mcs/mcs/ecore.cs

   1 //
   2 // ecore.cs: Core of the Expression representation for the intermediate tree.
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //   Marek Safar (marek.safar@seznam.cz)
   7 //
   8 // (C) 2001, 2002, 2003 Ximian, Inc.
   9 //
  10 //
  11
  12 namespace Mono.CSharp {
  13         using System;
  14         using System.Collections;
  15         using System.Diagnostics;
  16         using System.Reflection;
  17         using System.Reflection.Emit;
  18         using System.Text;
  19
  20         /// <remarks>
  21         ///   The ExprClass class contains the is used to pass the
  22         ///   classification of an expression (value, variable, namespace,
  23         ///   type, method group, property access, event access, indexer access,
  24         ///   nothing).
  25         /// </remarks>
  26         public enum ExprClass : byte {
  27                 Invalid,
  28
  29                 Value,
  30                 Variable,
  31                 Namespace,
  32                 Type,
  33                 MethodGroup,
  34                 PropertyAccess,
  35                 EventAccess,
  36                 IndexerAccess,
  37                 Nothing,
  38         }
  39
  40         /// <remarks>
  41         ///   This is used to tell Resolve in which types of expressions we're
  42         ///   interested.
  43         /// </remarks>
  44         [Flags]
  45         public enum ResolveFlags {
  46                 // Returns Value, Variable, PropertyAccess, EventAccess or IndexerAccess.
  47                 VariableOrValue         = 1,
  48
  49                 // Returns a type expression.
  50                 Type                    = 2,
  51
  52                 // Returns a method group.
  53                 MethodGroup             = 4,
  54
  55                 // Mask of all the expression class flags.
  56                 MaskExprClass           = 7,
  57
  58                 // Disable control flow analysis while resolving the expression.
  59                 // This is used when resolving the instance expression of a field expression.
  60                 DisableFlowAnalysis     = 8,
  61
  62                 // Set if this is resolving the first part of a MemberAccess.
  63                 Intermediate            = 16,
  64
  65                 // Disable control flow analysis _of struct_ while resolving the expression.
  66                 // This is used when resolving the instance expression of a field expression.
  67                 DisableStructFlowAnalysis       = 32,
  68
  69         }
  70
  71         //
  72         // This is just as a hint to AddressOf of what will be done with the
  73         // address.
  74         [Flags]
  75         public enum AddressOp {
  76                 Store = 1,
  77                 Load  = 2,
  78                 LoadStore = 3
  79         };
  80
  81         /// <summary>
  82         ///   This interface is implemented by variables
  83         /// </summary>
  84         public interface IMemoryLocation {
  85                 /// <summary>
  86                 ///   The AddressOf method should generate code that loads
  87                 ///   the address of the object and leaves it on the stack.
  88                 ///
  89                 ///   The `mode' argument is used to notify the expression
  90                 ///   of whether this will be used to read from the address or
  91                 ///   write to the address.
  92                 ///
  93                 ///   This is just a hint that can be used to provide good error
  94                 ///   reporting, and should have no other side effects.
  95                 /// </summary>
  96                 void AddressOf (EmitContext ec, AddressOp mode);
  97         }
  98
  99         /// <summary>
 100         ///   This interface is implemented by variables
 101         /// </summary>
 102         public interface IVariable {
 103                 VariableInfo VariableInfo {
 104                         get;
 105                 }
 106
 107                 bool VerifyFixed ();
 108         }
 109
 110         /// <remarks>
 111         ///   Base class for expressions
 112         /// </remarks>
 113         public abstract class Expression {
 114                 public ExprClass eclass;
 115                 protected Type type;
 116                 protected Location loc;
 117
 118                 public Type Type {
 119                         get { return type; }
 120                         set { type = value; }
 121                 }
 122
 123                 public virtual Location Location {
 124                         get { return loc; }
 125                 }
 126
 127                 /// <summary>
 128                 ///   Utility wrapper routine for Error, just to beautify the code
 129                 /// </summary>
 130                 public void Error (int error, string s)
 131                 {
 132                         Report.Error (error, loc, s);
 133                 }
 134
 135                 // Not nice but we have broken hierarchy.
 136                 public virtual void CheckMarshalByRefAccess ()
 137                 {
 138                 }
 139
 140                 public virtual bool GetAttributableValue (Type value_type, out object value)
 141                 {
 142                         Attribute.Error_AttributeArgumentNotValid (loc);
 143                         value = null;
 144                         return false;
 145                 }
 146
 147                 public virtual string GetSignatureForError ()
 148                 {
 149                         return TypeManager.CSharpName (type);
 150                 }
 151
 152                 public static bool IsAccessorAccessible (Type invocation_type, MethodInfo mi, out bool must_do_cs1540_check)
 153                 {
 154                         MethodAttributes ma = mi.Attributes & MethodAttributes.MemberAccessMask;
 155
 156                         must_do_cs1540_check = false; // by default we do not check for this
 157
 158                         if (ma == MethodAttributes.Public)
 159                                 return true;
 160
 161                         //
 162                         // If only accessible to the current class or children
 163                         //
 164                         if (ma == MethodAttributes.Private)
 165                                 return TypeManager.IsPrivateAccessible (invocation_type, mi.DeclaringType) ||
 166                                         TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType);
 167
 168                         if (mi.DeclaringType.Assembly == invocation_type.Assembly ||
 169                                         TypeManager.IsFriendAssembly (mi.DeclaringType.Assembly)) {
 170                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamORAssem)
 171                                         return true;
 172                         } else {
 173                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamANDAssem)
 174                                         return false;
 175                         }
 176
 177                         // Family and FamANDAssem require that we derive.
 178                         // FamORAssem requires that we derive if in different assemblies.
 179                         if (!TypeManager.IsNestedFamilyAccessible (invocation_type, mi.DeclaringType))
 180                                 return false;
 181
 182                         if (!TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType))
 183                                 must_do_cs1540_check = true;
 184
 185                         return true;
 186                 }
 187
 188                 /// <summary>
 189                 ///   Performs semantic analysis on the Expression
 190                 /// </summary>
 191                 ///
 192                 /// <remarks>
 193                 ///   The Resolve method is invoked to perform the semantic analysis
 194                 ///   on the node.
 195                 ///
 196                 ///   The return value is an expression (it can be the
 197                 ///   same expression in some cases) or a new
 198                 ///   expression that better represents this node.
 199                 ///
 200                 ///   For example, optimizations of Unary (LiteralInt)
 201                 ///   would return a new LiteralInt with a negated
 202                 ///   value.
 203                 ///
 204                 ///   If there is an error during semantic analysis,
 205                 ///   then an error should be reported (using Report)
 206                 ///   and a null value should be returned.
 207                 ///
 208                 ///   There are two side effects expected from calling
 209                 ///   Resolve(): the the field variable "eclass" should
 210                 ///   be set to any value of the enumeration
 211                 ///   `ExprClass' and the type variable should be set
 212                 ///   to a valid type (this is the type of the
 213                 ///   expression).
 214                 /// </remarks>
 215                 public abstract Expression DoResolve (EmitContext ec);
 216
 217                 public virtual Expression DoResolveLValue (EmitContext ec, Expression right_side)
 218                 {
 219                         return null;
 220                 }
 221
 222                 //
 223                 // This is used if the expression should be resolved as a type or namespace name.
 224                 // the default implementation fails.
 225                 //
 226                 public virtual FullNamedExpression ResolveAsTypeStep (IResolveContext ec,  bool silent)
 227                 {
 228                         return null;
 229                 }
 230
 231                 //
 232                 // C# 3.0 introduced contextual keywords (var) which behaves like a type if type with
 233                 // same name exists or as a keyword when no type was found
 234                 //
 235                 public virtual TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
 236                 {
 237                         return ResolveAsTypeTerminal (rc, silent);
 238                 }
 239
 240                 //
 241                 // This is used to resolve the expression as a type, a null
 242                 // value will be returned if the expression is not a type
 243                 // reference
 244                 //
 245                 public virtual TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
 246                 {
 247                         TypeExpr te = ResolveAsBaseTerminal (ec, silent);
 248                         if (te == null)
 249                                 return null;
 250
 251                         if (!silent) { // && !(te is TypeParameterExpr)) {
 252                                 ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (te.Type);
 253                                 if (obsolete_attr != null && !ec.IsInObsoleteScope) {
 254                                         AttributeTester.Report_ObsoleteMessage (obsolete_attr, te.GetSignatureForError (), Location);
 255                                 }
 256                         }
 257
 258                         // Constrains don't need to be checked for overrides
 259                         GenericMethod gm = ec.GenericDeclContainer as GenericMethod;
 260                         if (gm != null && (gm.ModFlags & Modifiers.OVERRIDE) != 0) {
 261                                 te.loc = loc;
 262                                 return te;
 263                         }
 264
 265                         ConstructedType ct = te as ConstructedType;
 266                         if ((ct != null) && !ct.CheckConstraints (ec))
 267                                 return null;
 268
 269                         return te;
 270                 }
 271
 272                 public TypeExpr ResolveAsBaseTerminal (IResolveContext ec, bool silent)
 273                 {
 274                         int errors = Report.Errors;
 275
 276                         FullNamedExpression fne = ResolveAsTypeStep (ec, silent);
 277
 278                         if (fne == null)
 279                                 return null;
 280
 281                         if (fne.eclass != ExprClass.Type) {
 282                                 if (!silent && errors == Report.Errors)
 283                                         fne.Error_UnexpectedKind (null, "type", loc);
 284                                 return null;
 285                         }
 286
 287                         TypeExpr te = fne as TypeExpr;
 288
 289                         if (!te.CheckAccessLevel (ec.DeclContainer)) {
 290                                 Report.SymbolRelatedToPreviousError (te.Type);
 291                                 ErrorIsInaccesible (loc, TypeManager.CSharpName (te.Type));
 292                                 return null;
 293                         }
 294
 295                         te.loc = loc;
 296                         return te;
 297                 }
 298
 299                 public static void ErrorIsInaccesible (Location loc, string name)
 300                 {
 301                         Report.Error (122, loc, "`{0}' is inaccessible due to its protection level", name);
 302                 }
 303
 304                 protected static void Error_CannotAccessProtected (Location loc, MemberInfo m, Type qualifier, Type container)
 305                 {
 306                         Report.Error (1540, loc, "Cannot access protected member `{0}' via a qualifier of type `{1}'."
 307                                 + " The qualifier must be of type `{2}' or derived from it",
 308                                 TypeManager.GetFullNameSignature (m),
 309                                 TypeManager.CSharpName (qualifier),
 310                                 TypeManager.CSharpName (container));
 311
 312                 }
 313
 314                 public static void Error_InvalidExpressionStatement (Location loc)
 315                 {
 316                         Report.Error (201, loc, "Only assignment, call, increment, decrement, and new object " +
 317                                        "expressions can be used as a statement");
 318                 }
 319
 320                 public void Error_InvalidExpressionStatement ()
 321                 {
 322                         Error_InvalidExpressionStatement (loc);
 323                 }
 324
 325                 protected void Error_CannotAssign (string to, string roContext)
 326                 {
 327                         Report.Error (1656, loc, "Cannot assign to `{0}' because it is a `{1}'",
 328                                 to, roContext);
 329                 }
 330
 331                 public static void Error_VoidInvalidInTheContext (Location loc)
 332                 {
 333                         Report.Error (1547, loc, "Keyword `void' cannot be used in this context");
 334                 }
 335
 336                 public virtual void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
 337                 {
 338                         // The error was already reported as CS1660
 339                         if (type == TypeManager.anonymous_method_type)
 340                                 return;
 341
 342                         if (TypeManager.IsGenericParameter (Type) && TypeManager.IsGenericParameter (target) && type.Name == target.Name) {
 343 #if GMCS_SOURCE
 344                                 string sig1 = Type.DeclaringMethod == null ?
 345                                         TypeManager.CSharpName (Type.DeclaringType) :
 346                                         TypeManager.CSharpSignature (Type.DeclaringMethod);
 347                                 string sig2 = target.DeclaringMethod == null ?
 348                                         TypeManager.CSharpName (target.DeclaringType) :
 349                                         TypeManager.CSharpSignature (target.DeclaringMethod);
 350                                 Report.ExtraInformation (loc,
 351                                         String.Format (
 352                                                 "The generic parameter `{0}' of `{1}' cannot be converted to the generic parameter `{0}' of `{2}' (in the previous ",
 353                                                 Type.Name, sig1, sig2));
 354 #endif
 355                         } else if (Type.FullName == target.FullName){
 356                                 Report.ExtraInformation (loc,
 357                                         String.Format (
 358                                         "The type `{0}' has two conflicting definitions, one comes from `{1}' and the other from `{2}' (in the previous ",
 359                                         Type.FullName, Type.Assembly.FullName, target.Assembly.FullName));
 360                         }
 361
 362                         if (expl) {
 363                                 Report.Error (30, loc, "Cannot convert type `{0}' to `{1}'",
 364                                         TypeManager.CSharpName (type), TypeManager.CSharpName (target));
 365                                 return;
 366                         }
 367
 368                         Expression e = (this is EnumConstant) ? ((EnumConstant)this).Child : this;
 369                         bool b = Convert.ExplicitNumericConversion (e, target) != null;
 370
 371                         if (b ||
 372                             Convert.ExplicitReferenceConversionExists (Type, target) ||
 373                             Convert.ExplicitUnsafe (e, target) != null ||
 374                             (ec != null && Convert.UserDefinedConversion (ec, this, target, Location.Null, true) != null))
 375                         {
 376                                 Report.Error (266, loc, "Cannot implicitly convert type `{0}' to `{1}'. " +
 377                                               "An explicit conversion exists (are you missing a cast?)",
 378                                         TypeManager.CSharpName (Type), TypeManager.CSharpName (target));
 379                                 return;
 380                         }
 381
 382                         if (Type != TypeManager.string_type && this is Constant && !(this is EmptyConstantCast)) {
 383                                 Report.Error (31, loc, "Constant value `{0}' cannot be converted to a `{1}'",
 384                                         ((Constant)(this)).GetValue ().ToString (), TypeManager.CSharpName (target));
 385                                 return;
 386                         }
 387
 388                         Report.Error (29, loc, "Cannot implicitly convert type `{0}' to `{1}'",
 389                                 TypeManager.CSharpName (type),
 390                                 TypeManager.CSharpName (target));
 391                 }
 392
 393                 protected void Error_VariableIsUsedBeforeItIsDeclared (string name)
 394                 {
 395                         Report.Error (841, loc, "The variable `{0}' cannot be used before it is declared",
 396                                 name);
 397                 }
 398
 399                 protected virtual void Error_TypeDoesNotContainDefinition (Type type, string name)
 400                 {
 401                         Error_TypeDoesNotContainDefinition (loc, type, name);
 402                 }
 403
 404                 public static void Error_TypeDoesNotContainDefinition (Location loc, Type type, string name)
 405                 {
 406                         Report.SymbolRelatedToPreviousError (type);
 407                         Report.Error (117, loc, "`{0}' does not contain a definition for `{1}'",
 408                                 TypeManager.CSharpName (type), name);
 409                 }
 410
 411                 protected static void Error_ValueAssignment (Location loc)
 412                 {
 413                         Report.Error (131, loc, "The left-hand side of an assignment must be a variable, a property or an indexer");
 414                 }
 415
 416                 ResolveFlags ExprClassToResolveFlags
 417                 {
 418                         get {
 419                                 switch (eclass) {
 420                                         case ExprClass.Type:
 421                                         case ExprClass.Namespace:
 422                                                 return ResolveFlags.Type;
 423
 424                                         case ExprClass.MethodGroup:
 425                                                 return ResolveFlags.MethodGroup;
 426
 427                                         case ExprClass.Value:
 428                                         case ExprClass.Variable:
 429                                         case ExprClass.PropertyAccess:
 430                                         case ExprClass.EventAccess:
 431                                         case ExprClass.IndexerAccess:
 432                                                 return ResolveFlags.VariableOrValue;
 433
 434                                         default:
 435                                                 throw new InternalErrorException (loc.ToString () + " " +  GetType () + " ExprClass is Invalid after resolve");
 436                                 }
 437                         }
 438                 }
 439
 440                 /// <summary>
 441                 ///   Resolves an expression and performs semantic analysis on it.
 442                 /// </summary>
 443                 ///
 444                 /// <remarks>
 445                 ///   Currently Resolve wraps DoResolve to perform sanity
 446                 ///   checking and assertion checking on what we expect from Resolve.
 447                 /// </remarks>
 448                 public Expression Resolve (EmitContext ec, ResolveFlags flags)
 449                 {
 450                         if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
 451                                 return ResolveAsTypeStep (ec, false);
 452
 453                         bool do_flow_analysis = ec.DoFlowAnalysis;
 454                         bool omit_struct_analysis = ec.OmitStructFlowAnalysis;
 455                         if ((flags & ResolveFlags.DisableFlowAnalysis) != 0)
 456                                 do_flow_analysis = false;
 457                         if ((flags & ResolveFlags.DisableStructFlowAnalysis) != 0)
 458                                 omit_struct_analysis = true;
 459
 460                         Expression e;
 461                         using (ec.WithFlowAnalysis (do_flow_analysis, omit_struct_analysis)) {
 462                                 if (this is SimpleName) {
 463                                         bool intermediate = (flags & ResolveFlags.Intermediate) == ResolveFlags.Intermediate;
 464                                         e = ((SimpleName) this).DoResolve (ec, intermediate);
 465                                 } else {
 466                                         e = DoResolve (ec);
 467                                 }
 468                         }
 469
 470                         if (e == null)
 471                                 return null;
 472
 473                         if ((flags & e.ExprClassToResolveFlags) == 0) {
 474                                 e.Error_UnexpectedKind (flags, loc);
 475                                 return null;
 476                         }
 477
 478                         if (e.type == null && !(e is Namespace)) {
 479                                 throw new Exception (
 480                                         "Expression " + e.GetType () +
 481                                         " did not set its type after Resolve\n" +
 482                                         "called from: " + this.GetType ());
 483                         }
 484
 485                         return e;
 486                 }
 487
 488                 /// <summary>
 489                 ///   Resolves an expression and performs semantic analysis on it.
 490                 /// </summary>
 491                 public Expression Resolve (EmitContext ec)
 492                 {
 493                         Expression e = Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
 494
 495                         if (e != null && e.eclass == ExprClass.MethodGroup && RootContext.Version == LanguageVersion.ISO_1) {
 496                                 ((MethodGroupExpr) e).ReportUsageError ();
 497                                 return null;
 498                         }
 499                         return e;
 500                 }
 501
 502                 public Constant ResolveAsConstant (EmitContext ec, MemberCore mc)
 503                 {
 504                         Expression e = Resolve (ec);
 505                         if (e == null)
 506                                 return null;
 507
 508                         Constant c = e as Constant;
 509                         if (c != null)
 510                                 return c;
 511
 512                         Const.Error_ExpressionMustBeConstant (loc, mc.GetSignatureForError ());
 513                         return null;
 514                 }
 515
 516                 /// <summary>
 517                 ///   Resolves an expression for LValue assignment
 518                 /// </summary>
 519                 ///
 520                 /// <remarks>
 521                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 522                 ///   checking and assertion checking on what we expect from Resolve
 523                 /// </remarks>
 524                 public Expression ResolveLValue (EmitContext ec, Expression right_side, Location loc)
 525                 {
 526                         int errors = Report.Errors;
 527                         bool out_access = right_side == EmptyExpression.OutAccess;
 528
 529                         Expression e = DoResolveLValue (ec, right_side);
 530
 531                         if (e != null && out_access && !(e is IMemoryLocation)) {
 532                                 // FIXME: There's no problem with correctness, the 'Expr = null' handles that.
 533                                 //        Enabling this 'throw' will "only" result in deleting useless code elsewhere,
 534
 535                                 //throw new InternalErrorException ("ResolveLValue didn't return an IMemoryLocation: " +
 536                                 //                                e.GetType () + " " + e.GetSignatureForError ());
 537                                 e = null;
 538                         }
 539
 540                         if (e == null) {
 541                                 if (errors == Report.Errors) {
 542                                         if (out_access)
 543                                                 Report.Error (1510, loc, "A ref or out argument must be an assignable variable");
 544                                         else
 545                                                 Error_ValueAssignment (loc);
 546                                 }
 547                                 return null;
 548                         }
 549
 550                         if (e.eclass == ExprClass.Invalid)
 551                                 throw new Exception ("Expression " + e + " ExprClass is Invalid after resolve");
 552
 553                         if (e.eclass == ExprClass.MethodGroup) {
 554                                 ((MethodGroupExpr) e).ReportUsageError ();
 555                                 return null;
 556                         }
 557
 558                         if ((e.type == null) && !(e is ConstructedType))
 559                                 throw new Exception ("Expression " + e + " did not set its type after Resolve");
 560
 561                         return e;
 562                 }
 563
 564                 /// <summary>
 565                 ///   Emits the code for the expression
 566                 /// </summary>
 567                 ///
 568                 /// <remarks>
 569                 ///   The Emit method is invoked to generate the code
 570                 ///   for the expression.
 571                 /// </remarks>
 572                 public abstract void Emit (EmitContext ec);
 573
 574                 public virtual void EmitBranchable (EmitContext ec, Label target, bool on_true)
 575                 {
 576                         Emit (ec);
 577                         ec.ig.Emit (on_true ? OpCodes.Brtrue : OpCodes.Brfalse, target);
 578                 }
 579
 580                 /// <summary>
 581                 ///   Protected constructor.  Only derivate types should
 582                 ///   be able to be created
 583                 /// </summary>
 584
 585                 protected Expression ()
 586                 {
 587                         eclass = ExprClass.Invalid;
 588                         type = null;
 589                 }
 590
 591                 /// <summary>
 592                 ///   Returns a fully formed expression after a MemberLookup
 593                 /// </summary>
 594                 ///
 595                 public static Expression ExprClassFromMemberInfo (Type container_type, MemberInfo mi, Location loc)
 596                 {
 597                         if (mi is EventInfo)
 598                                 return new EventExpr ((EventInfo) mi, loc);
 599                         else if (mi is FieldInfo)
 600                                 return new FieldExpr ((FieldInfo) mi, loc);
 601                         else if (mi is PropertyInfo)
 602                                 return new PropertyExpr (container_type, (PropertyInfo) mi, loc);
 603                         else if (mi is Type){
 604                                 return new TypeExpression ((System.Type) mi, loc);
 605                         }
 606
 607                         return null;
 608                 }
 609
 610                 protected static ArrayList almost_matched_members = new ArrayList (4);
 611
 612                 //
 613                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 614                 //
 615                 // This code could use some optimizations, but we need to do some
 616                 // measurements.  For example, we could use a delegate to `flag' when
 617                 // something can not any longer be a method-group (because it is something
 618                 // else).
 619                 //
 620                 // Return values:
 621                 //     If the return value is an Array, then it is an array of
 622                 //     MethodBases
 623                 //
 624                 //     If the return value is an MemberInfo, it is anything, but a Method
 625                 //
 626                 //     null on error.
