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).DoResolveAllowStatic (ec, intermediate);
 369
 370                         else
 371                                 e = DoResolve (ec);
 372
 373                         ec.DoFlowAnalysis = old_do_flow_analysis;
 374
 375                         if (e == null)
 376                                 return null;
 377
 378                         if ((e is TypeExpr) || (e is ComposedCast) || (e is Namespace)) {
 379                                 if ((flags & ResolveFlags.Type) == 0) {
 380                                         e.Error_UnexpectedKind (flags, loc);
 381                                         return null;
 382                                 }
 383
 384                                 return e;
 385                         }
 386
 387                         switch (e.eclass) {
 388                         case ExprClass.Type:
 389                         case ExprClass.Namespace:
 390                                 if ((flags & ResolveFlags.VariableOrValue) == 0) {
 391                                         e.Error_UnexpectedKind (flags, loc);
 392                                         return null;
 393                                 }
 394                                 break;
 395
 396                         case ExprClass.MethodGroup:
 397                                 if (RootContext.Version == LanguageVersion.ISO_1){
 398                                         if ((flags & ResolveFlags.MethodGroup) == 0) {
 399                                                 ((MethodGroupExpr) e).ReportUsageError ();
 400                                                 return null;
 401                                         }
 402                                 }
 403                                 break;
 404
 405                         case ExprClass.Value:
 406                         case ExprClass.Variable:
 407                         case ExprClass.PropertyAccess:
 408                         case ExprClass.EventAccess:
 409                         case ExprClass.IndexerAccess:
 410                                 if ((flags & ResolveFlags.VariableOrValue) == 0) {
 411                                         Console.WriteLine ("I got: {0} and {1}", e.GetType (), e);
 412                                         Console.WriteLine ("I am {0} and {1}", this.GetType (), this);
 413                                         FieldInfo fi = ((FieldExpr) e).FieldInfo;
 414
 415                                         Console.WriteLine ("{0} and {1}", fi.DeclaringType, fi.Name);
 416                                         e.Error_UnexpectedKind (flags, loc);
 417                                         return null;
 418                                 }
 419                                 break;
 420
 421                         default:
 422                                 throw new Exception ("Expression " + e.GetType () +
 423                                                      " ExprClass is Invalid after resolve");
 424                         }
 425
 426                         if (e.type == null && !(e is Namespace)) {
 427                                 throw new Exception (
 428                                         "Expression " + e.GetType () +
 429                                         " did not set its type after Resolve\n" +
 430                                         "called from: " + this.GetType ());
 431                         }
 432
 433                         return e;
 434                 }
 435
 436                 /// <summary>
 437                 ///   Resolves an expression and performs semantic analysis on it.
 438                 /// </summary>
 439                 public Expression Resolve (EmitContext ec)
 440                 {
 441                         return Resolve (ec, ResolveFlags.VariableOrValue);
 442                 }
 443
 444                 /// <summary>
 445                 ///   Resolves an expression for LValue assignment
 446                 /// </summary>
 447                 ///
 448                 /// <remarks>
 449                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 450                 ///   checking and assertion checking on what we expect from Resolve
 451                 /// </remarks>
 452                 public Expression ResolveLValue (EmitContext ec, Expression right_side)
 453                 {
 454                         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, new Location (-1));
 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 static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
2043                 {
2044                         if (ec.IsFieldInitializer)
2045                                 Report.Error (
2046                                         236, l,
2047                                         "A field initializer cannot reference the non-static field, " +
2048                                         "method or property `"+name+"'");
2049                         else
2050                                 Report.Error (
2051                                         120, l,
2052                                         "An object reference is required " +
2053                                         "for the non-static field `"+name+"'");
2054                 }
2055
2056                 //
2057                 // Checks whether we are trying to access an instance
2058                 // property, method or field from a static body.
2059                 //
2060                 Expression MemberStaticCheck (EmitContext ec, Expression e)
2061                 {
2062                         if (e is IMemberExpr){
2063                                 IMemberExpr member = (IMemberExpr) e;
2064
2065                                 if (!member.IsStatic){
2066                                         Error_ObjectRefRequired (ec, loc, Name);
2067                                         return null;
2068                                 }
2069                         }
2070
2071                         return e;
2072                 }
2073
2074                 public override Expression DoResolve (EmitContext ec)
2075                 {
2076                         return SimpleNameResolve (ec, null, false, false);
2077                 }
2078
2079                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
2080                 {
2081                         return SimpleNameResolve (ec, right_side, false, false);
2082                 }
2083
2084
2085                 public Expression DoResolveAllowStatic (EmitContext ec, bool intermediate)
2086                 {
2087                         return SimpleNameResolve (ec, null, true, intermediate);
2088                 }
2089
2090                 public override FullNamedExpression ResolveAsTypeStep (EmitContext ec)
2091                 {
2092                         DeclSpace ds = ec.DeclSpace;
2093                         FullNamedExpression dt;
2094
2095                         dt = ds.LookupGeneric (Name, loc);
2096                         if (dt != null)
2097                                 return dt.ResolveAsTypeStep (ec);
2098
2099                         int errors = Report.Errors;
2100                         dt = ec.ResolvingTypeTree
2101                                 ? ds.FindType (loc, Name)
2102                                 : ds.LookupType (Name, loc, /*silent=*/ true, /*ignore_cs0104=*/ false);
2103                         if (Report.Errors != errors)
2104                                 return null;
2105
2106                         return dt;
2107                 }
2108
2109                 Expression SimpleNameResolve (EmitContext ec, Expression right_side,
2110                                               bool allow_static, bool intermediate)
2111                 {
2112                         Expression e = DoSimpleNameResolve (ec, right_side, allow_static, intermediate);
2113                         if (e == null)
2114                                 return null;
2115
2116                         Block current_block = ec.CurrentBlock;
2117                         if (current_block != null){
2118                                 if (current_block.IsVariableNameUsedInChildBlock (Name)) {
2119                                         Report.Error (135, Location,
2120                                                       "'{0}' has a different meaning in a child block", Name);
2121                                         return null;
2122                                 }
2123                         }
2124
2125                         if (e.Type != null && e.Type.IsPointer && !ec.InUnsafe) {
2126                                 UnsafeError (loc);
2127                                 return null;
2128                         }
2129
2130                         return e;
2131                 }
2132
2133                 /// <remarks>
2134                 ///   7.5.2: Simple Names.
2135                 ///
2136                 ///   Local Variables and Parameters are handled at
2137                 ///   parse time, so they never occur as SimpleNames.
2138                 ///
2139                 ///   The `allow_static' flag is used by MemberAccess only
2140                 ///   and it is used to inform us that it is ok for us to
2141                 ///   avoid the static check, because MemberAccess might end
2142                 ///   up resolving the Name as a Type name and the access as
2143                 ///   a static type access.
2144                 ///
2145                 ///   ie: Type Type; .... { Type.GetType (""); }
2146                 ///
2147                 ///   Type is both an instance variable and a Type;  Type.GetType
2148                 ///   is the static method not an instance method of type.
2149                 /// </remarks>
2150                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool allow_static, bool intermediate)
2151                 {
2152                         Expression e = null;
2153
2154                         //
2155                         // Stage 1: Performed by the parser (binding to locals or parameters).
