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 // Copyright 2001, 2002, 2003 Ximian, Inc.
   9 // Copyright 2003-2008 Novell, Inc.
  10 //
  11 //
  12
  13 namespace Mono.CSharp {
  14         using System;
  15         using System.Collections;
  16         using System.Diagnostics;
  17         using System.Reflection;
  18         using System.Reflection.Emit;
  19         using System.Text;
  20
  21         /// <remarks>
  22         ///   The ExprClass class contains the is used to pass the
  23         ///   classification of an expression (value, variable, namespace,
  24         ///   type, method group, property access, event access, indexer access,
  25         ///   nothing).
  26         /// </remarks>
  27         public enum ExprClass : byte {
  28                 Invalid,
  29
  30                 Value,
  31                 Variable,
  32                 Namespace,
  33                 Type,
  34                 MethodGroup,
  35                 PropertyAccess,
  36                 EventAccess,
  37                 IndexerAccess,
  38                 Nothing,
  39         }
  40
  41         /// <remarks>
  42         ///   This is used to tell Resolve in which types of expressions we're
  43         ///   interested.
  44         /// </remarks>
  45         [Flags]
  46         public enum ResolveFlags {
  47                 // Returns Value, Variable, PropertyAccess, EventAccess or IndexerAccess.
  48                 VariableOrValue         = 1,
  49
  50                 // Returns a type expression.
  51                 Type                    = 2,
  52
  53                 // Returns a method group.
  54                 MethodGroup             = 4,
  55
  56                 // Mask of all the expression class flags.
  57                 MaskExprClass           = 7,
  58
  59                 // Disable control flow analysis while resolving the expression.
  60                 // This is used when resolving the instance expression of a field expression.
  61                 DisableFlowAnalysis     = 8,
  62
  63                 // Set if this is resolving the first part of a MemberAccess.
  64                 Intermediate            = 16,
  65
  66                 // Disable control flow analysis _of struct_ while resolving the expression.
  67                 // This is used when resolving the instance expression of a field expression.
  68                 DisableStructFlowAnalysis       = 32,
  69
  70         }
  71
  72         //
  73         // This is just as a hint to AddressOf of what will be done with the
  74         // address.
  75         [Flags]
  76         public enum AddressOp {
  77                 Store = 1,
  78                 Load  = 2,
  79                 LoadStore = 3
  80         };
  81
  82         /// <summary>
  83         ///   This interface is implemented by variables
  84         /// </summary>
  85         public interface IMemoryLocation {
  86                 /// <summary>
  87                 ///   The AddressOf method should generate code that loads
  88                 ///   the address of the object and leaves it on the stack.
  89                 ///
  90                 ///   The `mode' argument is used to notify the expression
  91                 ///   of whether this will be used to read from the address or
  92                 ///   write to the address.
  93                 ///
  94                 ///   This is just a hint that can be used to provide good error
  95                 ///   reporting, and should have no other side effects.
  96                 /// </summary>
  97                 void AddressOf (EmitContext ec, AddressOp mode);
  98         }
  99
 100         // TODO: Rename to something meaningful, this is flow-analysis interface only
 101         public interface IVariable {
 102                 VariableInfo VariableInfo { get; }
 103                 bool IsFixed { get; }
 104         }
 105
 106         /// <remarks>
 107         ///   Base class for expressions
 108         /// </remarks>
 109         public abstract class Expression {
 110                 public ExprClass eclass;
 111                 protected Type type;
 112                 protected Location loc;
 113
 114                 public Type Type {
 115                         get { return type; }
 116                         set { type = value; }
 117                 }
 118
 119                 public virtual Location Location {
 120                         get { return loc; }
 121                 }
 122
 123                 /// <summary>
 124                 ///   Utility wrapper routine for Error, just to beautify the code
 125                 /// </summary>
 126                 public void Error (int error, string s)
 127                 {
 128                         Report.Error (error, loc, s);
 129                 }
 130
 131                 // Not nice but we have broken hierarchy.
 132                 public virtual void CheckMarshalByRefAccess (EmitContext ec)
 133                 {
 134                 }
 135
 136                 public virtual bool GetAttributableValue (Type value_type, out object value)
 137                 {
 138                         Attribute.Error_AttributeArgumentNotValid (loc);
 139                         value = null;
 140                         return false;
 141                 }
 142
 143                 public virtual string GetSignatureForError ()
 144                 {
 145                         return TypeManager.CSharpName (type);
 146                 }
 147
 148                 public static bool IsAccessorAccessible (Type invocation_type, MethodInfo mi, out bool must_do_cs1540_check)
 149                 {
 150                         MethodAttributes ma = mi.Attributes & MethodAttributes.MemberAccessMask;
 151
 152                         must_do_cs1540_check = false; // by default we do not check for this
 153
 154                         if (ma == MethodAttributes.Public)
 155                                 return true;
 156
 157                         //
 158                         // If only accessible to the current class or children
 159                         //
 160                         if (ma == MethodAttributes.Private)
 161                                 return TypeManager.IsPrivateAccessible (invocation_type, mi.DeclaringType) ||
 162                                         TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType);
 163
 164                         if (TypeManager.IsThisOrFriendAssembly (mi.DeclaringType.Assembly)) {
 165                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamORAssem)
 166                                         return true;
 167                         } else {
 168                                 if (ma == MethodAttributes.Assembly || ma == MethodAttributes.FamANDAssem)
 169                                         return false;
 170                         }
 171
 172                         // Family and FamANDAssem require that we derive.
 173                         // FamORAssem requires that we derive if in different assemblies.
 174                         if (!TypeManager.IsNestedFamilyAccessible (invocation_type, mi.DeclaringType))
 175                                 return false;
 176
 177                         if (!TypeManager.IsNestedChildOf (invocation_type, mi.DeclaringType))
 178                                 must_do_cs1540_check = true;
 179
 180                         return true;
 181                 }
 182
 183                 public virtual bool IsNull {
 184                         get {
 185                                 return false;
 186                         }
 187                 }
 188
 189                 /// <summary>
 190                 ///   Performs semantic analysis on the Expression
 191                 /// </summary>
 192                 ///
 193                 /// <remarks>
 194                 ///   The Resolve method is invoked to perform the semantic analysis
 195                 ///   on the node.
 196                 ///
 197                 ///   The return value is an expression (it can be the
 198                 ///   same expression in some cases) or a new
 199                 ///   expression that better represents this node.
 200                 ///
 201                 ///   For example, optimizations of Unary (LiteralInt)
 202                 ///   would return a new LiteralInt with a negated
 203                 ///   value.
 204                 ///
 205                 ///   If there is an error during semantic analysis,
 206                 ///   then an error should be reported (using Report)
 207                 ///   and a null value should be returned.
 208                 ///
 209                 ///   There are two side effects expected from calling
 210                 ///   Resolve(): the the field variable "eclass" should
 211                 ///   be set to any value of the enumeration
 212                 ///   `ExprClass' and the type variable should be set
 213                 ///   to a valid type (this is the type of the
 214                 ///   expression).
 215                 /// </remarks>
 216                 public abstract Expression DoResolve (EmitContext ec);
 217
 218                 public virtual Expression DoResolveLValue (EmitContext ec, Expression right_side)
 219                 {
 220                         return null;
 221                 }
 222
 223                 //
 224                 // This is used if the expression should be resolved as a type or namespace name.
 225                 // the default implementation fails.
 226                 //
 227                 public virtual FullNamedExpression ResolveAsTypeStep (IResolveContext rc,  bool silent)
 228                 {
 229                         if (!silent) {
 230                                 Expression e = this;
 231                                 EmitContext ec = rc as EmitContext;
 232                                 if (ec != null)
 233                                         e = e.Resolve (ec);
 234                                 if (e != null)
 235                                         e.Error_UnexpectedKind (ResolveFlags.Type, loc);
 236                         }
 237                         return null;
 238                 }
 239
 240                 //
 241                 // C# 3.0 introduced contextual keywords (var) which behaves like a type if type with
 242                 // same name exists or as a keyword when no type was found
 243                 //
 244                 public virtual TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
 245                 {
 246                         return ResolveAsTypeTerminal (rc, silent);
 247                 }
 248
 249                 //
 250                 // This is used to resolve the expression as a type, a null
 251                 // value will be returned if the expression is not a type
 252                 // reference
 253                 //
 254                 public virtual TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
 255                 {
 256                         TypeExpr te = ResolveAsBaseTerminal (ec, silent);
 257                         if (te == null)
 258                                 return null;
 259
 260                         if (!silent) { // && !(te is TypeParameterExpr)) {
 261                                 ObsoleteAttribute obsolete_attr = AttributeTester.GetObsoleteAttribute (te.Type);
 262                                 if (obsolete_attr != null && !ec.IsInObsoleteScope) {
 263                                         AttributeTester.Report_ObsoleteMessage (obsolete_attr, te.GetSignatureForError (), Location);
 264                                 }
 265                         }
 266
 267                         // Constrains don't need to be checked for overrides
 268                         GenericMethod gm = ec.GenericDeclContainer as GenericMethod;
 269                         if (gm != null && (gm.ModFlags & Modifiers.OVERRIDE) != 0) {
 270                                 te.loc = loc;
 271                                 return te;
 272                         }
 273
 274                         ConstructedType ct = te as ConstructedType;
 275                         if ((ct != null) && !ct.CheckConstraints (ec))
 276                                 return null;
 277
 278                         return te;
 279                 }
 280
 281                 public TypeExpr ResolveAsBaseTerminal (IResolveContext ec, bool silent)
 282                 {
 283                         int errors = Report.Errors;
 284
 285                         FullNamedExpression fne = ResolveAsTypeStep (ec, silent);
 286
 287                         if (fne == null)
 288                                 return null;
 289
 290                         if (fne.eclass != ExprClass.Type) {
 291                                 if (!silent && errors == Report.Errors)
 292                                         fne.Error_UnexpectedKind (null, "type", loc);
 293                                 return null;
 294                         }
 295
 296                         TypeExpr te = fne as TypeExpr;
 297
 298                         if (!te.CheckAccessLevel (ec.DeclContainer)) {
 299                                 Report.SymbolRelatedToPreviousError (te.Type);
 300                                 ErrorIsInaccesible (loc, TypeManager.CSharpName (te.Type));
 301                                 return null;
 302                         }
 303
 304                         te.loc = loc;
 305                         return te;
 306                 }
 307
 308                 public static void ErrorIsInaccesible (Location loc, string name)
 309                 {
 310                         Report.Error (122, loc, "`{0}' is inaccessible due to its protection level", name);
 311                 }
 312
 313                 protected static void Error_CannotAccessProtected (Location loc, MemberInfo m, Type qualifier, Type container)
 314                 {
 315                         Report.Error (1540, loc, "Cannot access protected member `{0}' via a qualifier of type `{1}'."
 316                                 + " The qualifier must be of type `{2}' or derived from it",
 317                                 TypeManager.GetFullNameSignature (m),
 318                                 TypeManager.CSharpName (qualifier),
 319                                 TypeManager.CSharpName (container));
 320
 321                 }
 322
 323                 public static void Error_InvalidExpressionStatement (Location loc)
 324                 {
 325                         Report.Error (201, loc, "Only assignment, call, increment, decrement, and new object " +
 326                                        "expressions can be used as a statement");
 327                 }
 328
 329                 public void Error_InvalidExpressionStatement ()
 330                 {
 331                         Error_InvalidExpressionStatement (loc);
 332                 }
 333
 334                 protected void Error_CannotAssign (string to, string roContext)
 335                 {
 336                         Report.Error (1656, loc, "Cannot assign to `{0}' because it is a `{1}'",
 337                                 to, roContext);
 338                 }
 339
 340                 public static void Error_VoidInvalidInTheContext (Location loc)
 341                 {
 342                         Report.Error (1547, loc, "Keyword `void' cannot be used in this context");
 343                 }
 344
 345                 public virtual void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
 346                 {
 347                         // The error was already reported as CS1660
 348                         if (type == TypeManager.anonymous_method_type)
 349                                 return;
 350
 351                         if (TypeManager.IsGenericParameter (Type) && TypeManager.IsGenericParameter (target) && type.Name == target.Name) {
 352 #if GMCS_SOURCE
 353                                 string sig1 = type.DeclaringMethod == null ?
 354                                         TypeManager.CSharpName (type.DeclaringType) :
 355                                         TypeManager.CSharpSignature (type.DeclaringMethod);
 356                                 string sig2 = target.DeclaringMethod == null ?
 357                                         TypeManager.CSharpName (target.DeclaringType) :
 358                                         TypeManager.CSharpSignature (target.DeclaringMethod);
 359                                 Report.ExtraInformation (loc,
 360                                         String.Format (
 361                                                 "The generic parameter `{0}' of `{1}' cannot be converted to the generic parameter `{0}' of `{2}' (in the previous ",
 362                                                 Type.Name, sig1, sig2));
 363 #endif
 364                         } else if (Type.FullName == target.FullName){
 365                                 Report.ExtraInformation (loc,
 366                                         String.Format (
 367                                         "The type `{0}' has two conflicting definitions, one comes from `{1}' and the other from `{2}' (in the previous ",
 368                                         Type.FullName, Type.Assembly.FullName, target.Assembly.FullName));
 369                         }
 370
 371                         if (expl) {
 372                                 Report.Error (30, loc, "Cannot convert type `{0}' to `{1}'",
 373                                         TypeManager.CSharpName (type), TypeManager.CSharpName (target));
 374                                 return;
 375                         }
 376
 377                         Expression e = (this is EnumConstant) ? ((EnumConstant)this).Child : this;
 378                         bool b = Convert.ExplicitNumericConversion (e, target) != null;
 379
 380                         if (b ||
 381                             Convert.ExplicitReferenceConversionExists (Type, target) ||
 382                             Convert.ExplicitUnsafe (e, target) != null ||
 383                             (ec != null && Convert.ExplicitUserConversion (ec, this, target, Location.Null) != null))
 384                         {
 385                                 Report.Error (266, loc, "Cannot implicitly convert type `{0}' to `{1}'. " +
 386                                               "An explicit conversion exists (are you missing a cast?)",
 387                                         TypeManager.CSharpName (Type), TypeManager.CSharpName (target));
 388                                 return;
 389                         }
 390
 391                         Report.Error (29, loc, "Cannot implicitly convert type `{0}' to `{1}'",
 392                                 TypeManager.CSharpName (type),
 393                                 TypeManager.CSharpName (target));
 394                 }
 395
 396                 protected void Error_VariableIsUsedBeforeItIsDeclared (string name)
 397                 {
 398                         Report.Error (841, loc, "The variable `{0}' cannot be used before it is declared",
 399                                 name);
 400                 }
 401
 402                 protected virtual void Error_TypeDoesNotContainDefinition (Type type, string name)
 403                 {
 404                         Error_TypeDoesNotContainDefinition (loc, type, name);
 405                 }
 406
 407                 public static void Error_TypeDoesNotContainDefinition (Location loc, Type type, string name)
 408                 {
 409                         Report.SymbolRelatedToPreviousError (type);
 410                         Report.Error (117, loc, "`{0}' does not contain a definition for `{1}'",
 411                                 TypeManager.CSharpName (type), name);
 412                 }
 413
 414                 protected static void Error_ValueAssignment (Location loc)
 415                 {
 416                         Report.Error (131, loc, "The left-hand side of an assignment must be a variable, a property or an indexer");
 417                 }
 418
 419                 ResolveFlags ExprClassToResolveFlags
 420                 {
 421                         get {
 422                                 switch (eclass) {
 423                                         case ExprClass.Type:
 424                                         case ExprClass.Namespace:
 425                                                 return ResolveFlags.Type;
 426
 427                                         case ExprClass.MethodGroup:
 428                                                 return ResolveFlags.MethodGroup;
 429
 430                                         case ExprClass.Value:
 431                                         case ExprClass.Variable:
 432                                         case ExprClass.PropertyAccess:
 433                                         case ExprClass.EventAccess:
 434                                         case ExprClass.IndexerAccess:
 435                                                 return ResolveFlags.VariableOrValue;
 436
 437                                         default:
 438                                                 throw new InternalErrorException (loc.ToString () + " " +  GetType () + " ExprClass is Invalid after resolve");
 439                                 }
 440                         }
 441                 }
 442
 443                 /// <summary>
 444                 ///   Resolves an expression and performs semantic analysis on it.
 445                 /// </summary>
 446                 ///
 447                 /// <remarks>
 448                 ///   Currently Resolve wraps DoResolve to perform sanity
 449                 ///   checking and assertion checking on what we expect from Resolve.
 450                 /// </remarks>
 451                 public Expression Resolve (EmitContext ec, ResolveFlags flags)
 452                 {
 453                         if ((flags & ResolveFlags.MaskExprClass) == ResolveFlags.Type)
 454                                 return ResolveAsTypeStep (ec, false);
 455
 456                         bool do_flow_analysis = ec.DoFlowAnalysis;
 457                         bool omit_struct_analysis = ec.OmitStructFlowAnalysis;
 458                         if ((flags & ResolveFlags.DisableFlowAnalysis) != 0)
 459                                 do_flow_analysis = false;
 460                         if ((flags & ResolveFlags.DisableStructFlowAnalysis) != 0)
 461                                 omit_struct_analysis = true;
 462
 463                         Expression e;
 464                         using (ec.WithFlowAnalysis (do_flow_analysis, omit_struct_analysis)) {
 465                                 if (this is SimpleName) {
 466                                         bool intermediate = (flags & ResolveFlags.Intermediate) == ResolveFlags.Intermediate;
 467                                         e = ((SimpleName) this).DoResolve (ec, intermediate);
 468                                 } else {
 469                                         e = DoResolve (ec);
 470                                 }
 471                         }
 472
 473                         if (e == null)
 474                                 return null;
 475
 476                         if ((flags & e.ExprClassToResolveFlags) == 0) {
 477                                 e.Error_UnexpectedKind (flags, loc);
 478                                 return null;
 479                         }
 480
 481                         if (e.type == null && !(e is Namespace)) {
 482                                 throw new Exception (
 483                                         "Expression " + e.GetType () +
 484                                         " did not set its type after Resolve\n" +
 485                                         "called from: " + this.GetType ());
 486                         }
 487
 488                         return e;
 489                 }
 490
 491                 /// <summary>
 492                 ///   Resolves an expression and performs semantic analysis on it.
 493                 /// </summary>
 494                 public Expression Resolve (EmitContext ec)
 495                 {
 496                         Expression e = Resolve (ec, ResolveFlags.VariableOrValue | ResolveFlags.MethodGroup);
 497
 498                         if (e != null && e.eclass == ExprClass.MethodGroup && RootContext.Version == LanguageVersion.ISO_1) {
 499                                 ((MethodGroupExpr) e).ReportUsageError ();
 500                                 return null;
 501                         }
 502                         return e;
 503                 }
 504
 505                 public Constant ResolveAsConstant (EmitContext ec, MemberCore mc)
 506                 {
 507                         Expression e = Resolve (ec);
 508                         if (e == null)
 509                                 return null;
 510
 511                         Constant c = e as Constant;
 512                         if (c != null)
 513                                 return c;
 514
 515                         Const.Error_ExpressionMustBeConstant (loc, mc.GetSignatureForError ());
 516                         return null;
 517                 }
 518
 519                 /// <summary>
 520                 ///   Resolves an expression for LValue assignment
 521                 /// </summary>
 522                 ///
 523                 /// <remarks>
 524                 ///   Currently ResolveLValue wraps DoResolveLValue to perform sanity
 525                 ///   checking and assertion checking on what we expect from Resolve
 526                 /// </remarks>
 527                 public Expression ResolveLValue (EmitContext ec, Expression right_side, Location loc)
 528                 {
 529                         int errors = Report.Errors;
 530                         bool out_access = right_side == EmptyExpression.OutAccess;
 531
 532                         Expression e = DoResolveLValue (ec, right_side);
 533
 534                         if (e != null && out_access && !(e is IMemoryLocation)) {
 535                                 // FIXME: There's no problem with correctness, the 'Expr = null' handles that.