 627                 //
 628                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 629                 // the arguments here and have MemberLookup return only the methods that
 630                 // match the argument count/type, unlike we are doing now (we delay this
 631                 // decision).
 632                 //
 633                 // This is so we can catch correctly attempts to invoke instance methods
 634                 // from a static body (scan for error 120 in ResolveSimpleName).
 635                 //
 636                 //
 637                 // FIXME: Potential optimization, have a static ArrayList
 638                 //
 639
 640                 public static Expression MemberLookup (Type container_type, Type queried_type, string name,
 641                                                        MemberTypes mt, BindingFlags bf, Location loc)
 642                 {
 643                         return MemberLookup (container_type, null, queried_type, name, mt, bf, loc);
 644                 }
 645
 646                 //
 647                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 648                 // `qualifier_type' or null to lookup members in the current class.
 649                 //
 650
 651                 public static Expression MemberLookup (Type container_type,
 652                                                        Type qualifier_type, Type queried_type,
 653                                                        string name, MemberTypes mt,
 654                                                        BindingFlags bf, Location loc)
 655                 {
 656                         almost_matched_members.Clear ();
 657
 658                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 659                                                                      queried_type, mt, bf, name, almost_matched_members);
 660
 661                         if (mi == null)
 662                                 return null;
 663
 664                         if (mi.Length > 1) {
 665                                 bool is_interface = qualifier_type != null && qualifier_type.IsInterface;
 666                                 ArrayList methods = new ArrayList (2);
 667                                 ArrayList non_methods = null;
 668
 669                                 foreach (MemberInfo m in mi) {
 670                                         if (m is MethodBase) {
 671                                                 methods.Add (m);
 672                                                 continue;
 673                                         }
 674
 675                                         if (non_methods == null) {
 676                                                 non_methods = new ArrayList (2);
 677                                                 non_methods.Add (m);
 678                                                 continue;
 679                                         }
 680
 681                                         foreach (MemberInfo n_m in non_methods) {
 682                                                 if (m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (m.DeclaringType, n_m.DeclaringType))
 683                                                         continue;
 684
 685                                                 Report.SymbolRelatedToPreviousError (m);
 686                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 687                                                         TypeManager.GetFullNameSignature (m), TypeManager.GetFullNameSignature (n_m));
 688                                                 return null;
 689                                         }
 690                                 }
 691
 692                                 if (methods.Count == 0)
 693                                         return ExprClassFromMemberInfo (container_type, (MemberInfo)non_methods [0], loc);
 694
 695                                 if (non_methods != null) {
 696                                         MethodBase method = (MethodBase) methods [0];
 697                                         MemberInfo non_method = (MemberInfo) non_methods [0];
 698                                         if (method.DeclaringType == non_method.DeclaringType) {
 699                                                 // Cannot happen with C# code, but is valid in IL
 700                                                 Report.SymbolRelatedToPreviousError (method);
 701                                                 Report.SymbolRelatedToPreviousError (non_method);
 702                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 703                                                               TypeManager.GetFullNameSignature (non_method),
 704                                                               TypeManager.CSharpSignature (method));
 705                                                 return null;
 706                                         }
 707
 708                                         if (is_interface) {
 709                                                 Report.SymbolRelatedToPreviousError (method);
 710                                                 Report.SymbolRelatedToPreviousError (non_method);
 711                                                 Report.Warning (467, 2, loc, "Ambiguity between method `{0}' and non-method `{1}'. Using method `{0}'",
 712                                                                 TypeManager.CSharpSignature (method), TypeManager.GetFullNameSignature (non_method));
 713                                         }
 714                                 }
 715
 716                                 return new MethodGroupExpr (methods, queried_type, loc);
 717                         }
 718
 719                         if (mi [0] is MethodBase)
 720                                 return new MethodGroupExpr (mi, queried_type, loc);
 721
 722                         return ExprClassFromMemberInfo (container_type, mi [0], loc);
 723                 }
 724
 725                 public const MemberTypes AllMemberTypes =
 726                         MemberTypes.Constructor |
 727                         MemberTypes.Event       |
 728                         MemberTypes.Field       |
 729                         MemberTypes.Method      |
 730                         MemberTypes.NestedType  |
 731                         MemberTypes.Property;
 732
 733                 public const BindingFlags AllBindingFlags =
 734                         BindingFlags.Public |
 735                         BindingFlags.Static |
 736                         BindingFlags.Instance;
 737
 738                 public static Expression MemberLookup (Type container_type, Type queried_type,
 739                                                        string name, Location loc)
 740                 {
 741                         return MemberLookup (container_type, null, queried_type, name,
 742                                              AllMemberTypes, AllBindingFlags, loc);
 743                 }
 744
 745                 public static Expression MemberLookup (Type container_type, Type qualifier_type,
 746                                                        Type queried_type, string name, Location loc)
 747                 {
 748                         return MemberLookup (container_type, qualifier_type, queried_type,
 749                                              name, AllMemberTypes, AllBindingFlags, loc);
 750                 }
 751
 752                 public static MethodGroupExpr MethodLookup (Type container_type, Type queried_type,
 753                                                        string name, Location loc)
 754                 {
 755                         return (MethodGroupExpr)MemberLookup (container_type, null, queried_type, name,
 756                                              MemberTypes.Method, AllBindingFlags, loc);
 757                 }
 758
 759                 /// <summary>
 760                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 761                 ///   to find a final definition.  If the final definition is not found, we
 762                 ///   look for private members and display a useful debugging message if we
 763                 ///   find it.
 764                 /// </summary>
 765                 protected Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 766                                                             Type queried_type, string name,
 767                                                             MemberTypes mt, BindingFlags bf,
 768                                                             Location loc)
 769                 {
 770                         Expression e;
 771
 772                         int errors = Report.Errors;
 773
 774                         e = MemberLookup (ec.ContainerType, qualifier_type, queried_type, name, mt, bf, loc);
 775
 776                         if (e != null || errors != Report.Errors)
 777                                 return e;
 778
 779                         // No errors were reported by MemberLookup, but there was an error.
 780                         return Error_MemberLookupFailed (ec.ContainerType, qualifier_type, queried_type,
 781                                         name, null, mt, bf);
 782                 }
 783
 784                 protected virtual Expression Error_MemberLookupFailed (Type container_type, Type qualifier_type,
 785                                                        Type queried_type, string name, string class_name,
 786                                                            MemberTypes mt, BindingFlags bf)
 787                 {
 788                         if (almost_matched_members.Count != 0) {
 789                                 for (int i = 0; i < almost_matched_members.Count; ++i) {
 790                                         MemberInfo m = (MemberInfo) almost_matched_members [i];
 791                                         for (int j = 0; j < i; ++j) {
 792                                                 if (m == almost_matched_members [j]) {
 793                                                         m = null;
 794                                                         break;
 795                                                 }
 796                                         }
 797                                         if (m == null)
 798                                                 continue;
 799
 800                                         Type declaring_type = m.DeclaringType;
 801
 802                                         Report.SymbolRelatedToPreviousError (m);
 803                                         if (qualifier_type == null) {
 804                                                 Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
 805                                                               TypeManager.CSharpName (m.DeclaringType),
 806                                                               TypeManager.CSharpName (container_type));
 807
 808                                         } else if (qualifier_type != container_type &&
 809                                                    TypeManager.IsNestedFamilyAccessible (container_type, declaring_type)) {
 810                                                 // Although a derived class can access protected members of
 811                                                 // its base class it cannot do so through an instance of the
 812                                                 // base class (CS1540).  If the qualifier_type is a base of the
 813                                                 // ec.ContainerType and the lookup succeeds with the latter one,
 814                                                 // then we are in this situation.
 815                                                 Error_CannotAccessProtected (loc, m, qualifier_type, container_type);
 816                                         } else {
 817                                                 ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (m));
 818                                         }
 819                                 }
 820                                 almost_matched_members.Clear ();
 821                                 return null;
 822                         }
 823
 824                         MemberInfo[] lookup = null;
 825                         if (queried_type == null) {
 826                                 class_name = "global::";
 827                         } else {
 828                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 829                                         mt, (bf & ~BindingFlags.Public) | BindingFlags.NonPublic,
 830                                         name, null);
 831
 832                                 if (lookup != null) {
 833                                         Report.SymbolRelatedToPreviousError (lookup [0]);
 834                                         ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (lookup [0]));
 835                                         return Error_MemberLookupFailed (lookup);
 836                                 }
 837
 838                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 839                                         AllMemberTypes, AllBindingFlags | BindingFlags.NonPublic,
 840                                         name, null);
 841                         }
 842
 843                         if (lookup == null) {
 844                                 if (class_name != null) {
 845                                         Report.Error (103, loc, "The name `{0}' does not exist in the current context",
 846                                                 name);
 847                                 } else {
 848                                         Error_TypeDoesNotContainDefinition (queried_type, name);
 849                                 }
 850                                 return null;
 851                         }
 852
 853                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 854                                                       AllMemberTypes, AllBindingFlags |
 855                                                       BindingFlags.NonPublic, name, null) == null) {
 856                                 if ((lookup.Length == 1) && (lookup [0] is Type)) {
 857                                         Type t = (Type) lookup [0];
 858
 859                                         Report.Error (305, loc,
 860                                                       "Using the generic type `{0}' " +
 861                                                       "requires {1} type arguments",
 862                                                       TypeManager.CSharpName (t),
 863                                                       TypeManager.GetNumberOfTypeArguments (t).ToString ());
 864                                         return null;
 865                                 }
 866                         }
 867
 868                         return Error_MemberLookupFailed (lookup);
 869                 }
 870
 871                 protected virtual Expression Error_MemberLookupFailed (MemberInfo[] members)
 872                 {
 873                         for (int i = 0; i < members.Length; ++i) {
 874                                 if (!(members [i] is MethodBase))
 875                                         return null;
 876                         }
 877
 878                         // By default propagate the closest candidates upwards
 879                         return new MethodGroupExpr (members, type, loc);
 880                 }
 881
 882                 /// <summary>
 883                 ///   Returns an expression that can be used to invoke operator true
 884                 ///   on the expression if it exists.
 885                 /// </summary>
 886                 static public Expression GetOperatorTrue (EmitContext ec, Expression e, Location loc)
 887                 {
 888                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 889                 }
 890
 891                 /// <summary>
 892                 ///   Returns an expression that can be used to invoke operator false
 893                 ///   on the expression if it exists.
 894                 /// </summary>
 895                 static public Expression GetOperatorFalse (EmitContext ec, Expression e, Location loc)
 896                 {
 897                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 898                 }
 899
 900                 static Expression GetOperatorTrueOrFalse (EmitContext ec, Expression e, bool is_true, Location loc)
 901                 {
 902                         MethodGroupExpr operator_group;
 903
 904 #if GMCS_SOURCE
 905                         if (TypeManager.IsNullableType (e.Type))
 906                                 return new Nullable.OperatorTrueOrFalse (e, is_true, loc).Resolve (ec);
 907 #endif
 908
 909                         operator_group = MethodLookup (ec.ContainerType, e.Type, is_true ? "op_True" : "op_False", loc) as MethodGroupExpr;
 910                         if (operator_group == null)
 911                                 return null;
 912
 913                         ArrayList arguments = new ArrayList (1);
 914                         arguments.Add (new Argument (e, Argument.AType.Expression));
 915                         operator_group = operator_group.OverloadResolve (
 916                                 ec, arguments, false, loc);
 917
 918                         if (operator_group == null)
 919                                 return null;
 920
 921                         return new StaticCallExpr ((MethodInfo) operator_group, arguments, loc);
 922                 }
 923
 924                 /// <summary>
 925                 ///   Resolves the expression `e' into a boolean expression: either through
 926                 ///   an implicit conversion, or through an `operator true' invocation
 927                 /// </summary>
 928                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 929                 {
 930                         e = e.Resolve (ec);
 931                         if (e == null)
 932                                 return null;
 933
 934                         if (e.Type == TypeManager.bool_type)
 935                                 return e;
 936
 937                         Expression converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, Location.Null);
 938
 939                         if (converted != null)
 940                                 return converted;
 941
 942                         //
 943                         // If no implicit conversion to bool exists, try using `operator true'
 944                         //
 945                         converted = Expression.GetOperatorTrue (ec, e, loc);
 946                         if (converted == null){
 947                                 e.Error_ValueCannotBeConverted (ec, loc, TypeManager.bool_type, false);
 948                                 return null;
 949                         }
 950                         return converted;
 951                 }
 952
 953                 public virtual string ExprClassName
 954                 {
 955                         get {
 956                                 switch (eclass){
 957                                         case ExprClass.Invalid:
 958                                                 return "Invalid";
 959                                         case ExprClass.Value:
 960                                                 return "value";
 961                                         case ExprClass.Variable:
 962                                                 return "variable";
 963                                         case ExprClass.Namespace:
 964                                                 return "namespace";
 965                                         case ExprClass.Type:
 966                                                 return "type";
 967                                         case ExprClass.MethodGroup:
 968                                                 return "method group";
 969                                         case ExprClass.PropertyAccess:
 970                                                 return "property access";
 971                                         case ExprClass.EventAccess:
 972                                                 return "event access";
 973                                         case ExprClass.IndexerAccess:
 974                                                 return "indexer access";
 975                                         case ExprClass.Nothing:
 976                                                 return "null";
 977                                 }
 978                                 throw new Exception ("Should not happen");
 979                         }
 980                 }
 981
 982                 /// <summary>
 983                 ///   Reports that we were expecting `expr' to be of class `expected'
 984                 /// </summary>
 985                 public void Error_UnexpectedKind (DeclSpace ds, string expected, Location loc)
 986                 {
 987                         Error_UnexpectedKind (ds, expected, ExprClassName, loc);
 988                 }
 989
 990                 public void Error_UnexpectedKind (DeclSpace ds, string expected, string was, Location loc)
 991                 {
 992                         string name = GetSignatureForError ();
 993                         if (ds != null)
 994                                 name = ds.GetSignatureForError () + '.' + name;
 995
 996                         Report.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
 997                               name, was, expected);
 998                 }
 999
1000                 public void Error_UnexpectedKind (ResolveFlags flags, Location loc)
1001                 {
1002                         string [] valid = new string [4];
1003                         int count = 0;
1004
1005                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
1006                                 valid [count++] = "variable";
1007                                 valid [count++] = "value";
1008                         }
1009
1010                         if ((flags & ResolveFlags.Type) != 0)
1011                                 valid [count++] = "type";
1012
1013                         if ((flags & ResolveFlags.MethodGroup) != 0)
1014                                 valid [count++] = "method group";
1015
1016                         if (count == 0)
1017                                 valid [count++] = "unknown";
1018
1019                         StringBuilder sb = new StringBuilder (valid [0]);
1020                         for (int i = 1; i < count - 1; i++) {
1021                                 sb.Append ("', `");
1022                                 sb.Append (valid [i]);
1023                         }
1024                         if (count > 1) {
1025                                 sb.Append ("' or `");
1026                                 sb.Append (valid [count - 1]);
1027                         }
1028
1029                         Report.Error (119, loc,
1030                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
1031                 }
1032
1033                 public static void UnsafeError (Location loc)
1034                 {
1035                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
1036                 }
1037
1038                 //
1039                 // Load the object from the pointer.
1040                 //
1041                 public static void LoadFromPtr (ILGenerator ig, Type t)
1042                 {
1043                         if (t == TypeManager.int32_type)
1044                                 ig.Emit (OpCodes.Ldind_I4);
1045                         else if (t == TypeManager.uint32_type)
1046                                 ig.Emit (OpCodes.Ldind_U4);
1047                         else if (t == TypeManager.short_type)
1048                                 ig.Emit (OpCodes.Ldind_I2);
1049                         else if (t == TypeManager.ushort_type)
1050                                 ig.Emit (OpCodes.Ldind_U2);
1051                         else if (t == TypeManager.char_type)
1052                                 ig.Emit (OpCodes.Ldind_U2);
1053                         else if (t == TypeManager.byte_type)
1054                                 ig.Emit (OpCodes.Ldind_U1);
1055                         else if (t == TypeManager.sbyte_type)
1056                                 ig.Emit (OpCodes.Ldind_I1);
1057                         else if (t == TypeManager.uint64_type)
1058                                 ig.Emit (OpCodes.Ldind_I8);
1059                         else if (t == TypeManager.int64_type)
1060                                 ig.Emit (OpCodes.Ldind_I8);
1061                         else if (t == TypeManager.float_type)
1062                                 ig.Emit (OpCodes.Ldind_R4);
1063                         else if (t == TypeManager.double_type)
1064                                 ig.Emit (OpCodes.Ldind_R8);
1065                         else if (t == TypeManager.bool_type)
1066                                 ig.Emit (OpCodes.Ldind_I1);
1067                         else if (t == TypeManager.intptr_type)
1068                                 ig.Emit (OpCodes.Ldind_I);
1069                         else if (TypeManager.IsEnumType (t)) {
1070                                 if (t == TypeManager.enum_type)
1071                                         ig.Emit (OpCodes.Ldind_Ref);
1072                                 else
1073                                         LoadFromPtr (ig, TypeManager.EnumToUnderlying (t));
1074                         } else if (t.IsValueType || TypeManager.IsGenericParameter (t))
1075                                 ig.Emit (OpCodes.Ldobj, t);
1076                         else if (t.IsPointer)
1077                                 ig.Emit (OpCodes.Ldind_I);
1078                         else
1079                                 ig.Emit (OpCodes.Ldind_Ref);
1080                 }
1081
1082                 //
1083                 // The stack contains the pointer and the value of type `type'
1084                 //
1085                 public static void StoreFromPtr (ILGenerator ig, Type type)
1086                 {
1087                         if (TypeManager.IsEnumType (type))
1088                                 type = TypeManager.EnumToUnderlying (type);
1089                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1090                                 ig.Emit (OpCodes.Stind_I4);
1091                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1092                                 ig.Emit (OpCodes.Stind_I8);
1093                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1094                                  type == TypeManager.ushort_type)
1095                                 ig.Emit (OpCodes.Stind_I2);
1096                         else if (type == TypeManager.float_type)
1097                                 ig.Emit (OpCodes.Stind_R4);
1098                         else if (type == TypeManager.double_type)
1099                                 ig.Emit (OpCodes.Stind_R8);
1100                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1101                                  type == TypeManager.bool_type)
1102                                 ig.Emit (OpCodes.Stind_I1);
1103                         else if (type == TypeManager.intptr_type)
1104                                 ig.Emit (OpCodes.Stind_I);
1105                         else if (type.IsValueType || TypeManager.IsGenericParameter (type))
1106                                 ig.Emit (OpCodes.Stobj, type);
1107                         else
1108                                 ig.Emit (OpCodes.Stind_Ref);
1109                 }
1110
1111                 //
1112                 // Returns the size of type `t' if known, otherwise, 0
1113                 //
1114                 public static int GetTypeSize (Type t)
1115                 {
1116                         t = TypeManager.TypeToCoreType (t);
1117                         if (t == TypeManager.int32_type ||
1118                             t == TypeManager.uint32_type ||
1119                             t == TypeManager.float_type)
1120                                 return 4;
1121                         else if (t == TypeManager.int64_type ||
1122                                  t == TypeManager.uint64_type ||
1123                                  t == TypeManager.double_type)
1124                                 return 8;
1125                         else if (t == TypeManager.byte_type ||
1126                                  t == TypeManager.sbyte_type ||
1127                                  t == TypeManager.bool_type)
1128                                 return 1;
1129                         else if (t == TypeManager.short_type ||
1130                                  t == TypeManager.char_type ||
1131                                  t == TypeManager.ushort_type)
1132                                 return 2;
1133                         else if (t == TypeManager.decimal_type)
1134                                 return 16;
1135                         else
1136                                 return 0;
1137                 }
1138
1139                 public static void Error_NegativeArrayIndex (Location loc)
1140                 {
1141                         Report.Error (248, loc, "Cannot create an array with a negative size");
1142                 }
1143
1144                 protected void Error_CannotCallAbstractBase (string name)
1145                 {
1146                         Report.Error (205, loc, "Cannot call an abstract base member `{0}'", name);
1147                 }
1148
1149                 //
1150                 // Converts `source' to an int, uint, long or ulong.
1151                 //
1152                 public Expression ExpressionToArrayArgument (EmitContext ec, Expression source, Location loc)
1153                 {
1154                         Expression target;
1155
1156                         using (ec.With (EmitContext.Flags.CheckState, true)) {
1157                                 target = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, loc);
1158                                 if (target == null)
1159                                         target = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, loc);
1160                                 if (target == null)
1161                                         target = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, loc);
1162                                 if (target == null)
1163                                         target = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, loc);
1164
1165                                 if (target == null) {
1166                                         source.Error_ValueCannotBeConverted (ec, loc, TypeManager.int32_type, false);
1167                                         return null;
1168                                 }
1169                         }
1170
1171                         //
1172                         // Only positive constants are allowed at compile time
1173                         //
1174                         if (target is Constant){
1175                                 if (target is IntConstant){
1176                                         if (((IntConstant) target).Value < 0){
1177                                                 Error_NegativeArrayIndex (loc);
1178                                                 return null;
1179                                         }
1180                                 }
1181
1182                                 if (target is LongConstant){
1183                                         if (((LongConstant) target).Value < 0){
1184                                                 Error_NegativeArrayIndex (loc);
1185                                                 return null;
1186                                         }
1187                                 }
1188
1189                         }
1190
1191                         return target;
1192                 }
1193
1194                 //
1195                 // Derived classes implement this method by cloning the fields that
1196                 // could become altered during the Resolve stage
1197                 //
1198                 // Only expressions that are created for the parser need to implement
1199                 // this.
1200                 //
1201                 protected virtual void CloneTo (CloneContext clonectx, Expression target)
1202                 {
1203                         throw new NotImplementedException (
1204                                 String.Format (
1205                                         "CloneTo not implemented for expression {0}", this.GetType ()));
1206                 }
1207
1208                 //
1209                 // Clones an expression created by the parser.
1210                 //
1211                 // We only support expressions created by the parser so far, not
1212                 // expressions that have been resolved (many more classes would need
1213                 // to implement CloneTo).
1214                 //
1215                 // This infrastructure is here merely for Lambda expressions which
1216                 // compile the same code using different type values for the same
1217                 // arguments to find the correct overload
1218                 //
1219                 public Expression Clone (CloneContext clonectx)
1220                 {
1221                         Expression cloned = (Expression) MemberwiseClone ();
1222                         CloneTo (clonectx, cloned);
1223
1224                         return cloned;
1225                 }
1226         }
1227
1228         /// <summary>
1229         ///   This is just a base class for expressions that can
1230         ///   appear on statements (invocations, object creation,
1231         ///   assignments, post/pre increment and decrement).  The idea
1232         ///   being that they would support an extra Emition interface that
1233         ///   does not leave a result on the stack.