2156                         //
2157                         Block current_block = ec.CurrentBlock;
2158                         if (current_block != null){
2159                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2160                                 if (vi != null){
2161                                         Expression var;
2162
2163                                         var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2164
2165                                         if (right_side != null)
2166                                                 return var.ResolveLValue (ec, right_side);
2167                                         else
2168                                                 return var.Resolve (ec);
2169                                 }
2170
2171                                 ParameterReference pref = current_block.GetParameterReference (Name, loc);
2172                                 if (pref != null) {
2173                                         if (right_side != null)
2174                                                 return pref.ResolveLValue (ec, right_side);
2175                                         else
2176                                                 return pref.Resolve (ec);
2177                                 }
2178                         }
2179
2180                         //
2181                         // Stage 2: Lookup members
2182                         //
2183
2184                         DeclSpace lookup_ds = ec.DeclSpace;
2185                         Type almost_matched_type = null;
2186                         ArrayList almost_matched = null;
2187                         do {
2188                                 if (lookup_ds.TypeBuilder == null)
2189                                         break;
2190
2191                                 e = MemberLookup (ec, lookup_ds.TypeBuilder, Name, loc);
2192                                 if (e != null)
2193                                         break;
2194
2195                                 if (almost_matched == null && almostMatchedMembers.Count > 0) {
2196                                         almost_matched_type = lookup_ds.TypeBuilder;
2197                                         almost_matched = (ArrayList) almostMatchedMembers.Clone ();
2198                                 }
2199
2200                                 lookup_ds =lookup_ds.Parent;
2201                         } while (lookup_ds != null);
2202
2203                         if (e == null && ec.ContainerType != null)
2204                                 e = MemberLookup (ec, ec.ContainerType, Name, loc);
2205
2206                         if (e == null) {
2207                                 if (almost_matched == null && almostMatchedMembers.Count > 0) {
2208                                         almost_matched_type = ec.ContainerType;
2209                                         almost_matched = (ArrayList) almostMatchedMembers.Clone ();
2210                                 }
2211                                 e = ResolveAsTypeStep (ec);
2212                         }
2213
2214                         if (e == null) {
2215                                 if (almost_matched != null)
2216                                         almostMatchedMembers = almost_matched;
2217                                 if (almost_matched_type == null)
2218                                         almost_matched_type = ec.ContainerType;
2219                                 MemberLookupFailed (ec, null, almost_matched_type, ((SimpleName) this).Name, ec.DeclSpace.Name, true, loc);
2220                                 return null;
2221                         }
2222
2223                         if (e is TypeExpr)
2224                                 return e;
2225
2226                         if (e is IMemberExpr) {
2227                                 e = MemberAccess.ResolveMemberAccess (ec, e, null, loc, this);
2228                                 if (e == null)
2229                                         return null;
2230
2231                                 IMemberExpr me = e as IMemberExpr;
2232                                 if (me == null)
2233                                         return e;
2234
2235                                 if (Arguments != null) {
2236                                         MethodGroupExpr mg = me as MethodGroupExpr;
2237                                         if (mg == null)
2238                                                 return null;
2239
2240                                         return mg.ResolveGeneric (ec, Arguments);
2241                                 }
2242
2243                                 // This fails if ResolveMemberAccess() was unable to decide whether
2244                                 // it's a field or a type of the same name.
2245
2246                                 if (!me.IsStatic && (me.InstanceExpression == null))
2247                                         return e;
2248
2249                                 if (!me.IsStatic &&
2250                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2251                                     me.InstanceExpression.Type != me.DeclaringType &&
2252                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2253                                     (!intermediate || !MemberAccess.IdenticalNameAndTypeName (ec, this, e, loc))) {
2254                                         Error (38, "Cannot access nonstatic member `" + me.Name + "' of " +
2255                                                "outer type `" + me.DeclaringType + "' via nested type `" +
2256                                                me.InstanceExpression.Type + "'");
2257                                         return null;
2258                                 }
2259
2260                                 return (right_side != null)
2261                                         ? e.DoResolveLValue (ec, right_side)
2262                                         : e.DoResolve (ec);
2263                         }
2264
2265                         if (ec.IsStatic || ec.IsFieldInitializer){
2266                                 if (allow_static)
2267                                         return e;
2268
2269                                 return MemberStaticCheck (ec, e);
2270                         } else
2271                                 return e;
2272                 }
2273
2274                 public override void Emit (EmitContext ec)
2275                 {
2276                         //
2277                         // If this is ever reached, then we failed to
2278                         // find the name as a namespace
2279                         //
2280
2281                         Error (103, "The name `" + Name +
2282                                "' does not exist in the class `" +
2283                                ec.DeclSpace.Name + "'");
2284                 }
2285
2286                 public override string ToString ()
2287                 {
2288                         return Name;
2289                 }
2290         }
2291
2292         /// <summary>
2293         ///   Represents a namespace or a type.  The name of the class was inspired by
2294         ///   section 10.8.1 (Fully Qualified Names).
2295         /// </summary>
2296         public abstract class FullNamedExpression : Expression {
2297                 public override FullNamedExpression ResolveAsTypeStep (EmitContext ec)
2298                 {
2299                         return this;
2300                 }
2301
2302                 public abstract string FullName {
2303                         get;
2304                 }
2305         }
2306
2307         /// <summary>
2308         ///   Fully resolved expression that evaluates to a type
2309         /// </summary>
2310         public abstract class TypeExpr : FullNamedExpression {
2311                 override public FullNamedExpression ResolveAsTypeStep (EmitContext ec)
2312                 {
2313                         TypeExpr t = DoResolveAsTypeStep (ec);
2314                         if (t == null)
2315                                 return null;
2316
2317                         eclass = ExprClass.Type;
2318                         return t;
2319                 }
2320
2321                 override public Expression DoResolve (EmitContext ec)
2322                 {
2323                         return ResolveAsTypeTerminal (ec);
2324                 }
2325
2326                 override public void Emit (EmitContext ec)
2327                 {
2328                         throw new Exception ("Should never be called");
2329                 }
2330
2331                 public virtual bool CheckAccessLevel (DeclSpace ds)
2332                 {
2333                         return ds.CheckAccessLevel (Type);
2334                 }
2335
2336                 public virtual bool AsAccessible (DeclSpace ds, int flags)
2337                 {
2338                         return ds.AsAccessible (Type, flags);
2339                 }
2340
2341                 public virtual bool IsClass {
2342                         get { return Type.IsClass; }
2343                 }
2344
2345                 public virtual bool IsValueType {
2346                         get { return Type.IsValueType; }
2347                 }
2348
2349                 public virtual bool IsInterface {
2350                         get { return Type.IsInterface; }
2351                 }
2352
2353                 public virtual bool IsSealed {
2354                         get { return Type.IsSealed; }
2355                 }
2356
2357                 public virtual bool CanInheritFrom ()
2358                 {
2359                         if (Type == TypeManager.enum_type ||
2360                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2361                             Type == TypeManager.multicast_delegate_type ||
2362                             Type == TypeManager.delegate_type ||
2363                             Type == TypeManager.array_type)
2364                                 return false;
2365
2366                         return true;
2367                 }
2368
2369                 public virtual bool IsAttribute {
2370                         get {
2371                                 return Type == TypeManager.attribute_type ||
2372                                         Type.IsSubclassOf (TypeManager.attribute_type);
2373                         }
2374                 }
2375
2376                 protected abstract TypeExpr DoResolveAsTypeStep (EmitContext ec);
2377
2378                 public virtual Type ResolveType (EmitContext ec)
2379                 {
2380                         TypeExpr t = ResolveAsTypeTerminal (ec);
2381                         if (t == null)
2382                                 return null;
2383
2384                         return t.Type;
2385                 }
2386
2387                 public abstract string Name {
2388                         get;
2389                 }
2390
2391                 public override bool Equals (object obj)
2392                 {
2393                         TypeExpr tobj = obj as TypeExpr;
2394                         if (tobj == null)
2395                                 return false;
2396
2397                         return Type == tobj.Type;
2398                 }
2399
2400                 public override int GetHashCode ()
2401                 {
2402                         return Type.GetHashCode ();
2403                 }
2404
2405                 public override string ToString ()
2406                 {
2407                         return Name;
2408                 }
2409         }
2410
2411         public class TypeExpression : TypeExpr {
2412                 public TypeExpression (Type t, Location l)
2413                 {
2414                         Type = t;
2415                         eclass = ExprClass.Type;
2416                         loc = l;
2417                 }
2418
2419                 protected override TypeExpr DoResolveAsTypeStep (EmitContext ec)
2420                 {
2421                         return this;
2422                 }
2423
2424                 public override string Name {
2425                         get {
2426                                 return Type.ToString ();
2427                         }
2428                 }
2429
2430                 public override string FullName {
2431                         get {
2432                                 return Type.FullName != null ? Type.FullName : Type.Name;
2433                         }
2434                 }
2435         }
2436
2437         /// <summary>
2438         ///   Used to create types from a fully qualified name.  These are just used
2439         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2440         ///   classified as a type.