 536                                 //        Enabling this 'throw' will "only" result in deleting useless code elsewhere,
 537
 538                                 //throw new InternalErrorException ("ResolveLValue didn't return an IMemoryLocation: " +
 539                                 //                                e.GetType () + " " + e.GetSignatureForError ());
 540                                 e = null;
 541                         }
 542
 543                         if (e == null) {
 544                                 if (errors == Report.Errors) {
 545                                         if (out_access)
 546                                                 Report.Error (1510, loc, "A ref or out argument must be an assignable variable");
 547                                         else
 548                                                 Error_ValueAssignment (loc);
 549                                 }
 550                                 return null;
 551                         }
 552
 553                         if (e.eclass == ExprClass.Invalid)
 554                                 throw new Exception ("Expression " + e + " ExprClass is Invalid after resolve");
 555
 556                         if (e.eclass == ExprClass.MethodGroup) {
 557                                 ((MethodGroupExpr) e).ReportUsageError ();
 558                                 return null;
 559                         }
 560
 561                         if ((e.type == null) && !(e is ConstructedType))
 562                                 throw new Exception ("Expression " + e + " did not set its type after Resolve");
 563
 564                         return e;
 565                 }
 566
 567                 /// <summary>
 568                 ///   Emits the code for the expression
 569                 /// </summary>
 570                 ///
 571                 /// <remarks>
 572                 ///   The Emit method is invoked to generate the code
 573                 ///   for the expression.
 574                 /// </remarks>
 575                 public abstract void Emit (EmitContext ec);
 576
 577                 // Emit code to branch to @target if this expression is equivalent to @on_true.
 578                 // The default implementation is to emit the value, and then emit a brtrue or brfalse.
 579                 // Subclasses can provide more efficient implementations, but those MUST be equivalent,
 580                 // including the use of conditional branches.  Note also that a branch MUST be emitted
 581                 public virtual void EmitBranchable (EmitContext ec, Label target, bool on_true)
 582                 {
 583                         Emit (ec);
 584                         ec.ig.Emit (on_true ? OpCodes.Brtrue : OpCodes.Brfalse, target);
 585                 }
 586
 587                 // Emit this expression for its side effects, not for its value.
 588                 // The default implementation is to emit the value, and then throw it away.
 589                 // Subclasses can provide more efficient implementations, but those MUST be equivalent
 590                 public virtual void EmitSideEffect (EmitContext ec)
 591                 {
 592                         Emit (ec);
 593                         ec.ig.Emit (OpCodes.Pop);
 594                 }
 595
 596                 /// <summary>
 597                 ///   Protected constructor.  Only derivate types should
 598                 ///   be able to be created
 599                 /// </summary>
 600
 601                 protected Expression ()
 602                 {
 603                         eclass = ExprClass.Invalid;
 604                         type = null;
 605                 }
 606
 607                 /// <summary>
 608                 ///   Returns a fully formed expression after a MemberLookup
 609                 /// </summary>
 610                 ///
 611                 public static Expression ExprClassFromMemberInfo (Type container_type, MemberInfo mi, Location loc)
 612                 {
 613                         if (mi is EventInfo)
 614                                 return new EventExpr ((EventInfo) mi, loc);
 615                         else if (mi is FieldInfo) {
 616                                 FieldInfo fi = (FieldInfo) mi;
 617                                 if (fi.IsLiteral || (fi.IsInitOnly && fi.FieldType == TypeManager.decimal_type))
 618                                         return new ConstantExpr (fi, loc);
 619                                 return new FieldExpr (fi, loc);
 620                         } else if (mi is PropertyInfo)
 621                                 return new PropertyExpr (container_type, (PropertyInfo) mi, loc);
 622                         else if (mi is Type) {
 623                                 return new TypeExpression ((System.Type) mi, loc);
 624                         }
 625
 626                         return null;
 627                 }
 628
 629                 protected static ArrayList almost_matched_members = new ArrayList (4);
 630
 631                 //
 632                 // FIXME: Probably implement a cache for (t,name,current_access_set)?
 633                 //
 634                 // This code could use some optimizations, but we need to do some
 635                 // measurements.  For example, we could use a delegate to `flag' when
 636                 // something can not any longer be a method-group (because it is something
 637                 // else).
 638                 //
 639                 // Return values:
 640                 //     If the return value is an Array, then it is an array of
 641                 //     MethodBases
 642                 //
 643                 //     If the return value is an MemberInfo, it is anything, but a Method
 644                 //
 645                 //     null on error.
 646                 //
 647                 // FIXME: When calling MemberLookup inside an `Invocation', we should pass
 648                 // the arguments here and have MemberLookup return only the methods that
 649                 // match the argument count/type, unlike we are doing now (we delay this
 650                 // decision).
 651                 //
 652                 // This is so we can catch correctly attempts to invoke instance methods
 653                 // from a static body (scan for error 120 in ResolveSimpleName).
 654                 //
 655                 //
 656                 // FIXME: Potential optimization, have a static ArrayList
 657                 //
 658
 659                 public static Expression MemberLookup (Type container_type, Type queried_type, string name,
 660                                                        MemberTypes mt, BindingFlags bf, Location loc)
 661                 {
 662                         return MemberLookup (container_type, null, queried_type, name, mt, bf, loc);
 663                 }
 664
 665                 //
 666                 // Lookup type `queried_type' for code in class `container_type' with a qualifier of
 667                 // `qualifier_type' or null to lookup members in the current class.
 668                 //
 669
 670                 public static Expression MemberLookup (Type container_type,
 671                                                        Type qualifier_type, Type queried_type,
 672                                                        string name, MemberTypes mt,
 673                                                        BindingFlags bf, Location loc)
 674                 {
 675                         almost_matched_members.Clear ();
 676
 677                         MemberInfo [] mi = TypeManager.MemberLookup (container_type, qualifier_type,
 678                                                                      queried_type, mt, bf, name, almost_matched_members);
 679
 680                         if (mi == null)
 681                                 return null;
 682
 683                         if (mi.Length > 1) {
 684                                 bool is_interface = qualifier_type != null && qualifier_type.IsInterface;
 685                                 ArrayList methods = new ArrayList (2);
 686                                 ArrayList non_methods = null;
 687
 688                                 foreach (MemberInfo m in mi) {
 689                                         if (m is MethodBase) {
 690                                                 methods.Add (m);
 691                                                 continue;
 692                                         }
 693
 694                                         if (non_methods == null) {
 695                                                 non_methods = new ArrayList (2);
 696                                                 non_methods.Add (m);
 697                                                 continue;
 698                                         }
 699
 700                                         foreach (MemberInfo n_m in non_methods) {
 701                                                 if (m.DeclaringType.IsInterface && TypeManager.ImplementsInterface (m.DeclaringType, n_m.DeclaringType))
 702                                                         continue;
 703
 704                                                 Report.SymbolRelatedToPreviousError (m);
 705                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 706                                                         TypeManager.GetFullNameSignature (m), TypeManager.GetFullNameSignature (n_m));
 707                                                 return null;
 708                                         }
 709                                 }
 710
 711                                 if (methods.Count == 0)
 712                                         return ExprClassFromMemberInfo (container_type, (MemberInfo)non_methods [0], loc);
 713
 714                                 if (non_methods != null) {
 715                                         MethodBase method = (MethodBase) methods [0];
 716                                         MemberInfo non_method = (MemberInfo) non_methods [0];
 717                                         if (method.DeclaringType == non_method.DeclaringType) {
 718                                                 // Cannot happen with C# code, but is valid in IL
 719                                                 Report.SymbolRelatedToPreviousError (method);
 720                                                 Report.SymbolRelatedToPreviousError (non_method);
 721                                                 Report.Error (229, loc, "Ambiguity between `{0}' and `{1}'",
 722                                                               TypeManager.GetFullNameSignature (non_method),
 723                                                               TypeManager.CSharpSignature (method));
 724                                                 return null;
 725                                         }
 726
 727                                         if (is_interface) {
 728                                                 Report.SymbolRelatedToPreviousError (method);
 729                                                 Report.SymbolRelatedToPreviousError (non_method);
 730                                                 Report.Warning (467, 2, loc, "Ambiguity between method `{0}' and non-method `{1}'. Using method `{0}'",
 731                                                                 TypeManager.CSharpSignature (method), TypeManager.GetFullNameSignature (non_method));
 732                                         }
 733                                 }
 734
 735                                 return new MethodGroupExpr (methods, queried_type, loc);
 736                         }
 737
 738                         if (mi [0] is MethodBase)
 739                                 return new MethodGroupExpr (mi, queried_type, loc);
 740
 741                         return ExprClassFromMemberInfo (container_type, mi [0], loc);
 742                 }
 743
 744                 public const MemberTypes AllMemberTypes =
 745                         MemberTypes.Constructor |
 746                         MemberTypes.Event       |
 747                         MemberTypes.Field       |
 748                         MemberTypes.Method      |
 749                         MemberTypes.NestedType  |
 750                         MemberTypes.Property;
 751
 752                 public const BindingFlags AllBindingFlags =
 753                         BindingFlags.Public |
 754                         BindingFlags.Static |
 755                         BindingFlags.Instance;
 756
 757                 public static Expression MemberLookup (Type container_type, Type queried_type,
 758                                                        string name, Location loc)
 759                 {
 760                         return MemberLookup (container_type, null, queried_type, name,
 761                                              AllMemberTypes, AllBindingFlags, loc);
 762                 }
 763
 764                 public static Expression MemberLookup (Type container_type, Type qualifier_type,
 765                                                        Type queried_type, string name, Location loc)
 766                 {
 767                         return MemberLookup (container_type, qualifier_type, queried_type,
 768                                              name, AllMemberTypes, AllBindingFlags, loc);
 769                 }
 770
 771                 public static MethodGroupExpr MethodLookup (Type container_type, Type queried_type,
 772                                                        string name, Location loc)
 773                 {
 774                         return (MethodGroupExpr)MemberLookup (container_type, null, queried_type, name,
 775                                              MemberTypes.Method, AllBindingFlags, loc);
 776                 }
 777
 778                 /// <summary>
 779                 ///   This is a wrapper for MemberLookup that is not used to "probe", but
 780                 ///   to find a final definition.  If the final definition is not found, we
 781                 ///   look for private members and display a useful debugging message if we
 782                 ///   find it.
 783                 /// </summary>
 784                 protected Expression MemberLookupFinal (EmitContext ec, Type qualifier_type,
 785                                                             Type queried_type, string name,
 786                                                             MemberTypes mt, BindingFlags bf,
 787                                                             Location loc)
 788                 {
 789                         Expression e;
 790
 791                         int errors = Report.Errors;
 792
 793                         e = MemberLookup (ec.ContainerType, qualifier_type, queried_type, name, mt, bf, loc);
 794
 795                         if (e != null || errors != Report.Errors)
 796                                 return e;
 797
 798                         // No errors were reported by MemberLookup, but there was an error.
 799                         return Error_MemberLookupFailed (ec.ContainerType, qualifier_type, queried_type,
 800                                         name, null, mt, bf);
 801                 }
 802
 803                 protected virtual Expression Error_MemberLookupFailed (Type container_type, Type qualifier_type,
 804                                                        Type queried_type, string name, string class_name,
 805                                                            MemberTypes mt, BindingFlags bf)
 806                 {
 807                         if (almost_matched_members.Count != 0) {
 808                                 for (int i = 0; i < almost_matched_members.Count; ++i) {
 809                                         MemberInfo m = (MemberInfo) almost_matched_members [i];
 810                                         for (int j = 0; j < i; ++j) {
 811                                                 if (m == almost_matched_members [j]) {
 812                                                         m = null;
 813                                                         break;
 814                                                 }
 815                                         }
 816                                         if (m == null)
 817                                                 continue;
 818
 819                                         Type declaring_type = m.DeclaringType;
 820
 821                                         Report.SymbolRelatedToPreviousError (m);
 822                                         if (qualifier_type == null) {
 823                                                 Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
 824                                                               TypeManager.CSharpName (m.DeclaringType),
 825                                                               TypeManager.CSharpName (container_type));
 826
 827                                         } else if (qualifier_type != container_type &&
 828                                                    TypeManager.IsNestedFamilyAccessible (container_type, declaring_type)) {
 829                                                 // Although a derived class can access protected members of
 830                                                 // its base class it cannot do so through an instance of the
 831                                                 // base class (CS1540).  If the qualifier_type is a base of the
 832                                                 // ec.ContainerType and the lookup succeeds with the latter one,
 833                                                 // then we are in this situation.
 834                                                 Error_CannotAccessProtected (loc, m, qualifier_type, container_type);
 835                                         } else {
 836                                                 ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (m));
 837                                         }
 838                                 }
 839                                 almost_matched_members.Clear ();
 840                                 return null;
 841                         }
 842
 843                         MemberInfo[] lookup = null;
 844                         if (queried_type == null) {
 845                                 class_name = "global::";
 846                         } else {
 847                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 848                                         mt, (bf & ~BindingFlags.Public) | BindingFlags.NonPublic,
 849                                         name, null);
 850
 851                                 if (lookup != null) {
 852                                         Report.SymbolRelatedToPreviousError (lookup [0]);
 853                                         ErrorIsInaccesible (loc, TypeManager.GetFullNameSignature (lookup [0]));
 854                                         return Error_MemberLookupFailed (lookup);
 855                                 }
 856
 857                                 lookup = TypeManager.MemberLookup (queried_type, null, queried_type,
 858                                         AllMemberTypes, AllBindingFlags | BindingFlags.NonPublic,
 859                                         name, null);
 860                         }
 861
 862                         if (lookup == null) {
 863                                 if (class_name != null) {
 864                                         Report.Error (103, loc, "The name `{0}' does not exist in the current context",
 865                                                 name);
 866                                 } else {
 867                                         Error_TypeDoesNotContainDefinition (queried_type, name);
 868                                 }
 869                                 return null;
 870                         }
 871
 872                         if (TypeManager.MemberLookup (queried_type, null, queried_type,
 873                                                       AllMemberTypes, AllBindingFlags |
 874                                                       BindingFlags.NonPublic, name, null) == null) {
 875                                 if ((lookup.Length == 1) && (lookup [0] is Type)) {
 876                                         Type t = (Type) lookup [0];
 877
 878                                         Report.Error (305, loc,
 879                                                       "Using the generic type `{0}' " +
 880                                                       "requires {1} type arguments",
 881                                                       TypeManager.CSharpName (t),
 882                                                       TypeManager.GetNumberOfTypeArguments (t).ToString ());
 883                                         return null;
 884                                 }
 885                         }
 886
 887                         return Error_MemberLookupFailed (lookup);
 888                 }
 889
 890                 protected virtual Expression Error_MemberLookupFailed (MemberInfo[] members)
 891                 {
 892                         for (int i = 0; i < members.Length; ++i) {
 893                                 if (!(members [i] is MethodBase))
 894                                         return null;
 895                         }
 896
 897                         // By default propagate the closest candidates upwards
 898                         return new MethodGroupExpr (members, type, loc);
 899                 }
 900
 901                 protected virtual void Error_NegativeArrayIndex (Location loc)
 902                 {
 903                         throw new NotImplementedException ();
 904                 }
 905
 906                 protected void Error_PointerInsideExpressionTree ()
 907                 {
 908                         Report.Error (1944, loc, "An expression tree cannot contain an unsafe pointer operation");
 909                 }
 910
 911                 /// <summary>
 912                 ///   Returns an expression that can be used to invoke operator true
 913                 ///   on the expression if it exists.
 914                 /// </summary>
 915                 static public Expression GetOperatorTrue (EmitContext ec, Expression e, Location loc)
 916                 {
 917                         return GetOperatorTrueOrFalse (ec, e, true, loc);
 918                 }
 919
 920                 /// <summary>
 921                 ///   Returns an expression that can be used to invoke operator false
 922                 ///   on the expression if it exists.
 923                 /// </summary>
 924                 static public Expression GetOperatorFalse (EmitContext ec, Expression e, Location loc)
 925                 {
 926                         return GetOperatorTrueOrFalse (ec, e, false, loc);
 927                 }
 928
 929                 static Expression GetOperatorTrueOrFalse (EmitContext ec, Expression e, bool is_true, Location loc)
 930                 {
 931                         MethodGroupExpr operator_group;
 932                         string mname = Operator.GetMetadataName (is_true ? Operator.OpType.True : Operator.OpType.False);
 933                         operator_group = MethodLookup (ec.ContainerType, e.Type, mname, loc) as MethodGroupExpr;
 934                         if (operator_group == null)
 935                                 return null;
 936
 937                         ArrayList arguments = new ArrayList (1);
 938                         arguments.Add (new Argument (e, Argument.AType.Expression));
 939                         operator_group = operator_group.OverloadResolve (
 940                                 ec, ref arguments, false, loc);
 941
 942                         if (operator_group == null)
 943                                 return null;
 944
 945                         return new UserOperatorCall (operator_group, arguments, null, loc);
 946                 }
 947
 948                 /// <summary>
 949                 ///   Resolves the expression `e' into a boolean expression: either through
 950                 ///   an implicit conversion, or through an `operator true' invocation
 951                 /// </summary>
 952                 public static Expression ResolveBoolean (EmitContext ec, Expression e, Location loc)
 953                 {
 954                         e = e.Resolve (ec);
 955                         if (e == null)
 956                                 return null;
 957
 958                         if (e.Type == TypeManager.bool_type)
 959                                 return e;
 960
 961                         Expression converted = Convert.ImplicitConversion (ec, e, TypeManager.bool_type, Location.Null);
 962
 963                         if (converted != null)
 964                                 return converted;
 965
 966                         //
 967                         // If no implicit conversion to bool exists, try using `operator true'
 968                         //
 969                         converted = Expression.GetOperatorTrue (ec, e, loc);
 970                         if (converted == null){
 971                                 e.Error_ValueCannotBeConverted (ec, loc, TypeManager.bool_type, false);
 972                                 return null;
 973                         }
 974                         return converted;
 975                 }
 976
 977                 public virtual string ExprClassName
 978                 {
 979                         get {
 980                                 switch (eclass){
 981                                         case ExprClass.Invalid:
 982                                                 return "Invalid";
 983                                         case ExprClass.Value:
 984                                                 return "value";
 985                                         case ExprClass.Variable:
 986                                                 return "variable";
 987                                         case ExprClass.Namespace:
 988                                                 return "namespace";
 989                                         case ExprClass.Type:
 990                                                 return "type";
 991                                         case ExprClass.MethodGroup:
 992                                                 return "method group";
 993                                         case ExprClass.PropertyAccess:
 994                                                 return "property access";
 995                                         case ExprClass.EventAccess:
 996                                                 return "event access";
 997                                         case ExprClass.IndexerAccess:
 998                                                 return "indexer access";
 999                                         case ExprClass.Nothing:
1000                                                 return "null";
1001                                 }
1002                                 throw new Exception ("Should not happen");
1003                         }
1004                 }
1005
1006                 /// <summary>
1007                 ///   Reports that we were expecting `expr' to be of class `expected'
1008                 /// </summary>
1009                 public void Error_UnexpectedKind (DeclSpace ds, string expected, Location loc)
1010                 {
1011                         Error_UnexpectedKind (ds, expected, ExprClassName, loc);
1012                 }
1013
1014                 public void Error_UnexpectedKind (DeclSpace ds, string expected, string was, Location loc)
1015                 {
1016                         string name = GetSignatureForError ();
1017                         if (ds != null)
1018                                 name = ds.GetSignatureForError () + '.' + name;
1019
1020                         Report.Error (118, loc, "`{0}' is a `{1}' but a `{2}' was expected",
1021                               name, was, expected);
1022                 }
1023
1024                 public void Error_UnexpectedKind (ResolveFlags flags, Location loc)
1025                 {
1026                         string [] valid = new string [4];
1027                         int count = 0;
1028
1029                         if ((flags & ResolveFlags.VariableOrValue) != 0) {
1030                                 valid [count++] = "variable";
1031                                 valid [count++] = "value";
1032                         }
1033
1034                         if ((flags & ResolveFlags.Type) != 0)
1035                                 valid [count++] = "type";
1036
1037                         if ((flags & ResolveFlags.MethodGroup) != 0)
1038                                 valid [count++] = "method group";
1039
1040                         if (count == 0)
1041                                 valid [count++] = "unknown";
1042
1043                         StringBuilder sb = new StringBuilder (valid [0]);
1044                         for (int i = 1; i < count - 1; i++) {
1045                                 sb.Append ("', `");
1046                                 sb.Append (valid [i]);
1047                         }
1048                         if (count > 1) {
1049                                 sb.Append ("' or `");
1050                                 sb.Append (valid [count - 1]);
1051                         }
1052
1053                         Report.Error (119, loc,
1054                                 "Expression denotes a `{0}', where a `{1}' was expected", ExprClassName, sb.ToString ());
1055                 }
1056
1057                 public static void UnsafeError (Location loc)
1058                 {
1059                         Report.Error (214, loc, "Pointers and fixed size buffers may only be used in an unsafe context");
1060                 }
1061
1062                 //
1063                 // Load the object from the pointer.