1234         /// </summary>
1235         public abstract class ExpressionStatement : Expression {
1236
1237                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1238                 {
1239                         Expression e = Resolve (ec);
1240                         if (e == null)
1241                                 return null;
1242
1243                         ExpressionStatement es = e as ExpressionStatement;
1244                         if (es == null)
1245                                 Error_InvalidExpressionStatement ();
1246
1247                         return es;
1248                 }
1249
1250                 /// <summary>
1251                 ///   Requests the expression to be emitted in a `statement'
1252                 ///   context.  This means that no new value is left on the
1253                 ///   stack after invoking this method (constrasted with
1254                 ///   Emit that will always leave a value on the stack).
1255                 /// </summary>
1256                 public abstract void EmitStatement (EmitContext ec);
1257         }
1258
1259         /// <summary>
1260         ///   This kind of cast is used to encapsulate the child
1261         ///   whose type is child.Type into an expression that is
1262         ///   reported to return "return_type".  This is used to encapsulate
1263         ///   expressions which have compatible types, but need to be dealt
1264         ///   at higher levels with.
1265         ///
1266         ///   For example, a "byte" expression could be encapsulated in one
1267         ///   of these as an "unsigned int".  The type for the expression
1268         ///   would be "unsigned int".
1269         ///
1270         /// </summary>
1271         public class EmptyCast : Expression
1272         {
1273                 protected Expression child;
1274
1275                 protected EmptyCast (Expression child, Type return_type)
1276                 {
1277                         eclass = child.eclass;
1278                         loc = child.Location;
1279                         type = return_type;
1280                         this.child = child;
1281                 }
1282
1283                 public static Expression Create (Expression child, Type type)
1284                 {
1285                         Constant c = child as Constant;
1286                         if (c != null)
1287                                 return new EmptyConstantCast (c, type);
1288
1289                         return new EmptyCast (child, type);
1290                 }
1291
1292                 public override Expression DoResolve (EmitContext ec)
1293                 {
1294                         // This should never be invoked, we are born in fully
1295                         // initialized state.
1296
1297                         return this;
1298                 }
1299
1300                 public override void Emit (EmitContext ec)
1301                 {
1302                         child.Emit (ec);
1303                 }
1304
1305                 public override bool GetAttributableValue (Type value_type, out object value)
1306                 {
1307                         return child.GetAttributableValue (value_type, out value);
1308                 }
1309
1310                 protected override void CloneTo (CloneContext clonectx, Expression t)
1311                 {
1312                         EmptyCast target = (EmptyCast) t;
1313
1314                         target.child = child.Clone (clonectx);
1315                 }
1316         }
1317
1318         /// <summary>
1319         ///    Performs a cast using an operator (op_Explicit or op_Implicit)
1320         /// </summary>
1321         public class OperatorCast : EmptyCast {
1322                 MethodInfo conversion_operator;
1323                 bool find_explicit;
1324
1325                 public OperatorCast (Expression child, Type target_type) : this (child, target_type, false) {}
1326
1327                 public OperatorCast (Expression child, Type target_type, bool find_explicit)
1328                         : base (child, target_type)
1329                 {
1330                         this.find_explicit = find_explicit;
1331                 }
1332
1333                 // Returns the implicit operator that converts from
1334                 // 'child.Type' to our target type (type)
1335                 MethodInfo GetConversionOperator (bool find_explicit)
1336                 {
1337                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1338
1339                         MemberInfo [] mi;
1340
1341                         mi = TypeManager.MemberLookup (child.Type, child.Type, child.Type, MemberTypes.Method,
1342                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1343
1344                         if (mi == null){
1345                                 mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1346                                                                BindingFlags.Static | BindingFlags.Public, operator_name, null);
1347                         }
1348
1349                         foreach (MethodInfo oper in mi) {
1350                                 ParameterData pd = TypeManager.GetParameterData (oper);
1351
1352                                 if (pd.ParameterType (0) == child.Type && oper.ReturnType == type)
1353                                         return oper;
1354                         }
1355
1356                         return null;
1357
1358
1359                 }
1360                 public override void Emit (EmitContext ec)
1361                 {
1362                         ILGenerator ig = ec.ig;
1363
1364                         child.Emit (ec);
1365                         conversion_operator = GetConversionOperator (find_explicit);
1366
1367                         if (conversion_operator == null)
1368                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1369
1370                         ig.Emit (OpCodes.Call, conversion_operator);
1371                 }
1372
1373         }
1374
1375         /// <summary>
1376         ///     This is a numeric cast to a Decimal
1377         /// </summary>
1378         public class CastToDecimal : EmptyCast {
1379                 MethodInfo conversion_operator;
1380
1381                 public CastToDecimal (Expression child)
1382                         : this (child, false)
1383                 {
1384                 }
1385
1386                 public CastToDecimal (Expression child, bool find_explicit)
1387                         : base (child, TypeManager.decimal_type)
1388                 {
1389                         conversion_operator = GetConversionOperator (find_explicit);
1390
1391                         if (conversion_operator == null)
1392                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1393                 }
1394
1395                 // Returns the implicit operator that converts from
1396                 // 'child.Type' to System.Decimal.
1397                 MethodInfo GetConversionOperator (bool find_explicit)
1398                 {
1399                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1400
1401                         MemberInfo [] mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1402                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1403
1404                         foreach (MethodInfo oper in mi) {
1405                                 ParameterData pd = TypeManager.GetParameterData (oper);
1406
1407                                 if (pd.ParameterType (0) == child.Type && oper.ReturnType == type)
1408                                         return oper;
1409                         }
1410
1411                         return null;
1412                 }
1413                 public override void Emit (EmitContext ec)
1414                 {
1415                         ILGenerator ig = ec.ig;
1416                         child.Emit (ec);
1417
1418                         ig.Emit (OpCodes.Call, conversion_operator);
1419                 }
1420         }
1421
1422         /// <summary>
1423         ///     This is an explicit numeric cast from a Decimal
1424         /// </summary>
1425         public class CastFromDecimal : EmptyCast
1426         {
1427                 static IDictionary operators;
1428
1429                 public CastFromDecimal (Expression child, Type return_type)
1430                         : base (child, return_type)
1431                 {
1432                         if (child.Type != TypeManager.decimal_type)
1433                                 throw new InternalErrorException (
1434                                         "The expected type is Decimal, instead it is " + child.Type.FullName);
1435                 }
1436
1437                 // Returns the explicit operator that converts from an
1438                 // express of type System.Decimal to 'type'.
1439                 public Expression Resolve ()
1440                 {
1441                         if (operators == null) {
1442                                  MemberInfo[] all_oper = TypeManager.MemberLookup (TypeManager.decimal_type,
1443                                         TypeManager.decimal_type, TypeManager.decimal_type, MemberTypes.Method,
1444                                         BindingFlags.Static | BindingFlags.Public, "op_Explicit", null);
1445
1446                                 operators = new System.Collections.Specialized.HybridDictionary ();
1447                                 foreach (MethodInfo oper in all_oper) {
1448                                         ParameterData pd = TypeManager.GetParameterData (oper);
1449                                         if (pd.ParameterType (0) == TypeManager.decimal_type)
1450                                                 operators.Add (oper.ReturnType, oper);
1451                                 }
1452                         }
1453
1454                         return operators.Contains (type) ? this : null;
1455                 }
1456
1457                 public override void Emit (EmitContext ec)
1458                 {
1459                         ILGenerator ig = ec.ig;
1460                         child.Emit (ec);
1461
1462                         ig.Emit (OpCodes.Call, (MethodInfo)operators [type]);
1463                 }
1464         }
1465
1466
1467         //
1468         // Constant specialization of EmptyCast.
1469         // We need to special case this since an empty cast of
1470         // a constant is still a constant.
1471         //
1472         public class EmptyConstantCast : Constant
1473         {
1474                 public readonly Constant child;
1475
1476                 public EmptyConstantCast(Constant child, Type type)
1477                         : base (child.Location)
1478                 {
1479                         eclass = child.eclass;
1480                         this.child = child;
1481                         this.type = type;
1482                 }
1483
1484                 public override string AsString ()
1485                 {
1486                         return child.AsString ();
1487                 }
1488
1489                 public override object GetValue ()
1490                 {
1491                         return child.GetValue ();
1492                 }
1493
1494                 public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
1495                 {
1496                         // FIXME: check that 'type' can be converted to 'target_type' first
1497                         return child.ConvertExplicitly (in_checked_context, target_type);
1498                 }
1499
1500                 public override Constant Increment ()
1501                 {
1502                         return child.Increment ();
1503                 }
1504
1505                 public override bool IsDefaultValue {
1506                         get { return child.IsDefaultValue; }
1507                 }
1508
1509                 public override bool IsNegative {
1510                         get { return child.IsNegative; }
1511                 }
1512
1513                 public override bool IsZeroInteger {
1514                         get { return child.IsZeroInteger; }
1515                 }
1516
1517                 public override void Emit (EmitContext ec)
1518                 {
1519                         child.Emit (ec);
1520                 }
1521
1522                 public override Constant ConvertImplicitly (Type target_type)
1523                 {
1524                         // FIXME: Do we need to check user conversions?
1525                         if (!Convert.ImplicitStandardConversionExists (this, target_type))
1526                                 return null;
1527                         return child.ConvertImplicitly (target_type);
1528                 }
1529         }
1530
1531
1532         /// <summary>
1533         ///  This class is used to wrap literals which belong inside Enums
1534         /// </summary>
1535         public class EnumConstant : Constant {
1536                 public Constant Child;
1537
1538                 public EnumConstant (Constant child, Type enum_type):
1539                         base (child.Location)
1540                 {
1541                         eclass = child.eclass;
1542                         this.Child = child;
1543                         type = enum_type;
1544                 }
1545
1546                 public override Expression DoResolve (EmitContext ec)
1547                 {
1548                         // This should never be invoked, we are born in fully
1549                         // initialized state.
1550
1551                         return this;
1552                 }
1553
1554                 public override void Emit (EmitContext ec)
1555                 {
1556                         Child.Emit (ec);
1557                 }
1558
1559                 public override bool GetAttributableValue (Type value_type, out object value)
1560                 {
1561                         value = GetTypedValue ();
1562                         return true;
1563                 }
1564
1565                 public override string GetSignatureForError()
1566                 {
1567                         return TypeManager.CSharpName (Type);
1568                 }
1569
1570                 public override object GetValue ()
1571                 {
1572                         return Child.GetValue ();
1573                 }
1574
1575                 public override object GetTypedValue ()
1576                 {
1577                         // FIXME: runtime is not ready to work with just emited enums
1578                         if (!RootContext.StdLib) {
1579                                 return Child.GetValue ();
1580                         }
1581
1582                         return System.Enum.ToObject (type, Child.GetValue ());
1583                 }
1584
1585                 public override string AsString ()
1586                 {
1587                         return TypeManager.CSharpEnumValue (type, Child.GetValue ());
1588                 }
1589
1590                 public override Constant Increment()
1591                 {
1592                         return new EnumConstant (Child.Increment (), type);
1593                 }
1594
1595                 public override bool IsDefaultValue {
1596                         get {
1597                                 return Child.IsDefaultValue;
1598                         }
1599                 }
1600
1601                 public override bool IsZeroInteger {
1602                         get { return Child.IsZeroInteger; }
1603                 }
1604
1605                 public override bool IsNegative {
1606                         get {
1607                                 return Child.IsNegative;
1608                         }
1609                 }
1610
1611                 public override Constant ConvertExplicitly(bool in_checked_context, Type target_type)
1612                 {
1613                         if (Child.Type == target_type)
1614                                 return Child;
1615
1616                         return Child.ConvertExplicitly (in_checked_context, target_type);
1617                 }
1618
1619                 public override Constant ConvertImplicitly (Type type)
1620                 {
1621                         Type this_type = TypeManager.DropGenericTypeArguments (Type);
1622                         type = TypeManager.DropGenericTypeArguments (type);
1623
1624                         if (this_type == type) {
1625                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1626                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1627                                         return this;
1628
1629                                 Type child_type = TypeManager.DropGenericTypeArguments (Child.Type);
1630                                 if (type.UnderlyingSystemType != child_type)
1631                                         Child = Child.ConvertImplicitly (type.UnderlyingSystemType);
1632                                 return this;
1633                         }
1634
1635                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1636                                 return null;
1637                         }
1638
1639                         return Child.ConvertImplicitly(type);
1640                 }
1641
1642         }
1643
1644         /// <summary>
1645         ///   This kind of cast is used to encapsulate Value Types in objects.
1646         ///
1647         ///   The effect of it is to box the value type emitted by the previous
1648         ///   operation.
1649         /// </summary>
1650         public class BoxedCast : EmptyCast {
1651
1652                 public BoxedCast (Expression expr, Type target_type)
1653                         : base (expr, target_type)
1654                 {
1655                         eclass = ExprClass.Value;
1656                 }
1657
1658                 public override Expression DoResolve (EmitContext ec)
1659                 {
1660                         // This should never be invoked, we are born in fully
1661                         // initialized state.
1662
1663                         return this;
1664                 }
1665
1666                 public override void Emit (EmitContext ec)
1667                 {
1668                         base.Emit (ec);
1669
1670                         ec.ig.Emit (OpCodes.Box, child.Type);
1671                 }
1672         }
1673
1674         public class UnboxCast : EmptyCast {
1675                 public UnboxCast (Expression expr, Type return_type)
1676                         : base (expr, return_type)
1677                 {
1678                 }
1679
1680                 public override Expression DoResolve (EmitContext ec)
1681                 {
1682                         // This should never be invoked, we are born in fully
1683                         // initialized state.
1684
1685                         return this;
1686                 }
1687
1688                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1689                 {
1690                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
1691                                 Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1692                         return base.DoResolveLValue (ec, right_side);
1693                 }
1694
1695                 public override void Emit (EmitContext ec)
1696                 {
1697                         Type t = type;
1698                         ILGenerator ig = ec.ig;
1699
1700                         base.Emit (ec);
1701 #if GMCS_SOURCE
1702                         if (t.IsGenericParameter || t.IsGenericType && t.IsValueType)
1703                                 ig.Emit (OpCodes.Unbox_Any, t);
1704                         else
1705 #endif
1706                         {
1707                                 ig.Emit (OpCodes.Unbox, t);
1708
1709                                 LoadFromPtr (ig, t);
1710                         }
1711                 }
1712         }
1713
1714         /// <summary>
1715         ///   This is used to perform explicit numeric conversions.
1716         ///
1717         ///   Explicit numeric conversions might trigger exceptions in a checked
1718         ///   context, so they should generate the conv.ovf opcodes instead of
1719         ///   conv opcodes.
1720         /// </summary>
1721         public class ConvCast : EmptyCast {
1722                 public enum Mode : byte {
1723                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1724                         U1_I1, U1_CH,
1725                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1726                         U2_I1, U2_U1, U2_I2, U2_CH,
1727                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1728                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1729                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH,
1730                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH,
1731                         CH_I1, CH_U1, CH_I2,
1732                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1733                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4
1734                 }
1735
1736                 Mode mode;
1737
1738                 public ConvCast (Expression child, Type return_type, Mode m)
1739                         : base (child, return_type)
1740                 {
1741                         mode = m;
1742                 }
1743
1744                 public override Expression DoResolve (EmitContext ec)
1745                 {
1746                         // This should never be invoked, we are born in fully
1747                         // initialized state.
1748
1749                         return this;
1750                 }
1751
1752                 public override string ToString ()
1753                 {
1754                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1755                 }
1756
1757                 public override void Emit (EmitContext ec)
1758                 {
1759                         ILGenerator ig = ec.ig;
1760
1761                         base.Emit (ec);
1762
1763                         if (ec.CheckState){
1764                                 switch (mode){
1765                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1766                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1767                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1768                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1769                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1770
1771                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1772                                 case Mode.U1_CH: /* nothing */ break;
1773
1774                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1775                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1776                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1777                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1778                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1779                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1780
1781                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1782                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1783                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1784                                 case Mode.U2_CH: /* nothing */ break;
1785
1786                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1787                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1788                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1789                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1790                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1791                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1792                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1793
1794                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1795                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1796                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1797                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1798                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1799                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1800
1801                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1802                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1803                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1804                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1805                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1806                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1807                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1808                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1809
1810                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1811                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1812                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1813                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1814                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1815                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1816                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1817                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1818
1819                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1820                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1821                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1822
1823                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1824                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1825                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1826                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1827                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1828                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1829                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1830                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1831                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1832
1833                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1834                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1835                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1836                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1837                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1838                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1839                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1840                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1841                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1842                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1843                                 }
1844                         } else {
1845                                 switch (mode){
1846                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1847                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1848                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1849                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
1850                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
1851
1852                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
1853                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
1854
1855                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
1856                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
1857                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
1858                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
1859                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
1860                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
1861
1862                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
1863                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
1864                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
1865                                 case Mode.U2_CH: /* nothing */ break;
1866
1867                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
1868                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
1869                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
1870                                 case Mode.I4_U4: /* nothing */ break;
1871                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
1872                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
1873                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
1874
1875                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
1876                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
1877                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
1878                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
1879                                 case Mode.U4_I4: /* nothing */ break;
1880                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
1881
1882                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
1883                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
1884                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
1885                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
1886                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
1887                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
1888                                 case Mode.I8_U8: /* nothing */ break;
1889                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
1890
1891                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
1892                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
1893                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
1894                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
1895                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
1896                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
1897                                 case Mode.U8_I8: /* nothing */ break;
1898                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
1899
1900                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
1901                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
1902                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
1903
1904                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
1905                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
1906                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
1907                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
1908                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
1909                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
1910                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
1911                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
1912                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
1913
1914                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
1915                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
1916                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
1917                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
1918                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
1919                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
1920                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
1921                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
1922                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
1923                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1924                                 }
1925                         }
1926                 }
1927         }
1928
1929         public class OpcodeCast : EmptyCast {
1930                 OpCode op, op2;
1931                 bool second_valid;
1932
1933                 public OpcodeCast (Expression child, Type return_type, OpCode op)
1934                         : base (child, return_type)
1935
1936                 {
1937                         this.op = op;
1938                         second_valid = false;
1939                 }
1940
1941                 public OpcodeCast (Expression child, Type return_type, OpCode op, OpCode op2)
1942                         : base (child, return_type)
1943
1944                 {
1945                         this.op = op;
1946                         this.op2 = op2;
1947                         second_valid = true;
1948                 }
1949
1950                 public override Expression DoResolve (EmitContext ec)
1951                 {
1952                         // This should never be invoked, we are born in fully
1953                         // initialized state.
1954
1955                         return this;
1956                 }
1957
1958                 public override void Emit (EmitContext ec)
1959                 {
1960                         base.Emit (ec);
1961                         ec.ig.Emit (op);
1962
1963                         if (second_valid)
1964                                 ec.ig.Emit (op2);
1965                 }
1966         }
1967
1968         /// <summary>
1969         ///   This kind of cast is used to encapsulate a child and cast it
1970         ///   to the class requested
1971         /// </summary>
1972         public class ClassCast : EmptyCast {
1973                 public ClassCast (Expression child, Type return_type)
1974                         : base (child, return_type)
1975
1976                 {
1977                 }
1978
1979                 public override Expression DoResolve (EmitContext ec)
1980                 {
1981                         // This should never be invoked, we are born in fully
1982                         // initialized state.
1983
1984                         return this;
1985                 }
1986
1987                 public override void Emit (EmitContext ec)
1988                 {
1989                         base.Emit (ec);
1990
1991                         if (TypeManager.IsGenericParameter (child.Type))
1992                                 ec.ig.Emit (OpCodes.Box, child.Type);
1993
1994 #if GMCS_SOURCE
1995                         if (type.IsGenericParameter)
1996                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
1997                         else
1998 #endif
1999                                 ec.ig.Emit (OpCodes.Castclass, type);
2000                 }
2001         }
2002
2003         /// <summary>
2004         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2005         ///   of a dotted-name.
