498                                 //
3499                                 // The following condition happens if the PropertyExpr was
3500                                 // created, but is invalid (ie, the property is inaccessible),
3501                                 // and we did not want to embed the knowledge about this in
3502                                 // the caller routine.  This only avoids double error reporting.
3503                                 //
3504                                 if (setter == null)
3505                                         return null;
3506
3507                                 Report.Error (154, loc,
3508                                               "The property `" + PropertyInfo.Name +
3509                                               "' can not be used in " +
3510                                               "this context because it lacks a get accessor");
3511                                 return null;
3512                         }
3513
3514                         bool must_do_cs1540_check;
3515                         if (!IsAccessorAccessible (ec.ContainerType, getter, out must_do_cs1540_check)) {
3516                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter) as PropertyBase.PropertyMethod;
3517                                 if (pm != null && pm.HasCustomAccessModifier) {
3518                                         Report.SymbolRelatedToPreviousError (pm);
3519                                         Report.Error (271, loc, "The property or indexer '{0}' cannot be used in this context because the get accessor is inaccessible",
3520                                                 TypeManager.CSharpSignature (getter));
3521                                 }
3522                                 else
3523                                         Report.Error (122, loc, "'{0}' is inaccessible due to its protection level",
3524                                                 TypeManager.CSharpSignature (getter));
3525                                 return null;
3526                         }
3527
3528                         if (!InstanceResolve (ec, must_do_cs1540_check))
3529                                 return null;
3530
3531                         //
3532                         // Only base will allow this invocation to happen.
3533                         //
3534                         if (IsBase && getter.IsAbstract){
3535                                 Report.Error (205, loc, "Cannot call an abstract base property: " +
3536                                               PropertyInfo.DeclaringType + "." +PropertyInfo.Name);
3537                                 return null;
3538                         }
3539
3540                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe){
3541                                 UnsafeError (loc);
3542                                 return null;
3543                         }
3544
3545                         return this;
3546                 }
3547
3548                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3549                 {
3550                         if (setter == null){
3551                                 //
3552                                 // The following condition happens if the PropertyExpr was
3553                                 // created, but is invalid (ie, the property is inaccessible),
3554                                 // and we did not want to embed the knowledge about this in
3555                                 // the caller routine.  This only avoids double error reporting.
3556                                 //
3557                                 if (getter == null)
3558                                         return null;
3559
3560                                 // TODO: Print better property name
3561                                 Report.Error (200, loc, "Property or indexer '{0}' cannot be assigned to -- it is read only",
3562                                               PropertyInfo.Name);
3563                                 return null;
3564                         }
3565
3566                         if (TypeManager.GetArgumentTypes (setter).Length != 1){
3567                                 Report.Error (
3568                                         117, loc, "`{0}' does not contain a " +
3569                                         "definition for `{1}'.", getter.DeclaringType,
3570                                         Name);
3571                                 return null;
3572                         }
3573
3574                         bool must_do_cs1540_check;
3575                         if (!IsAccessorAccessible (ec.ContainerType, setter, out must_do_cs1540_check)) {
3576                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter) as PropertyBase.PropertyMethod;
3577                                 if (pm != null && pm.HasCustomAccessModifier) {
3578                                         Report.SymbolRelatedToPreviousError (pm);
3579                                         Report.Error (272, loc, "The property or indexer '{0}' cannot be used in this context because the set accessor is inaccessible",
3580                                                 TypeManager.CSharpSignature (setter));
3581                                 }
3582                                 else
3583                                         Report.Error (122, loc, "'{0}' is inaccessible due to its protection level",
3584                                                 TypeManager.CSharpSignature (setter));
3585                                 return null;
3586                         }
3587
3588                         if (!InstanceResolve (ec, must_do_cs1540_check))
3589                                 return null;
3590
3591                         //
3592                         // Only base will allow this invocation to happen.
3593                         //
3594                         if (IsBase && setter.IsAbstract){
3595                                 Report.Error (205, loc, "Cannot call an abstract base property: " +
3596                                               PropertyInfo.DeclaringType + "." +PropertyInfo.Name);
3597                                 return null;
3598                         }
3599
3600                         //
3601                         // Check that we are not making changes to a temporary memory location
3602                         //
3603                         if (instance_expr != null && instance_expr.Type.IsValueType && !(instance_expr is IMemoryLocation)) {
3604                                 // FIXME: Provide better error reporting.