1064                 //
1065                 public static void LoadFromPtr (ILGenerator ig, Type t)
1066                 {
1067                         if (t == TypeManager.int32_type)
1068                                 ig.Emit (OpCodes.Ldind_I4);
1069                         else if (t == TypeManager.uint32_type)
1070                                 ig.Emit (OpCodes.Ldind_U4);
1071                         else if (t == TypeManager.short_type)
1072                                 ig.Emit (OpCodes.Ldind_I2);
1073                         else if (t == TypeManager.ushort_type)
1074                                 ig.Emit (OpCodes.Ldind_U2);
1075                         else if (t == TypeManager.char_type)
1076                                 ig.Emit (OpCodes.Ldind_U2);
1077                         else if (t == TypeManager.byte_type)
1078                                 ig.Emit (OpCodes.Ldind_U1);
1079                         else if (t == TypeManager.sbyte_type)
1080                                 ig.Emit (OpCodes.Ldind_I1);
1081                         else if (t == TypeManager.uint64_type)
1082                                 ig.Emit (OpCodes.Ldind_I8);
1083                         else if (t == TypeManager.int64_type)
1084                                 ig.Emit (OpCodes.Ldind_I8);
1085                         else if (t == TypeManager.float_type)
1086                                 ig.Emit (OpCodes.Ldind_R4);
1087                         else if (t == TypeManager.double_type)
1088                                 ig.Emit (OpCodes.Ldind_R8);
1089                         else if (t == TypeManager.bool_type)
1090                                 ig.Emit (OpCodes.Ldind_I1);
1091                         else if (t == TypeManager.intptr_type)
1092                                 ig.Emit (OpCodes.Ldind_I);
1093                         else if (TypeManager.IsEnumType (t)) {
1094                                 if (t == TypeManager.enum_type)
1095                                         ig.Emit (OpCodes.Ldind_Ref);
1096                                 else
1097                                         LoadFromPtr (ig, TypeManager.GetEnumUnderlyingType (t));
1098                         } else if (t.IsValueType || TypeManager.IsGenericParameter (t))
1099                                 ig.Emit (OpCodes.Ldobj, t);
1100                         else if (t.IsPointer)
1101                                 ig.Emit (OpCodes.Ldind_I);
1102                         else
1103                                 ig.Emit (OpCodes.Ldind_Ref);
1104                 }
1105
1106                 //
1107                 // The stack contains the pointer and the value of type `type'
1108                 //
1109                 public static void StoreFromPtr (ILGenerator ig, Type type)
1110                 {
1111                         if (TypeManager.IsEnumType (type))
1112                                 type = TypeManager.GetEnumUnderlyingType (type);
1113                         if (type == TypeManager.int32_type || type == TypeManager.uint32_type)
1114                                 ig.Emit (OpCodes.Stind_I4);
1115                         else if (type == TypeManager.int64_type || type == TypeManager.uint64_type)
1116                                 ig.Emit (OpCodes.Stind_I8);
1117                         else if (type == TypeManager.char_type || type == TypeManager.short_type ||
1118                                  type == TypeManager.ushort_type)
1119                                 ig.Emit (OpCodes.Stind_I2);
1120                         else if (type == TypeManager.float_type)
1121                                 ig.Emit (OpCodes.Stind_R4);
1122                         else if (type == TypeManager.double_type)
1123                                 ig.Emit (OpCodes.Stind_R8);
1124                         else if (type == TypeManager.byte_type || type == TypeManager.sbyte_type ||
1125                                  type == TypeManager.bool_type)
1126                                 ig.Emit (OpCodes.Stind_I1);
1127                         else if (type == TypeManager.intptr_type)
1128                                 ig.Emit (OpCodes.Stind_I);
1129                         else if (type.IsValueType || TypeManager.IsGenericParameter (type))
1130                                 ig.Emit (OpCodes.Stobj, type);
1131                         else
1132                                 ig.Emit (OpCodes.Stind_Ref);
1133                 }
1134
1135                 //
1136                 // Returns the size of type `t' if known, otherwise, 0
1137                 //
1138                 public static int GetTypeSize (Type t)
1139                 {
1140                         t = TypeManager.TypeToCoreType (t);
1141                         if (t == TypeManager.int32_type ||
1142                             t == TypeManager.uint32_type ||
1143                             t == TypeManager.float_type)
1144                                 return 4;
1145                         else if (t == TypeManager.int64_type ||
1146                                  t == TypeManager.uint64_type ||
1147                                  t == TypeManager.double_type)
1148                                 return 8;
1149                         else if (t == TypeManager.byte_type ||
1150                                  t == TypeManager.sbyte_type ||
1151                                  t == TypeManager.bool_type)
1152                                 return 1;
1153                         else if (t == TypeManager.short_type ||
1154                                  t == TypeManager.char_type ||
1155                                  t == TypeManager.ushort_type)
1156                                 return 2;
1157                         else if (t == TypeManager.decimal_type)
1158                                 return 16;
1159                         else
1160                                 return 0;
1161                 }
1162
1163                 protected void Error_CannotCallAbstractBase (string name)
1164                 {
1165                         Report.Error (205, loc, "Cannot call an abstract base member `{0}'", name);
1166                 }
1167
1168                 protected void Error_CannotModifyIntermediateExpressionValue (EmitContext ec)
1169                 {
1170                         Report.SymbolRelatedToPreviousError (type);
1171                         if (ec.CurrentInitializerVariable != null) {
1172                                 Report.Error (1918, loc, "Members of a value type property `{0}' cannot be assigned with an object initializer",
1173                                         GetSignatureForError ());
1174                         } else {
1175                                 Report.Error (1612, loc, "Cannot modify a value type return value of `{0}'. Consider storing the value in a temporary variable",
1176                                         GetSignatureForError ());
1177                         }
1178                 }
1179
1180                 //
1181                 // Converts `source' to an int, uint, long or ulong.
1182                 //
1183                 public Expression ConvertExpressionToArrayIndex (EmitContext ec, Expression source)
1184                 {
1185                         Expression converted;
1186
1187                         using (ec.With (EmitContext.Flags.CheckState, true)) {
1188                                 converted = Convert.ImplicitConversion (ec, source, TypeManager.int32_type, source.loc);
1189                                 if (converted == null)
1190                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint32_type, source.loc);
1191                                 if (converted == null)
1192                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.int64_type, source.loc);
1193                                 if (converted == null)
1194                                         converted = Convert.ImplicitConversion (ec, source, TypeManager.uint64_type, source.loc);
1195
1196                                 if (converted == null) {
1197                                         source.Error_ValueCannotBeConverted (ec, source.loc, TypeManager.int32_type, false);
1198                                         return null;
1199                                 }
1200                         }
1201
1202                         //
1203                         // Only positive constants are allowed at compile time
1204                         //
1205                         Constant c = converted as Constant;
1206                         if (c != null) {
1207                                 if (c.IsNegative) {
1208                                         Error_NegativeArrayIndex (source.loc);
1209                                 }
1210                                 return c;
1211                         }
1212
1213                         return new ArrayIndexCast (converted).Resolve (ec);
1214                 }
1215
1216                 //
1217                 // Derived classes implement this method by cloning the fields that
1218                 // could become altered during the Resolve stage
1219                 //
1220                 // Only expressions that are created for the parser need to implement
1221                 // this.
1222                 //
1223                 protected virtual void CloneTo (CloneContext clonectx, Expression target)
1224                 {
1225                         throw new NotImplementedException (
1226                                 String.Format (
1227                                         "CloneTo not implemented for expression {0}", this.GetType ()));
1228                 }
1229
1230                 //
1231                 // Clones an expression created by the parser.
1232                 //
1233                 // We only support expressions created by the parser so far, not
1234                 // expressions that have been resolved (many more classes would need
1235                 // to implement CloneTo).
1236                 //
1237                 // This infrastructure is here merely for Lambda expressions which
1238                 // compile the same code using different type values for the same
1239                 // arguments to find the correct overload
1240                 //
1241                 public Expression Clone (CloneContext clonectx)
1242                 {
1243                         Expression cloned = (Expression) MemberwiseClone ();
1244                         CloneTo (clonectx, cloned);
1245
1246                         return cloned;
1247                 }
1248
1249                 //
1250                 // Implementation of expression to expression tree conversion
1251                 //
1252                 public abstract Expression CreateExpressionTree (EmitContext ec);
1253
1254                 protected Expression CreateExpressionFactoryCall (string name, ArrayList args)
1255                 {
1256                         return CreateExpressionFactoryCall (name, null, args, loc);
1257                 }
1258
1259                 protected Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args)
1260                 {
1261                         return CreateExpressionFactoryCall (name, typeArguments, args, loc);
1262                 }
1263
1264                 public static Expression CreateExpressionFactoryCall (string name, TypeArguments typeArguments, ArrayList args, Location loc)
1265                 {
1266                         return new Invocation (new MemberAccess (CreateExpressionTypeExpression (loc), name, typeArguments, loc), args);
1267                 }
1268
1269                 protected static TypeExpr CreateExpressionTypeExpression (Location loc)
1270                 {
1271                         TypeExpr texpr = TypeManager.expression_type_expr;
1272                         if (texpr == null) {
1273                                 Type t = TypeManager.CoreLookupType ("System.Linq.Expressions", "Expression", Kind.Class, true);
1274                                 if (t == null)
1275                                         return null;
1276
1277                                 TypeManager.expression_type_expr = texpr = new TypeExpression (t, Location.Null);
1278                         }
1279
1280                         return texpr;
1281                 }
1282         }
1283
1284         /// <summary>
1285         ///   This is just a base class for expressions that can
1286         ///   appear on statements (invocations, object creation,
1287         ///   assignments, post/pre increment and decrement).  The idea
1288         ///   being that they would support an extra Emition interface that
1289         ///   does not leave a result on the stack.
1290         /// </summary>
1291         public abstract class ExpressionStatement : Expression {
1292
1293                 public virtual ExpressionStatement ResolveStatement (EmitContext ec)
1294                 {
1295                         Expression e = Resolve (ec);
1296                         if (e == null)
1297                                 return null;
1298
1299                         ExpressionStatement es = e as ExpressionStatement;
1300                         if (es == null)
1301                                 Error_InvalidExpressionStatement ();
1302
1303                         return es;
1304                 }
1305
1306                 /// <summary>
1307                 ///   Requests the expression to be emitted in a `statement'
1308                 ///   context.  This means that no new value is left on the
1309                 ///   stack after invoking this method (constrasted with
1310                 ///   Emit that will always leave a value on the stack).
1311                 /// </summary>
1312                 public abstract void EmitStatement (EmitContext ec);
1313
1314                 public override void EmitSideEffect (EmitContext ec)
1315                 {
1316                         EmitStatement (ec);
1317                 }
1318         }
1319
1320         /// <summary>
1321         ///   This kind of cast is used to encapsulate the child
1322         ///   whose type is child.Type into an expression that is
1323         ///   reported to return "return_type".  This is used to encapsulate
1324         ///   expressions which have compatible types, but need to be dealt
1325         ///   at higher levels with.
1326         ///
1327         ///   For example, a "byte" expression could be encapsulated in one
1328         ///   of these as an "unsigned int".  The type for the expression
1329         ///   would be "unsigned int".
1330         ///
1331         /// </summary>
1332         public abstract class TypeCast : Expression
1333         {
1334                 protected Expression child;
1335
1336                 protected TypeCast (Expression child, Type return_type)
1337                 {
1338                         eclass = child.eclass;
1339                         loc = child.Location;
1340                         type = return_type;
1341                         this.child = child;
1342                 }
1343
1344                 public override Expression CreateExpressionTree (EmitContext ec)
1345                 {
1346                         ArrayList args = new ArrayList (2);
1347                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1348                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1349
1350                         if (type.IsPointer || child.Type.IsPointer)
1351                                 Error_PointerInsideExpressionTree ();
1352
1353                         return CreateExpressionFactoryCall (ec.CheckState ? "ConvertChecked" : "Convert", args);
1354                 }
1355
1356                 public override Expression DoResolve (EmitContext ec)
1357                 {
1358                         // This should never be invoked, we are born in fully
1359                         // initialized state.
1360
1361                         return this;
1362                 }
1363
1364                 public override void Emit (EmitContext ec)
1365                 {
1366                         child.Emit (ec);
1367                 }
1368
1369                 public override bool GetAttributableValue (Type value_type, out object value)
1370                 {
1371                         return child.GetAttributableValue (value_type, out value);
1372                 }
1373
1374                 protected override void CloneTo (CloneContext clonectx, Expression t)
1375                 {
1376                         TypeCast target = (TypeCast) t;
1377
1378                         target.child = child.Clone (clonectx);
1379                 }
1380
1381                 public override bool IsNull {
1382                         get { return child.IsNull; }
1383                 }
1384         }
1385
1386         public class EmptyCast : TypeCast {
1387                 EmptyCast (Expression child, Type target_type)
1388                         : base (child, target_type)
1389                 {
1390                 }
1391
1392                 public static Expression Create (Expression child, Type type)
1393                 {
1394                         Constant c = child as Constant;
1395                         if (c != null)
1396                                 return new EmptyConstantCast (c, type);
1397
1398                         EmptyCast e = child as EmptyCast;
1399                         if (e != null)
1400                                 return new EmptyCast (e.child, type);
1401
1402                         return new EmptyCast (child, type);
1403                 }
1404
1405                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1406                 {
1407                         child.EmitBranchable (ec, label, on_true);
1408                 }
1409
1410                 public override void EmitSideEffect (EmitContext ec)
1411                 {
1412                         child.EmitSideEffect (ec);
1413                 }
1414         }
1415
1416         /// <summary>
1417         ///    Performs a cast using an operator (op_Explicit or op_Implicit)
1418         /// </summary>
1419         public class OperatorCast : TypeCast {
1420                 MethodInfo conversion_operator;
1421                 bool find_explicit;
1422
1423                 public OperatorCast (Expression child, Type target_type) : this (child, target_type, false) {}
1424
1425                 public OperatorCast (Expression child, Type target_type, bool find_explicit)
1426                         : base (child, target_type)
1427                 {
1428                         this.find_explicit = find_explicit;
1429                 }
1430
1431                 // Returns the implicit operator that converts from
1432                 // 'child.Type' to our target type (type)
1433                 MethodInfo GetConversionOperator (bool find_explicit)
1434                 {
1435                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1436
1437                         MemberInfo [] mi;
1438
1439                         mi = TypeManager.MemberLookup (child.Type, child.Type, child.Type, MemberTypes.Method,
1440                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1441
1442                         if (mi == null){
1443                                 mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1444                                                                BindingFlags.Static | BindingFlags.Public, operator_name, null);
1445                         }
1446
1447                         foreach (MethodInfo oper in mi) {
1448                                 ParameterData pd = TypeManager.GetParameterData (oper);
1449
1450                                 if (pd.ParameterType (0) == child.Type && TypeManager.TypeToCoreType (oper.ReturnType) == type)
1451                                         return oper;
1452                         }
1453
1454                         return null;
1455
1456
1457                 }
1458                 public override void Emit (EmitContext ec)
1459                 {
1460                         ILGenerator ig = ec.ig;
1461
1462                         child.Emit (ec);
1463                         conversion_operator = GetConversionOperator (find_explicit);
1464
1465                         if (conversion_operator == null)
1466                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1467
1468                         ig.Emit (OpCodes.Call, conversion_operator);
1469                 }
1470
1471         }
1472
1473         /// <summary>
1474         ///     This is a numeric cast to a Decimal
1475         /// </summary>
1476         public class CastToDecimal : TypeCast {
1477                 MethodInfo conversion_operator;
1478
1479                 public CastToDecimal (Expression child)
1480                         : this (child, false)
1481                 {
1482                 }
1483
1484                 public CastToDecimal (Expression child, bool find_explicit)
1485                         : base (child, TypeManager.decimal_type)
1486                 {
1487                         conversion_operator = GetConversionOperator (find_explicit);
1488
1489                         if (conversion_operator == null)
1490                                 throw new InternalErrorException ("Outer conversion routine is out of sync");
1491                 }
1492
1493                 // Returns the implicit operator that converts from
1494                 // 'child.Type' to System.Decimal.
1495                 MethodInfo GetConversionOperator (bool find_explicit)
1496                 {
1497                         string operator_name = find_explicit ? "op_Explicit" : "op_Implicit";
1498
1499                         MemberInfo [] mi = TypeManager.MemberLookup (type, type, type, MemberTypes.Method,
1500                                 BindingFlags.Static | BindingFlags.Public, operator_name, null);
1501
1502                         foreach (MethodInfo oper in mi) {
1503                                 ParameterData pd = TypeManager.GetParameterData (oper);
1504
1505                                 if (pd.ParameterType (0) == child.Type && TypeManager.TypeToCoreType (oper.ReturnType) == type)
1506                                         return oper;
1507                         }
1508
1509                         return null;
1510                 }
1511                 public override void Emit (EmitContext ec)
1512                 {
1513                         ILGenerator ig = ec.ig;
1514                         child.Emit (ec);
1515
1516                         ig.Emit (OpCodes.Call, conversion_operator);
1517                 }
1518         }
1519
1520         /// <summary>
1521         ///     This is an explicit numeric cast from a Decimal
1522         /// </summary>
1523         public class CastFromDecimal : TypeCast
1524         {
1525                 static IDictionary operators;
1526
1527                 public CastFromDecimal (Expression child, Type return_type)
1528                         : base (child, return_type)
1529                 {
1530                         if (child.Type != TypeManager.decimal_type)
1531                                 throw new InternalErrorException (
1532                                         "The expected type is Decimal, instead it is " + child.Type.FullName);
1533                 }
1534
1535                 // Returns the explicit operator that converts from an
1536                 // express of type System.Decimal to 'type'.
1537                 public Expression Resolve ()
1538                 {
1539                         if (operators == null) {
1540                                  MemberInfo[] all_oper = TypeManager.MemberLookup (TypeManager.decimal_type,
1541                                         TypeManager.decimal_type, TypeManager.decimal_type, MemberTypes.Method,
1542                                         BindingFlags.Static | BindingFlags.Public, "op_Explicit", null);
1543
1544                                 operators = new System.Collections.Specialized.HybridDictionary ();
1545                                 foreach (MethodInfo oper in all_oper) {
1546                                         ParameterData pd = TypeManager.GetParameterData (oper);
1547                                         if (pd.ParameterType (0) == TypeManager.decimal_type)
1548                                                 operators.Add (TypeManager.TypeToCoreType (oper.ReturnType), oper);
1549                                 }
1550                         }
1551
1552                         return operators.Contains (type) ? this : null;
1553                 }
1554
1555                 public override void Emit (EmitContext ec)
1556                 {
1557                         ILGenerator ig = ec.ig;
1558                         child.Emit (ec);
1559
1560                         ig.Emit (OpCodes.Call, (MethodInfo)operators [type]);
1561                 }
1562         }
1563
1564
1565         //
1566         // Constant specialization of EmptyCast.