2006         /// </summary>
2007         public class SimpleName : Expression {
2008                 public readonly string Name;
2009                 public readonly TypeArguments Arguments;
2010                 bool in_transit;
2011
2012                 public SimpleName (string name, Location l)
2013                 {
2014                         Name = name;
2015                         loc = l;
2016                 }
2017
2018                 public SimpleName (string name, TypeArguments args, Location l)
2019                 {
2020                         Name = name;
2021                         Arguments = args;
2022                         loc = l;
2023                 }
2024
2025                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2026                 {
2027                         Name = name;
2028                         loc = l;
2029
2030                         Arguments = new TypeArguments (l);
2031                         foreach (TypeParameter type_param in type_params)
2032                                 Arguments.Add (new TypeParameterExpr (type_param, l));
2033                 }
2034
2035                 public static string RemoveGenericArity (string name)
2036                 {
2037                         int start = 0;
2038                         StringBuilder sb = null;
2039                         do {
2040                                 int pos = name.IndexOf ('`', start);
2041                                 if (pos < 0) {
2042                                         if (start == 0)
2043                                                 return name;
2044
2045                                         sb.Append (name.Substring (start));
2046                                         break;
2047                                 }
2048
2049                                 if (sb == null)
2050                                         sb = new StringBuilder ();
2051                                 sb.Append (name.Substring (start, pos-start));
2052
2053                                 pos++;
2054                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2055                                         pos++;
2056
2057                                 start = pos;
2058                         } while (start < name.Length);
2059
2060                         return sb.ToString ();
2061                 }
2062
2063                 public SimpleName GetMethodGroup ()
2064                 {
2065                         return new SimpleName (RemoveGenericArity (Name), Arguments, loc);
2066                 }
2067
2068                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
2069                 {
2070                         if (ec.IsInFieldInitializer)
2071                                 Report.Error (236, l,
2072                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2073                                         name);
2074                         else
2075                                 Report.Error (
2076                                         120, l, "`{0}': An object reference is required for the nonstatic field, method or property",
2077                                         name);
2078                 }
2079
2080                 public bool IdenticalNameAndTypeName (EmitContext ec, Expression resolved_to, Location loc)
2081                 {
2082                         return resolved_to != null && resolved_to.Type != null &&
2083                                 resolved_to.Type.Name == Name &&
2084                                 (ec.DeclContainer.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2085                 }
2086
2087                 public override Expression DoResolve (EmitContext ec)
2088                 {
2089                         return SimpleNameResolve (ec, null, false);
2090                 }
2091
2092                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
2093                 {
2094                         return SimpleNameResolve (ec, right_side, false);
2095                 }
2096
2097
2098                 public Expression DoResolve (EmitContext ec, bool intermediate)
2099                 {
2100                         return SimpleNameResolve (ec, null, intermediate);
2101                 }
2102
2103                 private bool IsNestedChild (Type t, Type parent)
2104                 {
2105                         if (parent == null)
2106                                 return false;
2107
2108                         while (parent != null) {
2109                                 parent = TypeManager.DropGenericTypeArguments (parent);
2110                                 if (TypeManager.IsNestedChildOf (t, parent))
2111                                         return true;
2112
2113                                 parent = parent.BaseType;
2114                         }
2115
2116                         return false;
2117                 }
2118
2119                 FullNamedExpression ResolveNested (IResolveContext ec, Type t)
2120                 {
2121                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2122                                 return null;
2123
2124                         DeclSpace ds = ec.DeclContainer;
2125                         while (ds != null) {
2126                                 if (IsNestedChild (t, ds.TypeBuilder))
2127                                         break;
2128
2129                                 ds = ds.Parent;
2130                         }
2131
2132                         if (ds == null)
2133                                 return null;
2134
2135                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2136
2137                         int arg_count = Arguments != null ? Arguments.Count : 0;
2138
2139                         for (; (ds != null) && ds.IsGeneric; ds = ds.Parent) {
2140                                 if (arg_count + ds.CountTypeParameters == gen_params.Length) {
2141                                         TypeArguments new_args = new TypeArguments (loc);
2142                                         foreach (TypeParameter param in ds.TypeParameters)
2143                                                 new_args.Add (new TypeParameterExpr (param, loc));
2144
2145                                         if (Arguments != null)
2146                                                 new_args.Add (Arguments);
2147
2148                                         return new ConstructedType (t, new_args, loc);
2149                                 }
2150                         }
2151
2152                         return null;
2153                 }
2154
2155                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2156                 {
2157                         FullNamedExpression fne = ec.GenericDeclContainer.LookupGeneric (Name, loc);
2158                         if (fne != null)
2159                                 return fne.ResolveAsTypeStep (ec, silent);
2160
2161                         int errors = Report.Errors;
2162                         fne = ec.DeclContainer.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2163
2164                         if (fne != null) {
2165                                 if (fne.Type == null)
2166                                         return fne;
2167
2168                                 FullNamedExpression nested = ResolveNested (ec, fne.Type);
2169                                 if (nested != null)
2170                                         return nested.ResolveAsTypeStep (ec, false);
2171
2172                                 if (Arguments != null) {
2173                                         ConstructedType ct = new ConstructedType (fne, Arguments, loc);
2174                                         return ct.ResolveAsTypeStep (ec, false);
2175                                 }
2176
2177                                 return fne;
2178                         }
2179
2180                         if (silent || errors != Report.Errors)
2181                                 return null;
2182
2183                         Error_TypeOrNamespaceNotFound (ec);
2184                         return null;
2185                 }
2186
2187                 protected virtual void Error_TypeOrNamespaceNotFound (IResolveContext ec)
2188                 {
2189                         MemberCore mc = ec.DeclContainer.GetDefinition (Name);
2190                         if (mc != null) {
2191                                 Error_UnexpectedKind (ec.DeclContainer, "type", GetMemberType (mc), loc);
2192                                 return;
2193                         }
2194
2195                         string ns = ec.DeclContainer.NamespaceEntry.NS.Name;
2196                         string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2197                         foreach (Assembly a in RootNamespace.Global.Assemblies) {
2198                                 Type type = a.GetType (fullname);
2199                                 if (type != null) {
2200                                         Report.SymbolRelatedToPreviousError (type);
2201                                         Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type));
2202                                         return;
2203                                 }
2204                         }
2205
2206                         Type t = ec.DeclContainer.LookupAnyGeneric (Name);
2207                         if (t != null) {
2208                                 Namespace.Error_InvalidNumberOfTypeArguments (t, loc);
2209                                 return;
2210                         }
2211
2212                         if (Arguments != null) {
2213                                 FullNamedExpression retval = ec.DeclContainer.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2214                                 if (retval != null) {
2215                                         Namespace.Error_TypeArgumentsCannotBeUsed (retval.Type, loc, "type");
2216                                         return;
2217                                 }
2218                         }
2219
2220                         NamespaceEntry.Error_NamespaceNotFound (loc, Name);
2221                 }
2222
2223                 // TODO: I am still not convinced about this. If someone else will need it
2224                 // implement this as virtual property in MemberCore hierarchy
2225                 public static string GetMemberType (MemberCore mc)
2226                 {
2227                         if (mc is Property)
2228                                 return "property";
2229                         if (mc is Indexer)
2230                                 return "indexer";
2231                         if (mc is FieldBase)
2232                                 return "field";
2233                         if (mc is MethodCore)
2234                                 return "method";
2235                         if (mc is EnumMember)
2236                                 return "enum";
2237                         if (mc is Event)
2238                                 return "event";
2239
2240                         return "type";
2241                 }
2242
2243                 Expression SimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2244                 {
2245                         if (in_transit)
2246                                 return null;
2247
2248                         in_transit = true;
2249                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2250                         in_transit = false;
2251
2252                         if (e == null)
2253                                 return null;
2254
2255                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2256                                 return e;
2257
2258                         return null;
2259                 }
2260
2261                 /// <remarks>
2262                 ///   7.5.2: Simple Names.
2263                 ///
2264                 ///   Local Variables and Parameters are handled at
2265                 ///   parse time, so they never occur as SimpleNames.
2266                 ///
2267                 ///   The `intermediate' flag is used by MemberAccess only
2268                 ///   and it is used to inform us that it is ok for us to
2269                 ///   avoid the static check, because MemberAccess might end
2270                 ///   up resolving the Name as a Type name and the access as
2271                 ///   a static type access.
2272                 ///
2273                 ///   ie: Type Type; .... { Type.GetType (""); }
2274                 ///
2275                 ///   Type is both an instance variable and a Type;  Type.GetType
2276                 ///   is the static method not an instance method of type.
2277                 /// </remarks>
2278                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2279                 {
2280                         Expression e = null;
2281
2282                         //
2283                         // Stage 1: Performed by the parser (binding to locals or parameters).
2284                         //
2285                         Block current_block = ec.CurrentBlock;
2286                         if (current_block != null){
2287                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2288                                 if (vi != null){
2289                                         if (Arguments != null) {
2290                                                 Report.Error (307, loc,
2291                                                               "The variable `{0}' cannot be used with type arguments",
2292                                                               Name);
2293                                                 return null;
2294                                         }
2295
2296                                         LocalVariableReference var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2297                                         if (right_side != null) {
2298                                                 return var.ResolveLValue (ec, right_side, loc);
2299                                         } else {
2300                                                 ResolveFlags rf = ResolveFlags.VariableOrValue;
2301                                                 if (intermediate)
2302                                                         rf |= ResolveFlags.DisableFlowAnalysis;
2303                                                 return var.Resolve (ec, rf);
2304                                         }
2305                                 }
2306
2307                                 ParameterReference pref = current_block.Toplevel.GetParameterReference (Name, loc);
2308                                 if (pref != null) {
2309                                         if (Arguments != null) {
2310                                                 Report.Error (307, loc,
2311                                                               "The variable `{0}' cannot be used with type arguments",
2312                                                               Name);
2313                                                 return null;
2314                                         }
2315
2316                                         if (right_side != null)
2317                                                 return pref.ResolveLValue (ec, right_side, loc);
2318                                         else
2319                                                 return pref.Resolve (ec);
2320                                 }
2321
2322                                 Expression expr = current_block.Toplevel.GetTransparentIdentifier (Name);
2323                                 if (expr != null) {
2324                                         if (right_side != null)
2325                                                 return expr.ResolveLValue (ec, right_side, loc);
2326                                         return expr.Resolve (ec);
2327                                 }
2328                         }
2329
2330                         //
2331                         // Stage 2: Lookup members
2332                         //
2333
2334                         Type almost_matched_type = null;
2335                         ArrayList almost_matched = null;
2336                         for (DeclSpace lookup_ds = ec.DeclContainer; lookup_ds != null; lookup_ds = lookup_ds.Parent) {
2337                                 // either RootDeclSpace or GenericMethod
2338                                 if (lookup_ds.TypeBuilder == null)
2339                                         continue;
2340
2341                                 e = MemberLookup (ec.ContainerType, lookup_ds.TypeBuilder, Name, loc);
2342                                 if (e != null) {
2343                                         if (e is PropertyExpr) {
2344                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2345                                                 // it doesn't know which accessor to check permissions against
2346                                                 if (((PropertyExpr) e).IsAccessibleFrom (ec.ContainerType, right_side != null))
2347                                                         break;
2348                                         } else if (e is EventExpr) {
2349                                                 if (((EventExpr) e).IsAccessibleFrom (ec.ContainerType))
2350                                                         break;
2351                                         } else {
2352                                                 break;
2353                                         }
2354                                         e = null;
2355                                 }
2356
2357                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2358                                         almost_matched_type = lookup_ds.TypeBuilder;
2359                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2360                                 }
2361                         }
2362
2363                         if (e == null) {
2364                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2365                                         almost_matched_type = ec.ContainerType;
2366                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2367                                 }
2368                                 e = ResolveAsTypeStep (ec, true);
2369                         }
2370
2371                         if (e == null) {
2372                                 if (current_block != null) {
2373                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2374                                         if (ikv != null) {
2375                                                 LocalInfo li = ikv as LocalInfo;
2376                                                 // Supress CS0219 warning
2377                                                 if (li != null)
2378                                                         li.Used = true;
2379
2380                                                 Error_VariableIsUsedBeforeItIsDeclared (Name);
2381                                                 return null;
2382                                         }
2383                                 }
2384
2385                                 if (almost_matched != null)
2386                                         almost_matched_members = almost_matched;
2387                                 if (almost_matched_type == null)
2388                                         almost_matched_type = ec.ContainerType;
2389                                 Error_MemberLookupFailed (ec.ContainerType, null, almost_matched_type, Name,
2390                                         ec.DeclContainer.Name, AllMemberTypes, AllBindingFlags);
2391                                 return null;
2392                         }
2393
2394                         if (e is TypeExpr) {
2395                                 if (Arguments == null)
2396                                         return e;
2397
2398                                 ConstructedType ct = new ConstructedType (
2399                                         (FullNamedExpression) e, Arguments, loc);
2400                                 return ct.ResolveAsTypeStep (ec, false);
2401                         }
2402
2403                         if (e is MemberExpr) {
2404                                 MemberExpr me = (MemberExpr) e;
2405
2406                                 Expression left;
2407                                 if (me.IsInstance) {
2408                                         if (ec.IsStatic || ec.IsInFieldInitializer) {
2409                                                 //
2410                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2411                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2412                                                 // and each predicate is true if the MethodGroupExpr contains
2413                                                 // at least one of that kind of method.
2414                                                 //
2415
2416                                                 if (!me.IsStatic &&
2417                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2418                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2419                                                         return EmptyExpression.Null;
2420                                                 }
2421
2422                                                 //
2423                                                 // Pass the buck to MemberAccess and Invocation.
2424                                                 //
2425                                                 left = EmptyExpression.Null;
2426                                         } else {
2427                                                 left = ec.GetThis (loc);
2428                                         }
2429                                 } else {
2430                                         left = new TypeExpression (ec.ContainerType, loc);
2431                                 }
2432
2433                                 e = me.ResolveMemberAccess (ec, left, loc, null);
2434                                 if (e == null)
2435                                         return null;
2436
2437                                 me = e as MemberExpr;
2438                                 if (me == null)
2439                                         return e;
2440
2441                                 if (Arguments != null) {
2442                                         MethodGroupExpr mg = me as MethodGroupExpr;
2443                                         if (mg == null)
2444                                                 return null;
2445
2446                                         return mg.ResolveGeneric (ec, Arguments);
2447                                 }
2448
2449                                 if (!me.IsStatic && (me.InstanceExpression != null) &&
2450                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2451                                     me.InstanceExpression.Type != me.DeclaringType &&
2452                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2453                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2454                                         Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2455                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2456                                         return null;
2457                                 }
2458
2459                                 return (right_side != null)
2460                                         ? me.DoResolveLValue (ec, right_side)
2461                                         : me.DoResolve (ec);
2462                         }
2463
2464                         return e;
2465                 }
2466
2467                 public override void Emit (EmitContext ec)
2468                 {
2469                         throw new InternalErrorException ("The resolve phase was not executed");
2470                 }
2471
2472                 public override string ToString ()
2473                 {
2474                         return Name;
2475                 }
2476
2477                 public override string GetSignatureForError ()
2478                 {
2479                         if (Arguments != null) {
2480                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2481                                         Arguments.GetSignatureForError () + ">";
2482                         }
2483
2484                         return Name;
2485                 }
2486
2487                 protected override void CloneTo (CloneContext clonectx, Expression target)
2488                 {
2489                         // CloneTo: Nothing, we do not keep any state on this expression
2490                 }
2491         }
2492
2493         /// <summary>
2494         ///   Represents a namespace or a type.  The name of the class was inspired by
2495         ///   section 10.8.1 (Fully Qualified Names).
2496         /// </summary>
2497         public abstract class FullNamedExpression : Expression {
2498                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2499                 {
2500                         return this;
2501                 }
2502
2503                 public abstract string FullName {
2504                         get;
2505                 }
2506         }
2507
2508         /// <summary>
2509         ///   Expression that evaluates to a type
2510         /// </summary>
2511         public abstract class TypeExpr : FullNamedExpression {
2512                 override public FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2513                 {
2514                         TypeExpr t = DoResolveAsTypeStep (ec);
2515                         if (t == null)
2516                                 return null;
2517
2518                         eclass = ExprClass.Type;
2519                         return t;
2520                 }
2521
2522                 override public Expression DoResolve (EmitContext ec)
2523                 {
2524                         return ResolveAsTypeTerminal (ec, false);
2525                 }
2526
2527                 override public void Emit (EmitContext ec)
2528                 {
2529                         throw new Exception ("Should never be called");
2530                 }
2531
2532                 public virtual bool CheckAccessLevel (DeclSpace ds)
2533                 {
2534                         return ds.CheckAccessLevel (Type);
2535                 }
2536
2537                 public virtual bool AsAccessible (DeclSpace ds, int flags)
2538                 {
2539                         return ds.AsAccessible (Type, flags);
2540                 }
2541
2542                 public virtual bool IsClass {
2543                         get { return Type.IsClass; }
2544                 }
2545
2546                 public virtual bool IsValueType {
2547                         get { return Type.IsValueType; }
2548                 }
2549
2550                 public virtual bool IsInterface {
2551                         get { return Type.IsInterface; }
2552                 }
2553
2554                 public virtual bool IsSealed {
2555                         get { return Type.IsSealed; }
2556                 }
2557
2558                 public virtual bool CanInheritFrom ()
2559                 {
2560                         if (Type == TypeManager.enum_type ||
2561                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2562                             Type == TypeManager.multicast_delegate_type ||
2563                             Type == TypeManager.delegate_type ||
2564                             Type == TypeManager.array_type)
2565                                 return false;
2566
2567                         return true;
2568                 }
2569
2570                 protected abstract TypeExpr DoResolveAsTypeStep (IResolveContext ec);
2571
2572                 public abstract string Name {
2573                         get;
2574                 }
2575
2576                 public override bool Equals (object obj)
2577                 {
2578                         TypeExpr tobj = obj as TypeExpr;
2579                         if (tobj == null)
2580                                 return false;
2581
2582                         return Type == tobj.Type;
2583                 }
2584
2585                 public override int GetHashCode ()
2586                 {
2587                         return Type.GetHashCode ();
2588                 }
2589
2590                 public override string ToString ()
2591                 {
2592                         return Name;
2593                 }
2594         }
2595
2596         /// <summary>
2597         ///   Fully resolved Expression that already evaluated to a type
2598         /// </summary>
2599         public class TypeExpression : TypeExpr {
2600                 public TypeExpression (Type t, Location l)
2601                 {
2602                         Type = t;
2603                         eclass = ExprClass.Type;
2604                         loc = l;
2605                 }
2606
2607                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2608                 {
2609                         return this;
2610                 }
2611
2612                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2613                 {
2614                         return this;
2615                 }
2616
2617                 public override string Name {
2618                         get { return Type.ToString (); }
2619                 }
2620
2621                 public override string FullName {
2622                         get { return Type.FullName; }
2623                 }
2624         }
2625
2626         /// <summary>
2627         ///   Used to create types from a fully qualified name.  These are just used
2628         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2629         ///   classified as a type.
2630         /// </summary>
2631         public sealed class TypeLookupExpression : TypeExpr {
2632                 readonly string name;
2633
2634                 public TypeLookupExpression (string name)
2635                 {
2636                         this.name = name;
2637                         eclass = ExprClass.Type;
2638                 }
2639
2640                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2641                 {
2642                         // It's null for corlib compilation only
2643                         if (type == null)
2644                                 return DoResolveAsTypeStep (ec);
2645
2646                         return this;
2647                 }
2648
2649                 private class UnexpectedType
2650                 {
2651                 }
2652
2653                 // This performes recursive type lookup, providing support for generic types.
2654                 // For example, given the type:
2655                 //
2656                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]
2657                 //
2658                 // The types will be checked in the following order:
2659                 //                                                                             _
2660                 // System                                                                       |
2661                 // System.Collections                                                           |
2662                 // System.Collections.Generic                                                   |
2663                 //                        _                                                     |
2664                 //     System              | recursive call 1                                   |
2665                 //     System.Int32       _|                                                    | main method call
2666                 //                        _                                                     |
2667                 //     System              | recursive call 2                                   |
2668                 //     System.String      _|                                                    |
2669                 //                                                                              |
2670                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]   _|
2671                 //
2672                 private Type TypeLookup (IResolveContext ec, string name)
2673                 {
2674                         int index = 0;
2675                         int dot = 0;
2676                         bool done = false;
2677                         FullNamedExpression resolved = null;
2678                         Type type = null;
2679                         Type recursive_type = null;
2680                         while (index < name.Length) {
2681                                 if (name[index] == '[') {
2682                                         int open = index;
2683                                         int braces = 1;
2684                                         do {
2685                                                 index++;
2686                                                 if (name[index] == '[')
2687                                                         braces++;
2688                                                 else if (name[index] == ']')
2689                                                         braces--;
2690                                         } while (braces > 0);
2691                                         recursive_type = TypeLookup (ec, name.Substring (open + 1, index - open - 1));
2692                                         if (recursive_type == null || (recursive_type == typeof(UnexpectedType)))
2693                                                 return recursive_type;
2694                                 }
2695                                 else {
2696                                         if (name[index] == ',')
2697                                                 done = true;
2698                                         else if ((name[index] == '.' && !done) || (index == name.Length && name[0] != '[')) {
2699                                                 string substring = name.Substring(dot, index - dot);
2700
2701                                                 if (resolved == null)
2702                                                         resolved = RootNamespace.Global.Lookup (ec.DeclContainer, substring, Location.Null);
2703                                                 else if (resolved is Namespace)
2704                                                     resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2705                                                 else if (type != null)
2706                                                         type = TypeManager.GetNestedType (type, substring);
2707                                                 else
2708                                                         return null;
2709
2710                                                 if (resolved == null)
2711                                                         return null;
2712                                                 else if (type == null && resolved is TypeExpr)
2713                                                         type = resolved.Type;
2714
2715                                                 dot = index + 1;
2716                                         }
2717                                 }
2718                                 index++;
2719                         }
2720                         if (name[0] != '[') {
2721                                 string substring = name.Substring(dot, index - dot);
2722
2723                                 if (type != null)
2724                                         return TypeManager.GetNestedType (type, substring);
2725
2726                                 if (resolved != null) {
2727                                         resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2728                                         if (resolved is TypeExpr)
2729                                                 return resolved.Type;
2730
2731                                         if (resolved == null)
2732                                                 return null;
2733
2734                                         resolved.Error_UnexpectedKind (ec.DeclContainer, "type", loc);
2735                                         return typeof (UnexpectedType);
2736                                 }
2737                                 else
2738                                         return null;
2739                         }
2740                         else
2741                                 return recursive_type;
2742                         }
2743
2744                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2745                 {
2746                         Type t = TypeLookup (ec, name);
2747                         if (t == null) {
2748                                 NamespaceEntry.Error_NamespaceNotFound (loc, name);
2749                                 return null;
2750                         }
2751                         if (t == typeof(UnexpectedType))
2752                                 return null;
2753                         type = t;
2754                         return this;
2755                 }
2756
2757                 public override string Name {
2758                         get { return name; }
2759                 }
2760
2761                 public override string FullName {
2762                         get { return name; }
2763                 }
2764
2765                 protected override void CloneTo (CloneContext clonectx, Expression target)
2766                 {
2767                         // CloneTo: Nothing, we do not keep any state on this expression
2768                 }
2769
2770                 public override string GetSignatureForError ()
2771                 {
2772                         if (type == null)
2773                                 return TypeManager.CSharpName (name);
2774
2775                         return base.GetSignatureForError ();
2776                 }
2777         }
2778
2779         /// <summary>
2780         ///   Represents an "unbound generic type", ie. typeof (Foo<>).
2781         ///   See 14.5.11.
2782         /// </summary>
2783         public class UnboundTypeExpression : TypeExpr
2784         {
2785                 MemberName name;
2786
2787                 public UnboundTypeExpression (MemberName name, Location l)
2788                 {
2789                         this.name = name;
2790                         loc = l;
2791                 }
2792
2793                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2794                 {
2795                         Expression expr;
2796                         if (name.Left != null) {
2797                                 Expression lexpr = name.Left.GetTypeExpression ();
2798                                 expr = new MemberAccess (lexpr, name.Basename);
2799                         } else {
2800                                 expr = new SimpleName (name.Basename, loc);
2801                         }
2802
2803                         FullNamedExpression fne = expr.ResolveAsTypeStep (ec, false);
2804                         if (fne == null)
2805                                 return null;
2806
2807                         type = fne.Type;
2808                         return new TypeExpression (type, loc);
2809                 }
2810
2811                 public override string Name {
2812                         get { return name.FullName; }
2813                 }
2814
2815                 public override string FullName {
2816                         get { return name.FullName; }
2817                 }
2818         }
2819
2820         public class TypeAliasExpression : TypeExpr {
2821                 FullNamedExpression alias;
2822                 TypeExpr texpr;
2823                 TypeArguments args;
2824                 string name;
2825
2826                 public TypeAliasExpression (FullNamedExpression alias, TypeArguments args, Location l)
2827                 {
2828                         this.alias = alias;
2829                         this.args = args;
2830                         loc = l;
2831
2832                         eclass = ExprClass.Type;
2833                         if (args != null)
2834                                 name = alias.FullName + "<" + args.ToString () + ">";
2835                         else
2836                                 name = alias.FullName;
2837                 }
2838
2839                 public override string Name {
2840                         get { return alias.FullName; }
2841                 }
2842
2843                 public override string FullName {
2844                         get { return name; }
2845                 }
2846
2847                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2848                 {
2849                         texpr = alias.ResolveAsTypeTerminal (ec, false);
2850                         if (texpr == null)
2851                                 return null;
2852
2853                         Type type = texpr.Type;
2854                         int num_args = TypeManager.GetNumberOfTypeArguments (type);
2855
2856                         if (args != null) {
2857                                 if (num_args == 0) {
2858                                         Report.Error (308, loc,
2859                                                       "The non-generic type `{0}' cannot " +
2860                                                       "be used with type arguments.",
2861                                                       TypeManager.CSharpName (type));
2862                                         return null;
2863                                 }
2864
2865                                 ConstructedType ctype = new ConstructedType (type, args, loc);
2866                                 return ctype.ResolveAsTypeTerminal (ec, false);
2867                         } else if (num_args > 0) {
2868                                 Report.Error (305, loc,
2869                                               "Using the generic type `{0}' " +
2870                                               "requires {1} type arguments",
2871                                               TypeManager.CSharpName (type), num_args.ToString ());
2872                                 return null;
2873                         }
2874
2875                         return texpr;
2876                 }
2877
2878                 public override bool CheckAccessLevel (DeclSpace ds)
2879                 {
2880                         return texpr.CheckAccessLevel (ds);
2881                 }
2882
2883                 public override bool AsAccessible (DeclSpace ds, int flags)
2884                 {
2885                         return texpr.AsAccessible (ds, flags);
2886                 }
2887
2888                 public override bool IsClass {
2889                         get { return texpr.IsClass; }
2890                 }
2891
2892                 public override bool IsValueType {
2893                         get { return texpr.IsValueType; }
2894                 }
2895
2896                 public override bool IsInterface {
2897                         get { return texpr.IsInterface; }
2898                 }
2899
2900                 public override bool IsSealed {
2901                         get { return texpr.IsSealed; }
2902                 }
2903         }
2904
2905         /// <summary>
2906         ///   This class denotes an expression which evaluates to a member
2907         ///   of a struct or a class.