2441         /// </summary>
2442         public class TypeLookupExpression : TypeExpr {
2443                 string name;
2444
2445                 public TypeLookupExpression (string name)
2446                 {
2447                         this.name = name;
2448                 }
2449
2450                 protected override TypeExpr DoResolveAsTypeStep (EmitContext ec)
2451                 {
2452                         if (type == null) {
2453                                 FullNamedExpression t = ec.DeclSpace.LookupType (
2454                                         name, Location.Null, /*silent=*/ false, /*ignore_cs0104=*/ false);
2455                                 if (t == null)
2456                                         return null;
2457                                 if (!(t is TypeExpr))
2458                                         return null;
2459                                 type = ((TypeExpr) t).ResolveType (ec);
2460                         }
2461
2462                         return this;
2463                 }
2464
2465                 public override string Name {
2466                         get {
2467                                 return name;
2468                         }
2469                 }
2470
2471                 public override string FullName {
2472                         get {
2473                                 return name;
2474                         }
2475                 }
2476         }
2477
2478         /// <summary>
2479         ///   Represents an "unbound generic type", ie. typeof (Foo<>).
2480         ///   See 14.5.11.
2481         /// </summary>
2482         public class UnboundTypeExpression : TypeLookupExpression {
2483                 public UnboundTypeExpression (string name)
2484                         : base (name)
2485                 { }
2486         }
2487
2488         public class TypeAliasExpression : TypeExpr {
2489                 FullNamedExpression alias;
2490                 TypeExpr texpr;
2491                 TypeArguments args;
2492                 string name;
2493
2494                 public TypeAliasExpression (FullNamedExpression alias, TypeArguments args, Location l)
2495                 {
2496                         this.alias = alias;
2497                         this.args = args;
2498                         loc = l;
2499
2500                         eclass = ExprClass.Type;
2501                         if (args != null)
2502                                 name = alias.FullName + "<" + args.ToString () + ">";
2503                         else
2504                                 name = alias.FullName;
2505                 }
2506
2507                 public override string Name {
2508                         get { return alias.FullName; }
2509                 }
2510
2511                 public override string FullName {
2512                         get { return name; }
2513                 }
2514
2515                 protected override TypeExpr DoResolveAsTypeStep (EmitContext ec)
2516                 {
2517                         texpr = alias.ResolveAsTypeTerminal (ec);
2518                         if (texpr == null)
2519                                 return null;
2520
2521                         Type type = texpr.Type;
2522                         int num_args = TypeManager.GetNumberOfTypeArguments (type);
2523
2524                         if (args != null) {
2525                                 if (num_args == 0) {
2526                                         Report.Error (308, loc,
2527                                                       "The non-generic type `{0}' cannot " +
2528                                                       "be used with type arguments.",
2529                                                       TypeManager.CSharpName (type));
2530                                         return null;
2531                                 }
2532
2533                                 ConstructedType ctype = new ConstructedType (type, args, loc);
2534                                 return ctype.ResolveAsTypeTerminal (ec);
2535                         } else if (num_args > 0) {
2536                                 Report.Error (305, loc,
2537                                               "Using the generic type `{0}' " +
2538                                               "requires {1} type arguments",
2539                                               TypeManager.GetFullName (type), num_args);
2540                                 return null;
2541                         }
2542
2543                         return new TypeExpression (type, loc);
2544                 }
2545
2546                 public override bool CheckAccessLevel (DeclSpace ds)
2547                 {
2548                         return texpr.CheckAccessLevel (ds);
2549                 }
2550
2551                 public override bool AsAccessible (DeclSpace ds, int flags)
2552                 {
2553                         return texpr.AsAccessible (ds, flags);
2554                 }
2555
2556                 public override bool IsClass {
2557                         get { return texpr.IsClass; }
2558                 }
2559
2560                 public override bool IsValueType {
2561                         get { return texpr.IsValueType; }
2562                 }
2563
2564                 public override bool IsInterface {
2565                         get { return texpr.IsInterface; }
2566                 }
2567
2568                 public override bool IsSealed {
2569                         get { return texpr.IsSealed; }
2570                 }
2571
2572                 public override bool IsAttribute {
2573                         get { return texpr.IsAttribute; }
2574                 }
2575         }
2576
2577         /// <summary>
2578         ///   MethodGroup Expression.