1567         // We need to special case this since an empty cast of
1568         // a constant is still a constant.
1569         //
1570         public class EmptyConstantCast : Constant
1571         {
1572                 public readonly Constant child;
1573
1574                 public EmptyConstantCast(Constant child, Type type)
1575                         : base (child.Location)
1576                 {
1577                         eclass = child.eclass;
1578                         this.child = child;
1579                         this.type = type;
1580                 }
1581
1582                 public override string AsString ()
1583                 {
1584                         return child.AsString ();
1585                 }
1586
1587                 public override object GetValue ()
1588                 {
1589                         return child.GetValue ();
1590                 }
1591
1592                 public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
1593                 {
1594                         // FIXME: check that 'type' can be converted to 'target_type' first
1595                         return child.ConvertExplicitly (in_checked_context, target_type);
1596                 }
1597
1598                 public override Expression CreateExpressionTree (EmitContext ec)
1599                 {
1600                         ArrayList args = new ArrayList (2);
1601                         args.Add (new Argument (child.CreateExpressionTree (ec)));
1602                         args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
1603                         if (type.IsPointer)
1604                                 Error_PointerInsideExpressionTree ();
1605
1606                         return CreateExpressionFactoryCall ("Convert", args);
1607                 }
1608
1609                 public override Constant Increment ()
1610                 {
1611                         return child.Increment ();
1612                 }
1613
1614                 public override bool IsDefaultValue {
1615                         get { return child.IsDefaultValue; }
1616                 }
1617
1618                 public override bool IsNegative {
1619                         get { return child.IsNegative; }
1620                 }
1621
1622                 public override bool IsNull {
1623                         get { return child.IsNull; }
1624                 }
1625
1626                 public override bool IsZeroInteger {
1627                         get { return child.IsZeroInteger; }
1628                 }
1629
1630                 public override void Emit (EmitContext ec)
1631                 {
1632                         child.Emit (ec);
1633                 }
1634
1635                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1636                 {
1637                         child.EmitBranchable (ec, label, on_true);
1638                 }
1639
1640                 public override void EmitSideEffect (EmitContext ec)
1641                 {
1642                         child.EmitSideEffect (ec);
1643                 }
1644
1645                 public override Constant ConvertImplicitly (Type target_type)
1646                 {
1647                         // FIXME: Do we need to check user conversions?
1648                         if (!Convert.ImplicitStandardConversionExists (this, target_type))
1649                                 return null;
1650                         return child.ConvertImplicitly (target_type);
1651                 }
1652         }
1653
1654
1655         /// <summary>
1656         ///  This class is used to wrap literals which belong inside Enums
1657         /// </summary>
1658         public class EnumConstant : Constant {
1659                 public Constant Child;
1660
1661                 public EnumConstant (Constant child, Type enum_type):
1662                         base (child.Location)
1663                 {
1664                         eclass = child.eclass;
1665                         this.Child = child;
1666                         type = enum_type;
1667                 }
1668
1669                 public override Expression DoResolve (EmitContext ec)
1670                 {
1671                         // This should never be invoked, we are born in fully
1672                         // initialized state.
1673
1674                         return this;
1675                 }
1676
1677                 public override void Emit (EmitContext ec)
1678                 {
1679                         Child.Emit (ec);
1680                 }
1681
1682                 public override void EmitBranchable (EmitContext ec, Label label, bool on_true)
1683                 {
1684                         Child.EmitBranchable (ec, label, on_true);
1685                 }
1686
1687                 public override void EmitSideEffect (EmitContext ec)
1688                 {
1689                         Child.EmitSideEffect (ec);
1690                 }
1691
1692                 public override bool GetAttributableValue (Type value_type, out object value)
1693                 {
1694                         value = GetTypedValue ();
1695                         return true;
1696                 }
1697
1698                 public override string GetSignatureForError()
1699                 {
1700                         return TypeManager.CSharpName (Type);
1701                 }
1702
1703                 public override object GetValue ()
1704                 {
1705                         return Child.GetValue ();
1706                 }
1707
1708                 public override object GetTypedValue ()
1709                 {
1710                         // FIXME: runtime is not ready to work with just emited enums
1711                         if (!RootContext.StdLib) {
1712                                 return Child.GetValue ();
1713                         }
1714
1715                         return System.Enum.ToObject (type, Child.GetValue ());
1716                 }
1717
1718                 public override string AsString ()
1719                 {
1720                         return TypeManager.CSharpEnumValue (type, Child.GetValue ());
1721                 }
1722
1723                 public override Constant Increment()
1724                 {
1725                         return new EnumConstant (Child.Increment (), type);
1726                 }
1727
1728                 public override bool IsDefaultValue {
1729                         get {
1730                                 return Child.IsDefaultValue;
1731                         }
1732                 }
1733
1734                 public override bool IsZeroInteger {
1735                         get { return Child.IsZeroInteger; }
1736                 }
1737
1738                 public override bool IsNegative {
1739                         get {
1740                                 return Child.IsNegative;
1741                         }
1742                 }
1743
1744                 public override Constant ConvertExplicitly(bool in_checked_context, Type target_type)
1745                 {
1746                         if (Child.Type == target_type)
1747                                 return Child;
1748
1749                         return Child.ConvertExplicitly (in_checked_context, target_type);
1750                 }
1751
1752                 public override Constant ConvertImplicitly (Type type)
1753                 {
1754                         Type this_type = TypeManager.DropGenericTypeArguments (Type);
1755                         type = TypeManager.DropGenericTypeArguments (type);
1756
1757                         if (this_type == type) {
1758                                 // This is workaround of mono bug. It can be removed when the latest corlib spreads enough
1759                                 if (TypeManager.IsEnumType (type.UnderlyingSystemType))
1760                                         return this;
1761
1762                                 Type child_type = TypeManager.DropGenericTypeArguments (Child.Type);
1763                                 if (type.UnderlyingSystemType != child_type)
1764                                         Child = Child.ConvertImplicitly (type.UnderlyingSystemType);
1765                                 return this;
1766                         }
1767
1768                         if (!Convert.ImplicitStandardConversionExists (this, type)){
1769                                 return null;
1770                         }
1771
1772                         return Child.ConvertImplicitly(type);
1773                 }
1774
1775         }
1776
1777         /// <summary>
1778         ///   This kind of cast is used to encapsulate Value Types in objects.
1779         ///
1780         ///   The effect of it is to box the value type emitted by the previous
1781         ///   operation.
1782         /// </summary>
1783         public class BoxedCast : TypeCast {
1784
1785                 public BoxedCast (Expression expr, Type target_type)
1786                         : base (expr, target_type)
1787                 {
1788                         eclass = ExprClass.Value;
1789                 }
1790
1791                 public override Expression DoResolve (EmitContext ec)
1792                 {
1793                         // This should never be invoked, we are born in fully
1794                         // initialized state.
1795
1796                         return this;
1797                 }
1798
1799                 public override void Emit (EmitContext ec)
1800                 {
1801                         base.Emit (ec);
1802
1803                         ec.ig.Emit (OpCodes.Box, child.Type);
1804                 }
1805
1806                 public override void EmitSideEffect (EmitContext ec)
1807                 {
1808                         // boxing is side-effectful, since it involves runtime checks, except when boxing to Object or ValueType
1809                         // so, we need to emit the box+pop instructions in most cases
1810                         if (child.Type.IsValueType &&
1811                             (type == TypeManager.object_type || type == TypeManager.value_type))
1812                                 child.EmitSideEffect (ec);
1813                         else
1814                                 base.EmitSideEffect (ec);
1815                 }
1816         }
1817
1818         public class UnboxCast : TypeCast {
1819                 public UnboxCast (Expression expr, Type return_type)
1820                         : base (expr, return_type)
1821                 {
1822                 }
1823
1824                 public override Expression DoResolve (EmitContext ec)
1825                 {
1826                         // This should never be invoked, we are born in fully
1827                         // initialized state.
1828
1829                         return this;
1830                 }
1831
1832                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
1833                 {
1834                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
1835                                 Report.Error (445, loc, "Cannot modify the result of an unboxing conversion");
1836                         return base.DoResolveLValue (ec, right_side);
1837                 }
1838
1839                 public override void Emit (EmitContext ec)
1840                 {
1841                         Type t = type;
1842                         ILGenerator ig = ec.ig;
1843
1844                         base.Emit (ec);
1845 #if GMCS_SOURCE
1846                         if (t.IsGenericParameter || t.IsGenericType && t.IsValueType)
1847                                 ig.Emit (OpCodes.Unbox_Any, t);
1848                         else
1849 #endif
1850                         {
1851                                 ig.Emit (OpCodes.Unbox, t);
1852
1853                                 LoadFromPtr (ig, t);
1854                         }
1855                 }
1856         }
1857
1858         /// <summary>
1859         ///   This is used to perform explicit numeric conversions.
1860         ///
1861         ///   Explicit numeric conversions might trigger exceptions in a checked
1862         ///   context, so they should generate the conv.ovf opcodes instead of
1863         ///   conv opcodes.
1864         /// </summary>
1865         public class ConvCast : TypeCast {
1866                 public enum Mode : byte {
1867                         I1_U1, I1_U2, I1_U4, I1_U8, I1_CH,
1868                         U1_I1, U1_CH,
1869                         I2_I1, I2_U1, I2_U2, I2_U4, I2_U8, I2_CH,
1870                         U2_I1, U2_U1, U2_I2, U2_CH,
1871                         I4_I1, I4_U1, I4_I2, I4_U2, I4_U4, I4_U8, I4_CH,
1872                         U4_I1, U4_U1, U4_I2, U4_U2, U4_I4, U4_CH,
1873                         I8_I1, I8_U1, I8_I2, I8_U2, I8_I4, I8_U4, I8_U8, I8_CH,
1874                         U8_I1, U8_U1, U8_I2, U8_U2, U8_I4, U8_U4, U8_I8, U8_CH,
1875                         CH_I1, CH_U1, CH_I2,
1876                         R4_I1, R4_U1, R4_I2, R4_U2, R4_I4, R4_U4, R4_I8, R4_U8, R4_CH,
1877                         R8_I1, R8_U1, R8_I2, R8_U2, R8_I4, R8_U4, R8_I8, R8_U8, R8_CH, R8_R4
1878                 }
1879
1880                 Mode mode;
1881
1882                 public ConvCast (Expression child, Type return_type, Mode m)
1883                         : base (child, return_type)
1884                 {
1885                         mode = m;
1886                 }
1887
1888                 public override Expression DoResolve (EmitContext ec)
1889                 {
1890                         // This should never be invoked, we are born in fully
1891                         // initialized state.
1892
1893                         return this;
1894                 }
1895
1896                 public override string ToString ()
1897                 {
1898                         return String.Format ("ConvCast ({0}, {1})", mode, child);
1899                 }
1900
1901                 public override void Emit (EmitContext ec)
1902                 {
1903                         ILGenerator ig = ec.ig;
1904
1905                         base.Emit (ec);
1906
1907                         if (ec.CheckState){
1908                                 switch (mode){
1909                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1910                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1911                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1912                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1913                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1914
1915                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1916                                 case Mode.U1_CH: /* nothing */ break;
1917
1918                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1919                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1920                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1921                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1922                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1923                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1924
1925                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1926                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1927                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1928                                 case Mode.U2_CH: /* nothing */ break;
1929
1930                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1931                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1932                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1933                                 case Mode.I4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1934                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1935                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1936                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1937
1938                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1939                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1940                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1941                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1942                                 case Mode.U4_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1943                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1944
1945                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1946                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1947                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1948                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1949                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1950                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1951                                 case Mode.I8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1952                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1953
1954                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1955                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1956                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1957                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1958                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_Ovf_I4_Un); break;
1959                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_Ovf_U4_Un); break;
1960                                 case Mode.U8_I8: ig.Emit (OpCodes.Conv_Ovf_I8_Un); break;
1961                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_Ovf_U2_Un); break;
1962
1963                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_Ovf_I1_Un); break;
1964                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_Ovf_U1_Un); break;
1965                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_Ovf_I2_Un); break;
1966
1967                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1968                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1969                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1970                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1971                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1972                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1973                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1974                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1975                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1976
1977                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_Ovf_I1); break;
1978                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_Ovf_U1); break;
1979                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_Ovf_I2); break;
1980                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1981                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_Ovf_I4); break;
1982                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_Ovf_U4); break;
1983                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_Ovf_I8); break;
1984                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_Ovf_U8); break;
1985                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_Ovf_U2); break;
1986                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
1987                                 }
1988                         } else {
1989                                 switch (mode){
1990                                 case Mode.I1_U1: ig.Emit (OpCodes.Conv_U1); break;
1991                                 case Mode.I1_U2: ig.Emit (OpCodes.Conv_U2); break;
1992                                 case Mode.I1_U4: ig.Emit (OpCodes.Conv_U4); break;
1993                                 case Mode.I1_U8: ig.Emit (OpCodes.Conv_I8); break;
1994                                 case Mode.I1_CH: ig.Emit (OpCodes.Conv_U2); break;
1995
1996                                 case Mode.U1_I1: ig.Emit (OpCodes.Conv_I1); break;
1997                                 case Mode.U1_CH: ig.Emit (OpCodes.Conv_U2); break;
1998
1999                                 case Mode.I2_I1: ig.Emit (OpCodes.Conv_I1); break;
2000                                 case Mode.I2_U1: ig.Emit (OpCodes.Conv_U1); break;
2001                                 case Mode.I2_U2: ig.Emit (OpCodes.Conv_U2); break;
2002                                 case Mode.I2_U4: ig.Emit (OpCodes.Conv_U4); break;
2003                                 case Mode.I2_U8: ig.Emit (OpCodes.Conv_I8); break;
2004                                 case Mode.I2_CH: ig.Emit (OpCodes.Conv_U2); break;
2005
2006                                 case Mode.U2_I1: ig.Emit (OpCodes.Conv_I1); break;
2007                                 case Mode.U2_U1: ig.Emit (OpCodes.Conv_U1); break;
2008                                 case Mode.U2_I2: ig.Emit (OpCodes.Conv_I2); break;
2009                                 case Mode.U2_CH: /* nothing */ break;
2010
2011                                 case Mode.I4_I1: ig.Emit (OpCodes.Conv_I1); break;
2012                                 case Mode.I4_U1: ig.Emit (OpCodes.Conv_U1); break;
2013                                 case Mode.I4_I2: ig.Emit (OpCodes.Conv_I2); break;
2014                                 case Mode.I4_U4: /* nothing */ break;
2015                                 case Mode.I4_U2: ig.Emit (OpCodes.Conv_U2); break;
2016                                 case Mode.I4_U8: ig.Emit (OpCodes.Conv_I8); break;
2017                                 case Mode.I4_CH: ig.Emit (OpCodes.Conv_U2); break;
2018
2019                                 case Mode.U4_I1: ig.Emit (OpCodes.Conv_I1); break;
2020                                 case Mode.U4_U1: ig.Emit (OpCodes.Conv_U1); break;
2021                                 case Mode.U4_I2: ig.Emit (OpCodes.Conv_I2); break;
2022                                 case Mode.U4_U2: ig.Emit (OpCodes.Conv_U2); break;
2023                                 case Mode.U4_I4: /* nothing */ break;
2024                                 case Mode.U4_CH: ig.Emit (OpCodes.Conv_U2); break;
2025
2026                                 case Mode.I8_I1: ig.Emit (OpCodes.Conv_I1); break;
2027                                 case Mode.I8_U1: ig.Emit (OpCodes.Conv_U1); break;
2028                                 case Mode.I8_I2: ig.Emit (OpCodes.Conv_I2); break;
2029                                 case Mode.I8_U2: ig.Emit (OpCodes.Conv_U2); break;
2030                                 case Mode.I8_I4: ig.Emit (OpCodes.Conv_I4); break;
2031                                 case Mode.I8_U4: ig.Emit (OpCodes.Conv_U4); break;
2032                                 case Mode.I8_U8: /* nothing */ break;
2033                                 case Mode.I8_CH: ig.Emit (OpCodes.Conv_U2); break;
2034
2035                                 case Mode.U8_I1: ig.Emit (OpCodes.Conv_I1); break;
2036                                 case Mode.U8_U1: ig.Emit (OpCodes.Conv_U1); break;
2037                                 case Mode.U8_I2: ig.Emit (OpCodes.Conv_I2); break;
2038                                 case Mode.U8_U2: ig.Emit (OpCodes.Conv_U2); break;
2039                                 case Mode.U8_I4: ig.Emit (OpCodes.Conv_I4); break;
2040                                 case Mode.U8_U4: ig.Emit (OpCodes.Conv_U4); break;
2041                                 case Mode.U8_I8: /* nothing */ break;
2042                                 case Mode.U8_CH: ig.Emit (OpCodes.Conv_U2); break;
2043
2044                                 case Mode.CH_I1: ig.Emit (OpCodes.Conv_I1); break;
2045                                 case Mode.CH_U1: ig.Emit (OpCodes.Conv_U1); break;
2046                                 case Mode.CH_I2: ig.Emit (OpCodes.Conv_I2); break;
2047
2048                                 case Mode.R4_I1: ig.Emit (OpCodes.Conv_I1); break;
2049                                 case Mode.R4_U1: ig.Emit (OpCodes.Conv_U1); break;
2050                                 case Mode.R4_I2: ig.Emit (OpCodes.Conv_I2); break;
2051                                 case Mode.R4_U2: ig.Emit (OpCodes.Conv_U2); break;
2052                                 case Mode.R4_I4: ig.Emit (OpCodes.Conv_I4); break;
2053                                 case Mode.R4_U4: ig.Emit (OpCodes.Conv_U4); break;
2054                                 case Mode.R4_I8: ig.Emit (OpCodes.Conv_I8); break;
2055                                 case Mode.R4_U8: ig.Emit (OpCodes.Conv_U8); break;
2056                                 case Mode.R4_CH: ig.Emit (OpCodes.Conv_U2); break;
2057
2058                                 case Mode.R8_I1: ig.Emit (OpCodes.Conv_I1); break;
2059                                 case Mode.R8_U1: ig.Emit (OpCodes.Conv_U1); break;
2060                                 case Mode.R8_I2: ig.Emit (OpCodes.Conv_I2); break;
2061                                 case Mode.R8_U2: ig.Emit (OpCodes.Conv_U2); break;
2062                                 case Mode.R8_I4: ig.Emit (OpCodes.Conv_I4); break;
2063                                 case Mode.R8_U4: ig.Emit (OpCodes.Conv_U4); break;
2064                                 case Mode.R8_I8: ig.Emit (OpCodes.Conv_I8); break;
2065                                 case Mode.R8_U8: ig.Emit (OpCodes.Conv_U8); break;
2066                                 case Mode.R8_CH: ig.Emit (OpCodes.Conv_U2); break;
2067                                 case Mode.R8_R4: ig.Emit (OpCodes.Conv_R4); break;
2068                                 }
2069                         }
2070                 }
2071         }
2072
2073         public class OpcodeCast : TypeCast {
2074                 OpCode op, op2;
2075                 bool second_valid;
2076
2077                 public OpcodeCast (Expression child, Type return_type, OpCode op)
2078                         : base (child, return_type)
2079
2080                 {
2081                         this.op = op;
2082                         second_valid = false;
2083                 }
2084
2085                 public OpcodeCast (Expression child, Type return_type, OpCode op, OpCode op2)
2086                         : base (child, return_type)
2087
2088                 {
2089                         this.op = op;
2090                         this.op2 = op2;
2091                         second_valid = true;
2092                 }
2093
2094                 public override Expression DoResolve (EmitContext ec)
2095                 {
2096                         // This should never be invoked, we are born in fully
2097                         // initialized state.