2908         /// </summary>
2909         public abstract class MemberExpr : Expression
2910         {
2911                 /// <summary>
2912                 ///   The name of this member.
2913                 /// </summary>
2914                 public abstract string Name {
2915                         get;
2916                 }
2917
2918                 /// <summary>
2919                 ///   Whether this is an instance member.
2920                 /// </summary>
2921                 public abstract bool IsInstance {
2922                         get;
2923                 }
2924
2925                 /// <summary>
2926                 ///   Whether this is a static member.
2927                 /// </summary>
2928                 public abstract bool IsStatic {
2929                         get;
2930                 }
2931
2932                 /// <summary>
2933                 ///   The type which declares this member.
2934                 /// </summary>
2935                 public abstract Type DeclaringType {
2936                         get;
2937                 }
2938
2939                 /// <summary>
2940                 ///   The instance expression associated with this member, if it's a
2941                 ///   non-static member.
2942                 /// </summary>
2943                 public Expression InstanceExpression;
2944
2945                 public static void error176 (Location loc, string name)
2946                 {
2947                         Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
2948                                       "with an instance reference, qualify it with a type name instead", name);
2949                 }
2950
2951                 // TODO: possible optimalization
2952                 // Cache resolved constant result in FieldBuilder <-> expression map
2953                 public virtual Expression ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
2954                                                                SimpleName original)
2955                 {
2956                         //
2957                         // Precondition:
2958                         //   original == null || original.Resolve (...) ==> left
2959                         //
2960
2961                         if (left is TypeExpr) {
2962                                 left = left.ResolveAsTypeTerminal (ec, true);
2963                                 if (left == null)
2964                                         return null;
2965
2966                                 if (!IsStatic) {
2967                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
2968                                         return null;
2969                                 }
2970
2971                                 return this;
2972                         }
2973
2974                         if (!IsInstance) {
2975                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
2976                                         return this;
2977
2978                                 error176 (loc, GetSignatureForError ());
2979                                 return null;
2980                         }
2981
2982                         InstanceExpression = left;
2983
2984                         return this;
2985                 }
2986
2987                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
2988                 {
2989                         if (IsStatic)
2990                                 return;
2991
2992                         if (InstanceExpression == EmptyExpression.Null) {
2993                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
2994                                 return;
2995                         }
2996
2997                         if (InstanceExpression.Type.IsValueType) {
2998                                 if (InstanceExpression is IMemoryLocation) {
2999                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3000                                 } else {
3001                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3002                                         InstanceExpression.Emit (ec);
3003                                         t.Store (ec);
3004                                         t.AddressOf (ec, AddressOp.Store);
3005                                 }
3006                         } else
3007                                 InstanceExpression.Emit (ec);
3008
3009                         if (prepare_for_load)
3010                                 ec.ig.Emit (OpCodes.Dup);
3011                 }
3012         }
3013
3014         ///
3015         /// Represents group of extension methods
3016         ///
3017         public class ExtensionMethodGroupExpr : MethodGroupExpr
3018         {
3019                 readonly NamespaceEntry namespace_entry;
3020                 public Expression ExtensionExpression;
3021                 Argument extension_argument;
3022
3023                 public ExtensionMethodGroupExpr (ArrayList list, NamespaceEntry n, Type extensionType, Location l)
3024                         : base (list, extensionType, l)
3025                 {
3026                         this.namespace_entry = n;
3027                 }
3028
3029                 public override bool IsBase {
3030                         get { return true; }
3031                 }
3032
3033                 public override bool IsStatic {
3034                         get { return true; }
3035                 }
3036
3037                 public bool IsTopLevel {
3038                         get { return namespace_entry == null; }
3039                 }
3040
3041                 public override void EmitArguments (EmitContext ec, ArrayList arguments)
3042                 {
3043                         if (arguments == null)
3044                                 arguments = new ArrayList (1);
3045                         arguments.Insert (0, extension_argument);
3046                         base.EmitArguments (ec, arguments);
3047                 }
3048
3049                 public override void EmitCall (EmitContext ec, ArrayList arguments)
3050                 {
3051                         if (arguments == null)
3052                                 arguments = new ArrayList (1);
3053                         arguments.Insert (0, extension_argument);
3054                         base.EmitCall (ec, arguments);
3055                 }
3056
3057                 public override MethodGroupExpr OverloadResolve (EmitContext ec, ArrayList arguments, bool may_fail, Location loc)
3058                 {
3059                         if ((ExtensionExpression.eclass & (ExprClass.Value | ExprClass.Variable)) == 0)
3060                                 return base.OverloadResolve (ec, arguments, may_fail, loc);
3061
3062                         if (arguments == null)
3063                                 arguments = new ArrayList (1);
3064
3065                         arguments.Insert (0, new Argument (ExtensionExpression));
3066                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, arguments, namespace_entry, loc);
3067
3068                         // Store resolved argument and restore original arguments
3069                         if (mg != null)
3070                                 ((ExtensionMethodGroupExpr)mg).extension_argument = (Argument)arguments [0];
3071                         arguments.RemoveAt (0);
3072
3073                         return mg;
3074                 }
3075
3076                 MethodGroupExpr ResolveOverloadExtensions (EmitContext ec, ArrayList arguments, NamespaceEntry ns, Location loc)
3077                 {
3078                         // Use normal resolve rules
3079                         MethodGroupExpr mg = base.OverloadResolve (ec, arguments, ns != null, loc);
3080                         if (mg != null)
3081                                 return mg;
3082
3083                         if (ns == null)
3084                                 return null;
3085
3086                         // Search continues
3087                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, null, Name);
3088                         if (e == null)
3089                                 return base.OverloadResolve (ec, arguments, false, loc);
3090
3091                         e.ExtensionExpression = ExtensionExpression;
3092                         return e.ResolveOverloadExtensions (ec, arguments, e.namespace_entry, loc);
3093                 }
3094         }
3095
3096         /// <summary>
3097         ///   MethodGroupExpr represents a group of method candidates which
3098         ///   can be resolved to the best method overload
3099         /// </summary>
3100         public class MethodGroupExpr : MemberExpr
3101         {
3102                 public interface IErrorHandler
3103                 {
3104                         bool NoExactMatch (EmitContext ec, MethodBase method);
3105                 }
3106
3107                 public IErrorHandler CustomErrorHandler;
3108                 public MethodBase [] Methods;
3109                 MethodBase best_candidate;
3110                 bool has_type_arguments;
3111                 bool identical_type_name;
3112                 bool is_base;
3113                 Type delegate_type;
3114
3115                 public MethodGroupExpr (MemberInfo [] mi, Type type, Location l)
3116                         : this (type, l)
3117                 {
3118                         Methods = new MethodBase [mi.Length];
3119                         mi.CopyTo (Methods, 0);
3120                 }
3121
3122                 public MethodGroupExpr (ArrayList list, Type type, Location l)
3123                         : this (type, l)
3124                 {
3125                         try {
3126                                 Methods = (MethodBase[])list.ToArray (typeof (MethodBase));
3127                         } catch {
3128                                 foreach (MemberInfo m in list){
3129                                         if (!(m is MethodBase)){
3130                                                 Console.WriteLine ("Name " + m.Name);
3131                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
3132                                         }
3133                                 }
3134                                 throw;
3135                         }
3136
3137
3138                 }
3139
3140                 protected MethodGroupExpr (Type type, Location loc)
3141                 {
3142                         this.loc = loc;
3143                         eclass = ExprClass.MethodGroup;
3144                         this.type = type;
3145                 }
3146
3147                 public override Type DeclaringType {
3148                         get {
3149                                 //
3150                                 // We assume that the top-level type is in the end
3151                                 //
3152                                 return Methods [Methods.Length - 1].DeclaringType;
3153                                 //return Methods [0].DeclaringType;
3154                         }
3155                 }
3156
3157                 public Type DelegateType {
3158                         set {
3159                                 delegate_type = value;
3160                         }
3161                 }
3162
3163                 public bool HasTypeArguments {
3164                         get {
3165                                 return has_type_arguments;
3166                         }
3167                 }
3168
3169                 public bool IdenticalTypeName {
3170                         get {
3171                                 return identical_type_name;
3172                         }
3173
3174                         set {
3175                                 identical_type_name = value;
3176                         }
3177                 }
3178
3179                 public virtual bool IsBase {
3180                         get {
3181                                 return is_base;
3182                         }
3183                         set {
3184                                 is_base = value;
3185                         }
3186                 }
3187
3188                 public override string GetSignatureForError ()
3189                 {
3190                         if (best_candidate != null)
3191                                 return TypeManager.CSharpSignature (best_candidate);
3192
3193                         return TypeManager.CSharpSignature (Methods [0]);
3194                 }
3195
3196                 public override string Name {
3197                         get {
3198                                 return Methods [0].Name;
3199                         }
3200                 }
3201
3202                 public override bool IsInstance {
3203                         get {
3204                                 foreach (MethodBase mb in Methods)
3205                                         if (!mb.IsStatic)
3206                                                 return true;
3207
3208                                 return false;
3209                         }
3210                 }
3211
3212                 public override bool IsStatic {
3213                         get {
3214                                 foreach (MethodBase mb in Methods)
3215                                         if (mb.IsStatic)
3216                                                 return true;
3217
3218                                 return false;
3219                         }
3220                 }
3221
3222                 public static explicit operator ConstructorInfo (MethodGroupExpr mg)
3223                 {
3224                         return (ConstructorInfo)mg.best_candidate;
3225                 }
3226
3227                 public static explicit operator MethodInfo (MethodGroupExpr mg)
3228                 {
3229                         return (MethodInfo)mg.best_candidate;
3230                 }
3231
3232                 /// <summary>
3233                 ///   Determines "better conversion" as specified in 14.4.2.3
3234                 ///
3235                 ///    Returns : p    if a->p is better,
3236                 ///              q    if a->q is better,
3237                 ///              null if neither is better
3238                 /// </summary>
3239                 static Type BetterConversion (EmitContext ec, Argument a, Type p, Type q)
3240                 {
3241                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3242                         Expression argument_expr = a.Expr;
3243
3244                         if (argument_type == null)
3245                                 throw new Exception ("Expression of type " + a.Expr +
3246                                         " does not resolve its type");
3247
3248                         if (p == null || q == null)
3249                                 throw new InternalErrorException ("BetterConversion Got a null conversion");
3250
3251                         if (p == q)
3252                                 return null;
3253
3254                         if (argument_expr is NullLiteral)
3255                         {
3256                                 //
3257                                 // If the argument is null and one of the types to compare is 'object' and
3258                                 // the other is a reference type, we prefer the other.
3259                                 //
3260                                 // This follows from the usual rules:
3261                                 //   * There is an implicit conversion from 'null' to type 'object'
3262                                 //   * There is an implicit conversion from 'null' to any reference type
3263                                 //   * There is an implicit conversion from any reference type to type 'object'
3264                                 //   * There is no implicit conversion from type 'object' to other reference types
3265                                 //  => Conversion of 'null' to a reference type is better than conversion to 'object'
3266                                 //
3267                                 //  FIXME: This probably isn't necessary, since the type of a NullLiteral is the
3268                                 //         null type. I think it used to be 'object' and thus needed a special
3269                                 //         case to avoid the immediately following two checks.
3270                                 //
3271                                 if (!p.IsValueType && q == TypeManager.object_type)
3272                                         return p;
3273                                 if (!q.IsValueType && p == TypeManager.object_type)
3274                                         return q;
3275                         }
3276
3277                         if (argument_type == p)
3278                                 return p;
3279
3280                         if (argument_type == q)
3281                                 return q;
3282
3283                         Expression p_tmp = new EmptyExpression (p);
3284                         Expression q_tmp = new EmptyExpression (q);
3285
3286                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3287                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3288
3289                         if (p_to_q && !q_to_p)
3290                                 return p;
3291
3292                         if (q_to_p && !p_to_q)
3293                                 return q;
3294
3295                         if (p == TypeManager.sbyte_type)
3296                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3297                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3298                                         return p;
3299                         if (q == TypeManager.sbyte_type)
3300                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3301                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3302                                         return q;
3303
3304                         if (p == TypeManager.short_type)
3305                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3306                                         q == TypeManager.uint64_type)
3307                                         return p;
3308                         if (q == TypeManager.short_type)
3309                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3310                                         p == TypeManager.uint64_type)
3311                                         return q;
3312
3313                         if (p == TypeManager.int32_type)
3314                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3315                                         return p;
3316                         if (q == TypeManager.int32_type)
3317                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3318                                         return q;
3319
3320                         if (p == TypeManager.int64_type)
3321                                 if (q == TypeManager.uint64_type)
3322                                         return p;
3323                         if (q == TypeManager.int64_type)
3324                                 if (p == TypeManager.uint64_type)
3325                                         return q;
3326
3327                         return null;
3328                 }
3329
3330                 /// <summary>
3331                 ///   Determines "Better function" between candidate
3332                 ///   and the current best match
3333                 /// </summary>
3334                 /// <remarks>
3335                 ///    Returns a boolean indicating :
3336                 ///     false if candidate ain't better
3337                 ///     true  if candidate is better than the current best match
3338                 /// </remarks>
3339                 static bool BetterFunction (EmitContext ec, ArrayList args, int argument_count,
3340                         MethodBase candidate, bool candidate_params,
3341                         MethodBase best, bool best_params)
3342                 {
3343                         ParameterData candidate_pd = TypeManager.GetParameterData (candidate);
3344                         ParameterData best_pd = TypeManager.GetParameterData (best);
3345
3346                         bool better_at_least_one = false;
3347                         bool same = true;
3348                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3349                         {
3350                                 Argument a = (Argument) args [j];
3351
3352                                 Type ct = TypeManager.TypeToCoreType (candidate_pd.ParameterType (c_idx));
3353                                 Type bt = TypeManager.TypeToCoreType (best_pd.ParameterType (b_idx));
3354
3355                                 if (candidate_params && candidate_pd.ParameterModifier (c_idx) == Parameter.Modifier.PARAMS)
3356                                 {
3357                                         ct = TypeManager.GetElementType (ct);
3358                                         --c_idx;
3359                                 }
3360
3361                                 if (best_params && best_pd.ParameterModifier (b_idx) == Parameter.Modifier.PARAMS)
3362                                 {
3363                                         bt = TypeManager.GetElementType (bt);
3364                                         --b_idx;
3365                                 }
3366
3367                                 if (ct.Equals (bt))
3368                                         continue;
3369
3370                                 same = false;
3371                                 Type better = BetterConversion (ec, a, ct, bt);
3372
3373                                 // for each argument, the conversion to 'ct' should be no worse than
3374                                 // the conversion to 'bt'.
3375                                 if (better == bt)
3376                                         return false;
3377
3378                                 // for at least one argument, the conversion to 'ct' should be better than
3379                                 // the conversion to 'bt'.
3380                                 if (better == ct)
3381                                         better_at_least_one = true;
3382                         }
3383
3384                         if (better_at_least_one)
3385                                 return true;
3386
3387                         //
3388                         // This handles the case
3389                         //
3390                         //   Add (float f1, float f2, float f3);
3391                         //   Add (params decimal [] foo);
3392                         //
3393                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3394                         // first candidate would've chosen as better.
3395                         //
3396                         if (!same)
3397                                 return false;
3398
3399                         //
3400                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3401                         //
3402                         if (TypeManager.IsGenericMethod (best) && !TypeManager.IsGenericMethod (candidate))
3403                                 return true;
3404                         if (!TypeManager.IsGenericMethod (best) && TypeManager.IsGenericMethod (candidate))
3405                                 return false;
3406
3407                         //
3408                         // This handles the following cases:
3409                         //
3410                         //   Trim () is better than Trim (params char[] chars)
3411                         //   Concat (string s1, string s2, string s3) is better than
3412                         //     Concat (string s1, params string [] srest)
3413                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3414                         //
3415                         if (!candidate_params && best_params)
3416                                 return true;
3417                         if (candidate_params && !best_params)
3418                                 return false;
3419
3420                         int candidate_param_count = candidate_pd.Count;
3421                         int best_param_count = best_pd.Count;
3422
3423                         if (candidate_param_count != best_param_count)
3424                                 // can only happen if (candidate_params && best_params)
3425                                 return candidate_param_count > best_param_count;
3426
3427                         //
3428                         // now, both methods have the same number of parameters, and the parameters have the same types
3429                         // Pick the "more specific" signature
3430                         //
3431
3432                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3433                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3434
3435                         ParameterData orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3436                         ParameterData orig_best_pd = TypeManager.GetParameterData (orig_best);
3437
3438                         bool specific_at_least_once = false;
3439                         for (int j = 0; j < candidate_param_count; ++j)
3440                         {
3441                                 Type ct = TypeManager.TypeToCoreType (orig_candidate_pd.ParameterType (j));
3442                                 Type bt = TypeManager.TypeToCoreType (orig_best_pd.ParameterType (j));
3443                                 if (ct.Equals (bt))
3444                                         continue;
3445                                 Type specific = MoreSpecific (ct, bt);
3446                                 if (specific == bt)
3447                                         return false;
3448                                 if (specific == ct)
3449                                         specific_at_least_once = true;
3450                         }
3451
3452                         if (specific_at_least_once)
3453                                 return true;
3454
3455                         // FIXME: handle lifted operators
3456                         // ...
3457
3458                         return false;
3459                 }
3460
3461                 public override Expression ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3462                                                                 SimpleName original)
3463                 {
3464                         if (!(left is TypeExpr) &&
3465                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3466                                 IdenticalTypeName = true;
3467
3468                         return base.ResolveMemberAccess (ec, left, loc, original);
3469                 }
3470
3471                 override public Expression DoResolve (EmitContext ec)
3472                 {
3473                         if (InstanceExpression != null) {
3474                                 InstanceExpression = InstanceExpression.DoResolve (ec);
3475                                 if (InstanceExpression == null)
3476                                         return null;
3477                         }
3478
3479                         return this;
3480                 }
3481
3482                 public void ReportUsageError ()
3483                 {
3484                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
3485                                       Name + "()' is referenced without parentheses");
3486                 }
3487
3488                 override public void Emit (EmitContext ec)
3489                 {
3490                         ReportUsageError ();
3491                 }
3492
3493                 public virtual void EmitArguments (EmitContext ec, ArrayList arguments)
3494                 {
3495                         Invocation.EmitArguments (ec, best_candidate, arguments, false, null);
3496                 }
3497
3498                 public virtual void EmitCall (EmitContext ec, ArrayList arguments)
3499                 {
3500                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3501                 }
3502
3503                 protected virtual void Error_InvalidArguments (EmitContext ec, Location loc, int idx, MethodBase method,
3504                                                                                                         Argument a, ParameterData expected_par)
3505                 {
3506                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3507                                 Report.SymbolRelatedToPreviousError (method);
3508                                 if ((expected_par.ParameterModifier (idx) & Parameter.Modifier.ISBYREF) != 0) {
3509                                         Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3510                                                 TypeManager.CSharpSignature (method));
3511                                         return;
3512                                 }
3513                                 Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3514                                           TypeManager.CSharpSignature (method));
3515                         } else if (delegate_type == null) {
3516                                 Report.SymbolRelatedToPreviousError (method);
3517                                 Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3518                                                   TypeManager.CSharpSignature (method));
3519                         } else
3520                                 Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3521                                         TypeManager.CSharpName (delegate_type));
3522
3523                         Parameter.Modifier mod = expected_par.ParameterModifier (idx);
3524
3525                         string index = (idx + 1).ToString ();
3526                         if ((mod & Parameter.Modifier.ISBYREF) != (a.Modifier & Parameter.Modifier.ISBYREF) ||
3527                                 (mod & Parameter.Modifier.ISBYREF) != 0) {
3528                                 if ((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) == 0)
3529                                         Report.Error (1615, loc, "Argument `{0}' should not be passed with the `{1}' keyword",
3530                                                 index, Parameter.GetModifierSignature (a.Modifier));
3531                                 else
3532                                         Report.Error (1620, loc, "Argument `{0}' must be passed with the `{1}' keyword",
3533                                                 index, Parameter.GetModifierSignature (mod));
3534                         } else {
3535                                 string p1 = Argument.FullDesc (a);
3536                                 string p2 = TypeManager.CSharpName (expected_par.ParameterType (idx));
3537
3538                                 if (p1 == p2) {
3539                                         Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3540                                         Report.SymbolRelatedToPreviousError (a.Expr.Type);
3541                                         Report.SymbolRelatedToPreviousError (expected_par.ParameterType (idx));
3542                                 }
3543                                 Report.Error (1503, loc, "Argument {0}: Cannot convert type `{1}' to `{2}'", index, p1, p2);
3544                         }
3545                 }
3546
3547                 protected virtual int GetApplicableParametersCount (MethodBase method, ParameterData parameters)
3548                 {
3549                         return parameters.Count;
3550                 }
3551
3552                 public static bool IsAncestralType (Type first_type, Type second_type)
3553                 {
3554                         return first_type != second_type &&
3555                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3556                                 TypeManager.ImplementsInterface (second_type, first_type));
3557                 }
3558
3559                 ///
3560                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3561                 /// to the given set of arguments
3562                 /// A return value rates candidate method compatibility,
3563                 /// 0 = the best, int.MaxValue = the worst
3564                 ///
3565                 public int IsApplicable (EmitContext ec,
3566                                                  ArrayList arguments, int arg_count, ref MethodBase method)
3567                 {
3568                         MethodBase candidate = method;
3569
3570                         ParameterData pd = TypeManager.GetParameterData (candidate);
3571                         int param_count = GetApplicableParametersCount (candidate, pd);
3572
3573                         if (arg_count != param_count)
3574                                 return int.MaxValue - arg_count - param_count;
3575
3576                         //
3577                         // 1. Infer type arguments for generic method
3578                         //
3579 #if GMCS_SOURCE
3580                         if (!HasTypeArguments && TypeManager.IsGenericMethod (method)) {
3581                                 int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3582                                 if (score != 0)
3583                                         return score - 1024;
3584
3585                                 if (TypeManager.IsGenericMethodDefinition (candidate))
3586                                         throw new InternalErrorException ("a generic method definition took part in overload resolution");
3587
3588                                 pd = TypeManager.GetParameterData (candidate);
3589                         }
3590 #endif
3591
3592                         //
3593                         // 2. Each argument has to be implicitly convertible to method parameter
3594                         //
3595                         for (int i = arg_count; i > 0; ) {
3596                                 i--;
3597
3598                                 Argument a = (Argument) arguments [i];
3599
3600                                 Parameter.Modifier a_mod = a.Modifier &
3601                                         ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3602
3603                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
3604                                         ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK | Parameter.Modifier.PARAMS);
3605
3606                                 Type pt = pd.ParameterType (i);
3607
3608                                 // FIXME: Kill this abomination (EmitContext.TempEc)
3609                                 EmitContext prevec = EmitContext.TempEc;
3610                                 EmitContext.TempEc = ec;
3611                                 try {
3612                                         if (pt.IsByRef)
3613                                                 pt = pt.GetElementType ();
3614
3615                                         if (delegate_type != null ?