3605                                 Error (1612, "Cannot modify expression because it is not a variable.");
3606                                 return null;
3607                         }
3608
3609                         return this;
3610                 }
3611
3612
3613
3614                 public override void Emit (EmitContext ec)
3615                 {
3616                         Emit (ec, false);
3617                 }
3618
3619                 void EmitInstance (EmitContext ec)
3620                 {
3621                         if (is_static)
3622                                 return;
3623
3624                         //
3625                         // In case it escapes StaticMemberCheck due to IdenticalTypeAndName.
3626                         // This happens in cases like 'string String', 'int Int32', etc.
3627                         // where the "IdenticalTypeAndName" mechanism is fooled.
3628                         //
3629                         if (instance_expr == null) {
3630                                 SimpleName.Error_ObjectRefRequired (ec, loc, PropertyInfo.Name);
3631                                 return;
3632                         }
3633
3634                         if (instance_expr.Type.IsValueType) {
3635                                 if (instance_expr is IMemoryLocation) {
3636                                         ((IMemoryLocation) instance_expr).AddressOf (ec, AddressOp.LoadStore);
3637                                 } else {
3638                                         LocalTemporary t = new LocalTemporary (ec, instance_expr.Type);
3639                                         instance_expr.Emit (ec);
3640                                         t.Store (ec);
3641                                         t.AddressOf (ec, AddressOp.Store);
3642                                 }
3643                         } else
3644                                 instance_expr.Emit (ec);
3645
3646                         if (prepared)
3647                                 ec.ig.Emit (OpCodes.Dup);
3648                 }
3649
3650
3651                 public void Emit (EmitContext ec, bool leave_copy)
3652                 {
3653                         if (!prepared)
3654                                 EmitInstance (ec);
3655
3656                         //
3657                         // Special case: length of single dimension array property is turned into ldlen
3658                         //
3659                         if ((getter == TypeManager.system_int_array_get_length) ||
3660                             (getter == TypeManager.int_array_get_length)){
3661                                 Type iet = instance_expr.Type;
3662
3663                                 //
3664                                 // System.Array.Length can be called, but the Type does not
3665                                 // support invoking GetArrayRank, so test for that case first
3666                                 //
3667                                 if (iet != TypeManager.array_type && (iet.GetArrayRank () == 1)) {
3668                                         ec.ig.Emit (OpCodes.Ldlen);
3669                                         ec.ig.Emit (OpCodes.Conv_I4);
3670                                         return;
3671                                 }
3672                         }
3673
3674                         Invocation.EmitCall (ec, IsBase, IsStatic, new EmptyAddressOf (), getter, null, loc);
3675
3676                         if (!leave_copy)
3677                                 return;
3678
3679                         ec.ig.Emit (OpCodes.Dup);
3680                         if (!is_static) {
3681                                 temp = new LocalTemporary (ec, this.Type);
3682                                 temp.Store (ec);
3683                         }
3684                 }
3685
3686                 //
3687                 // Implements the IAssignMethod interface for assignments
3688                 //
3689                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
3690                 {
3691                         prepared = prepare_for_load;
3692
3693                         EmitInstance (ec);
3694
3695                         source.Emit (ec);
3696                         if (leave_copy) {
3697                                 ec.ig.Emit (OpCodes.Dup);
3698                                 if (!is_static) {
3699                                         temp = new LocalTemporary (ec, this.Type);
3700                                         temp.Store (ec);
3701                                 }
3702                         }
3703
3704                         ArrayList args = new ArrayList (1);
3705                         args.Add (new Argument (new EmptyAddressOf (), Argument.AType.Expression));
3706
3707                         Invocation.EmitCall (ec, IsBase, IsStatic, new EmptyAddressOf (), setter, args, loc);
3708
3709                         if (temp != null)
3710                                 temp.Emit (ec);
3711                 }
3712
3713                 override public void EmitStatement (EmitContext ec)
3714                 {
3715                         Emit (ec);
3716                         ec.ig.Emit (OpCodes.Pop);
3717                 }
3718         }
3719
3720         /// <summary>
3721         ///   Fully resolved expression that evaluates to an Event
3722         /// </summary>
3723         public class EventExpr : Expression, IMemberExpr {
3724                 public readonly EventInfo EventInfo;
3725                 Expression instance_expr;
3726
3727                 bool is_static;
3728                 MethodInfo add_accessor, remove_accessor;
3729
3730                 public EventExpr (EventInfo ei, Location loc)
3731                 {
3732                         EventInfo = ei;
3733                         this.loc = loc;
3734                         eclass = ExprClass.EventAccess;
3735
3736                         add_accessor = TypeManager.GetAddMethod (ei);
3737                         remove_accessor = TypeManager.GetRemoveMethod (ei);
3738