2098
2099                         return this;
2100                 }
2101
2102                 public override void Emit (EmitContext ec)
2103                 {
2104                         base.Emit (ec);
2105                         ec.ig.Emit (op);
2106
2107                         if (second_valid)
2108                                 ec.ig.Emit (op2);
2109                 }
2110
2111                 public Type UnderlyingType {
2112                         get { return child.Type; }
2113                 }
2114         }
2115
2116         /// <summary>
2117         ///   This kind of cast is used to encapsulate a child and cast it
2118         ///   to the class requested
2119         /// </summary>
2120         public class ClassCast : TypeCast {
2121                 public ClassCast (Expression child, Type return_type)
2122                         : base (child, return_type)
2123
2124                 {
2125                 }
2126
2127                 public override Expression DoResolve (EmitContext ec)
2128                 {
2129                         // This should never be invoked, we are born in fully
2130                         // initialized state.
2131
2132                         return this;
2133                 }
2134
2135                 public override void Emit (EmitContext ec)
2136                 {
2137                         base.Emit (ec);
2138
2139                         if (TypeManager.IsGenericParameter (child.Type))
2140                                 ec.ig.Emit (OpCodes.Box, child.Type);
2141
2142 #if GMCS_SOURCE
2143                         if (type.IsGenericParameter)
2144                                 ec.ig.Emit (OpCodes.Unbox_Any, type);
2145                         else
2146 #endif
2147                                 ec.ig.Emit (OpCodes.Castclass, type);
2148                 }
2149         }
2150
2151         //
2152         // Used when resolved expression has different representations for
2153         // expression trees and emit phase
2154         //
2155         public class ReducedExpression : Expression
2156         {
2157                 class ReducedConstantExpression : Constant
2158                 {
2159                         readonly Constant expr;
2160                         readonly Expression orig_expr;
2161
2162                         public ReducedConstantExpression (Constant expr, Expression orig_expr)
2163                                 : base (expr.Location)
2164                         {
2165                                 this.expr = expr;
2166                                 this.orig_expr = orig_expr;
2167                                 eclass = expr.eclass;
2168                                 type = expr.Type;
2169                         }
2170
2171                         public override string AsString ()
2172                         {
2173                                 return expr.AsString ();
2174                         }
2175
2176                         public override Expression CreateExpressionTree (EmitContext ec)
2177                         {
2178                                 return orig_expr.CreateExpressionTree (ec);
2179                         }
2180
2181                         public override object GetValue ()
2182                         {
2183                                 return expr.GetValue ();
2184                         }
2185
2186                         public override Constant ConvertExplicitly (bool in_checked_context, Type target_type)
2187                         {
2188                                 throw new NotImplementedException ();
2189                         }
2190
2191                         public override Expression DoResolve (EmitContext ec)
2192                         {
2193                                 return this;
2194                         }
2195
2196                         public override Constant Increment ()
2197                         {
2198                                 throw new NotImplementedException ();
2199                         }
2200
2201                         public override bool IsDefaultValue {
2202                                 get {
2203                                         return expr.IsDefaultValue;
2204                                 }
2205                         }
2206
2207                         public override bool IsNegative {
2208                                 get {
2209                                         return expr.IsNegative;
2210                                 }
2211                         }
2212
2213                         public override void Emit (EmitContext ec)
2214                         {
2215                                 expr.Emit (ec);
2216                         }
2217                 }
2218
2219                 readonly Expression expr, orig_expr;
2220
2221                 private ReducedExpression (Expression expr, Expression orig_expr)
2222                 {
2223                         this.expr = expr;
2224                         this.orig_expr = orig_expr;
2225                         this.loc = orig_expr.Location;
2226                 }
2227
2228                 public static Expression Create (Constant expr, Expression original_expr)
2229                 {
2230                         return new ReducedConstantExpression (expr, original_expr);
2231                 }
2232
2233                 public static Expression Create (Expression expr, Expression original_expr)
2234                 {
2235                         Constant c = expr as Constant;
2236                         if (c != null)
2237                                 return Create (c, original_expr);
2238
2239                         return new ReducedExpression (expr, original_expr);
2240                 }
2241
2242                 public override Expression CreateExpressionTree (EmitContext ec)
2243                 {
2244                         return orig_expr.CreateExpressionTree (ec);
2245                 }
2246
2247                 public override Expression DoResolve (EmitContext ec)
2248                 {
2249                         eclass = expr.eclass;
2250                         type = expr.Type;
2251                         return this;
2252                 }
2253
2254                 public override void Emit (EmitContext ec)
2255                 {
2256                         expr.Emit (ec);
2257                 }
2258
2259                 public override void EmitBranchable (EmitContext ec, Label target, bool on_true)
2260                 {
2261                         expr.EmitBranchable (ec, target, on_true);
2262                 }
2263         }
2264
2265         //
2266         // Unresolved type name expressions
2267         //
2268         public abstract class ATypeNameExpression : FullNamedExpression
2269         {
2270                 public readonly string Name;
2271                 protected TypeArguments targs;
2272
2273                 protected ATypeNameExpression (string name, Location l)
2274                 {
2275                         Name = name;
2276                         loc = l;
2277                 }
2278
2279                 protected ATypeNameExpression (string name, TypeArguments targs, Location l)
2280                 {
2281                         Name = name;
2282                         this.targs = targs;
2283                         loc = l;
2284                 }
2285
2286                 public bool HasTypeArguments {
2287                         get {
2288                                 return targs != null;
2289                         }
2290                 }
2291
2292                 public override string GetSignatureForError ()
2293                 {
2294                         if (targs != null) {
2295                                 return TypeManager.RemoveGenericArity (Name) + "<" +
2296                                         targs.GetSignatureForError () + ">";
2297                         }
2298
2299                         return Name;
2300                 }
2301         }
2302
2303         /// <summary>
2304         ///   SimpleName expressions are formed of a single word and only happen at the beginning
2305         ///   of a dotted-name.
2306         /// </summary>
2307         public class SimpleName : ATypeNameExpression {
2308                 bool in_transit;
2309
2310                 public SimpleName (string name, Location l)
2311                         : base (name, l)
2312                 {
2313                 }
2314
2315                 public SimpleName (string name, TypeArguments args, Location l)
2316                         : base (name, args, l)
2317                 {
2318                 }
2319
2320                 public SimpleName (string name, TypeParameter[] type_params, Location l)
2321                         : base (name, l)
2322                 {
2323                         targs = new TypeArguments (l);
2324                         foreach (TypeParameter type_param in type_params)
2325                                 targs.Add (new TypeParameterExpr (type_param, l));
2326                 }
2327
2328                 public static string RemoveGenericArity (string name)
2329                 {
2330                         int start = 0;
2331                         StringBuilder sb = null;
2332                         do {
2333                                 int pos = name.IndexOf ('`', start);
2334                                 if (pos < 0) {
2335                                         if (start == 0)
2336                                                 return name;
2337
2338                                         sb.Append (name.Substring (start));
2339                                         break;
2340                                 }
2341
2342                                 if (sb == null)
2343                                         sb = new StringBuilder ();
2344                                 sb.Append (name.Substring (start, pos-start));
2345
2346                                 pos++;
2347                                 while ((pos < name.Length) && Char.IsNumber (name [pos]))
2348                                         pos++;
2349
2350                                 start = pos;
2351                         } while (start < name.Length);
2352
2353                         return sb.ToString ();
2354                 }
2355
2356                 public SimpleName GetMethodGroup ()
2357                 {
2358                         return new SimpleName (RemoveGenericArity (Name), targs, loc);
2359                 }
2360
2361                 public static void Error_ObjectRefRequired (EmitContext ec, Location l, string name)
2362                 {
2363                         if (ec.IsInFieldInitializer)
2364                                 Report.Error (236, l,
2365                                         "A field initializer cannot reference the nonstatic field, method, or property `{0}'",
2366                                         name);
2367                         else
2368                                 Report.Error (
2369                                         120, l, "`{0}': An object reference is required for the nonstatic field, method or property",
2370                                         name);
2371                 }
2372
2373                 public bool IdenticalNameAndTypeName (EmitContext ec, Expression resolved_to, Location loc)
2374                 {
2375                         return resolved_to != null && resolved_to.Type != null &&
2376                                 resolved_to.Type.Name == Name &&
2377                                 (ec.DeclContainer.LookupNamespaceOrType (Name, loc, /* ignore_cs0104 = */ true) != null);
2378                 }
2379
2380                 public override Expression DoResolve (EmitContext ec)
2381                 {
2382                         return SimpleNameResolve (ec, null, false);
2383                 }
2384
2385                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
2386                 {
2387                         return SimpleNameResolve (ec, right_side, false);
2388                 }
2389
2390
2391                 public Expression DoResolve (EmitContext ec, bool intermediate)
2392                 {
2393                         return SimpleNameResolve (ec, null, intermediate);
2394                 }
2395
2396                 static bool IsNestedChild (Type t, Type parent)
2397                 {
2398                         while (parent != null) {
2399                                 if (TypeManager.IsNestedChildOf (t, TypeManager.DropGenericTypeArguments (parent)))
2400                                         return true;
2401
2402                                 parent = parent.BaseType;
2403                         }
2404
2405                         return false;
2406                 }
2407
2408                 FullNamedExpression ResolveNested (IResolveContext ec, Type t)
2409                 {
2410                         if (!TypeManager.IsGenericTypeDefinition (t) && !TypeManager.IsGenericType (t))
2411                                 return null;
2412
2413                         DeclSpace ds = ec.DeclContainer;
2414                         while (ds != null && !IsNestedChild (t, ds.TypeBuilder))
2415                                 ds = ds.Parent;
2416
2417                         if (ds == null)
2418                                 return null;
2419
2420                         Type[] gen_params = TypeManager.GetTypeArguments (t);
2421
2422                         int arg_count = targs != null ? targs.Count : 0;
2423
2424                         for (; (ds != null) && ds.IsGeneric; ds = ds.Parent) {
2425                                 if (arg_count + ds.CountTypeParameters == gen_params.Length) {
2426                                         TypeArguments new_args = new TypeArguments (loc);
2427                                         foreach (TypeParameter param in ds.TypeParameters)
2428                                                 new_args.Add (new TypeParameterExpr (param, loc));
2429
2430                                         if (targs != null)
2431                                                 new_args.Add (targs);
2432
2433                                         return new ConstructedType (t, new_args, loc);
2434                                 }
2435                         }
2436
2437                         return null;
2438                 }
2439
2440                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2441                 {
2442                         FullNamedExpression fne = ec.GenericDeclContainer.LookupGeneric (Name, loc);
2443                         if (fne != null)
2444                                 return fne.ResolveAsTypeStep (ec, silent);
2445
2446                         int errors = Report.Errors;
2447                         fne = ec.DeclContainer.LookupNamespaceOrType (Name, loc, /*ignore_cs0104=*/ false);
2448
2449                         if (fne != null) {
2450                                 if (fne.Type == null)
2451                                         return fne;
2452
2453                                 FullNamedExpression nested = ResolveNested (ec, fne.Type);
2454                                 if (nested != null)
2455                                         return nested.ResolveAsTypeStep (ec, false);
2456
2457                                 if (targs != null) {
2458                                         ConstructedType ct = new ConstructedType (fne, targs, loc);
2459                                         return ct.ResolveAsTypeStep (ec, false);
2460                                 }
2461
2462                                 return fne;
2463                         }
2464
2465                         if (silent || errors != Report.Errors)
2466                                 return null;
2467
2468                         Error_TypeOrNamespaceNotFound (ec);
2469                         return null;
2470                 }
2471
2472                 protected virtual void Error_TypeOrNamespaceNotFound (IResolveContext ec)
2473                 {
2474                         MemberCore mc = ec.DeclContainer.GetDefinition (Name);
2475                         if (mc != null) {
2476                                 Error_UnexpectedKind (ec.DeclContainer, "type", GetMemberType (mc), loc);
2477                                 return;
2478                         }
2479
2480                         string ns = ec.DeclContainer.NamespaceEntry.NS.Name;
2481                         string fullname = (ns.Length > 0) ? ns + "." + Name : Name;
2482                         foreach (Assembly a in RootNamespace.Global.Assemblies) {
2483                                 Type type = a.GetType (fullname);
2484                                 if (type != null) {
2485                                         Report.SymbolRelatedToPreviousError (type);
2486                                         Expression.ErrorIsInaccesible (loc, TypeManager.CSharpName (type));
2487                                         return;
2488                                 }
2489                         }
2490
2491                         Type t = ec.DeclContainer.LookupAnyGeneric (Name);
2492                         if (t != null) {
2493                                 Namespace.Error_InvalidNumberOfTypeArguments (t, loc);
2494                                 return;
2495                         }
2496
2497                         if (targs != null) {
2498                                 FullNamedExpression retval = ec.DeclContainer.LookupNamespaceOrType (SimpleName.RemoveGenericArity (Name), loc, true);
2499                                 if (retval != null) {
2500                                         Namespace.Error_TypeArgumentsCannotBeUsed (retval.Type, loc);
2501                                         return;
2502                                 }
2503                         }
2504
2505                         NamespaceEntry.Error_NamespaceNotFound (loc, Name);
2506                 }
2507
2508                 // TODO: I am still not convinced about this. If someone else will need it
2509                 // implement this as virtual property in MemberCore hierarchy
2510                 public static string GetMemberType (MemberCore mc)
2511                 {
2512                         if (mc is Property)
2513                                 return "property";
2514                         if (mc is Indexer)
2515                                 return "indexer";
2516                         if (mc is FieldBase)
2517                                 return "field";
2518                         if (mc is MethodCore)
2519                                 return "method";
2520                         if (mc is EnumMember)
2521                                 return "enum";
2522                         if (mc is Event)
2523                                 return "event";
2524
2525                         return "type";
2526                 }
2527
2528                 Expression SimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2529                 {
2530                         if (in_transit)
2531                                 return null;
2532
2533                         in_transit = true;
2534                         Expression e = DoSimpleNameResolve (ec, right_side, intermediate);
2535                         in_transit = false;
2536
2537                         if (e == null)
2538                                 return null;
2539
2540                         if (ec.CurrentBlock == null || ec.CurrentBlock.CheckInvariantMeaningInBlock (Name, e, Location))
2541                                 return e;
2542
2543                         return null;
2544                 }
2545
2546                 /// <remarks>
2547                 ///   7.5.2: Simple Names.
2548                 ///
2549                 ///   Local Variables and Parameters are handled at
2550                 ///   parse time, so they never occur as SimpleNames.
2551                 ///
2552                 ///   The `intermediate' flag is used by MemberAccess only
2553                 ///   and it is used to inform us that it is ok for us to
2554                 ///   avoid the static check, because MemberAccess might end
2555                 ///   up resolving the Name as a Type name and the access as
2556                 ///   a static type access.
2557                 ///
2558                 ///   ie: Type Type; .... { Type.GetType (""); }
2559                 ///
2560                 ///   Type is both an instance variable and a Type;  Type.GetType
2561                 ///   is the static method not an instance method of type.
2562                 /// </remarks>
2563                 Expression DoSimpleNameResolve (EmitContext ec, Expression right_side, bool intermediate)
2564                 {
2565                         Expression e = null;
2566
2567                         //
2568                         // Stage 1: Performed by the parser (binding to locals or parameters).
2569                         //
2570                         Block current_block = ec.CurrentBlock;
2571                         if (current_block != null){
2572                                 LocalInfo vi = current_block.GetLocalInfo (Name);
2573                                 if (vi != null){
2574                                         if (targs != null) {
2575                                                 Report.Error (307, loc,
2576                                                               "The variable `{0}' cannot be used with type arguments",
2577                                                               Name);
2578                                                 return null;
2579                                         }
2580
2581                                         LocalVariableReference var = new LocalVariableReference (ec.CurrentBlock, Name, loc);
2582                                         if (right_side != null) {
2583                                                 return var.ResolveLValue (ec, right_side, loc);
2584                                         } else {
2585                                                 ResolveFlags rf = ResolveFlags.VariableOrValue;
2586                                                 if (intermediate)
2587                                                         rf |= ResolveFlags.DisableFlowAnalysis;
2588                                                 return var.Resolve (ec, rf);
2589                                         }
2590                                 }
2591
2592                                 ParameterReference pref = current_block.Toplevel.GetParameterReference (Name, loc);
2593                                 if (pref != null) {
2594                                         if (targs != null) {
2595                                                 Report.Error (307, loc,
2596                                                               "The variable `{0}' cannot be used with type arguments",
2597                                                               Name);
2598                                                 return null;
2599                                         }
2600
2601                                         if (right_side != null)
2602                                                 return pref.ResolveLValue (ec, right_side, loc);
2603                                         else
2604                                                 return pref.Resolve (ec);
2605                                 }
2606
2607                                 Expression expr = current_block.Toplevel.GetTransparentIdentifier (Name);
2608                                 if (expr != null) {
2609                                         if (right_side != null)
2610                                                 return expr.ResolveLValue (ec, right_side, loc);
2611                                         return expr.Resolve (ec);
2612                                 }
2613                         }
2614
2615                         //
2616                         // Stage 2: Lookup members
2617                         //
2618
2619                         Type almost_matched_type = null;
2620                         ArrayList almost_matched = null;
2621                         for (DeclSpace lookup_ds = ec.DeclContainer; lookup_ds != null; lookup_ds = lookup_ds.Parent) {
2622                                 // either RootDeclSpace or GenericMethod
2623                                 if (lookup_ds.TypeBuilder == null)
2624                                         continue;
2625
2626                                 e = MemberLookup (ec.ContainerType, lookup_ds.TypeBuilder, Name, loc);
2627                                 if (e != null) {
2628                                         if (e is PropertyExpr) {
2629                                                 // since TypeManager.MemberLookup doesn't know if we're doing a lvalue access or not,
2630                                                 // it doesn't know which accessor to check permissions against
2631                                                 if (((PropertyExpr) e).IsAccessibleFrom (ec.ContainerType, right_side != null))
2632                                                         break;
2633                                         } else if (e is EventExpr) {
2634                                                 if (((EventExpr) e).IsAccessibleFrom (ec.ContainerType))
2635                                                         break;
2636                                         } else {
2637                                                 break;
2638                                         }
2639                                         e = null;
2640                                 }
2641
2642                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2643                                         almost_matched_type = lookup_ds.TypeBuilder;
2644                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2645                                 }
2646                         }
2647
2648                         if (e == null) {
2649                                 if (almost_matched == null && almost_matched_members.Count > 0) {
2650                                         almost_matched_type = ec.ContainerType;
2651                                         almost_matched = (ArrayList) almost_matched_members.Clone ();
2652                                 }
2653                                 e = ResolveAsTypeStep (ec, true);
2654                         }
2655
2656                         if (e == null) {
2657                                 if (current_block != null) {
2658                                         IKnownVariable ikv = current_block.Explicit.GetKnownVariable (Name);
2659                                         if (ikv != null) {
2660                                                 LocalInfo li = ikv as LocalInfo;
2661                                                 // Supress CS0219 warning
2662                                                 if (li != null)
2663                                                         li.Used = true;
2664
2665                                                 Error_VariableIsUsedBeforeItIsDeclared (Name);
2666                                                 return null;
2667                                         }
2668                                 }
2669
2670                                 if (almost_matched != null)
2671                                         almost_matched_members = almost_matched;
2672                                 if (almost_matched_type == null)
2673                                         almost_matched_type = ec.ContainerType;
2674                                 Error_MemberLookupFailed (ec.ContainerType, null, almost_matched_type, Name,
2675                                         ec.DeclContainer.Name, AllMemberTypes, AllBindingFlags);
2676                                 return null;
2677                         }
2678
2679                         if (e is TypeExpr) {
2680                                 if (targs == null)
2681                                         return e;
2682
2683                                 ConstructedType ct = new ConstructedType (
2684                                         e.Type, targs, loc);
2685                                 return ct.ResolveAsTypeStep (ec, false);
2686                         }
2687
2688                         if (e is MemberExpr) {
2689                                 MemberExpr me = (MemberExpr) e;
2690
2691                                 Expression left;
2692                                 if (me.IsInstance) {
2693                                         if (ec.IsStatic || ec.IsInFieldInitializer) {
2694                                                 //
2695                                                 // Note that an MemberExpr can be both IsInstance and IsStatic.