2579         ///
2580         ///   This is a fully resolved expression that evaluates to a type
2581         /// </summary>
2582         public class MethodGroupExpr : Expression, IMemberExpr {
2583                 public MethodBase [] Methods;
2584                 Expression instance_expression = null;
2585                 bool is_explicit_impl = false;
2586                 bool has_type_arguments = false;
2587                 bool identical_type_name = false;
2588                 bool is_base;
2589
2590                 public MethodGroupExpr (MemberInfo [] mi, Location l)
2591                 {
2592                         Methods = new MethodBase [mi.Length];
2593                         mi.CopyTo (Methods, 0);
2594                         eclass = ExprClass.MethodGroup;
2595                         type = TypeManager.object_type;
2596                         loc = l;
2597                 }
2598
2599                 public MethodGroupExpr (ArrayList list, Location l)
2600                 {
2601                         Methods = new MethodBase [list.Count];
2602
2603                         try {
2604                                 list.CopyTo (Methods, 0);
2605                         } catch {
2606                                 foreach (MemberInfo m in list){
2607                                         if (!(m is MethodBase)){
2608                                                 Console.WriteLine ("Name " + m.Name);
2609                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
2610                                         }
2611                                 }
2612                                 throw;
2613                         }
2614
2615                         loc = l;
2616                         eclass = ExprClass.MethodGroup;
2617                         type = TypeManager.object_type;
2618                 }
2619
2620                 public Type DeclaringType {
2621                         get {
2622                                 //
2623                                 // We assume that the top-level type is in the end
2624                                 //
2625                                 return Methods [Methods.Length - 1].DeclaringType;
2626                                 //return Methods [0].DeclaringType;
2627                         }
2628                 }
2629
2630                 //
2631                 // `A method group may have associated an instance expression'
2632                 //
2633                 public Expression InstanceExpression {
2634                         get {
2635                                 return instance_expression;
2636                         }
2637
2638                         set {
2639                                 instance_expression = value;
2640                         }
2641                 }
2642
2643                 public bool IsExplicitImpl {
2644                         get {
2645                                 return is_explicit_impl;
2646                         }
2647
2648                         set {
2649                                 is_explicit_impl = value;
2650                         }
2651                 }
2652
2653                 public bool HasTypeArguments {
2654                         get {
2655                                 return has_type_arguments;
2656                         }
2657
2658                         set {
2659                                 has_type_arguments = value;
2660                         }
2661                 }
2662
2663                 public bool IdenticalTypeName {
2664                         get {
2665                                 return identical_type_name;
2666                         }
2667
2668                         set {
2669                                 identical_type_name = value;
2670                         }
2671                 }
2672
2673                 public bool IsBase {
2674                         get {
2675                                 return is_base;
2676                         }
2677                         set {
2678                                 is_base = value;
2679                         }
2680                 }
2681
2682                 public string Name {
2683                         get {
2684                                 //return Methods [0].Name;
2685                                 return Methods [Methods.Length - 1].Name;
2686                         }
2687                 }
2688
2689                 public bool IsInstance {
2690                         get {
2691                                 foreach (MethodBase mb in Methods)
2692                                         if (!mb.IsStatic)
2693                                                 return true;
2694
2695                                 return false;
2696                         }
2697                 }
2698
2699                 public bool IsStatic {
2700                         get {
2701                                 foreach (MethodBase mb in Methods)
2702                                         if (mb.IsStatic)
2703                                                 return true;
2704
2705                                 return false;
2706                         }
2707                 }
2708
2709                 override public Expression DoResolve (EmitContext ec)
2710                 {
2711                         if (!IsInstance)
2712                                 instance_expression = null;
2713
2714                         if (instance_expression != null) {
2715                                 instance_expression = instance_expression.DoResolve (ec);
2716                                 if (instance_expression == null)
2717                                         return null;
2718                         }
2719
2720                         return this;
2721                 }
2722
2723                 public void ReportUsageError ()
2724                 {
2725                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
2726                                       Name + "()' is referenced without parentheses");
2727                 }
2728
2729                 override public void Emit (EmitContext ec)
2730                 {
2731                         ReportUsageError ();
2732                 }
2733
2734                 bool RemoveMethods (bool keep_static)
2735                 {
2736                         ArrayList smethods = new ArrayList ();
2737
2738                         foreach (MethodBase mb in Methods){
2739                                 if (mb.IsStatic == keep_static)
2740                                         smethods.Add (mb);
2741                         }
2742
2743                         if (smethods.Count == 0)
2744                                 return false;
2745
2746                         Methods = new MethodBase [smethods.Count];
2747                         smethods.CopyTo (Methods, 0);
2748
2749                         return true;
2750                 }
2751
2752                 /// <summary>
2753                 ///   Removes any instance methods from the MethodGroup, returns
2754                 ///   false if the resulting set is empty.
2755                 /// </summary>
2756                 public bool RemoveInstanceMethods ()
2757                 {
2758                         return RemoveMethods (true);
2759                 }
2760
2761                 /// <summary>
2762                 ///   Removes any static methods from the MethodGroup, returns
2763                 ///   false if the resulting set is empty.
2764                 /// </summary>
2765                 public bool RemoveStaticMethods ()
2766                 {
2767                         return RemoveMethods (false);
2768                 }
2769
2770                 public Expression ResolveGeneric (EmitContext ec, TypeArguments args)
2771                 {
2772                         if (args.Resolve (ec) == false)
2773                                 return null;
2774
2775                         Type[] atypes = args.Arguments;
2776
2777                         int first_count = 0;
2778                         MethodInfo first = null;
2779
2780                         ArrayList list = new ArrayList ();
2781                         foreach (MethodBase mb in Methods) {
2782                                 MethodInfo mi = mb as MethodInfo;
2783                                 if ((mi == null) || !mi.HasGenericParameters)
2784                                         continue;
2785
2786                                 Type[] gen_params = mi.GetGenericArguments ();
2787
2788                                 if (first == null) {
2789                                         first = mi;
2790                                         first_count = gen_params.Length;
2791                                 }
2792
2793                                 if (gen_params.Length != atypes.Length)
2794                                         continue;
2795
2796                                 list.Add (mi.BindGenericParameters (atypes));
2797                         }
2798
2799                         if (list.Count > 0) {
2800                                 MethodGroupExpr new_mg = new MethodGroupExpr (list, Location);
2801                                 new_mg.InstanceExpression = InstanceExpression;
2802                                 new_mg.HasTypeArguments = true;
2803                                 return new_mg;
2804                         }
2805
2806                         if (first != null)
2807                                 Report.Error (
2808                                         305, loc, "Using the generic method `{0}' " +
2809                                         "requires {1} type arguments", Name,
2810                                         first_count);
2811                         else
2812                                 Report.Error (
2813                                         308, loc, "The non-generic method `{0}' " +
2814                                         "cannot be used with type arguments", Name);
2815
2816                         return null;
2817                 }
2818         }
2819
2820         /// <summary>
2821         ///   Fully resolved expression that evaluates to a Field
2822         /// </summary>
2823         public class FieldExpr : Expression, IAssignMethod, IMemoryLocation, IMemberExpr, IVariable {
2824                 public readonly FieldInfo FieldInfo;
2825                 Expression instance_expr;
2826                 VariableInfo variable_info;
2827
2828                 LocalTemporary temp;
2829                 bool prepared;
2830                 bool is_field_initializer;
2831
2832                 public FieldExpr (FieldInfo fi, Location l)
2833                 {
2834                         FieldInfo = fi;
2835                         eclass = ExprClass.Variable;
2836                         type = TypeManager.TypeToCoreType (fi.FieldType);
2837                         loc = l;
2838                 }
2839
2840                 public string Name {
2841                         get {
2842                                 return FieldInfo.Name;
2843                         }
2844                 }
2845
2846                 public bool IsInstance {
2847                         get {
2848                                 return !FieldInfo.IsStatic;
2849                         }
2850                 }
2851
2852                 public bool IsStatic {
2853                         get {
2854                                 return FieldInfo.IsStatic;
2855                         }
2856                 }
2857
2858                 public Type DeclaringType {
2859                         get {
2860                                 return FieldInfo.DeclaringType;
2861                         }
2862                 }
2863
2864                 public Expression InstanceExpression {
2865                         get {
2866                                 return instance_expr;
2867                         }
2868
2869                         set {
2870                                 instance_expr = value;
2871                         }
2872                 }
2873
2874                 public bool IsFieldInitializer {
2875                         get {
2876                                 return is_field_initializer;
2877                         }
2878
2879                         set {
2880                                 is_field_initializer = value;
2881                         }
2882                 }
2883
2884                 public VariableInfo VariableInfo {
2885                         get {
2886                                 return variable_info;
2887                         }
2888                 }
2889
2890                 override public Expression DoResolve (EmitContext ec)
2891                 {
2892                         if (!FieldInfo.IsStatic){
2893                                 if (instance_expr == null){
2894                                         //
2895                                         // This can happen when referencing an instance field using
2896                                         // a fully qualified type expression: TypeName.InstanceField = xxx
2897                                         //
2898                                         SimpleName.Error_ObjectRefRequired (ec, loc, FieldInfo.Name);
2899                                         return null;
2900                                 }
2901
2902                                 // Resolve the field's instance expression while flow analysis is turned
2903                                 // off: when accessing a field "a.b", we must check whether the field
2904                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
2905                                 instance_expr = instance_expr.Resolve (ec, ResolveFlags.VariableOrValue |
2906                                                                        ResolveFlags.DisableFlowAnalysis);
2907                                 if (instance_expr == null)
2908                                         return null;
2909                         }
2910
2911                         ObsoleteAttribute oa;
2912                         FieldBase f = TypeManager.GetField (FieldInfo);
2913                         if (f != null) {
2914                                 oa = f.GetObsoleteAttribute (f.Parent);
2915                                 if (oa != null)
2916                                         AttributeTester.Report_ObsoleteMessage (oa, f.GetSignatureForError (), loc);
2917                                 // To be sure that type is external because we do not register generated fields
2918                         } else if (!(FieldInfo.DeclaringType is TypeBuilder)) {
2919                                 oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
2920                                 if (oa != null)
2921                                         AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
2922                         }
2923
2924                         if (ec.CurrentAnonymousMethod != null){
2925                                 if (!FieldInfo.IsStatic){
2926                                         if (ec.TypeContainer is Struct){
2927                                                 Report.Error (1673, loc, "Can not reference instance variables in anonymous methods hosted in structs");
2928                                                 return null;
2929                                         }
2930                                         ec.CaptureField (this);
2931                                 }
2932                         }
2933
2934                         // If the instance expression is a local variable or parameter.