3616                                                 !Delegate.IsTypeCovariant (a.Expr, pt) :
3617                                                 !Convert.ImplicitConversionExists (ec, a.Expr, pt))
3618                                                 return ++i * 2;
3619
3620                                         if (a_mod != p_mod)
3621                                                 return ++i * 2 - 1;
3622
3623                                 } finally {
3624                                         EmitContext.TempEc = prevec;
3625                                 }
3626                         }
3627
3628                         method = candidate;
3629                         return 0;
3630                 }
3631
3632                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
3633                 {
3634                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
3635                                 return false;
3636
3637                         ParameterData cand_pd = TypeManager.GetParameterData (cand_method);
3638                         ParameterData base_pd = TypeManager.GetParameterData (base_method);
3639
3640                         if (cand_pd.Count != base_pd.Count)
3641                                 return false;
3642
3643                         for (int j = 0; j < cand_pd.Count; ++j)
3644                         {
3645                                 Parameter.Modifier cm = cand_pd.ParameterModifier (j);
3646                                 Parameter.Modifier bm = base_pd.ParameterModifier (j);
3647                                 Type ct = TypeManager.TypeToCoreType (cand_pd.ParameterType (j));
3648                                 Type bt = TypeManager.TypeToCoreType (base_pd.ParameterType (j));
3649
3650                                 if (cm != bm || ct != bt)
3651                                         return false;
3652                         }
3653
3654                         return true;
3655                 }
3656
3657                 public bool IsParamsMethodApplicable (EmitContext ec,
3658                                                              ArrayList arguments, int arg_count,
3659                                                              ref MethodBase candidate)
3660                 {
3661                         return IsParamsMethodApplicable (
3662                                 ec, arguments, arg_count, false, ref candidate) ||
3663                                 IsParamsMethodApplicable (
3664                                         ec, arguments, arg_count, true, ref candidate);
3665
3666
3667                 }
3668
3669                 bool IsParamsMethodApplicable (EmitContext ec,
3670                                                       ArrayList arguments, int arg_count,
3671                                                       bool do_varargs, ref MethodBase candidate)
3672                 {
3673 #if GMCS_SOURCE
3674                         if (!HasTypeArguments &&
3675                             !TypeManager.InferParamsTypeArguments (ec, arguments, ref candidate))
3676                                 return false;
3677
3678                         if (TypeManager.IsGenericMethodDefinition (candidate))
3679                                 throw new InternalErrorException ("a generic method definition took part in overload resolution");
3680 #endif
3681
3682                         return IsParamsMethodApplicable (
3683                                 ec, arguments, arg_count, candidate, do_varargs);
3684                 }
3685
3686                 /// <summary>
3687                 ///   Determines if the candidate method, if a params method, is applicable
3688                 ///   in its expanded form to the given set of arguments
3689                 /// </summary>
3690                 bool IsParamsMethodApplicable (EmitContext ec, ArrayList arguments,
3691                                                       int arg_count, MethodBase candidate,
3692                                                       bool do_varargs)
3693                 {
3694                         ParameterData pd = TypeManager.GetParameterData (candidate);
3695                         int pd_count = GetApplicableParametersCount (candidate, pd);
3696                         if (pd_count == 0)
3697                                 return false;
3698
3699                         int count = pd_count - 1;
3700                         if (do_varargs) {
3701                                 if (pd.ParameterModifier (count) != Parameter.Modifier.ARGLIST)
3702                                         return false;
3703                                 if (pd_count != arg_count)
3704                                         return false;
3705
3706                                 if (!(((Argument) arguments [count]).Expr is Arglist))
3707                                         return false;
3708                                 --pd_count;
3709                         } else {
3710                                 if (!pd.HasParams)
3711                                         return false;
3712                         }
3713
3714                         if (count > arg_count)
3715                                 return false;
3716
3717                         if (pd_count == 1 && arg_count == 0)
3718                                 return true;
3719
3720                         //
3721                         // If we have come this far, the case which
3722                         // remains is when the number of parameters is
3723                         // less than or equal to the argument count.
3724                         //
3725                         int argument_index = 0;
3726                         Argument a;
3727                         for (int i = 0; i < pd_count; ++i) {
3728
3729                                 if ((pd.ParameterModifier (i) & Parameter.Modifier.PARAMS) != 0) {
3730                                         Type element_type = TypeManager.GetElementType (pd.ParameterType (i));
3731                                         int params_args_count = arg_count - pd_count;
3732                                         if (params_args_count < 0)
3733                                                 continue;
3734
3735                                         do {
3736                                                 a = (Argument) arguments [argument_index++];
3737
3738                                                 if (!Convert.ImplicitConversionExists (ec, a.Expr, element_type))
3739                                                         return false;
3740                                         } while (params_args_count-- > 0);
3741                                         continue;
3742                                 }
3743
3744                                 a = (Argument) arguments [argument_index++];
3745
3746                                 Parameter.Modifier a_mod = a.Modifier &
3747                                         (unchecked (~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK)));
3748                                 Parameter.Modifier p_mod = pd.ParameterModifier (i) &
3749                                         (unchecked (~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK)));
3750
3751                                 if (a_mod == p_mod) {
3752
3753                                         if (a_mod == Parameter.Modifier.NONE)
3754                                                 if (!Convert.ImplicitConversionExists (ec,
3755                                                         a.Expr,
3756                                                         pd.ParameterType (i)))
3757                                                         return false;
3758
3759                                         if ((a_mod & Parameter.Modifier.ISBYREF) != 0) {
3760                                                 Type pt = pd.ParameterType (i);
3761
3762                                                 if (!pt.IsByRef)
3763                                                         pt = TypeManager.GetReferenceType (pt);
3764
3765                                                 if (pt != a.Type)
3766                                                         return false;
3767                                         }
3768                                 } else
3769                                         return false;
3770
3771                         }
3772
3773                         return true;
3774                 }
3775
3776                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
3777                 {
3778                         MemberInfo [] miset;
3779                         MethodGroupExpr union;
3780
3781                         if (mg1 == null) {
3782                                 if (mg2 == null)
3783                                         return null;
3784                                 return (MethodGroupExpr) mg2;
3785                         } else {
3786                                 if (mg2 == null)
3787                                         return (MethodGroupExpr) mg1;
3788                         }
3789
3790                         MethodGroupExpr left_set = null, right_set = null;
3791                         int length1 = 0, length2 = 0;
3792
3793                         left_set = (MethodGroupExpr) mg1;
3794                         length1 = left_set.Methods.Length;
3795
3796                         right_set = (MethodGroupExpr) mg2;
3797                         length2 = right_set.Methods.Length;
3798
3799                         ArrayList common = new ArrayList ();
3800
3801                         foreach (MethodBase r in right_set.Methods){
3802                                 if (TypeManager.ArrayContainsMethod (left_set.Methods, r))
3803                                         common.Add (r);
3804                         }
3805
3806                         miset = new MemberInfo [length1 + length2 - common.Count];
3807                         left_set.Methods.CopyTo (miset, 0);
3808
3809                         int k = length1;
3810
3811                         foreach (MethodBase r in right_set.Methods) {
3812                                 if (!common.Contains (r))
3813                                         miset [k++] = r;
3814                         }
3815
3816                         union = new MethodGroupExpr (miset, mg1.Type, loc);
3817
3818                         return union;
3819                 }
3820
3821                 static Type MoreSpecific (Type p, Type q)
3822                 {
3823                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
3824                                 return q;
3825                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
3826                                 return p;
3827
3828                         if (TypeManager.HasElementType (p))
3829                         {
3830                                 Type pe = TypeManager.GetElementType (p);
3831                                 Type qe = TypeManager.GetElementType (q);
3832                                 Type specific = MoreSpecific (pe, qe);
3833                                 if (specific == pe)
3834                                         return p;
3835                                 if (specific == qe)
3836                                         return q;
3837                         }
3838                         else if (TypeManager.IsGenericType (p))
3839                         {
3840                                 Type[] pargs = TypeManager.GetTypeArguments (p);
3841                                 Type[] qargs = TypeManager.GetTypeArguments (q);
3842
3843                                 bool p_specific_at_least_once = false;
3844                                 bool q_specific_at_least_once = false;
3845
3846                                 for (int i = 0; i < pargs.Length; i++)
3847                                 {
3848                                         Type specific = MoreSpecific (pargs [i], qargs [i]);
3849                                         if (specific == pargs [i])
3850                                                 p_specific_at_least_once = true;
3851                                         if (specific == qargs [i])
3852                                                 q_specific_at_least_once = true;
3853                                 }
3854
3855                                 if (p_specific_at_least_once && !q_specific_at_least_once)
3856                                         return p;
3857                                 if (!p_specific_at_least_once && q_specific_at_least_once)
3858                                         return q;
3859                         }
3860
3861                         return null;
3862                 }
3863
3864                 /// <summary>
3865                 ///   Find the Applicable Function Members (7.4.2.1)
3866                 ///
3867                 ///   me: Method Group expression with the members to select.
3868                 ///       it might contain constructors or methods (or anything
3869                 ///       that maps to a method).
3870                 ///
3871                 ///   Arguments: ArrayList containing resolved Argument objects.
3872                 ///
3873                 ///   loc: The location if we want an error to be reported, or a Null
3874                 ///        location for "probing" purposes.
3875                 ///
3876                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
3877                 ///            that is the best match of me on Arguments.
3878                 ///
3879                 /// </summary>
3880                 public virtual MethodGroupExpr OverloadResolve (EmitContext ec, ArrayList Arguments,
3881                         bool may_fail, Location loc)
3882                 {
3883                         bool method_params = false;
3884                         Type applicable_type = null;
3885                         int arg_count = 0;
3886                         ArrayList candidates = new ArrayList (2);
3887                         ArrayList candidate_overrides = null;
3888
3889                         //
3890                         // Used to keep a map between the candidate
3891                         // and whether it is being considered in its
3892                         // normal or expanded form
3893                         //
3894                         // false is normal form, true is expanded form
3895                         //
3896                         Hashtable candidate_to_form = null;
3897
3898                         if (Arguments != null)
3899                                 arg_count = Arguments.Count;
3900
3901                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
3902                                 if (!may_fail)
3903                                         Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
3904                                 return null;
3905                         }
3906
3907                         int nmethods = Methods.Length;
3908
3909                         if (!IsBase) {
3910                                 //
3911                                 // Methods marked 'override' don't take part in 'applicable_type'
3912                                 // computation, nor in the actual overload resolution.
3913                                 // However, they still need to be emitted instead of a base virtual method.
3914                                 // So, we salt them away into the 'candidate_overrides' array.
3915                                 //
3916                                 // In case of reflected methods, we replace each overriding method with
3917                                 // its corresponding base virtual method.  This is to improve compatibility
3918                                 // with non-C# libraries which change the visibility of overrides (#75636)
3919                                 //
3920                                 int j = 0;
3921                                 for (int i = 0; i < Methods.Length; ++i) {
3922                                         MethodBase m = Methods [i];
3923 #if GMCS_SOURCE
3924                                         Type [] gen_args = null;
3925                                         if (m.IsGenericMethod && !m.IsGenericMethodDefinition)
3926                                                 gen_args = m.GetGenericArguments ();
3927 #endif
3928                                         if (TypeManager.IsOverride (m)) {
3929                                                 if (candidate_overrides == null)
3930                                                         candidate_overrides = new ArrayList ();
3931                                                 candidate_overrides.Add (m);
3932                                                 m = TypeManager.TryGetBaseDefinition (m);
3933 #if GMCS_SOURCE
3934                                                 if (m != null && gen_args != null) {
3935                                                         if (!m.IsGenericMethodDefinition)
3936                                                                 throw new InternalErrorException ("GetBaseDefinition didn't return a GenericMethodDefinition");
3937                                                         m = ((MethodInfo) m).MakeGenericMethod (gen_args);
3938                                                 }
3939 #endif
3940                                         }
3941                                         if (m != null)
3942                                                 Methods [j++] = m;
3943                                 }
3944                                 nmethods = j;
3945                         }
3946
3947                         //
3948                         // Enable message recording, it's used mainly by lambda expressions
3949                         //
3950                         Report.IMessageRecorder msg_recorder = new Report.MessageRecorder ();
3951                         Report.IMessageRecorder prev_recorder = Report.SetMessageRecorder (msg_recorder);
3952
3953                         //
3954                         // First we construct the set of applicable methods
3955                         //
3956                         bool is_sorted = true;
3957                         int best_candidate_rate = int.MaxValue;
3958                         for (int i = 0; i < nmethods; i++) {
3959                                 Type decl_type = Methods [i].DeclaringType;
3960
3961                                 //
3962                                 // If we have already found an applicable method
3963                                 // we eliminate all base types (Section 14.5.5.1)
3964                                 //
3965                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
3966                                         continue;
3967
3968                                 //
3969                                 // Check if candidate is applicable (section 14.4.2.1)
3970                                 //   Is candidate applicable in normal form?
3971                                 //
3972                                 int candidate_rate = IsApplicable (ec, Arguments, arg_count, ref Methods [i]);
3973
3974                                 if (candidate_rate != 0 && IsParamsMethodApplicable (ec, Arguments, arg_count, ref Methods [i])) {
3975                                         MethodBase candidate = Methods [i];
3976                                         if (candidate_to_form == null)
3977                                                 candidate_to_form = new PtrHashtable ();
3978                                         candidate_to_form [candidate] = candidate;
3979                                         // Candidate is applicable in expanded form
3980                                         candidate_rate = 0;
3981                                 }
3982
3983                                 if (candidate_rate < best_candidate_rate) {
3984                                         best_candidate_rate = candidate_rate;
3985                                         best_candidate = Methods [i];
3986                                 }
3987
3988                                 if (candidate_rate != 0) {
3989                                         if (msg_recorder != null)
3990                                                 msg_recorder.EndSession ();
3991                                         continue;
3992                                 }
3993
3994                                 msg_recorder = null;
3995
3996                                 candidates.Add (Methods [i]);
3997
3998                                 if (applicable_type == null)
3999                                         applicable_type = decl_type;
4000                                 else if (applicable_type != decl_type) {
4001                                         is_sorted = false;
4002                                         if (IsAncestralType (applicable_type, decl_type))
4003                                                 applicable_type = decl_type;
4004                                 }
4005                         }
4006
4007                         Report.SetMessageRecorder (prev_recorder);
4008                         if (msg_recorder != null && msg_recorder.PrintMessages ())
4009                                 return null;
4010
4011                         int candidate_top = candidates.Count;
4012
4013                         if (applicable_type == null) {
4014                                 //
4015                                 // When we found a top level method which does not match and it's
4016                                 // not an extension method. We start extension methods lookup from here
4017                                 //
4018                                 if (InstanceExpression != null) {
4019                                         ExtensionMethodGroupExpr ex_method_lookup = ec.TypeContainer.LookupExtensionMethod (type, Name);
4020                                         if (ex_method_lookup != null) {
4021                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
4022                                                 return ex_method_lookup.OverloadResolve (ec, Arguments, may_fail, loc);
4023                                         }
4024                                 }
4025
4026                                 if (ec.IsInProbingMode || may_fail)
4027                                         return null;
4028
4029                                 //
4030                                 // Okay so we have failed to find exact match so we
4031                                 // return error info about the closest match
4032                                 //
4033                                 if (best_candidate != null) {
4034                                         if (CustomErrorHandler != null) {
4035                                                 if (CustomErrorHandler.NoExactMatch (ec, best_candidate))
4036                                                         return null;
4037                                         }
4038
4039                                         if (TypeManager.IsGenericMethod (best_candidate)) {
4040                                                 Report.Error (411, loc,
4041                                                         "The type arguments for method `{0}' cannot be inferred from " +
4042                                                         "the usage. Try specifying the type arguments explicitly",
4043                                                         TypeManager.CSharpSignature (best_candidate));
4044                                                 return null;
4045                                         }
4046
4047                                         ParameterData pd = TypeManager.GetParameterData (best_candidate);
4048                                         if (arg_count == pd.Count) {
4049                                                 VerifyArgumentsCompat (ec, Arguments, arg_count, best_candidate, false, may_fail, loc);
4050                                                 return null;
4051                                         }
4052                                 }
4053
4054                                 if (almost_matched_members.Count != 0) {
4055                                         Error_MemberLookupFailed (ec.ContainerType, type, type, ".ctor",
4056                                         null, MemberTypes.Constructor, AllBindingFlags);
4057                                         return null;
4058                                 }
4059
4060                                 //
4061                                 // We failed to find any method with correct argument count
4062                                 //
4063                                 if (Name == ConstructorInfo.ConstructorName) {
4064                                         Report.SymbolRelatedToPreviousError (type);
4065                                         Report.Error (1729, loc,
4066                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4067                                                 TypeManager.CSharpName (type), arg_count);
4068                                 } else {
4069                                         Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
4070                                                 Name, arg_count.ToString ());
4071                                 }
4072
4073                                 return null;
4074                         }
4075
4076                         if (!is_sorted) {
4077                                 //
4078                                 // At this point, applicable_type is _one_ of the most derived types
4079                                 // in the set of types containing the methods in this MethodGroup.
4080                                 // Filter the candidates so that they only contain methods from the
4081                                 // most derived types.
4082                                 //
4083
4084                                 int finalized = 0; // Number of finalized candidates
4085
4086                                 do {
4087                                         // Invariant: applicable_type is a most derived type
4088
4089                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4090                                         // eliminating all it's base types.  At the same time, we'll also move
4091                                         // every unrelated type to the end of the array, and pick the next
4092                                         // 'applicable_type'.
4093
4094                                         Type next_applicable_type = null;
4095                                         int j = finalized; // where to put the next finalized candidate
4096                                         int k = finalized; // where to put the next undiscarded candidate
4097                                         for (int i = finalized; i < candidate_top; ++i) {
4098                                                 MethodBase candidate = (MethodBase) candidates [i];
4099                                                 Type decl_type = candidate.DeclaringType;
4100
4101                                                 if (decl_type == applicable_type) {
4102                                                         candidates [k++] = candidates [j];
4103                                                         candidates [j++] = candidates [i];
4104                                                         continue;
4105                                                 }
4106
4107                                                 if (IsAncestralType (decl_type, applicable_type))
4108                                                         continue;
4109
4110                                                 if (next_applicable_type != null &&
4111                                                         IsAncestralType (decl_type, next_applicable_type))
4112                                                         continue;
4113
4114                                                 candidates [k++] = candidates [i];
4115
4116                                                 if (next_applicable_type == null ||
4117                                                         IsAncestralType (next_applicable_type, decl_type))
4118                                                         next_applicable_type = decl_type;
4119                                         }
4120
4121                                         applicable_type = next_applicable_type;
4122                                         finalized = j;
4123                                         candidate_top = k;
4124                                 } while (applicable_type != null);
4125                         }
4126
4127                         //
4128                         // Now we actually find the best method
4129                         //
4130
4131                         best_candidate = (MethodBase) candidates [0];
4132                         method_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4133                         for (int ix = 1; ix < candidate_top; ix++) {
4134                                 MethodBase candidate = (MethodBase) candidates [ix];
4135
4136                                 if (candidate == best_candidate)
4137                                         continue;
4138
4139                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4140
4141                                 if (BetterFunction (ec, Arguments, arg_count,
4142                                         candidate, cand_params,
4143                                         best_candidate, method_params)) {
4144                                         best_candidate = candidate;
4145                                         method_params = cand_params;
4146                                 }
4147                         }
4148                         //
4149                         // Now check that there are no ambiguities i.e the selected method
4150                         // should be better than all the others
4151                         //
4152                         MethodBase ambiguous = null;
4153                         for (int ix = 0; ix < candidate_top; ix++) {
4154                                 MethodBase candidate = (MethodBase) candidates [ix];
4155
4156                                 if (candidate == best_candidate)
4157                                         continue;
4158
4159                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4160                                 if (!BetterFunction (ec, Arguments, arg_count,
4161                                         best_candidate, method_params,
4162                                         candidate, cand_params))
4163                                 {
4164                                         if (!may_fail)
4165                                                 Report.SymbolRelatedToPreviousError (candidate);
4166                                         ambiguous = candidate;
4167                                 }
4168                         }
4169
4170                         if (ambiguous != null) {
4171                                 Report.SymbolRelatedToPreviousError (best_candidate);
4172                                 Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
4173                                         TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate));
4174                                 return this;
4175                         }
4176
4177                         //
4178                         // If the method is a virtual function, pick an override closer to the LHS type.