2696                                                 // An unresolved MethodGroupExpr can contain both kinds of methods
2697                                                 // and each predicate is true if the MethodGroupExpr contains
2698                                                 // at least one of that kind of method.
2699                                                 //
2700
2701                                                 if (!me.IsStatic &&
2702                                                     (!intermediate || !IdenticalNameAndTypeName (ec, me, loc))) {
2703                                                         Error_ObjectRefRequired (ec, loc, me.GetSignatureForError ());
2704                                                         return null;
2705                                                 }
2706
2707                                                 //
2708                                                 // Pass the buck to MemberAccess and Invocation.
2709                                                 //
2710                                                 left = EmptyExpression.Null;
2711                                         } else {
2712                                                 left = ec.GetThis (loc);
2713                                         }
2714                                 } else {
2715                                         left = new TypeExpression (ec.ContainerType, loc);
2716                                 }
2717
2718                                 me = me.ResolveMemberAccess (ec, left, loc, null);
2719                                 if (me == null)
2720                                         return null;
2721
2722                                 if (targs != null) {
2723                                         targs.Resolve (ec);
2724                                         me.SetTypeArguments (targs);
2725                                 }
2726
2727                                 if (!me.IsStatic && (me.InstanceExpression != null) &&
2728                                     TypeManager.IsNestedFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2729                                     me.InstanceExpression.Type != me.DeclaringType &&
2730                                     !TypeManager.IsFamilyAccessible (me.InstanceExpression.Type, me.DeclaringType) &&
2731                                     (!intermediate || !IdenticalNameAndTypeName (ec, e, loc))) {
2732                                         Report.Error (38, loc, "Cannot access a nonstatic member of outer type `{0}' via nested type `{1}'",
2733                                                 TypeManager.CSharpName (me.DeclaringType), TypeManager.CSharpName (me.InstanceExpression.Type));
2734                                         return null;
2735                                 }
2736
2737                                 return (right_side != null)
2738                                         ? me.DoResolveLValue (ec, right_side)
2739                                         : me.DoResolve (ec);
2740                         }
2741
2742                         return e;
2743                 }
2744
2745                 protected override void CloneTo (CloneContext clonectx, Expression target)
2746                 {
2747                         // CloneTo: Nothing, we do not keep any state on this expression
2748                 }
2749         }
2750
2751         /// <summary>
2752         ///   Represents a namespace or a type.  The name of the class was inspired by
2753         ///   section 10.8.1 (Fully Qualified Names).
2754         /// </summary>
2755         public abstract class FullNamedExpression : Expression {
2756
2757                 public override Expression CreateExpressionTree (EmitContext ec)
2758                 {
2759                         throw new NotSupportedException ("ET");
2760                 }
2761
2762                 public override FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2763                 {
2764                         return this;
2765                 }
2766
2767                 public override void Emit (EmitContext ec)
2768                 {
2769                         throw new InternalErrorException ("FullNamedExpression `{0}' found in resolved tree",
2770                                 GetSignatureForError ());
2771                 }
2772         }
2773
2774         /// <summary>
2775         ///   Expression that evaluates to a type
2776         /// </summary>
2777         public abstract class TypeExpr : FullNamedExpression {
2778                 override public FullNamedExpression ResolveAsTypeStep (IResolveContext ec, bool silent)
2779                 {
2780                         TypeExpr t = DoResolveAsTypeStep (ec);
2781                         if (t == null)
2782                                 return null;
2783
2784                         eclass = ExprClass.Type;
2785                         return t;
2786                 }
2787
2788                 override public Expression DoResolve (EmitContext ec)
2789                 {
2790                         return ResolveAsTypeTerminal (ec, false);
2791                 }
2792
2793                 public virtual bool CheckAccessLevel (DeclSpace ds)
2794                 {
2795                         return ds.CheckAccessLevel (Type);
2796                 }
2797
2798                 public virtual bool AsAccessible (DeclSpace ds)
2799                 {
2800                         return ds.IsAccessibleAs (Type);
2801                 }
2802
2803                 public virtual bool IsClass {
2804                         get { return Type.IsClass; }
2805                 }
2806
2807                 public virtual bool IsValueType {
2808                         get { return Type.IsValueType; }
2809                 }
2810
2811                 public virtual bool IsInterface {
2812                         get { return Type.IsInterface; }
2813                 }
2814
2815                 public virtual bool IsSealed {
2816                         get { return Type.IsSealed; }
2817                 }
2818
2819                 public virtual bool CanInheritFrom ()
2820                 {
2821                         if (Type == TypeManager.enum_type ||
2822                             (Type == TypeManager.value_type && RootContext.StdLib) ||
2823                             Type == TypeManager.multicast_delegate_type ||
2824                             Type == TypeManager.delegate_type ||
2825                             Type == TypeManager.array_type)
2826                                 return false;
2827
2828                         return true;
2829                 }
2830
2831                 protected abstract TypeExpr DoResolveAsTypeStep (IResolveContext ec);
2832
2833                 public override bool Equals (object obj)
2834                 {
2835                         TypeExpr tobj = obj as TypeExpr;
2836                         if (tobj == null)
2837                                 return false;
2838
2839                         return Type == tobj.Type;
2840                 }
2841
2842                 public override int GetHashCode ()
2843                 {
2844                         return Type.GetHashCode ();
2845                 }
2846         }
2847
2848         /// <summary>
2849         ///   Fully resolved Expression that already evaluated to a type
2850         /// </summary>
2851         public class TypeExpression : TypeExpr {
2852                 public TypeExpression (Type t, Location l)
2853                 {
2854                         Type = t;
2855                         eclass = ExprClass.Type;
2856                         loc = l;
2857                 }
2858
2859                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2860                 {
2861                         return this;
2862                 }
2863
2864                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2865                 {
2866                         return this;
2867                 }
2868         }
2869
2870         /// <summary>
2871         ///   Used to create types from a fully qualified name.  These are just used
2872         ///   by the parser to setup the core types.  A TypeLookupExpression is always
2873         ///   classified as a type.
2874         /// </summary>
2875         public sealed class TypeLookupExpression : TypeExpr {
2876                 readonly string name;
2877
2878                 public TypeLookupExpression (string name)
2879                 {
2880                         this.name = name;
2881                         eclass = ExprClass.Type;
2882                 }
2883
2884                 public override TypeExpr ResolveAsTypeTerminal (IResolveContext ec, bool silent)
2885                 {
2886                         // It's null for corlib compilation only
2887                         if (type == null)
2888                                 return DoResolveAsTypeStep (ec);
2889
2890                         return this;
2891                 }
2892
2893                 private class UnexpectedType
2894                 {
2895                 }
2896
2897                 // This performes recursive type lookup, providing support for generic types.
2898                 // For example, given the type:
2899                 //
2900                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]
2901                 //
2902                 // The types will be checked in the following order:
2903                 //                                                                             _
2904                 // System                                                                       |
2905                 // System.Collections                                                           |
2906                 // System.Collections.Generic                                                   |
2907                 //                        _                                                     |
2908                 //     System              | recursive call 1                                   |
2909                 //     System.Int32       _|                                                    | main method call
2910                 //                        _                                                     |
2911                 //     System              | recursive call 2                                   |
2912                 //     System.String      _|                                                    |
2913                 //                                                                              |
2914                 // System.Collections.Generic.KeyValuePair`2[[System.Int32],[System.String]]   _|
2915                 //
2916                 private Type TypeLookup (IResolveContext ec, string name)
2917                 {
2918                         int index = 0;
2919                         int dot = 0;
2920                         bool done = false;
2921                         FullNamedExpression resolved = null;
2922                         Type type = null;
2923                         Type recursive_type = null;
2924                         while (index < name.Length) {
2925                                 if (name[index] == '[') {
2926                                         int open = index;
2927                                         int braces = 1;
2928                                         do {
2929                                                 index++;
2930                                                 if (name[index] == '[')
2931                                                         braces++;
2932                                                 else if (name[index] == ']')
2933                                                         braces--;
2934                                         } while (braces > 0);
2935                                         recursive_type = TypeLookup (ec, name.Substring (open + 1, index - open - 1));
2936                                         if (recursive_type == null || (recursive_type == typeof(UnexpectedType)))
2937                                                 return recursive_type;
2938                                 }
2939                                 else {
2940                                         if (name[index] == ',')
2941                                                 done = true;
2942                                         else if ((name[index] == '.' && !done) || (index == name.Length && name[0] != '[')) {
2943                                                 string substring = name.Substring(dot, index - dot);
2944
2945                                                 if (resolved == null)
2946                                                         resolved = RootNamespace.Global.Lookup (ec.DeclContainer, substring, Location.Null);
2947                                                 else if (resolved is Namespace)
2948                                                     resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2949                                                 else if (type != null)
2950                                                         type = TypeManager.GetNestedType (type, substring);
2951                                                 else
2952                                                         return null;
2953
2954                                                 if (resolved == null)
2955                                                         return null;
2956                                                 else if (type == null && resolved is TypeExpr)
2957                                                         type = resolved.Type;
2958
2959                                                 dot = index + 1;
2960                                         }
2961                                 }
2962                                 index++;
2963                         }
2964                         if (name[0] != '[') {
2965                                 string substring = name.Substring(dot, index - dot);
2966
2967                                 if (type != null)
2968                                         return TypeManager.GetNestedType (type, substring);
2969
2970                                 if (resolved != null) {
2971                                         resolved = (resolved as Namespace).Lookup (ec.DeclContainer, substring, Location.Null);
2972                                         if (resolved is TypeExpr)
2973                                                 return resolved.Type;
2974
2975                                         if (resolved == null)
2976                                                 return null;
2977
2978                                         resolved.Error_UnexpectedKind (ec.DeclContainer, "type", loc);
2979                                         return typeof (UnexpectedType);
2980                                 }
2981                                 else
2982                                         return null;
2983                         }
2984                         else
2985                                 return recursive_type;
2986                         }
2987
2988                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
2989                 {
2990                         Type t = TypeLookup (ec, name);
2991                         if (t == null) {
2992                                 NamespaceEntry.Error_NamespaceNotFound (loc, name);
2993                                 return null;
2994                         }
2995                         if (t == typeof(UnexpectedType))
2996                                 return null;
2997                         type = t;
2998                         return this;
2999                 }
3000
3001                 protected override void CloneTo (CloneContext clonectx, Expression target)
3002                 {
3003                         // CloneTo: Nothing, we do not keep any state on this expression
3004                 }
3005
3006                 public override string GetSignatureForError ()
3007                 {
3008                         if (type == null)
3009                                 return TypeManager.CSharpName (name);
3010
3011                         return base.GetSignatureForError ();
3012                 }
3013         }
3014
3015         /// <summary>
3016         ///   Represents an "unbound generic type", ie. typeof (Foo<>).
3017         ///   See 14.5.11.
3018         /// </summary>
3019         public class UnboundTypeExpression : TypeExpr
3020         {
3021                 MemberName name;
3022
3023                 public UnboundTypeExpression (MemberName name, Location l)
3024                 {
3025                         this.name = name;
3026                         loc = l;
3027                 }
3028
3029                 protected override void CloneTo (CloneContext clonectx, Expression target)
3030                 {
3031                         // Nothing to clone
3032                 }
3033
3034                 protected override TypeExpr DoResolveAsTypeStep (IResolveContext ec)
3035                 {
3036                         Expression expr;
3037                         if (name.Left != null) {
3038                                 Expression lexpr = name.Left.GetTypeExpression ();
3039                                 expr = new MemberAccess (lexpr, name.Basename);
3040                         } else {
3041                                 expr = new SimpleName (name.Basename, loc);
3042                         }
3043
3044                         FullNamedExpression fne = expr.ResolveAsTypeStep (ec, false);
3045                         if (fne == null)
3046                                 return null;
3047
3048                         type = fne.Type;
3049                         return new TypeExpression (type, loc);
3050                 }
3051         }
3052
3053         /// <summary>
3054         ///   This class denotes an expression which evaluates to a member
3055         ///   of a struct or a class.
3056         /// </summary>
3057         public abstract class MemberExpr : Expression
3058         {
3059                 protected bool is_base;
3060
3061                 /// <summary>
3062                 ///   The name of this member.
3063                 /// </summary>
3064                 public abstract string Name {
3065                         get;
3066                 }
3067
3068                 //
3069                 // When base.member is used
3070                 //
3071                 public bool IsBase {
3072                         get { return is_base; }
3073                         set { is_base = value; }
3074                 }
3075
3076                 /// <summary>
3077                 ///   Whether this is an instance member.
3078                 /// </summary>
3079                 public abstract bool IsInstance {
3080                         get;
3081                 }
3082
3083                 /// <summary>
3084                 ///   Whether this is a static member.
3085                 /// </summary>
3086                 public abstract bool IsStatic {
3087                         get;
3088                 }
3089
3090                 /// <summary>
3091                 ///   The type which declares this member.
3092                 /// </summary>
3093                 public abstract Type DeclaringType {
3094                         get;
3095                 }
3096
3097                 /// <summary>
3098                 ///   The instance expression associated with this member, if it's a
3099                 ///   non-static member.
3100                 /// </summary>
3101                 public Expression InstanceExpression;
3102
3103                 public static void error176 (Location loc, string name)
3104                 {
3105                         Report.Error (176, loc, "Static member `{0}' cannot be accessed " +
3106                                       "with an instance reference, qualify it with a type name instead", name);
3107                 }
3108
3109                 public static void Error_BaseAccessInExpressionTree (Location loc)
3110                 {
3111                         Report.Error (831, loc, "An expression tree may not contain a base access");
3112                 }
3113
3114                 // TODO: possible optimalization
3115                 // Cache resolved constant result in FieldBuilder <-> expression map
3116                 public virtual MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3117                                                                SimpleName original)
3118                 {
3119                         //
3120                         // Precondition:
3121                         //   original == null || original.Resolve (...) ==> left
3122                         //
3123
3124                         if (left is TypeExpr) {
3125                                 left = left.ResolveAsTypeTerminal (ec, true);
3126                                 if (left == null)
3127                                         return null;
3128
3129                                 if (!IsStatic) {
3130                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3131                                         return null;
3132                                 }
3133
3134                                 return this;
3135                         }
3136
3137                         if (!IsInstance) {
3138                                 if (original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3139                                         return this;
3140
3141                                 return ResolveExtensionMemberAccess (left);
3142                         }
3143
3144                         InstanceExpression = left;
3145                         return this;
3146                 }
3147
3148                 protected virtual MemberExpr ResolveExtensionMemberAccess (Expression left)
3149                 {
3150                         error176 (loc, GetSignatureForError ());
3151                         return this;
3152                 }
3153
3154                 protected void EmitInstance (EmitContext ec, bool prepare_for_load)
3155                 {
3156                         if (IsStatic)
3157                                 return;
3158
3159                         if (InstanceExpression == EmptyExpression.Null) {
3160                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
3161                                 return;
3162                         }
3163
3164                         if (InstanceExpression.Type.IsValueType) {
3165                                 if (InstanceExpression is IMemoryLocation) {
3166                                         ((IMemoryLocation) InstanceExpression).AddressOf (ec, AddressOp.LoadStore);
3167                                 } else {
3168                                         LocalTemporary t = new LocalTemporary (InstanceExpression.Type);
3169                                         InstanceExpression.Emit (ec);
3170                                         t.Store (ec);
3171                                         t.AddressOf (ec, AddressOp.Store);
3172                                 }
3173                         } else
3174                                 InstanceExpression.Emit (ec);
3175
3176                         if (prepare_for_load)
3177                                 ec.ig.Emit (OpCodes.Dup);
3178                 }
3179
3180                 public virtual void SetTypeArguments (TypeArguments ta)
3181                 {
3182                         // TODO: need to get correct member type
3183                         Report.Error (307, loc, "The property `{0}' cannot be used with type arguments",
3184                                 GetSignatureForError ());
3185                 }
3186         }
3187
3188         ///
3189         /// Represents group of extension methods
3190         ///
3191         public class ExtensionMethodGroupExpr : MethodGroupExpr
3192         {
3193                 readonly NamespaceEntry namespace_entry;
3194                 public Expression ExtensionExpression;
3195                 Argument extension_argument;
3196
3197                 public ExtensionMethodGroupExpr (ArrayList list, NamespaceEntry n, Type extensionType, Location l)
3198                         : base (list, extensionType, l)
3199                 {
3200                         this.namespace_entry = n;
3201                 }
3202
3203                 public override bool IsStatic {
3204                         get { return true; }
3205                 }
3206
3207                 public bool IsTopLevel {
3208                         get { return namespace_entry == null; }
3209                 }
3210
3211                 public override void EmitArguments (EmitContext ec, ArrayList arguments)
3212                 {
3213                         if (arguments == null)
3214                                 arguments = new ArrayList (1);
3215                         arguments.Insert (0, extension_argument);
3216                         base.EmitArguments (ec, arguments);
3217                 }
3218
3219                 public override void EmitCall (EmitContext ec, ArrayList arguments)
3220                 {
3221                         if (arguments == null)
3222                                 arguments = new ArrayList (1);
3223                         arguments.Insert (0, extension_argument);
3224                         base.EmitCall (ec, arguments);
3225                 }
3226
3227                 public override MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList arguments, bool may_fail, Location loc)
3228                 {
3229                         if (arguments == null)
3230                                 arguments = new ArrayList (1);
3231
3232                         arguments.Insert (0, new Argument (ExtensionExpression));
3233                         MethodGroupExpr mg = ResolveOverloadExtensions (ec, arguments, namespace_entry, loc);
3234
3235                         // Store resolved argument and restore original arguments
3236                         if (mg != null)
3237                                 ((ExtensionMethodGroupExpr)mg).extension_argument = (Argument)arguments [0];
3238                         arguments.RemoveAt (0);
3239
3240                         return mg;
3241                 }
3242
3243                 MethodGroupExpr ResolveOverloadExtensions (EmitContext ec, ArrayList arguments, NamespaceEntry ns, Location loc)
3244                 {
3245                         // Use normal resolve rules
3246                         MethodGroupExpr mg = base.OverloadResolve (ec, ref arguments, ns != null, loc);
3247                         if (mg != null)
3248                                 return mg;
3249
3250                         if (ns == null)
3251                                 return null;
3252
3253                         // Search continues
3254                         ExtensionMethodGroupExpr e = ns.LookupExtensionMethod (type, null, Name, loc);
3255                         if (e == null)
3256                                 return base.OverloadResolve (ec, ref arguments, false, loc);
3257
3258                         e.ExtensionExpression = ExtensionExpression;
3259                         return e.ResolveOverloadExtensions (ec, arguments, e.namespace_entry, loc);
3260                 }
3261         }
3262
3263         /// <summary>
3264         ///   MethodGroupExpr represents a group of method candidates which
3265         ///   can be resolved to the best method overload
3266         /// </summary>
3267         public class MethodGroupExpr : MemberExpr
3268         {
3269                 public interface IErrorHandler
3270                 {
3271                         bool NoExactMatch (EmitContext ec, MethodBase method);
3272                 }
3273
3274                 public IErrorHandler CustomErrorHandler;
3275                 public MethodBase [] Methods;
3276                 MethodBase best_candidate;
3277                 // TODO: make private
3278                 public TypeArguments type_arguments;
3279                 bool identical_type_name;
3280                 Type delegate_type;
3281
3282                 public MethodGroupExpr (MemberInfo [] mi, Type type, Location l)
3283                         : this (type, l)
3284                 {
3285                         Methods = new MethodBase [mi.Length];
3286                         mi.CopyTo (Methods, 0);
3287                 }
3288
3289                 public MethodGroupExpr (ArrayList list, Type type, Location l)
3290                         : this (type, l)
3291                 {
3292                         try {
3293                                 Methods = (MethodBase[])list.ToArray (typeof (MethodBase));
3294                         } catch {
3295                                 foreach (MemberInfo m in list){
3296                                         if (!(m is MethodBase)){
3297                                                 Console.WriteLine ("Name " + m.Name);
3298                                                 Console.WriteLine ("Found a: " + m.GetType ().FullName);
3299                                         }
3300                                 }
3301                                 throw;
3302                         }
3303
3304
3305                 }
3306
3307                 protected MethodGroupExpr (Type type, Location loc)
3308                 {
3309                         this.loc = loc;
3310                         eclass = ExprClass.MethodGroup;
3311                         this.type = type;
3312                 }
3313
3314                 public override Type DeclaringType {
3315                         get {
3316                                 //
3317                                 // We assume that the top-level type is in the end
3318                                 //
3319                                 return Methods [Methods.Length - 1].DeclaringType;
3320                                 //return Methods [0].DeclaringType;
3321                         }