2935                         IVariable var = instance_expr as IVariable;
2936                         if ((var == null) || (var.VariableInfo == null))
2937                                 return this;
2938
2939                         VariableInfo vi = var.VariableInfo;
2940                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
2941                                 return null;
2942
2943                         variable_info = vi.GetSubStruct (FieldInfo.Name);
2944                         return this;
2945                 }
2946
2947                 void Report_AssignToReadonly (bool is_instance)
2948                 {
2949                         string msg;
2950
2951                         if (is_instance)
2952                                 msg = "Readonly field can not be assigned outside " +
2953                                 "of constructor or variable initializer";
2954                         else
2955                                 msg = "A static readonly field can only be assigned in " +
2956                                 "a static constructor";
2957
2958                         Report.Error (is_instance ? 191 : 198, loc, msg);
2959                 }
2960
2961                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
2962                 {
2963                         IVariable var = instance_expr as IVariable;
2964                         if ((var != null) && (var.VariableInfo != null))
2965                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
2966
2967                         Expression e = DoResolve (ec);
2968
2969                         if (e == null)
2970                                 return null;
2971
2972                         if (!FieldInfo.IsStatic && (instance_expr.Type.IsValueType && !(instance_expr is IMemoryLocation))) {
2973                                 // FIXME: Provide better error reporting.
2974                                 Error (1612, "Cannot modify expression because it is not a variable.");
2975                                 return null;
2976                         }
2977
2978                         if (!FieldInfo.IsInitOnly)
2979                                 return this;
2980
2981                         FieldBase fb = TypeManager.GetField (FieldInfo);
2982                         if (fb != null)
2983                                 fb.SetAssigned ();
2984
2985                         //
2986                         // InitOnly fields can only be assigned in constructors
2987                         //
2988
2989                         if (ec.IsConstructor){
2990                                 if (IsStatic && !ec.IsStatic)
2991                                         Report_AssignToReadonly (false);
2992
2993                                 Type ctype;
2994                                 if (!is_field_initializer &&
2995                                     (ec.TypeContainer.CurrentType != null))
2996                                         ctype = ec.TypeContainer.CurrentType;
2997                                 else
2998                                         ctype = ec.ContainerType;
2999
3000                                 if (TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
3001                                         return this;
3002                         }
3003
3004                         Report_AssignToReadonly (!IsStatic);
3005
3006                         return null;
3007                 }
3008
3009                 public override void CheckMarshallByRefAccess (Type container)
3010                 {
3011                         if (!IsStatic && Type.IsValueType && !container.IsSubclassOf (TypeManager.mbr_type) && DeclaringType.IsSubclassOf (TypeManager.mbr_type)) {
3012                                 Report.SymbolRelatedToPreviousError (DeclaringType);
3013                                 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);
3014                         }
3015                 }
3016
3017                 public bool VerifyFixed (bool is_expression)
3018                 {
3019                         IVariable variable = instance_expr as IVariable;
3020                         if ((variable == null) || !variable.VerifyFixed (true))
3021                                 return false;
3022
3023                         return true;
3024                 }
3025
3026                 public void Emit (EmitContext ec, bool leave_copy)
3027                 {
3028                         ILGenerator ig = ec.ig;
3029                         bool is_volatile = false;
3030
3031                         if (FieldInfo is FieldBuilder){
3032                                 FieldBase f = TypeManager.GetField (FieldInfo);
3033                                 if (f != null){
3034                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0)
3035                                                 is_volatile = true;
3036
3037                                         f.status |= Field.Status.USED;
3038                                 }
3039                         }
3040
3041                         if (FieldInfo.IsStatic){
3042                                 if (is_volatile)
3043                                         ig.Emit (OpCodes.Volatile);
3044
3045                                 ig.Emit (OpCodes.Ldsfld, FieldInfo);
3046                         } else {
3047                                 if (!prepared)
3048                                         EmitInstance (ec);
3049
3050                                 if (is_volatile)
3051                                         ig.Emit (OpCodes.Volatile);
3052
3053                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
3054                                 if (ff != null)
3055                                 {
3056                                         ig.Emit (OpCodes.Ldflda, FieldInfo);
3057                                         ig.Emit (OpCodes.Ldflda, ff.Element);
3058                                 }
3059                                 else {
3060                                         ig.Emit (OpCodes.Ldfld, FieldInfo);
3061                                 }
3062                         }
3063
3064                         if (leave_copy) {
3065                                 ec.ig.Emit (OpCodes.Dup);
3066                                 if (!FieldInfo.IsStatic) {
3067                                         temp = new LocalTemporary (ec, this.Type);
3068                                         temp.Store (ec);
3069                                 }
3070                         }
3071                 }
3072
3073                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
3074                 {
3075                         FieldAttributes fa = FieldInfo.Attributes;
3076                         bool is_static = (fa & FieldAttributes.Static) != 0;
3077                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
3078                         ILGenerator ig = ec.ig;
3079                         prepared = prepare_for_load;
3080
3081                         if (is_readonly && !ec.IsConstructor){
3082                                 Report_AssignToReadonly (!is_static);
3083                                 return;
3084                         }
3085
3086                         if (!is_static) {
3087                                 EmitInstance (ec);
3088                                 if (prepare_for_load)
3089                                         ig.Emit (OpCodes.Dup);
3090                         }
3091
3092                         source.Emit (ec);
3093                         if (leave_copy) {
3094                                 ec.ig.Emit (OpCodes.Dup);
3095                                 if (!FieldInfo.IsStatic) {
3096                                         temp = new LocalTemporary (ec, this.Type);
3097                                         temp.Store (ec);
3098                                 }
3099                         }
3100
3101                         if (FieldInfo is FieldBuilder){
3102                                 FieldBase f = TypeManager.GetField (FieldInfo);
3103                                 if (f != null){
3104                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0)
3105                                                 ig.Emit (OpCodes.Volatile);
3106
3107                                         f.status |= Field.Status.ASSIGNED;
3108                                 }
3109                         }
3110
3111                         if (is_static)
3112                                 ig.Emit (OpCodes.Stsfld, FieldInfo);
3113                         else
3114                                 ig.Emit (OpCodes.Stfld, FieldInfo);
3115
3116                         if (temp != null)