4179                         //
4180                         if (!IsBase && best_candidate.IsVirtual) {
4181                                 if (TypeManager.IsOverride (best_candidate))
4182                                         throw new InternalErrorException (
4183                                                 "Should not happen.  An 'override' method took part in overload resolution: " + best_candidate);
4184
4185                                 if (candidate_overrides != null)
4186                                         foreach (MethodBase candidate in candidate_overrides) {
4187                                                 if (IsOverride (candidate, best_candidate))
4188                                                         best_candidate = candidate;
4189                                         }
4190                         }
4191
4192                         // We can stop here when probing is on
4193                         if (ec.IsInProbingMode)
4194                                 return this;
4195
4196                         //
4197                         // And now check if the arguments are all
4198                         // compatible, perform conversions if
4199                         // necessary etc. and return if everything is
4200                         // all right
4201                         //
4202                         if (!VerifyArgumentsCompat (ec, Arguments, arg_count, best_candidate,
4203                                 method_params, may_fail, loc))
4204                                 return null;
4205
4206                         if (best_candidate == null)
4207                                 return null;
4208
4209                         MethodBase the_method = TypeManager.DropGenericMethodArguments (best_candidate);
4210 #if GMCS_SOURCE
4211                         if (the_method.IsGenericMethodDefinition &&
4212                             !ConstraintChecker.CheckConstraints (ec, the_method, best_candidate, loc))
4213                                 return null;
4214 #endif
4215
4216                         IMethodData data = TypeManager.GetMethod (the_method);
4217                         if (data != null)
4218                                 data.SetMemberIsUsed ();
4219
4220                         return this;
4221                 }
4222
4223                 public Expression ResolveGeneric (EmitContext ec, TypeArguments args)
4224                 {
4225 #if GMCS_SOURCE
4226                         if (!args.Resolve (ec))
4227                                 return null;
4228
4229                         Type[] atypes = args.Arguments;
4230
4231                         int first_count = 0;
4232                         MethodInfo first = null;
4233
4234                         ArrayList list = new ArrayList ();
4235                         foreach (MethodBase mb in Methods) {
4236                                 MethodInfo mi = mb as MethodInfo;
4237                                 if ((mi == null) || !mb.IsGenericMethod)
4238                                         continue;
4239
4240                                 Type[] gen_params = mb.GetGenericArguments ();
4241
4242                                 if (first == null) {
4243                                         first = mi;
4244                                         first_count = gen_params.Length;
4245                                 }
4246
4247                                 if (gen_params.Length != atypes.Length)
4248                                         continue;
4249
4250                                 mi = mi.MakeGenericMethod (atypes);
4251                                 list.Add (mi);
4252
4253 #if MS_COMPATIBLE
4254                                 // MS implementation throws NotSupportedException for GetParameters
4255                                 // on unbaked generic method
4256                                 Parameters p = TypeManager.GetParameterData (mi) as Parameters;
4257                                 if (p != null) {
4258                                         p = p.Clone ();
4259                                         p.InflateTypes (gen_params, atypes);
4260                                         TypeManager.RegisterMethod (mi, p);
4261                                 }
4262 #endif
4263                         }
4264
4265                         if (list.Count > 0) {
4266                                 this.Methods = (MethodBase []) list.ToArray (typeof (MethodBase));
4267                                 has_type_arguments = true;
4268                                 return this;
4269                         }
4270
4271                         if (first != null) {
4272                                 Report.SymbolRelatedToPreviousError (first);
4273                                 Report.Error (
4274                                         305, loc, "Using the generic method `{0}' requires `{1}' type arguments",
4275                                         TypeManager.CSharpSignature (first), first_count.ToString ());
4276                         } else
4277                                 Report.Error (
4278                                         308, loc, "The non-generic method `{0}' " +
4279                                         "cannot be used with type arguments", Name);
4280
4281                         return null;
4282 #else
4283                         throw new NotImplementedException ();
4284 #endif
4285                 }
4286
4287                 public bool VerifyArgumentsCompat (EmitContext ec, ArrayList Arguments,
4288                                                           int arg_count, MethodBase method,
4289                                                           bool chose_params_expanded,
4290                                                           bool may_fail, Location loc)
4291                 {
4292                         ParameterData pd = TypeManager.GetParameterData (method);
4293                         int param_count = GetApplicableParametersCount (method, pd);
4294
4295                         int j;
4296                         int a_idx = 0;
4297                         Argument a = null;
4298                         int errors = Report.Errors;
4299                         for (j = 0; j < param_count; j++) {
4300                                 Type parameter_type = pd.ParameterType (j);
4301                                 Parameter.Modifier pm = pd.ParameterModifier (j);
4302
4303                                 if (pm == Parameter.Modifier.ARGLIST) {
4304                                         a = (Argument) Arguments [a_idx];
4305                                         if (!(a.Expr is Arglist))
4306                                                 break;
4307                                         ++a_idx;
4308                                         continue;
4309                                 }
4310
4311                                 int params_arg_count = 1;
4312                                 if (pm == Parameter.Modifier.PARAMS) {
4313                                         pm = Parameter.Modifier.NONE;
4314                                         params_arg_count = arg_count - param_count + 1;
4315                                         if (chose_params_expanded)
4316                                                 parameter_type = TypeManager.GetElementType (parameter_type);
4317                                 }
4318
4319                                 while (params_arg_count > 0) {
4320                                         a = (Argument) Arguments [a_idx];
4321                                         if (pm != a.Modifier)
4322                                                 break;
4323
4324                                         if (!TypeManager.IsEqual (a.Type, parameter_type)) {
4325                                                 if (pm == Parameter.Modifier.OUT || pm == Parameter.Modifier.REF)
4326                                                         break;
4327
4328                                                 Expression conv = Convert.ImplicitConversion (ec, a.Expr, parameter_type, loc);
4329                                                 if (conv == null)
4330                                                         break;
4331
4332                                                 // Update the argument with the implicit conversion
4333                                                 if (a.Expr != conv)
4334                                                         a.Expr = conv;
4335                                         }
4336
4337                                         --params_arg_count;
4338                                         ++a_idx;
4339                                 }
4340                                 if (params_arg_count > 0)
4341                                         break;
4342
4343                                 if (parameter_type.IsPointer && !ec.InUnsafe) {
4344                                         if (!may_fail)
4345                                                 UnsafeError (loc);
4346                                         return false;
4347                                 }
4348                         }
4349
4350                         if (a_idx == arg_count)
4351                                 return true;
4352
4353                         if (!may_fail && Report.Errors == errors)
4354                                 Error_InvalidArguments (ec, loc, a_idx, method, a, pd);
4355                         return false;
4356                 }
4357         }
4358
4359         /// <summary>
4360         ///   Fully resolved expression that evaluates to a Field
4361         /// </summary>
4362         public class FieldExpr : MemberExpr, IAssignMethod, IMemoryLocation, IVariable {
4363                 public readonly FieldInfo FieldInfo;
4364                 VariableInfo variable_info;
4365
4366                 LocalTemporary temp;
4367                 bool prepared;
4368                 bool in_initializer;
4369
4370                 public FieldExpr (FieldInfo fi, Location l, bool in_initializer):
4371                         this (fi, l)
4372                 {
4373                         this.in_initializer = in_initializer;
4374                 }
4375
4376                 public FieldExpr (FieldInfo fi, Location l)
4377                 {
4378                         FieldInfo = fi;
4379                         eclass = ExprClass.Variable;
4380                         type = TypeManager.TypeToCoreType (fi.FieldType);
4381                         loc = l;
4382                 }
4383
4384                 public override string Name {
4385                         get {
4386                                 return FieldInfo.Name;
4387                         }
4388                 }
4389
4390                 public override bool IsInstance {
4391                         get {
4392                                 return !FieldInfo.IsStatic;
4393                         }
4394                 }
4395
4396                 public override bool IsStatic {
4397                         get {
4398                                 return FieldInfo.IsStatic;
4399                         }
4400                 }
4401
4402                 public override Type DeclaringType {
4403                         get {
4404                                 return FieldInfo.DeclaringType;
4405                         }
4406                 }
4407
4408                 public override string GetSignatureForError ()
4409                 {
4410                         return TypeManager.GetFullNameSignature (FieldInfo);
4411                 }
4412
4413                 public VariableInfo VariableInfo {
4414                         get {
4415                                 return variable_info;
4416                         }
4417                 }
4418
4419                 public override Expression ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
4420                                                                 SimpleName original)
4421                 {
4422                         FieldInfo fi = TypeManager.GetGenericFieldDefinition (FieldInfo);
4423
4424                         Type t = fi.FieldType;
4425
4426                         if (fi.IsLiteral || (fi.IsInitOnly && t == TypeManager.decimal_type)) {
4427                                 IConstant ic = TypeManager.GetConstant (fi);
4428                                 if (ic == null) {
4429                                         if (fi.IsLiteral) {
4430                                                 ic = new ExternalConstant (fi);
4431                                         } else {
4432                                                 ic = ExternalConstant.CreateDecimal (fi);
4433                                                 if (ic == null) {
4434                                                         return base.ResolveMemberAccess (ec, left, loc, original);
4435                                                 }
4436                                         }
4437                                         TypeManager.RegisterConstant (fi, ic);
4438                                 }
4439
4440                                 bool left_is_type = left is TypeExpr;
4441                                 if (!left_is_type && (original == null || !original.IdenticalNameAndTypeName (ec, left, loc))) {
4442                                         Report.SymbolRelatedToPreviousError (FieldInfo);
4443                                         error176 (loc, TypeManager.GetFullNameSignature (FieldInfo));
4444                                         return null;
4445                                 }
4446
4447                                 if (ic.ResolveValue ()) {
4448                                         if (!ec.IsInObsoleteScope)
4449                                                 ic.CheckObsoleteness (loc);
4450                                 }
4451
4452                                 return ic.CreateConstantReference (loc);
4453                         }
4454
4455                         if (t.IsPointer && !ec.InUnsafe) {
4456                                 UnsafeError (loc);
4457                         }
4458
4459                         return base.ResolveMemberAccess (ec, left, loc, original);
4460                 }
4461
4462                 override public Expression DoResolve (EmitContext ec)
4463                 {
4464                         return DoResolve (ec, false, false);
4465                 }
4466
4467                 Expression DoResolve (EmitContext ec, bool lvalue_instance, bool out_access)
4468                 {
4469                         if (!FieldInfo.IsStatic){
4470                                 if (InstanceExpression == null){
4471                                         //
4472                                         // This can happen when referencing an instance field using
4473                                         // a fully qualified type expression: TypeName.InstanceField = xxx
4474                                         //
4475                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4476                                         return null;
4477                                 }
4478
4479                                 // Resolve the field's instance expression while flow analysis is turned
4480                                 // off: when accessing a field "a.b", we must check whether the field
4481                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
4482
4483                                 if (lvalue_instance) {
4484                                         using (ec.With (EmitContext.Flags.DoFlowAnalysis, false)) {
4485                                                 Expression right_side =
4486                                                         out_access ? EmptyExpression.LValueMemberOutAccess : EmptyExpression.LValueMemberAccess;
4487                                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, right_side, loc);
4488                                         }
4489                                 } else {
4490                                         ResolveFlags rf = ResolveFlags.VariableOrValue | ResolveFlags.DisableFlowAnalysis;
4491                                         InstanceExpression = InstanceExpression.Resolve (ec, rf);
4492                                 }
4493
4494                                 if (InstanceExpression == null)
4495                                         return null;
4496
4497                                 InstanceExpression.CheckMarshalByRefAccess ();
4498                         }
4499
4500                         if (!in_initializer && !ec.IsInFieldInitializer) {
4501                                 ObsoleteAttribute oa;
4502                                 FieldBase f = TypeManager.GetField (FieldInfo);
4503                                 if (f != null) {
4504                                         if (!ec.IsInObsoleteScope)
4505                                                 f.CheckObsoleteness (loc);
4506
4507                                         // To be sure that type is external because we do not register generated fields
4508                                 } else if (!(FieldInfo.DeclaringType is TypeBuilder)) {
4509                                         oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
4510                                         if (oa != null)
4511                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
4512                                 }
4513                         }
4514
4515                         AnonymousContainer am = ec.CurrentAnonymousMethod;
4516                         if (am != null){
4517                                 if (!FieldInfo.IsStatic){
4518                                         if (!am.IsIterator && (ec.TypeContainer is Struct)){
4519                                                 Report.Error (1673, loc,
4520                                                 "Anonymous methods inside structs cannot access instance members of `{0}'. Consider copying `{0}' to a local variable outside the anonymous method and using the local instead",
4521                                                         "this");
4522                                                 return null;
4523                                         }
4524                                 }
4525                         }
4526
4527                         IFixedBuffer fb = AttributeTester.GetFixedBuffer (FieldInfo);
4528                         if (fb != null) {
4529                                 if (!ec.InFixedInitializer && ec.ContainerType.IsValueType) {
4530                                         Report.Error (1666, loc, "You cannot use fixed size buffers contained in unfixed expressions. Try using the fixed statement");
4531                                 }
4532
4533                                 if (!(InstanceExpression is LocalVariableReference) &&
4534                                         !(InstanceExpression is This)) {
4535                                         Report.SymbolRelatedToPreviousError (FieldInfo);
4536                                         Report.Error (1708, loc, "`{0}': Fixed size buffers can only be accessed through locals or fields",
4537                                                 TypeManager.GetFullNameSignature (FieldInfo));
4538                                 }
4539
4540                                 return new FixedBufferPtr (this, fb.ElementType, loc).Resolve (ec);
4541                         }
4542
4543                         // If the instance expression is a local variable or parameter.
4544                         IVariable var = InstanceExpression as IVariable;
4545                         if ((var == null) || (var.VariableInfo == null))
4546                                 return this;
4547
4548                         VariableInfo vi = var.VariableInfo;
4549                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
4550                                 return null;
4551
4552                         variable_info = vi.GetSubStruct (FieldInfo.Name);
4553                         return this;
4554                 }
4555
4556                 static readonly int [] codes = {
4557                         191,    // instance, write access
4558                         192,    // instance, out access
4559                         198,    // static, write access
4560                         199,    // static, out access
4561                         1648,   // member of value instance, write access
4562                         1649,   // member of value instance, out access
4563                         1650,   // member of value static, write access
4564                         1651    // member of value static, out access
4565                 };
4566
4567                 static readonly string [] msgs = {
4568                         /*0191*/ "A readonly field `{0}' cannot be assigned to (except in a constructor or a variable initializer)",
4569                         /*0192*/ "A readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4570                         /*0198*/ "A static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4571                         /*0199*/ "A static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
4572                         /*1648*/ "Members of readonly field `{0}' cannot be modified (except in a constructor or a variable initializer)",
4573                         /*1649*/ "Members of readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4574                         /*1650*/ "Fields of static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4575                         /*1651*/ "Fields of static readonly field `{0}' cannot be passed ref or out (except in a static constructor)"
4576                 };
4577
4578                 // The return value is always null.  Returning a value simplifies calling code.
4579                 Expression Report_AssignToReadonly (Expression right_side)
4580                 {
4581                         int i = 0;
4582                         if (right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4583                                 i += 1;
4584                         if (IsStatic)
4585                                 i += 2;
4586                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4587                                 i += 4;
4588                         Report.Error (codes [i], loc, msgs [i], GetSignatureForError ());
4589
4590                         return null;
4591                 }
4592
4593                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
4594                 {
4595                         IVariable var = InstanceExpression as IVariable;
4596                         if ((var != null) && (var.VariableInfo != null))
4597                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
4598
4599                         bool lvalue_instance = !FieldInfo.IsStatic && FieldInfo.DeclaringType.IsValueType;
4600                         bool out_access = right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess;
4601
4602                         Expression e = DoResolve (ec, lvalue_instance, out_access);
4603
4604                         if (e == null)
4605                                 return null;
4606
4607                         FieldBase fb = TypeManager.GetField (FieldInfo);
4608                         if (fb != null)
4609                                 fb.SetAssigned ();
4610
4611                         if (FieldInfo.IsInitOnly) {
4612                                 // InitOnly fields can only be assigned in constructors or initializers
4613                                 if (!ec.IsInFieldInitializer && !ec.IsConstructor)
4614                                         return Report_AssignToReadonly (right_side);
4615
4616                                 if (ec.IsConstructor) {
4617                                         Type ctype = ec.TypeContainer.CurrentType;
4618                                         if (ctype == null)
4619                                                 ctype = ec.ContainerType;
4620
4621                                         // InitOnly fields cannot be assigned-to in a different constructor from their declaring type
4622                                         if (!TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
4623                                                 return Report_AssignToReadonly (right_side);
4624                                         // static InitOnly fields cannot be assigned-to in an instance constructor
4625                                         if (IsStatic && !ec.IsStatic)
4626                                                 return Report_AssignToReadonly (right_side);
4627                                         // instance constructors can't modify InitOnly fields of other instances of the same type
4628                                         if (!IsStatic && !(InstanceExpression is This))
4629                                                 return Report_AssignToReadonly (right_side);
4630                                 }
4631                         }
4632
4633                         if (right_side == EmptyExpression.OutAccess &&
4634                             !IsStatic && !(InstanceExpression is This) && DeclaringType.IsSubclassOf (TypeManager.mbr_type)) {
4635                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4636                                 Report.Warning (197, 1, loc,
4637                                                 "Passing `{0}' as ref or out or taking its address may cause a runtime exception because it is a field of a marshal-by-reference class",
4638                                                 GetSignatureForError ());
4639                         }
4640
4641                         return this;
4642                 }
4643
4644                 public override void CheckMarshalByRefAccess ()
4645                 {
4646                         if (!IsStatic && Type.IsValueType && !(InstanceExpression is This) && DeclaringType.IsSubclassOf (TypeManager.mbr_type)) {
4647                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4648                                 Report.Warning (1690, 1, loc, "Cannot call methods, properties, or indexers on `{0}' because it is a value type member of a marshal-by-reference class",
4649                                                 GetSignatureForError ());
4650                         }
4651                 }
4652
4653                 public bool VerifyFixed ()
4654                 {
4655                         IVariable variable = InstanceExpression as IVariable;
4656                         // A variable of the form V.I is fixed when V is a fixed variable of a struct type.
4657                         // We defer the InstanceExpression check after the variable check to avoid a
4658                         // separate null check on InstanceExpression.
4659                         return variable != null && InstanceExpression.Type.IsValueType && variable.VerifyFixed ();
4660                 }
4661
4662                 public override int GetHashCode ()
4663                 {
4664                         return FieldInfo.GetHashCode ();
4665                 }
4666
4667                 public override bool Equals (object obj)
4668                 {
4669                         FieldExpr fe = obj as FieldExpr;
4670                         if (fe == null)
4671                                 return false;
4672
4673                         if (FieldInfo != fe.FieldInfo)
4674                                 return false;
4675
4676                         if (InstanceExpression == null || fe.InstanceExpression == null)
4677                                 return true;
4678
4679                         return InstanceExpression.Equals (fe.InstanceExpression);
4680                 }
4681
4682                 public void Emit (EmitContext ec, bool leave_copy)
4683                 {
4684                         ILGenerator ig = ec.ig;
4685                         bool is_volatile = false;
4686
4687                         FieldBase f = TypeManager.GetField (FieldInfo);
4688                         if (f != null){
4689                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4690                                         is_volatile = true;
4691
4692                                 f.SetMemberIsUsed ();
4693                         }
4694
4695                         if (FieldInfo.IsStatic){
4696                                 if (is_volatile)
4697                                         ig.Emit (OpCodes.Volatile);
4698
4699                                 ig.Emit (OpCodes.Ldsfld, FieldInfo);
4700                         } else {
4701                                 if (!prepared)
4702                                         EmitInstance (ec, false);
4703
4704                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
4705                                 if (ff != null) {
4706                                         ig.Emit (OpCodes.Ldflda, FieldInfo);
4707                                         ig.Emit (OpCodes.Ldflda, ff.Element);
4708                                 } else {
4709                                         if (is_volatile)
4710                                                 ig.Emit (OpCodes.Volatile);
4711
4712                                         ig.Emit (OpCodes.Ldfld, FieldInfo);
4713                                 }
4714                         }
4715
4716                         if (leave_copy) {
4717                                 ec.ig.Emit (OpCodes.Dup);
4718                                 if (!FieldInfo.IsStatic) {
4719                                         temp = new LocalTemporary (this.Type);
4720                                         temp.Store (ec);
4721                                 }
4722                         }
4723                 }
4724
4725                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
4726                 {
4727                         FieldAttributes fa = FieldInfo.Attributes;
4728                         bool is_static = (fa & FieldAttributes.Static) != 0;
4729                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
4730                         ILGenerator ig = ec.ig;
4731
4732                         if (is_readonly && !ec.IsConstructor){
4733                                 Report_AssignToReadonly (source);
4734                                 return;
4735                         }
4736
4737                         //
4738                         // String concatenation creates a new string instance
4739                         //
4740                         prepared = prepare_for_load && !(source is StringConcat);
4741                         EmitInstance (ec, prepared);
4742
4743                         source.Emit (ec);
4744                         if (leave_copy) {
4745                                 ec.ig.Emit (OpCodes.Dup);
4746                                 if (!FieldInfo.IsStatic) {
4747                                         temp = new LocalTemporary (this.Type);
4748                                         temp.Store (ec);
4749                                 }
4750                         }
4751
4752                         FieldBase f = TypeManager.GetField (FieldInfo);
4753                         if (f != null){
4754                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4755                                         ig.Emit (OpCodes.Volatile);
4756
4757                                 f.SetAssigned ();
4758                         }
4759
4760                         if (is_static)
4761                                 ig.Emit (OpCodes.Stsfld, FieldInfo);
4762                         else
4763                                 ig.Emit (OpCodes.Stfld, FieldInfo);
4764
4765                         if (temp != null) {
4766                                 temp.Emit (ec);
4767                                 temp.Release (ec);
4768                         }
4769                 }
4770
4771                 public override void Emit (EmitContext ec)
4772                 {
4773                         Emit (ec, false);
4774                 }
4775
4776                 public void AddressOf (EmitContext ec, AddressOp mode)
4777                 {
4778                         ILGenerator ig = ec.ig;
4779
4780                         FieldBase f = TypeManager.GetField (FieldInfo);
4781                         if (f != null){
4782                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0){
4783                                         Report.Warning (420, 1, loc, "`{0}': A volatile field references will not be treated as volatile",
4784                                                         f.GetSignatureForError ());
4785                                 }
4786
4787                                 if ((mode & AddressOp.Store) != 0)
4788                                         f.SetAssigned ();
4789                                 if ((mode & AddressOp.Load) != 0)
4790                                         f.SetMemberIsUsed ();
4791                         }
4792
4793                         //
4794                         // Handle initonly fields specially: make a copy and then
4795                         // get the address of the copy.
4796                         //
4797                         bool need_copy;
4798                         if (FieldInfo.IsInitOnly){
4799                                 need_copy = true;
4800                                 if (ec.IsConstructor){
4801                                         if (FieldInfo.IsStatic){
4802                                                 if (ec.IsStatic)
4803                                                         need_copy = false;
4804                                         } else
4805                                                 need_copy = false;
4806                                 }
4807                         } else
4808                                 need_copy = false;
4809
4810                         if (need_copy){
4811                                 LocalBuilder local;
4812                                 Emit (ec);
4813                                 local = ig.DeclareLocal (type);
4814                                 ig.Emit (OpCodes.Stloc, local);
4815                                 ig.Emit (OpCodes.Ldloca, local);
4816                                 return;
4817                         }
4818
4819
4820                         if (FieldInfo.IsStatic){
4821                                 ig.Emit (OpCodes.Ldsflda, FieldInfo);
4822                         } else {
4823                                 if (!prepared)
4824                                         EmitInstance (ec, false);
4825                                 ig.Emit (OpCodes.Ldflda, FieldInfo);
4826                         }
4827                 }
4828         }
4829
4830         //
4831         // A FieldExpr whose address can not be taken
4832         //
4833         public class FieldExprNoAddress : FieldExpr, IMemoryLocation {
4834                 public FieldExprNoAddress (FieldInfo fi, Location loc) : base (fi, loc)
4835                 {
4836                 }
4837
4838                 public new void AddressOf (EmitContext ec, AddressOp mode)
4839                 {
4840                         Report.Error (-215, "Report this: Taking the address of a remapped parameter not supported");
4841                 }
4842         }
4843
4844         /// <summary>
4845         ///   Expression that evaluates to a Property.  The Assign class
4846         ///   might set the `Value' expression if we are in an assignment.