3322                 }
3323
3324                 public Type DelegateType {
3325                         set {
3326                                 delegate_type = value;
3327                         }
3328                 }
3329
3330                 public bool IdenticalTypeName {
3331                         get {
3332                                 return identical_type_name;
3333                         }
3334
3335                         set {
3336                                 identical_type_name = value;
3337                         }
3338                 }
3339
3340                 public override string GetSignatureForError ()
3341                 {
3342                         if (best_candidate != null)
3343                                 return TypeManager.CSharpSignature (best_candidate);
3344
3345                         return TypeManager.CSharpSignature (Methods [0]);
3346                 }
3347
3348                 public override string Name {
3349                         get {
3350                                 return Methods [0].Name;
3351                         }
3352                 }
3353
3354                 public override bool IsInstance {
3355                         get {
3356                                 if (best_candidate != null)
3357                                         return !best_candidate.IsStatic;
3358
3359                                 foreach (MethodBase mb in Methods)
3360                                         if (!mb.IsStatic)
3361                                                 return true;
3362
3363                                 return false;
3364                         }
3365                 }
3366
3367                 public override bool IsStatic {
3368                         get {
3369                                 if (best_candidate != null)
3370                                         return best_candidate.IsStatic;
3371
3372                                 foreach (MethodBase mb in Methods)
3373                                         if (mb.IsStatic)
3374                                                 return true;
3375
3376                                 return false;
3377                         }
3378                 }
3379
3380                 public static explicit operator ConstructorInfo (MethodGroupExpr mg)
3381                 {
3382                         return (ConstructorInfo)mg.best_candidate;
3383                 }
3384
3385                 public static explicit operator MethodInfo (MethodGroupExpr mg)
3386                 {
3387                         return (MethodInfo)mg.best_candidate;
3388                 }
3389
3390                 //
3391                 //  7.4.3.3  Better conversion from expression
3392                 //  Returns :   1    if a->p is better,
3393                 //              2    if a->q is better,
3394                 //              0 if neither is better
3395                 //
3396                 static int BetterExpressionConversion (EmitContext ec, Argument a, Type p, Type q)
3397                 {
3398                         Type argument_type = TypeManager.TypeToCoreType (a.Type);
3399                         if (argument_type == TypeManager.anonymous_method_type && RootContext.Version > LanguageVersion.ISO_2) {
3400                                 //
3401                                 // Uwrap delegate from Expression<T>
3402                                 //
3403                                 if (TypeManager.DropGenericTypeArguments (p) == TypeManager.expression_type) {
3404                                         p = TypeManager.GetTypeArguments (p) [0];
3405                                 }
3406                                 if (TypeManager.DropGenericTypeArguments (q) == TypeManager.expression_type) {
3407                                         q = TypeManager.GetTypeArguments (q) [0];
3408                                 }
3409
3410                                 p = Delegate.GetInvokeMethod (null, p).ReturnType;
3411                                 q = Delegate.GetInvokeMethod (null, q).ReturnType;
3412                         } else {
3413                                 if (argument_type == p)
3414                                         return 1;
3415
3416                                 if (argument_type == q)
3417                                         return 2;
3418                         }
3419
3420                         return BetterTypeConversion (ec, p, q);
3421                 }
3422
3423                 //
3424                 // 7.4.3.4  Better conversion from type
3425                 //
3426                 public static int BetterTypeConversion (EmitContext ec, Type p, Type q)
3427                 {
3428                         if (p == null || q == null)
3429                                 throw new InternalErrorException ("BetterTypeConversion got a null conversion");
3430
3431                         if (p == TypeManager.int32_type) {
3432                                 if (q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3433                                         return 1;
3434                         } else if (p == TypeManager.int64_type) {
3435                                 if (q == TypeManager.uint64_type)
3436                                         return 1;
3437                         } else if (p == TypeManager.sbyte_type) {
3438                                 if (q == TypeManager.byte_type || q == TypeManager.ushort_type ||
3439                                         q == TypeManager.uint32_type || q == TypeManager.uint64_type)
3440                                         return 1;
3441                         } else if (p == TypeManager.short_type) {
3442                                 if (q == TypeManager.ushort_type || q == TypeManager.uint32_type ||
3443                                         q == TypeManager.uint64_type)
3444                                         return 1;
3445                         }
3446
3447                         if (q == TypeManager.int32_type) {
3448                                 if (p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3449                                         return 2;
3450                         } if (q == TypeManager.int64_type) {
3451                                 if (p == TypeManager.uint64_type)
3452                                         return 2;
3453                         } else if (q == TypeManager.sbyte_type) {
3454                                 if (p == TypeManager.byte_type || p == TypeManager.ushort_type ||
3455                                         p == TypeManager.uint32_type || p == TypeManager.uint64_type)
3456                                         return 2;
3457                         } if (q == TypeManager.short_type) {
3458                                 if (p == TypeManager.ushort_type || p == TypeManager.uint32_type ||
3459                                         p == TypeManager.uint64_type)
3460                                         return 2;
3461                         }
3462
3463                         // TODO: this is expensive
3464                         Expression p_tmp = new EmptyExpression (p);
3465                         Expression q_tmp = new EmptyExpression (q);
3466
3467                         bool p_to_q = Convert.ImplicitConversionExists (ec, p_tmp, q);
3468                         bool q_to_p = Convert.ImplicitConversionExists (ec, q_tmp, p);
3469
3470                         if (p_to_q && !q_to_p)
3471                                 return 1;
3472
3473                         if (q_to_p && !p_to_q)
3474                                 return 2;
3475
3476                         return 0;
3477                 }
3478
3479                 /// <summary>
3480                 ///   Determines "Better function" between candidate
3481                 ///   and the current best match
3482                 /// </summary>
3483                 /// <remarks>
3484                 ///    Returns a boolean indicating :
3485                 ///     false if candidate ain't better
3486                 ///     true  if candidate is better than the current best match
3487                 /// </remarks>
3488                 static bool BetterFunction (EmitContext ec, ArrayList args, int argument_count,
3489                         MethodBase candidate, bool candidate_params,
3490                         MethodBase best, bool best_params)
3491                 {
3492                         ParameterData candidate_pd = TypeManager.GetParameterData (candidate);
3493                         ParameterData best_pd = TypeManager.GetParameterData (best);
3494
3495                         bool better_at_least_one = false;
3496                         bool same = true;
3497                         for (int j = 0, c_idx = 0, b_idx = 0; j < argument_count; ++j, ++c_idx, ++b_idx)
3498                         {
3499                                 Argument a = (Argument) args [j];
3500
3501                                 Type ct = TypeManager.TypeToCoreType (candidate_pd.ParameterType (c_idx));
3502                                 Type bt = TypeManager.TypeToCoreType (best_pd.ParameterType (b_idx));
3503
3504                                 if (candidate_params && candidate_pd.ParameterModifier (c_idx) == Parameter.Modifier.PARAMS)
3505                                 {
3506                                         ct = TypeManager.GetElementType (ct);
3507                                         --c_idx;
3508                                 }
3509
3510                                 if (best_params && best_pd.ParameterModifier (b_idx) == Parameter.Modifier.PARAMS)
3511                                 {
3512                                         bt = TypeManager.GetElementType (bt);
3513                                         --b_idx;
3514                                 }
3515
3516                                 if (ct.Equals (bt))
3517                                         continue;
3518
3519                                 same = false;
3520                                 int result = BetterExpressionConversion (ec, a, ct, bt);
3521
3522                                 // for each argument, the conversion to 'ct' should be no worse than
3523                                 // the conversion to 'bt'.
3524                                 if (result == 2)
3525                                         return false;
3526
3527                                 // for at least one argument, the conversion to 'ct' should be better than
3528                                 // the conversion to 'bt'.
3529                                 if (result != 0)
3530                                         better_at_least_one = true;
3531                         }
3532
3533                         if (better_at_least_one)
3534                                 return true;
3535
3536                         //
3537                         // This handles the case
3538                         //
3539                         //   Add (float f1, float f2, float f3);
3540                         //   Add (params decimal [] foo);
3541                         //
3542                         // The call Add (3, 4, 5) should be ambiguous.  Without this check, the
3543                         // first candidate would've chosen as better.
3544                         //
3545                         if (!same)
3546                                 return false;
3547
3548                         //
3549                         // The two methods have equal parameter types.  Now apply tie-breaking rules
3550                         //
3551                         if (TypeManager.IsGenericMethod (best) && !TypeManager.IsGenericMethod (candidate))
3552                                 return true;
3553                         if (!TypeManager.IsGenericMethod (best) && TypeManager.IsGenericMethod (candidate))
3554                                 return false;
3555
3556                         //
3557                         // This handles the following cases:
3558                         //
3559                         //   Trim () is better than Trim (params char[] chars)
3560                         //   Concat (string s1, string s2, string s3) is better than
3561                         //     Concat (string s1, params string [] srest)
3562                         //   Foo (int, params int [] rest) is better than Foo (params int [] rest)
3563                         //
3564                         if (!candidate_params && best_params)
3565                                 return true;
3566                         if (candidate_params && !best_params)
3567                                 return false;
3568
3569                         int candidate_param_count = candidate_pd.Count;
3570                         int best_param_count = best_pd.Count;
3571
3572                         if (candidate_param_count != best_param_count)
3573                                 // can only happen if (candidate_params && best_params)
3574                                 return candidate_param_count > best_param_count;
3575
3576                         //
3577                         // now, both methods have the same number of parameters, and the parameters have the same types
3578                         // Pick the "more specific" signature
3579                         //
3580
3581                         MethodBase orig_candidate = TypeManager.DropGenericMethodArguments (candidate);
3582                         MethodBase orig_best = TypeManager.DropGenericMethodArguments (best);
3583
3584                         ParameterData orig_candidate_pd = TypeManager.GetParameterData (orig_candidate);
3585                         ParameterData orig_best_pd = TypeManager.GetParameterData (orig_best);
3586
3587                         bool specific_at_least_once = false;
3588                         for (int j = 0; j < candidate_param_count; ++j)
3589                         {
3590                                 Type ct = TypeManager.TypeToCoreType (orig_candidate_pd.ParameterType (j));
3591                                 Type bt = TypeManager.TypeToCoreType (orig_best_pd.ParameterType (j));
3592                                 if (ct.Equals (bt))
3593                                         continue;
3594                                 Type specific = MoreSpecific (ct, bt);
3595                                 if (specific == bt)
3596                                         return false;
3597                                 if (specific == ct)
3598                                         specific_at_least_once = true;
3599                         }
3600
3601                         if (specific_at_least_once)
3602                                 return true;
3603
3604                         // FIXME: handle lifted operators
3605                         // ...
3606
3607                         return false;
3608                 }
3609
3610                 protected override MemberExpr ResolveExtensionMemberAccess (Expression left)
3611                 {
3612                         if (!IsStatic)
3613                                 return base.ResolveExtensionMemberAccess (left);
3614
3615                         //
3616                         // When left side is an expression and at least one candidate method is
3617                         // static, it can be extension method
3618                         //
3619                         InstanceExpression = left;
3620                         return this;
3621                 }
3622
3623                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
3624                                                                 SimpleName original)
3625                 {
3626                         if (!(left is TypeExpr) &&
3627                             original != null && original.IdenticalNameAndTypeName (ec, left, loc))
3628                                 IdenticalTypeName = true;
3629
3630                         return base.ResolveMemberAccess (ec, left, loc, original);
3631                 }
3632
3633                 public override Expression CreateExpressionTree (EmitContext ec)
3634                 {
3635                         if (best_candidate == null) {
3636                                 Report.Error (1953, loc, "An expression tree cannot contain an expression with method group");
3637                                 return null;
3638                         }
3639
3640                         if (best_candidate.IsConstructor)
3641                                 return new TypeOfConstructorInfo (best_candidate, loc);
3642
3643                         IMethodData md = TypeManager.GetMethod (best_candidate);
3644                         if (md != null && md.IsExcluded ())
3645                                 Report.Error (765, loc,
3646                                         "Partial methods with only a defining declaration or removed conditional methods cannot be used in an expression tree");
3647
3648                         return new TypeOfMethodInfo (best_candidate, loc);
3649                 }
3650
3651                 override public Expression DoResolve (EmitContext ec)
3652                 {
3653                         if (InstanceExpression != null) {
3654                                 InstanceExpression = InstanceExpression.DoResolve (ec);
3655                                 if (InstanceExpression == null)
3656                                         return null;
3657                         }
3658
3659                         return this;
3660                 }
3661
3662                 public void ReportUsageError ()
3663                 {
3664                         Report.Error (654, loc, "Method `" + DeclaringType + "." +
3665                                       Name + "()' is referenced without parentheses");
3666                 }
3667
3668                 override public void Emit (EmitContext ec)
3669                 {
3670                         ReportUsageError ();
3671                 }
3672
3673                 public virtual void EmitArguments (EmitContext ec, ArrayList arguments)
3674                 {
3675                         Invocation.EmitArguments (ec, arguments, false, null);
3676                 }
3677
3678                 public virtual void EmitCall (EmitContext ec, ArrayList arguments)
3679                 {
3680                         Invocation.EmitCall (ec, IsBase, InstanceExpression, best_candidate, arguments, loc);
3681                 }
3682
3683                 protected virtual void Error_InvalidArguments (EmitContext ec, Location loc, int idx, MethodBase method,
3684                                                                                                         Argument a, ParameterData expected_par, Type paramType)
3685                 {
3686                         if (a is CollectionElementInitializer.ElementInitializerArgument) {
3687                                 Report.SymbolRelatedToPreviousError (method);
3688                                 if ((expected_par.ParameterModifier (idx) & Parameter.Modifier.ISBYREF) != 0) {
3689                                         Report.Error (1954, loc, "The best overloaded collection initalizer method `{0}' cannot have 'ref', or `out' modifier",
3690                                                 TypeManager.CSharpSignature (method));
3691                                         return;
3692                                 }
3693                                 Report.Error (1950, loc, "The best overloaded collection initalizer method `{0}' has some invalid arguments",
3694                                           TypeManager.CSharpSignature (method));
3695                         } else if (delegate_type == null) {
3696                                 Report.SymbolRelatedToPreviousError (method);
3697                                 Report.Error (1502, loc, "The best overloaded method match for `{0}' has some invalid arguments",
3698                                                   TypeManager.CSharpSignature (method));
3699                         } else
3700                                 Report.Error (1594, loc, "Delegate `{0}' has some invalid arguments",
3701                                         TypeManager.CSharpName (delegate_type));
3702
3703                         Parameter.Modifier mod = expected_par.ParameterModifier (idx);
3704
3705                         string index = (idx + 1).ToString ();
3706                         if (((mod & (Parameter.Modifier.REF | Parameter.Modifier.OUT)) ^
3707                                 (a.Modifier & (Parameter.Modifier.REF | Parameter.Modifier.OUT))) != 0) {
3708                                 if ((mod & Parameter.Modifier.ISBYREF) == 0)
3709                                         Report.Error (1615, loc, "Argument `{0}' should not be passed with the `{1}' keyword",
3710                                                 index, Parameter.GetModifierSignature (a.Modifier));
3711                                 else
3712                                         Report.Error (1620, loc, "Argument `{0}' must be passed with the `{1}' keyword",
3713                                                 index, Parameter.GetModifierSignature (mod));
3714                         } else {
3715                                 string p1 = a.GetSignatureForError ();
3716                                 string p2 = TypeManager.CSharpName (paramType);
3717
3718                                 if (p1 == p2) {
3719                                         Report.ExtraInformation (loc, "(equally named types possibly from different assemblies in previous ");
3720                                         Report.SymbolRelatedToPreviousError (a.Expr.Type);
3721                                         Report.SymbolRelatedToPreviousError (paramType);
3722                                 }
3723                                 Report.Error (1503, loc, "Argument {0}: Cannot convert type `{1}' to `{2}'", index, p1, p2);
3724                         }
3725                 }
3726
3727                 public override void Error_ValueCannotBeConverted (EmitContext ec, Location loc, Type target, bool expl)
3728                 {
3729                         Report.Error (428, loc, "Cannot convert method group `{0}' to non-delegate type `{1}'. Consider using parentheses to invoke the method",
3730                                 Name, TypeManager.CSharpName (target));
3731                 }
3732
3733                 protected virtual int GetApplicableParametersCount (MethodBase method, ParameterData parameters)
3734                 {
3735                         return parameters.Count;
3736                 }
3737
3738                 public static bool IsAncestralType (Type first_type, Type second_type)
3739                 {
3740                         return first_type != second_type &&
3741                                 (TypeManager.IsSubclassOf (second_type, first_type) ||
3742                                 TypeManager.ImplementsInterface (second_type, first_type));
3743                 }
3744
3745                 ///
3746                 /// Determines if the candidate method is applicable (section 14.4.2.1)
3747                 /// to the given set of arguments
3748                 /// A return value rates candidate method compatibility,
3749                 /// 0 = the best, int.MaxValue = the worst
3750                 ///
3751                 public int IsApplicable (EmitContext ec,
3752                                                  ArrayList arguments, int arg_count, ref MethodBase method, ref bool params_expanded_form)
3753                 {
3754                         MethodBase candidate = method;
3755
3756                         ParameterData pd = TypeManager.GetParameterData (candidate);
3757                         int param_count = GetApplicableParametersCount (candidate, pd);
3758
3759                         if (arg_count != param_count) {
3760                                 if (!pd.HasParams)
3761                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3762                                 if (arg_count < param_count - 1)
3763                                         return int.MaxValue - 10000 + Math.Abs (arg_count - param_count);
3764                         }
3765
3766 #if GMCS_SOURCE
3767                         //
3768                         // 1. Handle generic method using type arguments when specified or type inference
3769                         //
3770                         if (TypeManager.IsGenericMethod (candidate)) {
3771                                 if (type_arguments != null) {
3772                                         Type [] g_args = candidate.GetGenericArguments ();
3773                                         if (g_args.Length != type_arguments.Count)
3774                                                 return int.MaxValue - 20000 + Math.Abs (type_arguments.Count - g_args.Length);
3775
3776                                         // TODO: Don't create new method, create Parameters only
3777                                         method = ((MethodInfo) candidate).MakeGenericMethod (type_arguments.Arguments);
3778                                         candidate = method;
3779                                         pd = TypeManager.GetParameterData (candidate);
3780                                 } else {
3781                                         int score = TypeManager.InferTypeArguments (ec, arguments, ref candidate);
3782                                         if (score != 0)
3783                                                 return score - 20000;
3784
3785                                         if (TypeManager.IsGenericMethodDefinition (candidate))
3786                                                 throw new InternalErrorException ("A generic method `{0}' definition took part in overload resolution",
3787                                                         TypeManager.CSharpSignature (candidate));
3788
3789                                         pd = TypeManager.GetParameterData (candidate);
3790                                 }
3791                         } else {
3792                                 if (type_arguments != null)
3793                                         return int.MaxValue - 15000;
3794                         }
3795 #endif
3796
3797                         //
3798                         // 2. Each argument has to be implicitly convertible to method parameter
3799                         //
3800                         method = candidate;
3801                         Parameter.Modifier p_mod = 0;
3802                         Type pt = null;
3803                         for (int i = 0; i < arg_count; i++) {
3804                                 Argument a = (Argument) arguments [i];
3805                                 Parameter.Modifier a_mod = a.Modifier &
3806                                         ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3807
3808                                 if (p_mod != Parameter.Modifier.PARAMS) {
3809                                         p_mod = pd.ParameterModifier (i) & ~(Parameter.Modifier.OUTMASK | Parameter.Modifier.REFMASK);
3810
3811                                         if (p_mod == Parameter.Modifier.ARGLIST) {
3812                                                 if (a.Type == TypeManager.runtime_argument_handle_type)
3813                                                         continue;
3814
3815                                                 p_mod = 0;
3816                                         }
3817
3818                                         pt = pd.ParameterType (i);
3819                                 } else {
3820                                         params_expanded_form = true;
3821                                 }
3822
3823                                 int score = 1;
3824                                 if (!params_expanded_form)
3825                                         score = IsArgumentCompatible (ec, a_mod, a, p_mod & ~Parameter.Modifier.PARAMS, pt);
3826
3827                                 if (score != 0 && (p_mod & Parameter.Modifier.PARAMS) != 0) {
3828                                         // It can be applicable in expanded form
3829                                         score = IsArgumentCompatible (ec, a_mod, a, 0, pt.GetElementType ());
3830                                         if (score == 0)
3831                                                 params_expanded_form = true;
3832                                 }
3833
3834                                 if (score != 0) {
3835                                         if (params_expanded_form)
3836                                                 ++score;
3837                                         return (arg_count - i) * 2 + score;
3838                                 }
3839                         }
3840
3841                         if (arg_count != param_count)
3842                                 params_expanded_form = true;
3843
3844                         return 0;
3845                 }
3846
3847                 int IsArgumentCompatible (EmitContext ec, Parameter.Modifier arg_mod, Argument argument, Parameter.Modifier param_mod, Type parameter)
3848                 {
3849                         //
3850                         // Types have to be identical when ref or out modifer is used
3851                         //
3852                         if (arg_mod != 0 || param_mod != 0) {
3853                                 if (TypeManager.HasElementType (parameter))
3854                                         parameter = parameter.GetElementType ();
3855
3856                                 Type a_type = argument.Type;
3857                                 if (TypeManager.HasElementType (a_type))
3858                                         a_type = a_type.GetElementType ();
3859
3860                                 if (a_type != parameter)
3861                                         return 2;
3862
3863                                 return 0;
3864                         }
3865
3866                         if (delegate_type != null ?