3117                                 temp.Emit (ec);
3118                 }
3119
3120                 void EmitInstance (EmitContext ec)
3121                 {
3122                         if (instance_expr.Type.IsValueType) {
3123                                 if (instance_expr is IMemoryLocation) {
3124                                         ((IMemoryLocation) instance_expr).AddressOf (ec, AddressOp.LoadStore);
3125                                 } else {
3126                                         LocalTemporary t = new LocalTemporary (ec, instance_expr.Type);
3127                                         instance_expr.Emit (ec);
3128                                         t.Store (ec);
3129                                         t.AddressOf (ec, AddressOp.Store);
3130                                 }
3131                         } else
3132                                 instance_expr.Emit (ec);
3133                 }
3134
3135                 public override void Emit (EmitContext ec)
3136                 {
3137                         Emit (ec, false);
3138                 }
3139
3140                 public void AddressOf (EmitContext ec, AddressOp mode)
3141                 {
3142                         ILGenerator ig = ec.ig;
3143
3144                         if (FieldInfo is FieldBuilder){
3145                                 FieldBase f = TypeManager.GetField (FieldInfo);
3146                                 if (f != null){
3147                                         if ((f.ModFlags & Modifiers.VOLATILE) != 0){
3148                                                 Error (676, "volatile variable: can not take its address, or pass as ref/out parameter");
3149                                                 return;
3150                                         }
3151
3152                                         if ((mode & AddressOp.Store) != 0)
3153                                                 f.status |= Field.Status.ASSIGNED;
3154                                         if ((mode & AddressOp.Load) != 0)
3155                                                 f.status |= Field.Status.USED;
3156                                 }
3157                         }
3158
3159                         //
3160                         // Handle initonly fields specially: make a copy and then
3161                         // get the address of the copy.
3162                         //
3163                         bool need_copy;
3164                         if (FieldInfo.IsInitOnly){
3165                                 need_copy = true;
3166                                 if (ec.IsConstructor){
3167                                         if (FieldInfo.IsStatic){
3168                                                 if (ec.IsStatic)
3169                                                         need_copy = false;
3170                                         } else
3171                                                 need_copy = false;
3172                                 }
3173                         } else
3174                                 need_copy = false;
3175
3176                         if (need_copy){
3177                                 LocalBuilder local;
3178                                 Emit (ec);
3179                                 local = ig.DeclareLocal (type);
3180                                 ig.Emit (OpCodes.Stloc, local);
3181                                 ig.Emit (OpCodes.Ldloca, local);
3182                                 return;
3183                         }
3184
3185
3186                         if (FieldInfo.IsStatic){
3187                                 ig.Emit (OpCodes.Ldsflda, FieldInfo);
3188                         } else {
3189                                 EmitInstance (ec);
3190                                 ig.Emit (OpCodes.Ldflda, FieldInfo);
3191                         }
3192                 }
3193         }
3194
3195         //
3196         // A FieldExpr whose address can not be taken
3197         //
3198         public class FieldExprNoAddress : FieldExpr, IMemoryLocation {
3199                 public FieldExprNoAddress (FieldInfo fi, Location loc) : base (fi, loc)
3200                 {
3201                 }
3202
3203                 public new void AddressOf (EmitContext ec, AddressOp mode)
3204                 {
3205                         Report.Error (-215, "Report this: Taking the address of a remapped parameter not supported");
3206                 }
3207         }
3208
3209         /// <summary>
3210         ///   Expression that evaluates to a Property.  The Assign class
3211         ///   might set the `Value' expression if we are in an assignment.
3212         ///
3213         ///   This is not an LValue because we need to re-write the expression, we
3214         ///   can not take data from the stack and store it.
3215         /// </summary>
3216         public class PropertyExpr : ExpressionStatement, IAssignMethod, IMemberExpr {
3217                 public readonly PropertyInfo PropertyInfo;
3218
3219                 //
3220                 // This is set externally by the  `BaseAccess' class
3221                 //
3222                 public bool IsBase;
3223                 MethodInfo getter, setter;
3224                 bool is_static;
3225
3226                 Expression instance_expr;
3227                 LocalTemporary temp;
3228                 bool prepared;
3229
3230                 internal static PtrHashtable AccessorTable = new PtrHashtable ();
3231
3232                 public PropertyExpr (EmitContext ec, PropertyInfo pi, Location l)
3233                 {
3234                         PropertyInfo = pi;
3235                         eclass = ExprClass.PropertyAccess;
3236                         is_static = false;
3237                         loc = l;
3238
3239                         type = TypeManager.TypeToCoreType (pi.PropertyType);
3240
3241                         ResolveAccessors (ec);
3242                 }
3243
3244                 public string Name {
3245                         get {
3246                                 return PropertyInfo.Name;
3247                         }
3248                 }
3249
3250                 public bool IsInstance {
3251                         get {
3252                                 return !is_static;
3253                         }
3254                 }
3255
3256                 public bool IsStatic {
3257                         get {
3258                                 return is_static;
3259                         }
3260                 }
3261
3262                 public Type DeclaringType {
3263                         get {
3264                                 return PropertyInfo.DeclaringType;
3265                         }
3266                 }
3267
3268                 //
3269                 // The instance expression associated with this expression
3270                 //
3271                 public Expression InstanceExpression {
3272                         set {
3273                                 instance_expr = value;
3274                         }
3275
3276                         get {
3277                                 return instance_expr;
3278                         }
3279                 }
3280
3281                 public bool VerifyAssignable ()
3282                 {
3283                         if (setter == null) {
3284                                 Report.Error (200, loc,
3285                                               "The property `" + PropertyInfo.Name +
3286                                               "' can not be assigned to, as it has not set accessor");
3287                                 return false;
3288                         }
3289
3290                         return true;
3291                 }
3292
3293                 void FindAccessors (Type invocation_type)
3294                 {
3295                         BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
3296                                 BindingFlags.Static | BindingFlags.Instance |
3297                                 BindingFlags.DeclaredOnly;
3298
3299                         Type current = PropertyInfo.DeclaringType;
3300                         for (; current != null; current = current.BaseType) {
3301                                 MemberInfo[] group = TypeManager.MemberLookup (
3302                                         invocation_type, invocation_type, current,
3303                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
3304
3305                                 if (group == null)
3306                                         continue;
3307
3308                                 if (group.Length != 1)
3309                                         // Oooops, can this ever happen ?