4847         ///
4848         ///   This is not an LValue because we need to re-write the expression, we
4849         ///   can not take data from the stack and store it.
4850         /// </summary>
4851         public class PropertyExpr : MemberExpr, IAssignMethod {
4852                 public readonly PropertyInfo PropertyInfo;
4853
4854                 //
4855                 // This is set externally by the  `BaseAccess' class
4856                 //
4857                 public bool IsBase;
4858                 MethodInfo getter, setter;
4859                 bool is_static;
4860
4861                 bool resolved;
4862
4863                 LocalTemporary temp;
4864                 bool prepared;
4865
4866                 public PropertyExpr (Type container_type, PropertyInfo pi, Location l)
4867                 {
4868                         PropertyInfo = pi;
4869                         eclass = ExprClass.PropertyAccess;
4870                         is_static = false;
4871                         loc = l;
4872
4873                         type = TypeManager.TypeToCoreType (pi.PropertyType);
4874
4875                         ResolveAccessors (container_type);
4876                 }
4877
4878                 public override string Name {
4879                         get {
4880                                 return PropertyInfo.Name;
4881                         }
4882                 }
4883
4884                 public override bool IsInstance {
4885                         get {
4886                                 return !is_static;
4887                         }
4888                 }
4889
4890                 public override bool IsStatic {
4891                         get {
4892                                 return is_static;
4893                         }
4894                 }
4895
4896                 public override Type DeclaringType {
4897                         get {
4898                                 return PropertyInfo.DeclaringType;
4899                         }
4900                 }
4901
4902                 public override string GetSignatureForError ()
4903                 {
4904                         return TypeManager.GetFullNameSignature (PropertyInfo);
4905                 }
4906
4907                 void FindAccessors (Type invocation_type)
4908                 {
4909                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
4910                                 BindingFlags.Static | BindingFlags.Instance |
4911                                 BindingFlags.DeclaredOnly;
4912
4913                         Type current = PropertyInfo.DeclaringType;
4914                         for (; current != null; current = current.BaseType) {
4915                                 MemberInfo[] group = TypeManager.MemberLookup (
4916                                         invocation_type, invocation_type, current,
4917                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
4918
4919                                 if (group == null)
4920                                         continue;
4921
4922                                 if (group.Length != 1)
4923                                         // Oooops, can this ever happen ?
4924                                         return;
4925
4926                                 PropertyInfo pi = (PropertyInfo) group [0];
4927
4928                                 if (getter == null)
4929                                         getter = pi.GetGetMethod (true);
4930
4931                                 if (setter == null)
4932                                         setter = pi.GetSetMethod (true);
4933
4934                                 MethodInfo accessor = getter != null ? getter : setter;
4935
4936                                 if (!accessor.IsVirtual)
4937                                         return;
4938                         }
4939                 }
4940
4941                 //
4942                 // We also perform the permission checking here, as the PropertyInfo does not
4943                 // hold the information for the accessibility of its setter/getter
4944                 //
4945                 // TODO: Refactor to use some kind of cache together with GetPropertyFromAccessor
4946                 void ResolveAccessors (Type container_type)
4947                 {
4948                         FindAccessors (container_type);
4949
4950                         if (getter != null) {
4951                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
4952                                 IMethodData md = TypeManager.GetMethod (the_getter);
4953                                 if (md != null)
4954                                         md.SetMemberIsUsed ();
4955
4956                                 is_static = getter.IsStatic;
4957                         }
4958
4959                         if (setter != null) {
4960                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
4961                                 IMethodData md = TypeManager.GetMethod (the_setter);
4962                                 if (md != null)
4963                                         md.SetMemberIsUsed ();
4964
4965                                 is_static = setter.IsStatic;
4966                         }
4967                 }
4968
4969                 bool InstanceResolve (EmitContext ec, bool lvalue_instance, bool must_do_cs1540_check)
4970                 {
4971                         if (is_static) {
4972                                 InstanceExpression = null;
4973                                 return true;
4974                         }
4975
4976                         if (InstanceExpression == null) {
4977                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4978                                 return false;
4979                         }
4980
4981                         InstanceExpression = InstanceExpression.DoResolve (ec);
4982                         if (lvalue_instance && InstanceExpression != null)
4983                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess, loc);
4984
4985                         if (InstanceExpression == null)
4986                                 return false;
4987
4988                         InstanceExpression.CheckMarshalByRefAccess ();
4989
4990                         if (must_do_cs1540_check && (InstanceExpression != EmptyExpression.Null) &&
4991                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.ContainerType) &&
4992                             !TypeManager.IsNestedChildOf (ec.ContainerType, InstanceExpression.Type) &&
4993                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.ContainerType)) {
4994                                 Report.SymbolRelatedToPreviousError (PropertyInfo);
4995                                 Error_CannotAccessProtected (loc, PropertyInfo, InstanceExpression.Type, ec.ContainerType);
4996                                 return false;
4997                         }
4998
4999                         return true;
5000                 }
5001
5002                 void Error_PropertyNotFound (MethodInfo mi, bool getter)
5003                 {
5004                         // TODO: correctly we should compare arguments but it will lead to bigger changes
5005                         if (mi is MethodBuilder) {
5006                                 Error_TypeDoesNotContainDefinition (loc, PropertyInfo.DeclaringType, Name);
5007                                 return;
5008                         }
5009
5010                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
5011                         sig.Append ('.');
5012                         ParameterData iparams = TypeManager.GetParameterData (mi);
5013                         sig.Append (getter ? "get_" : "set_");
5014                         sig.Append (Name);
5015                         sig.Append (iparams.GetSignatureForError ());
5016
5017                         Report.SymbolRelatedToPreviousError (mi);
5018                         Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
5019                                 Name, sig.ToString ());
5020                 }
5021
5022                 public bool IsAccessibleFrom (Type invocation_type, bool lvalue)
5023                 {
5024                         bool dummy;
5025                         MethodInfo accessor = lvalue ? setter : getter;
5026                         if (accessor == null && lvalue)
5027                                 accessor = getter;
5028                         return accessor != null && IsAccessorAccessible (invocation_type, accessor, out dummy);
5029                 }
5030
5031                 override public Expression DoResolve (EmitContext ec)
5032                 {
5033                         if (resolved)
5034                                 return this;
5035
5036                         if (getter != null){
5037                                 if (TypeManager.GetParameterData (getter).Count != 0){
5038                                         Error_PropertyNotFound (getter, true);
5039                                         return null;
5040                                 }
5041                         }
5042
5043                         if (getter == null){
5044                                 //
5045                                 // The following condition happens if the PropertyExpr was
5046                                 // created, but is invalid (ie, the property is inaccessible),
5047                                 // and we did not want to embed the knowledge about this in
5048                                 // the caller routine.  This only avoids double error reporting.
5049                                 //
5050                                 if (setter == null)
5051                                         return null;
5052
5053                                 if (InstanceExpression != EmptyExpression.Null) {
5054                                         Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
5055                                                 TypeManager.GetFullNameSignature (PropertyInfo));
5056                                         return null;
5057                                 }
5058                         }
5059
5060                         bool must_do_cs1540_check = false;
5061                         if (getter != null &&
5062                             !IsAccessorAccessible (ec.ContainerType, getter, out must_do_cs1540_check)) {
5063                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter) as PropertyBase.PropertyMethod;
5064                                 if (pm != null && pm.HasCustomAccessModifier) {
5065                                         Report.SymbolRelatedToPreviousError (pm);
5066                                         Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
5067                                                 TypeManager.CSharpSignature (getter));
5068                                 }
5069                                 else {
5070                                         Report.SymbolRelatedToPreviousError (getter);
5071                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter));
5072                                 }
5073                                 return null;
5074                         }
5075
5076                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
5077                                 return null;
5078
5079                         //
5080                         // Only base will allow this invocation to happen.
5081                         //
5082                         if (IsBase && getter.IsAbstract) {
5083                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5084                                 return null;
5085                         }
5086
5087                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe){
5088                                 UnsafeError (loc);
5089                                 return null;
5090                         }
5091
5092                         resolved = true;
5093
5094                         return this;
5095                 }
5096
5097                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5098                 {
5099                         if (right_side == EmptyExpression.OutAccess) {
5100                                 if (ec.CurrentBlock.Toplevel.GetTransparentIdentifier (PropertyInfo.Name) != null) {
5101                                         Report.Error (1939, loc, "A range variable `{0}' may not be passes as `ref' or `out' parameter",
5102                                             PropertyInfo.Name);
5103                                 } else {
5104                                         Report.Error (206, loc, "A property or indexer `{0}' may not be passed as `ref' or `out' parameter",
5105                                               GetSignatureForError ());
5106                                 }
5107                                 return null;
5108                         }
5109
5110                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess) {
5111                                 Report.Error (1612, loc, "Cannot modify the return value of `{0}' because it is not a variable",
5112                                               GetSignatureForError ());
5113                                 return null;
5114                         }
5115
5116                         if (setter == null){
5117                                 //
5118                                 // The following condition happens if the PropertyExpr was
5119                                 // created, but is invalid (ie, the property is inaccessible),
5120                                 // and we did not want to embed the knowledge about this in
5121                                 // the caller routine.  This only avoids double error reporting.
5122                                 //
5123                                 if (getter == null)
5124                                         return null;
5125                                 Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
5126                                               GetSignatureForError ());
5127                                 return null;
5128                         }
5129
5130                         if (TypeManager.GetParameterData (setter).Count != 1){
5131                                 Error_PropertyNotFound (setter, false);
5132                                 return null;
5133                         }
5134
5135                         bool must_do_cs1540_check;
5136                         if (!IsAccessorAccessible (ec.ContainerType, setter, out must_do_cs1540_check)) {
5137                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter) as PropertyBase.PropertyMethod;
5138                                 if (pm != null && pm.HasCustomAccessModifier) {
5139                                         Report.SymbolRelatedToPreviousError (pm);
5140                                         Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
5141                                                 TypeManager.CSharpSignature (setter));
5142                                 }
5143                                 else {
5144                                         Report.SymbolRelatedToPreviousError (setter);
5145                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter));
5146                                 }
5147                                 return null;
5148                         }
5149
5150                         if (!InstanceResolve (ec, PropertyInfo.DeclaringType.IsValueType, must_do_cs1540_check))
5151                                 return null;
5152
5153                         //
5154                         // Only base will allow this invocation to happen.
5155                         //
5156                         if (IsBase && setter.IsAbstract){
5157                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5158                                 return null;
5159                         }
5160
5161                         return this;
5162                 }
5163
5164                 public override void Emit (EmitContext ec)
5165                 {
5166                         Emit (ec, false);
5167                 }
5168
5169                 public void Emit (EmitContext ec, bool leave_copy)
5170                 {
5171                         //
5172                         // Special case: length of single dimension array property is turned into ldlen
5173                         //
5174                         if ((getter == TypeManager.system_int_array_get_length) ||
5175                             (getter == TypeManager.int_array_get_length)){
5176                                 Type iet = InstanceExpression.Type;
5177
5178                                 //
5179                                 // System.Array.Length can be called, but the Type does not
5180                                 // support invoking GetArrayRank, so test for that case first
5181                                 //
5182                                 if (iet != TypeManager.array_type && (iet.GetArrayRank () == 1)) {
5183                                         if (!prepared)
5184                                                 EmitInstance (ec, false);
5185                                         ec.ig.Emit (OpCodes.Ldlen);
5186                                         ec.ig.Emit (OpCodes.Conv_I4);
5187                                         return;
5188                                 }
5189                         }
5190
5191                         Invocation.EmitCall (ec, IsBase, InstanceExpression, getter, null, loc, prepared, false);
5192
5193                         if (leave_copy) {
5194                                 ec.ig.Emit (OpCodes.Dup);
5195                                 if (!is_static) {
5196                                         temp = new LocalTemporary (this.Type);
5197                                         temp.Store (ec);
5198                                 }
5199                         }
5200                 }
5201
5202                 //
5203                 // Implements the IAssignMethod interface for assignments
5204                 //
5205                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5206                 {
5207                         Expression my_source = source;
5208
5209                         if (prepare_for_load) {
5210                                 if (source is StringConcat)
5211                                         EmitInstance (ec, false);
5212                                 else
5213                                         prepared = true;
5214
5215                                 source.Emit (ec);
5216
5217                                 prepared = true;
5218                                 if (leave_copy) {
5219                                         ec.ig.Emit (OpCodes.Dup);
5220                                         if (!is_static) {
5221                                                 temp = new LocalTemporary (this.Type);
5222                                                 temp.Store (ec);
5223                                         }
5224                                 }
5225                         } else if (leave_copy) {
5226                                 source.Emit (ec);
5227                                 temp = new LocalTemporary (this.Type);
5228                                 temp.Store (ec);
5229                                 my_source = temp;
5230                         }
5231
5232                         ArrayList args = new ArrayList (1);
5233                         args.Add (new Argument (my_source, Argument.AType.Expression));
5234
5235                         Invocation.EmitCall (ec, IsBase, InstanceExpression, setter, args, loc, false, prepared);
5236
5237                         if (temp != null) {
5238                                 temp.Emit (ec);
5239                                 temp.Release (ec);
5240                         }
5241                 }
5242         }
5243
5244         /// <summary>
5245         ///   Fully resolved expression that evaluates to an Event
5246         /// </summary>
5247         public class EventExpr : MemberExpr {
5248                 public readonly EventInfo EventInfo;
5249                 public bool IsBase;
5250
5251                 bool is_static;
5252                 MethodInfo add_accessor, remove_accessor;
5253
5254                 public EventExpr (EventInfo ei, Location loc)
5255                 {
5256                         EventInfo = ei;
5257                         this.loc = loc;
5258                         eclass = ExprClass.EventAccess;
5259
5260                         add_accessor = TypeManager.GetAddMethod (ei);
5261                         remove_accessor = TypeManager.GetRemoveMethod (ei);
5262                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
5263                                 is_static = true;
5264
5265                         if (EventInfo is MyEventBuilder){
5266                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
5267                                 type = eb.EventType;
5268                                 eb.SetUsed ();
5269                         } else
5270                                 type = EventInfo.EventHandlerType;
5271                 }
5272
5273                 public override string Name {
5274                         get {
5275                                 return EventInfo.Name;
5276                         }
5277                 }
5278
5279                 public override bool IsInstance {
5280                         get {
5281                                 return !is_static;
5282                         }
5283                 }
5284
5285                 public override bool IsStatic {
5286                         get {
5287                                 return is_static;
5288                         }
5289                 }
5290
5291                 public override Type DeclaringType {
5292                         get {
5293                                 return EventInfo.DeclaringType;
5294                         }
5295                 }
5296
5297                 public override Expression ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
5298                                                                 SimpleName original)
5299                 {
5300                         //
5301                         // If the event is local to this class, we transform ourselves into a FieldExpr
5302                         //
5303
5304                         if (EventInfo.DeclaringType == ec.ContainerType ||
5305                             TypeManager.IsNestedChildOf(ec.ContainerType, EventInfo.DeclaringType)) {
5306                                 EventField mi = TypeManager.GetEventField (EventInfo);
5307
5308                                 if (mi != null) {
5309                                         if (!ec.IsInObsoleteScope)
5310                                                 mi.CheckObsoleteness (loc);
5311
5312                                         FieldExpr ml = new FieldExpr (mi.FieldBuilder, loc);
5313
5314                                         InstanceExpression = null;
5315
5316                                         return ml.ResolveMemberAccess (ec, left, loc, original);
5317                                 }
5318                         }
5319
5320                         return base.ResolveMemberAccess (ec, left, loc, original);
5321                 }
5322
5323
5324                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
5325                 {
5326                         if (is_static) {
5327                                 InstanceExpression = null;
5328                                 return true;
5329                         }
5330
5331                         if (InstanceExpression == null) {
5332                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5333                                 return false;
5334                         }
5335
5336                         InstanceExpression = InstanceExpression.DoResolve (ec);
5337                         if (InstanceExpression == null)
5338                                 return false;
5339
5340                         if (IsBase && add_accessor.IsAbstract) {
5341                                 Error_CannotCallAbstractBase(TypeManager.CSharpSignature(add_accessor));
5342                                 return false;
5343                         }
5344
5345                         //
5346                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
5347                         // However, in the Event case, we reported a CS0122 instead.
5348                         //
5349                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
5350                             InstanceExpression.Type != ec.ContainerType &&
5351                             ec.ContainerType.IsSubclassOf (InstanceExpression.Type)) {
5352                                 Report.SymbolRelatedToPreviousError (EventInfo);
5353                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5354                                 return false;
5355                         }
5356
5357                         return true;
5358                 }
5359
5360                 public bool IsAccessibleFrom (Type invocation_type)
5361                 {
5362                         bool dummy;
5363                         return IsAccessorAccessible (invocation_type, add_accessor, out dummy) &&
5364                                 IsAccessorAccessible (invocation_type, remove_accessor, out dummy);
5365                 }
5366
5367                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5368                 {
5369                         return DoResolve (ec);
5370                 }
5371
5372                 public override Expression DoResolve (EmitContext ec)
5373                 {
5374                         bool must_do_cs1540_check;
5375                         if (!(IsAccessorAccessible (ec.ContainerType, add_accessor, out must_do_cs1540_check) &&
5376                               IsAccessorAccessible (ec.ContainerType, remove_accessor, out must_do_cs1540_check))) {
5377                                 Report.SymbolRelatedToPreviousError (EventInfo);
5378                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5379                                 return null;
5380                         }
5381
5382                         if (!InstanceResolve (ec, must_do_cs1540_check))
5383                                 return null;
5384
5385                         return this;
5386                 }
5387
5388                 public override void Emit (EmitContext ec)
5389                 {
5390                         if (InstanceExpression is This)
5391                                 Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of += or -=", GetSignatureForError ());
5392                         else
5393                                 Report.Error (70, loc, "The event `{0}' can only appear on the left hand side of += or -= "+
5394                                               "(except on the defining type)", Name);
5395                 }
5396
5397                 public override string GetSignatureForError ()
5398                 {
5399                         return TypeManager.CSharpSignature (EventInfo);
5400                 }
5401
5402                 public void EmitAddOrRemove (EmitContext ec, Expression source)
5403                 {
5404                         BinaryDelegate source_del = source as BinaryDelegate;
5405                         if (source_del == null) {
5406                                 Emit (ec);
5407                                 return;
5408                         }
5409                         Expression handler = source_del.Right;
5410
5411                         Argument arg = new Argument (handler, Argument.AType.Expression);
5412                         ArrayList args = new ArrayList ();
5413
5414                         args.Add (arg);
5415
5416                         if (source_del.IsAddition)
5417                                 Invocation.EmitCall (
5418                                         ec, IsBase, InstanceExpression, add_accessor, args, loc);
5419                         else
5420                                 Invocation.EmitCall (
5421                                         ec, IsBase, InstanceExpression, remove_accessor, args, loc);
5422                 }
5423         }
5424
5425         public class TemporaryVariable : Expression, IMemoryLocation
5426         {
5427                 LocalInfo li;
5428                 Variable var;
5429
5430                 public TemporaryVariable (Type type, Location loc)
5431                 {
5432                         this.type = type;
5433                         this.loc = loc;
5434                         eclass = ExprClass.Value;
5435                 }
5436
5437                 public override Expression DoResolve (EmitContext ec)
5438                 {
5439                         if (li != null)
5440                                 return this;
5441
5442                         TypeExpr te = new TypeExpression (type, loc);
5443                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
5444                         if (!li.Resolve (ec))
5445                                 return null;
5446
5447                         if (ec.MustCaptureVariable (li)) {
5448                                 ScopeInfo scope = li.Block.CreateScopeInfo ();
5449                                 var = scope.AddLocal (li);
5450                                 type = var.Type;
5451                         }
5452
5453                         return this;
5454                 }
5455
5456                 public Variable Variable {
5457                         get { return var != null ? var : li.Variable; }
5458                 }
5459
5460                 public override void Emit (EmitContext ec)
5461                 {
5462                         Variable.EmitInstance (ec);
5463                         Variable.Emit (ec);
5464                 }
5465
5466                 public void EmitLoadAddress (EmitContext ec)
5467                 {
5468                         Variable.EmitInstance (ec);
5469                         Variable.EmitAddressOf (ec);
5470                 }
5471
5472                 public void Store (EmitContext ec, Expression right_side)
5473                 {
5474                         Variable.EmitInstance (ec);
5475                         right_side.Emit (ec);
5476                         Variable.EmitAssign (ec);
5477                 }
5478
5479                 public void EmitThis (EmitContext ec)
5480                 {
5481                         Variable.EmitInstance (ec);
5482                 }
5483
5484                 public void EmitStore (EmitContext ec)
5485                 {
5486                         Variable.EmitAssign (ec);
5487                 }
5488
5489                 public void AddressOf (EmitContext ec, AddressOp mode)
5490                 {
5491                         EmitLoadAddress (ec);
5492                 }
5493         }
5494
5495         ///
5496         /// Handles `var' contextual keyword; var becomes a keyword only
5497         /// if no type called var exists in a variable scope
5498         ///
5499         public class VarExpr : SimpleName
5500         {
5501                 // Used for error reporting only
5502                 ArrayList initializer;
5503
5504                 public VarExpr (string name, Location loc)
5505                         : base (name, loc)
5506                 {
5507                 }
5508
5509                 public ArrayList VariableInitializer {
5510                         set {
5511                                 this.initializer = value;
5512                         }
5513                 }
5514
5515                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5516                 {
5517                         if (type != null)
5518                                 throw new InternalErrorException ("An implicitly typed local variable could not be redefined");
5519
5520                         type = right_side.Type;
5521                         if (type == TypeManager.null_type || type == TypeManager.void_type || type == TypeManager.anonymous_method_type) {
5522                                 Report.Error (815, loc, "An implicitly typed local variable declaration cannot be initialized with `{0}'",
5523                                               right_side.GetSignatureForError ());
5524                                 return null;
5525                         }
5526
5527                         eclass = ExprClass.Variable;
5528                         return this;
5529                 }
5530
5531                 protected override void Error_TypeOrNamespaceNotFound (IResolveContext ec)
5532                 {
5533                         if (ec is FieldBase) {
5534                                 Report.Error (825, loc, "The contextual keyword `var' may only appear within a local variable declaration");
5535                                 return;
5536                         }
5537
5538                         base.Error_TypeOrNamespaceNotFound (ec);
5539                 }
5540
5541                 public override TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
5542                 {
5543                         TypeExpr te = base.ResolveAsContextualType (rc, true);
5544                         if (te != null)
5545                                 return te;
5546
5547                         if (initializer == null)
5548                                 return null;
5549
5550                         // TODO: refactor, the error is reported too many times
5551                         if (initializer.Count > 1) {
5552                                 Location loc = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [1]).Location;
5553                                 Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
5554                                 return null;
5555                         }
5556
5557                         Expression variable_initializer = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [0]).expression_or_array_initializer;
5558                         if (variable_initializer == null) {
5559                                 Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
5560                                 return null;
5561                         }
5562
5563                         return null;
5564                 }
5565         }
5566 }