3739                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
3740                                 is_static = true;
3741
3742                         if (EventInfo is MyEventBuilder){
3743                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
3744                                 type = eb.EventType;
3745                                 eb.SetUsed ();
3746                         } else
3747                                 type = EventInfo.EventHandlerType;
3748                 }
3749
3750                 public string Name {
3751                         get {
3752                                 return EventInfo.Name;
3753                         }
3754                 }
3755
3756                 public bool IsInstance {
3757                         get {
3758                                 return !is_static;
3759                         }
3760                 }
3761
3762                 public bool IsStatic {
3763                         get {
3764                                 return is_static;
3765                         }
3766                 }
3767
3768                 public Type DeclaringType {
3769                         get {
3770                                 return EventInfo.DeclaringType;
3771                         }
3772                 }
3773
3774                 public Expression InstanceExpression {
3775                         get {
3776                                 return instance_expr;
3777                         }
3778
3779                         set {
3780                                 instance_expr = value;
3781                         }
3782                 }
3783
3784                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
3785                 {
3786                         if ((instance_expr == null) && ec.IsStatic && !is_static) {
3787                                 SimpleName.Error_ObjectRefRequired (ec, loc, EventInfo.Name);
3788                                 return false;
3789                         }
3790
3791                         if (instance_expr != null) {
3792                                 instance_expr = instance_expr.DoResolve (ec);
3793                                 if (instance_expr == null)
3794                                         return false;
3795                         }
3796
3797                         //
3798                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
3799                         // However, in the Event case, we reported a CS0122 instead.
3800                         //
3801                         if (must_do_cs1540_check && (instance_expr != null)) {
3802                                 if ((instance_expr.Type != ec.ContainerType) &&
3803                                         ec.ContainerType.IsSubclassOf (instance_expr.Type)) {
3804                                         Report.Error (122, loc, "'{0}' is inaccessible due to its protection level",
3805                                                 DeclaringType.Name + "." + EventInfo.Name);
3806
3807                                         return false;
3808                                 }
3809                         }
3810
3811                         return true;
3812                 }
3813
3814                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
3815                 {
3816                         return DoResolve (ec);
3817                 }
3818
3819                 public override Expression DoResolve (EmitContext ec)
3820                 {
3821                         if (instance_expr != null) {
3822                                 instance_expr = instance_expr.DoResolve (ec);
3823                                 if (instance_expr == null)
3824                                         return null;
3825                         }
3826
3827                         bool must_do_cs1540_check;
3828                         if (!(IsAccessorAccessible (ec.ContainerType, add_accessor, out must_do_cs1540_check)
3829                                     && IsAccessorAccessible (ec.ContainerType, remove_accessor, out must_do_cs1540_check))) {
3830
3831                                Report.Error (122, loc, "'{0}' is inaccessible due to its protection level",
3832                                                DeclaringType.Name + "." + EventInfo.Name);
3833                                return null;
3834                         }
3835
3836                         if (!InstanceResolve (ec, must_do_cs1540_check))
3837                                 return null;
3838
3839                         return this;
3840                 }
3841
3842                 public override void Emit (EmitContext ec)
3843                 {
3844                         if (instance_expr is This)
3845                                 Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of += or -=, try calling the actual delegate", Name);
3846                         else
3847                                 Report.Error (70, loc, "The event `{0}' can only appear on the left hand side of += or -= "+
3848                                               "(except on the defining type)", Name);
3849                 }
3850
3851                 public void EmitAddOrRemove (EmitContext ec, Expression source)
3852                 {
3853                         BinaryDelegate source_del = (BinaryDelegate) source;
3854                         Expression handler = source_del.Right;
3855
3856                         Argument arg = new Argument (handler, Argument.AType.Expression);
3857                         ArrayList args = new ArrayList ();
3858
3859                         args.Add (arg);
3860
3861                         if (source_del.IsAddition)
3862                                 Invocation.EmitCall (
3863                                         ec, false, IsStatic, instance_expr, add_accessor, args, loc);
3864                         else
3865                                 Invocation.EmitCall (
3866                                         ec, false, IsStatic, instance_expr, remove_accessor, args, loc);
3867                 }
3868         }
3869 }