3310                                         return;
3311
3312                                 PropertyInfo pi = (PropertyInfo) group [0];
3313
3314                                 if (getter == null)
3315                                         getter = pi.GetGetMethod (true);
3316
3317                                 if (setter == null)
3318                                         setter = pi.GetSetMethod (true);
3319
3320                                 MethodInfo accessor = getter != null ? getter : setter;
3321
3322                                 if (!accessor.IsVirtual)
3323                                         return;
3324                         }
3325                 }
3326
3327                 //
3328                 // We also perform the permission checking here, as the PropertyInfo does not
3329                 // hold the information for the accessibility of its setter/getter
3330                 //
3331                 void ResolveAccessors (EmitContext ec)
3332                 {
3333                         FindAccessors (ec.ContainerType);
3334
3335                         if (getter != null) {
3336                                 AccessorTable [getter] = PropertyInfo;
3337                                 is_static = getter.IsStatic;
3338                         }
3339
3340                         if (setter != null) {
3341                                 AccessorTable [setter] = PropertyInfo;
3342                                 is_static = setter.IsStatic;
3343                         }
3344                 }
3345
3346                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
3347                 {
3348                         if ((instance_expr == null) && ec.IsStatic && !is_static) {
3349                                 SimpleName.Error_ObjectRefRequired (ec, loc, PropertyInfo.Name);
3350                                 return false;
3351                         }
3352
3353                         if (instance_expr != null) {
3354                                 instance_expr = instance_expr.DoResolve (ec);
3355                                 if (instance_expr == null)
3356                                         return false;
3357
3358                                 instance_expr.CheckMarshallByRefAccess (ec.ContainerType);
3359                         }
3360
3361                         if (must_do_cs1540_check && (instance_expr != null)) {
3362                                 if ((instance_expr.Type != ec.ContainerType) &&
3363                                     ec.ContainerType.IsSubclassOf (instance_expr.Type)) {
3364                                         Report.Error (1540, loc, "Cannot access protected member `" +
3365                                                       PropertyInfo.DeclaringType + "." + PropertyInfo.Name +
3366                                                       "' via a qualifier of type `" +
3367                                                       TypeManager.CSharpName (instance_expr.Type) +
3368                                                       "'; the qualifier must be of type `" +
3369                                                       TypeManager.CSharpName (ec.ContainerType) +
3370                                                       "' (or derived from it)");
3371                                         return false;
3372                                 }
3373                         }
3374
3375                         return true;
3376                 }
3377
3378                 override public Expression DoResolve (EmitContext ec)
3379                 {
3380                         if (getter != null){
3381                                 if (TypeManager.GetArgumentTypes (getter).Length != 0){
3382                                         Report.Error (
3383                                                 117, loc, "`{0}' does not contain a " +
3384                                                 "definition for `{1}'.", getter.DeclaringType,
3385                                                 Name);
3386                                         return null;
3387                                 }
3388                         }
3389
3390                         if (getter == null){
3391                                 //
3392                                 // The following condition happens if the PropertyExpr was
3393                                 // created, but is invalid (ie, the property is inaccessible),
3394                                 // and we did not want to embed the knowledge about this in
3395                                 // the caller routine.  This only avoids double error reporting.
3396                                 //
3397                                 if (setter == null)
3398                                         return null;
3399
3400                                 Report.Error (154, loc,
3401                                               "The property `" + PropertyInfo.Name +
3402                                               "' can not be used in " +
3403                                               "this context because it lacks a get accessor");
3404                                 return null;
3405                         }
3406
3407                         bool must_do_cs1540_check;
3408                         if (!IsAccessorAccessible (ec.ContainerType, getter, out must_do_cs1540_check)) {
3409                                 Report.Error (122, loc, "'{0}.get' is inaccessible due to its protection level", PropertyInfo.Name);
3410                                 return null;
3411                         }
3412
3413                         if (!InstanceResolve (ec, must_do_cs1540_check))
3414                                 return null;
3415
3416                         //
3417                         // Only base will allow this invocation to happen.
3418                         //
3419                         if (IsBase && getter.IsAbstract){
3420                                 Report.Error (205, loc, "Cannot call an abstract base property: " +
3421                                               PropertyInfo.DeclaringType + "." +PropertyInfo.Name);
3422                                 return null;
3423                         }
3424
3425                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe){
3426                                 UnsafeError (loc);
3427                                 return null;
3428                         }
3429
3430                         return this;
3431                 }
3432
3433                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
3434                 {
3435                         if (setter == null){
3436                                 //
3437                                 // The following condition happens if the PropertyExpr was
3438                                 // created, but is invalid (ie, the property is inaccessible),
3439                                 // and we did not want to embed the knowledge about this in
3440                                 // the caller routine.  This only avoids double error reporting.
3441                                 //
3442                                 if (getter == null)
3443                                         return null;
3444
3445                                 Report.Error (154, loc,
3446                                               "The property `" + PropertyInfo.Name +
3447                                               "' can not be used in " +
3448                                               "this context because it lacks a set accessor");
3449                                 return null;
3450                         }
3451
3452                         if (TypeManager.GetArgumentTypes (setter).Length != 1){
3453                                 Report.Error (
3454                                         117, loc, "`{0}' does not contain a " +
3455                                         "definition for `{1}'.", getter.DeclaringType,
3456                                         Name);
3457                                 return null;
3458                         }
3459
3460                         bool must_do_cs1540_check;
3461                         if (!IsAccessorAccessible (ec.ContainerType, setter, out must_do_cs1540_check)) {
3462                                 Report.Error (122, loc, "'{0}.set' is inaccessible due to its protection level", PropertyInfo.Name);
3463                                 return null;
3464                         }
3465
3466                         if (!InstanceResolve (ec, must_do_cs1540_check))
3467                                 return null;
3468
3469                         //
3470                         // Only base will allow this invocation to happen.
3471                         //
3472                         if (IsBase && setter.IsAbstract){
3473                                 Report.Error (205, loc, "Cannot call an abstract base property: " +
3474                                               PropertyInfo.DeclaringType + "." +PropertyInfo.Name);
3475                                 return null;
3476                         }
3477
3478                         //
3479                         // Check that we are not making changes to a temporary memory location
3480                         //
3481                         if (instance_expr != null && instance_expr.Type.IsValueType && !(instance_expr is IMemoryLocation)) {
3482                                 // FIXME: Provide better error reporting.
3483                                 Error (1612, "Cannot modify expression because it is not a variable.");
3484                                 return null;
3485                         }
3486
3487                         return this;
3488                 }
3489
3490
3491
3492                 public override void Emit (EmitContext ec)
3493                 {
3494                         Emit (ec, false);
3495                 }
3496
3497                 void EmitInstance (EmitContext ec)
3498                 {
3499                         if (is_static)
3500                                 return;
3501
3502                         if (instance_expr.Type.IsValueType) {
3503                                 if (instance_expr is IMemoryLocation) {
3504                                         ((IMemoryLocation) instance_expr).AddressOf (ec, AddressOp.LoadStore);
3505                                 } else {
3506                                         LocalTemporary t = new LocalTemporary (ec, instance_expr.Type);
3507                                         instance_expr.Emit (ec);
3508                                         t.Store (ec);
3509                                         t.AddressOf (ec, AddressOp.Store);
3510                                 }
3511                         } else
3512                                 instance_expr.Emit (ec);
3513
3514                         if (prepared)
3515                                 ec.ig.Emit (OpCodes.Dup);
3516                 }
3517
3518
3519                 public void Emit (EmitContext ec, bool leave_copy)
3520                 {
3521                         if (!prepared)
3522                                 EmitInstance (ec);
3523
3524                         //
3525                         // Special case: length of single dimension array property is turned into ldlen
3526                         //
3527                         if ((getter == TypeManager.system_int_array_get_length) ||
3528                             (getter == TypeManager.int_array_get_length)){
3529                                 Type iet = instance_expr.Type;
3530
3531                                 //
3532                                 // System.Array.Length can be called, but the Type does not
3533                                 // support invoking GetArrayRank, so test for that case first
3534                                 //
3535                                 if (iet != TypeManager.array_type && (iet.GetArrayRank () == 1)) {
3536                                         ec.ig.Emit (OpCodes.Ldlen);
3537                                         ec.ig.Emit (OpCodes.Conv_I4);
3538                                         return;
3539                                 }
3540                         }
3541
3542                         Invocation.EmitCall (ec, IsBase, IsStatic, new EmptyAddressOf (), getter, null, loc);
3543
3544                         if (!leave_copy)
3545                                 return;
3546
3547                         ec.ig.Emit (OpCodes.Dup);
3548                         if (!is_static) {
3549                                 temp = new LocalTemporary (ec, this.Type);
3550                                 temp.Store (ec);
3551                         }
3552                 }
3553
3554                 //
3555                 // Implements the IAssignMethod interface for assignments
3556                 //
3557                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
3558                 {
3559                         prepared = prepare_for_load;
3560
3561                         EmitInstance (ec);
3562
3563                         source.Emit (ec);
3564                         if (leave_copy) {
3565                                 ec.ig.Emit (OpCodes.Dup);
3566                                 if (!is_static) {
3567                                         temp = new LocalTemporary (ec, this.Type);
3568                                         temp.Store (ec);
3569                                 }
3570                         }
3571
3572                         ArrayList args = new ArrayList (1);
3573                         args.Add (new Argument (new EmptyAddressOf (), Argument.AType.Expression));
3574
3575                         Invocation.EmitCall (ec, IsBase, IsStatic, new EmptyAddressOf (), setter, args, loc);
3576
3577                         if (temp != null)
3578                                 temp.Emit (ec);
3579                 }
3580
3581                 override public void EmitStatement (EmitContext ec)
3582                 {
3583                         Emit (ec);
3584                         ec.ig.Emit (OpCodes.Pop);
3585                 }
3586         }
3587
3588         /// <summary>
3589         ///   Fully resolved expression that evaluates to an Event
3590         /// </summary>
3591         public class EventExpr : Expression, IMemberExpr {
3592                 public readonly EventInfo EventInfo;
3593                 Expression instance_expr;
3594
3595                 bool is_static;
3596                 MethodInfo add_accessor, remove_accessor;
3597
3598                 public EventExpr (EventInfo ei, Location loc)
3599                 {
3600                         EventInfo = ei;
3601                         this.loc = loc;
3602                         eclass = ExprClass.EventAccess;
3603
3604                         add_accessor = TypeManager.GetAddMethod (ei);
3605                         remove_accessor = TypeManager.GetRemoveMethod (ei);
3606
3607                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
3608                                 is_static = true;
3609
3610                         if (EventInfo is MyEventBuilder){
3611                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
3612                                 type = eb.EventType;
3613                                 eb.SetUsed ();
3614                         } else
3615                                 type = EventInfo.EventHandlerType;
3616                 }
3617
3618                 public string Name {
3619                         get {
3620                                 return EventInfo.Name;
3621                         }
3622                 }
3623
3624                 public bool IsInstance {
3625                         get {
3626                                 return !is_static;
3627                         }
3628                 }
3629
3630                 public bool IsStatic {
3631                         get {
3632                                 return is_static;
3633                         }
3634                 }
3635
3636                 public Type DeclaringType {
3637                         get {
3638                                 return EventInfo.DeclaringType;
3639                         }
3640                 }
3641
3642                 public Expression InstanceExpression {
3643                         get {
3644                                 return instance_expr;
3645                         }
3646
3647                         set {
3648                                 instance_expr = value;
3649                         }
3650                 }
3651
3652                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
3653                 {
3654                         if ((instance_expr == null) && ec.IsStatic && !is_static) {
3655                                 SimpleName.Error_ObjectRefRequired (ec, loc, EventInfo.Name);
3656                                 return false;
3657                         }
3658
3659                         if (instance_expr != null) {
3660                                 instance_expr = instance_expr.DoResolve (ec);
3661                                 if (instance_expr == null)
3662                                         return false;
3663                         }
3664
3665                         //
3666                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
3667                         // However, in the Event case, we reported a CS0122 instead.
3668                         //
3669                         if (must_do_cs1540_check && (instance_expr != null)) {
3670                                 if ((instance_expr.Type != ec.ContainerType) &&
3671                                         ec.ContainerType.IsSubclassOf (instance_expr.Type)) {
3672                                         Report.Error (122, loc, "'{0}' is inaccessible due to its protection level",
3673                                                 DeclaringType.Name + "." + EventInfo.Name);
3674
3675                                         return false;
3676                                 }
3677                         }
3678
3679                         return true;
3680                 }
3681
3682                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
3683                 {
3684                         return DoResolve (ec);
3685                 }
3686
3687                 public override Expression DoResolve (EmitContext ec)
3688                 {
3689                         if (instance_expr != null) {
3690                                 instance_expr = instance_expr.DoResolve (ec);
3691                                 if (instance_expr == null)
3692                                         return null;
3693                         }
3694
3695                         bool must_do_cs1540_check;
3696                         if (!(IsAccessorAccessible (ec.ContainerType, add_accessor, out must_do_cs1540_check)
3697                                     && IsAccessorAccessible (ec.ContainerType, remove_accessor, out must_do_cs1540_check))) {
3698
3699                                Report.Error (122, loc, "'{0}' is inaccessible due to its protection level",
3700                                                DeclaringType.Name + "." + EventInfo.Name);
3701                                return null;
3702                         }
3703
3704                         if (!InstanceResolve (ec, must_do_cs1540_check))
3705                                 return null;
3706
3707                         return this;
3708                 }
3709
3710                 public override void Emit (EmitContext ec)
3711                 {
3712                         if (instance_expr is This)
3713                                 Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of += or -=, try calling the actual delegate", Name);
3714                         else
3715                                 Report.Error (70, loc, "The event `{0}' can only appear on the left hand side of += or -= "+
3716                                               "(except on the defining type)", Name);
3717                 }
3718
3719                 public void EmitAddOrRemove (EmitContext ec, Expression source)
3720                 {
3721                         BinaryDelegate source_del = (BinaryDelegate) source;
3722                         Expression handler = source_del.Right;
3723
3724                         Argument arg = new Argument (handler, Argument.AType.Expression);
3725                         ArrayList args = new ArrayList ();
3726
3727                         args.Add (arg);
3728
3729                         if (source_del.IsAddition)
3730                                 Invocation.EmitCall (
3731                                         ec, false, IsStatic, instance_expr, add_accessor, args, loc);
3732                         else
3733                                 Invocation.EmitCall (
3734                                         ec, false, IsStatic, instance_expr, remove_accessor, args, loc);
3735                 }
3736         }
3737 }