3867                                 !Delegate.IsTypeCovariant (argument.Expr, parameter) :
3868                                 !Convert.ImplicitConversionExists (ec, argument.Expr, parameter))
3869                                 return 2;
3870
3871                         if (arg_mod != param_mod)
3872                                 return 1;
3873
3874                         return 0;
3875                 }
3876
3877                 public static bool IsOverride (MethodBase cand_method, MethodBase base_method)
3878                 {
3879                         if (!IsAncestralType (base_method.DeclaringType, cand_method.DeclaringType))
3880                                 return false;
3881
3882                         ParameterData cand_pd = TypeManager.GetParameterData (cand_method);
3883                         ParameterData base_pd = TypeManager.GetParameterData (base_method);
3884
3885                         if (cand_pd.Count != base_pd.Count)
3886                                 return false;
3887
3888                         for (int j = 0; j < cand_pd.Count; ++j)
3889                         {
3890                                 Parameter.Modifier cm = cand_pd.ParameterModifier (j);
3891                                 Parameter.Modifier bm = base_pd.ParameterModifier (j);
3892                                 Type ct = TypeManager.TypeToCoreType (cand_pd.ParameterType (j));
3893                                 Type bt = TypeManager.TypeToCoreType (base_pd.ParameterType (j));
3894
3895                                 if (cm != bm || ct != bt)
3896                                         return false;
3897                         }
3898
3899                         return true;
3900                 }
3901
3902                 public static MethodGroupExpr MakeUnionSet (Expression mg1, Expression mg2, Location loc)
3903                 {
3904                         MemberInfo [] miset;
3905                         MethodGroupExpr union;
3906
3907                         if (mg1 == null) {
3908                                 if (mg2 == null)
3909                                         return null;
3910                                 return (MethodGroupExpr) mg2;
3911                         } else {
3912                                 if (mg2 == null)
3913                                         return (MethodGroupExpr) mg1;
3914                         }
3915
3916                         MethodGroupExpr left_set = null, right_set = null;
3917                         int length1 = 0, length2 = 0;
3918
3919                         left_set = (MethodGroupExpr) mg1;
3920                         length1 = left_set.Methods.Length;
3921
3922                         right_set = (MethodGroupExpr) mg2;
3923                         length2 = right_set.Methods.Length;
3924
3925                         ArrayList common = new ArrayList ();
3926
3927                         foreach (MethodBase r in right_set.Methods){
3928                                 if (TypeManager.ArrayContainsMethod (left_set.Methods, r))
3929                                         common.Add (r);
3930                         }
3931
3932                         miset = new MemberInfo [length1 + length2 - common.Count];
3933                         left_set.Methods.CopyTo (miset, 0);
3934
3935                         int k = length1;
3936
3937                         foreach (MethodBase r in right_set.Methods) {
3938                                 if (!common.Contains (r))
3939                                         miset [k++] = r;
3940                         }
3941
3942                         union = new MethodGroupExpr (miset, mg1.Type, loc);
3943
3944                         return union;
3945                 }
3946
3947                 static Type MoreSpecific (Type p, Type q)
3948                 {
3949                         if (TypeManager.IsGenericParameter (p) && !TypeManager.IsGenericParameter (q))
3950                                 return q;
3951                         if (!TypeManager.IsGenericParameter (p) && TypeManager.IsGenericParameter (q))
3952                                 return p;
3953
3954                         if (TypeManager.HasElementType (p))
3955                         {
3956                                 Type pe = TypeManager.GetElementType (p);
3957                                 Type qe = TypeManager.GetElementType (q);
3958                                 Type specific = MoreSpecific (pe, qe);
3959                                 if (specific == pe)
3960                                         return p;
3961                                 if (specific == qe)
3962                                         return q;
3963                         }
3964                         else if (TypeManager.IsGenericType (p))
3965                         {
3966                                 Type[] pargs = TypeManager.GetTypeArguments (p);
3967                                 Type[] qargs = TypeManager.GetTypeArguments (q);
3968
3969                                 bool p_specific_at_least_once = false;
3970                                 bool q_specific_at_least_once = false;
3971
3972                                 for (int i = 0; i < pargs.Length; i++)
3973                                 {
3974                                         Type specific = MoreSpecific (pargs [i], qargs [i]);
3975                                         if (specific == pargs [i])
3976                                                 p_specific_at_least_once = true;
3977                                         if (specific == qargs [i])
3978                                                 q_specific_at_least_once = true;
3979                                 }
3980
3981                                 if (p_specific_at_least_once && !q_specific_at_least_once)
3982                                         return p;
3983                                 if (!p_specific_at_least_once && q_specific_at_least_once)
3984                                         return q;
3985                         }
3986
3987                         return null;
3988                 }
3989
3990                 /// <summary>
3991                 ///   Find the Applicable Function Members (7.4.2.1)
3992                 ///
3993                 ///   me: Method Group expression with the members to select.
3994                 ///       it might contain constructors or methods (or anything
3995                 ///       that maps to a method).
3996                 ///
3997                 ///   Arguments: ArrayList containing resolved Argument objects.
3998                 ///
3999                 ///   loc: The location if we want an error to be reported, or a Null
4000                 ///        location for "probing" purposes.
4001                 ///
4002                 ///   Returns: The MethodBase (either a ConstructorInfo or a MethodInfo)
4003                 ///            that is the best match of me on Arguments.
4004                 ///
4005                 /// </summary>
4006                 public virtual MethodGroupExpr OverloadResolve (EmitContext ec, ref ArrayList Arguments,
4007                         bool may_fail, Location loc)
4008                 {
4009                         bool method_params = false;
4010                         Type applicable_type = null;
4011                         int arg_count = 0;
4012                         ArrayList candidates = new ArrayList (2);
4013                         ArrayList candidate_overrides = null;
4014
4015                         //
4016                         // Used to keep a map between the candidate
4017                         // and whether it is being considered in its
4018                         // normal or expanded form
4019                         //
4020                         // false is normal form, true is expanded form
4021                         //
4022                         Hashtable candidate_to_form = null;
4023
4024                         if (Arguments != null)
4025                                 arg_count = Arguments.Count;
4026
4027                         if (RootContext.Version == LanguageVersion.ISO_1 && Name == "Invoke" && TypeManager.IsDelegateType (DeclaringType)) {
4028                                 if (!may_fail)
4029                                         Report.Error (1533, loc, "Invoke cannot be called directly on a delegate");
4030                                 return null;
4031                         }
4032
4033                         int nmethods = Methods.Length;
4034
4035                         if (!IsBase) {
4036                                 //
4037                                 // Methods marked 'override' don't take part in 'applicable_type'
4038                                 // computation, nor in the actual overload resolution.
4039                                 // However, they still need to be emitted instead of a base virtual method.
4040                                 // So, we salt them away into the 'candidate_overrides' array.
4041                                 //
4042                                 // In case of reflected methods, we replace each overriding method with
4043                                 // its corresponding base virtual method.  This is to improve compatibility
4044                                 // with non-C# libraries which change the visibility of overrides (#75636)
4045                                 //
4046                                 int j = 0;
4047                                 for (int i = 0; i < Methods.Length; ++i) {
4048                                         MethodBase m = Methods [i];
4049                                         if (TypeManager.IsOverride (m)) {
4050                                                 if (candidate_overrides == null)
4051                                                         candidate_overrides = new ArrayList ();
4052                                                 candidate_overrides.Add (m);
4053                                                 m = TypeManager.TryGetBaseDefinition (m);
4054                                         }
4055                                         if (m != null)
4056                                                 Methods [j++] = m;
4057                                 }
4058                                 nmethods = j;
4059                         }
4060
4061                         //
4062                         // Enable message recording, it's used mainly by lambda expressions
4063                         //
4064                         Report.IMessageRecorder msg_recorder = new Report.MessageRecorder ();
4065                         Report.IMessageRecorder prev_recorder = Report.SetMessageRecorder (msg_recorder);
4066
4067                         //
4068                         // First we construct the set of applicable methods
4069                         //
4070                         bool is_sorted = true;
4071                         int best_candidate_rate = int.MaxValue;
4072                         for (int i = 0; i < nmethods; i++) {
4073                                 Type decl_type = Methods [i].DeclaringType;
4074
4075                                 //
4076                                 // If we have already found an applicable method
4077                                 // we eliminate all base types (Section 14.5.5.1)
4078                                 //
4079                                 if (applicable_type != null && IsAncestralType (decl_type, applicable_type))
4080                                         continue;
4081
4082                                 //
4083                                 // Check if candidate is applicable (section 14.4.2.1)
4084                                 //
4085                                 bool params_expanded_form = false;
4086                                 int candidate_rate = IsApplicable (ec, Arguments, arg_count, ref Methods [i], ref params_expanded_form);
4087
4088                                 if (candidate_rate < best_candidate_rate) {
4089                                         best_candidate_rate = candidate_rate;
4090                                         best_candidate = Methods [i];
4091                                 }
4092
4093                                 if (params_expanded_form) {
4094                                         if (candidate_to_form == null)
4095                                                 candidate_to_form = new PtrHashtable ();
4096                                         MethodBase candidate = Methods [i];
4097                                         candidate_to_form [candidate] = candidate;
4098                                 }
4099
4100                                 if (candidate_rate != 0) {
4101                                         if (msg_recorder != null)
4102                                                 msg_recorder.EndSession ();
4103                                         continue;
4104                                 }
4105
4106                                 msg_recorder = null;
4107                                 candidates.Add (Methods [i]);
4108
4109                                 if (applicable_type == null)
4110                                         applicable_type = decl_type;
4111                                 else if (applicable_type != decl_type) {
4112                                         is_sorted = false;
4113                                         if (IsAncestralType (applicable_type, decl_type))
4114                                                 applicable_type = decl_type;
4115                                 }
4116                         }
4117
4118                         Report.SetMessageRecorder (prev_recorder);
4119                         if (msg_recorder != null && msg_recorder.PrintMessages ())
4120                                 return null;
4121
4122                         int candidate_top = candidates.Count;
4123
4124                         if (applicable_type == null) {
4125                                 //
4126                                 // When we found a top level method which does not match and it's
4127                                 // not an extension method. We start extension methods lookup from here
4128                                 //
4129                                 if (InstanceExpression != null) {
4130                                         ExtensionMethodGroupExpr ex_method_lookup = ec.TypeContainer.LookupExtensionMethod (type, Name, loc);
4131                                         if (ex_method_lookup != null) {
4132                                                 ex_method_lookup.ExtensionExpression = InstanceExpression;
4133                                                 ex_method_lookup.SetTypeArguments (type_arguments);
4134                                                 return ex_method_lookup.OverloadResolve (ec, ref Arguments, may_fail, loc);
4135                                         }
4136                                 }
4137
4138                                 if (may_fail)
4139                                         return null;
4140
4141                                 //
4142                                 // Okay so we have failed to find exact match so we
4143                                 // return error info about the closest match
4144                                 //
4145                                 if (best_candidate != null) {
4146                                         if (CustomErrorHandler != null) {
4147                                                 if (CustomErrorHandler.NoExactMatch (ec, best_candidate))
4148                                                         return null;
4149                                         }
4150
4151                                         ParameterData pd = TypeManager.GetParameterData (best_candidate);
4152                                         bool cand_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4153                                         if (arg_count == pd.Count || pd.HasParams) {
4154                                                 if (TypeManager.IsGenericMethodDefinition (best_candidate)) {
4155                                                         if (type_arguments == null) {
4156                                                                 Report.Error (411, loc,
4157                                                                         "The type arguments for method `{0}' cannot be inferred from " +
4158                                                                         "the usage. Try specifying the type arguments explicitly",
4159                                                                         TypeManager.CSharpSignature (best_candidate));
4160                                                                 return null;
4161                                                         }
4162
4163                                                         Type [] g_args = TypeManager.GetGenericArguments (best_candidate);
4164                                                         if (type_arguments.Count != g_args.Length) {
4165                                                                 Report.SymbolRelatedToPreviousError (best_candidate);
4166                                                                 Report.Error (305, loc, "Using the generic method `{0}' requires `{1}' type argument(s)",
4167                                                                         TypeManager.CSharpSignature (best_candidate),
4168                                                                         g_args.Length.ToString ());
4169                                                                 return null;
4170                                                         }
4171                                                 } else {
4172                                                         if (type_arguments != null && !TypeManager.IsGenericMethod (best_candidate)) {
4173                                                                 Namespace.Error_TypeArgumentsCannotBeUsed (best_candidate, loc);
4174                                                                 return null;
4175                                                         }
4176                                                 }
4177
4178                                                 if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate, cand_params, may_fail, loc))
4179                                                         return null;
4180                                         }
4181                                 }
4182
4183                                 if (almost_matched_members.Count != 0) {
4184                                         Error_MemberLookupFailed (ec.ContainerType, type, type, ".ctor",
4185                                         null, MemberTypes.Constructor, AllBindingFlags);
4186                                         return null;
4187                                 }
4188
4189                                 //
4190                                 // We failed to find any method with correct argument count
4191                                 //
4192                                 if (Name == ConstructorInfo.ConstructorName) {
4193                                         Report.SymbolRelatedToPreviousError (type);
4194                                         Report.Error (1729, loc,
4195                                                 "The type `{0}' does not contain a constructor that takes `{1}' arguments",
4196                                                 TypeManager.CSharpName (type), arg_count);
4197                                 } else {
4198                                         Report.Error (1501, loc, "No overload for method `{0}' takes `{1}' arguments",
4199                                                 Name, arg_count.ToString ());
4200                                 }
4201
4202                                 return null;
4203                         }
4204
4205                         if (!is_sorted) {
4206                                 //
4207                                 // At this point, applicable_type is _one_ of the most derived types
4208                                 // in the set of types containing the methods in this MethodGroup.
4209                                 // Filter the candidates so that they only contain methods from the
4210                                 // most derived types.
4211                                 //
4212
4213                                 int finalized = 0; // Number of finalized candidates
4214
4215                                 do {
4216                                         // Invariant: applicable_type is a most derived type
4217
4218                                         // We'll try to complete Section 14.5.5.1 for 'applicable_type' by
4219                                         // eliminating all it's base types.  At the same time, we'll also move
4220                                         // every unrelated type to the end of the array, and pick the next
4221                                         // 'applicable_type'.
4222
4223                                         Type next_applicable_type = null;
4224                                         int j = finalized; // where to put the next finalized candidate
4225                                         int k = finalized; // where to put the next undiscarded candidate
4226                                         for (int i = finalized; i < candidate_top; ++i) {
4227                                                 MethodBase candidate = (MethodBase) candidates [i];
4228                                                 Type decl_type = candidate.DeclaringType;
4229
4230                                                 if (decl_type == applicable_type) {
4231                                                         candidates [k++] = candidates [j];
4232                                                         candidates [j++] = candidates [i];
4233                                                         continue;
4234                                                 }
4235
4236                                                 if (IsAncestralType (decl_type, applicable_type))
4237                                                         continue;
4238
4239                                                 if (next_applicable_type != null &&
4240                                                         IsAncestralType (decl_type, next_applicable_type))
4241                                                         continue;
4242
4243                                                 candidates [k++] = candidates [i];
4244
4245                                                 if (next_applicable_type == null ||
4246                                                         IsAncestralType (next_applicable_type, decl_type))
4247                                                         next_applicable_type = decl_type;
4248                                         }
4249
4250                                         applicable_type = next_applicable_type;
4251                                         finalized = j;
4252                                         candidate_top = k;
4253                                 } while (applicable_type != null);
4254                         }
4255
4256                         //
4257                         // Now we actually find the best method
4258                         //
4259
4260                         best_candidate = (MethodBase) candidates [0];
4261                         if (delegate_type == null)
4262                                 method_params = candidate_to_form != null && candidate_to_form.Contains (best_candidate);
4263
4264                         for (int ix = 1; ix < candidate_top; ix++) {
4265                                 MethodBase candidate = (MethodBase) candidates [ix];
4266
4267                                 if (candidate == best_candidate)
4268                                         continue;
4269
4270                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4271
4272                                 if (BetterFunction (ec, Arguments, arg_count,
4273                                         candidate, cand_params,
4274                                         best_candidate, method_params)) {
4275                                         best_candidate = candidate;
4276                                         method_params = cand_params;
4277                                 }
4278                         }
4279                         //
4280                         // Now check that there are no ambiguities i.e the selected method
4281                         // should be better than all the others
4282                         //
4283                         MethodBase ambiguous = null;
4284                         for (int ix = 1; ix < candidate_top; ix++) {
4285                                 MethodBase candidate = (MethodBase) candidates [ix];
4286
4287                                 if (candidate == best_candidate)
4288                                         continue;
4289
4290                                 bool cand_params = candidate_to_form != null && candidate_to_form.Contains (candidate);
4291                                 if (!BetterFunction (ec, Arguments, arg_count,
4292                                         best_candidate, method_params,
4293                                         candidate, cand_params))
4294                                 {
4295                                         if (!may_fail)
4296                                                 Report.SymbolRelatedToPreviousError (candidate);
4297                                         ambiguous = candidate;
4298                                 }
4299                         }
4300
4301                         if (ambiguous != null) {
4302                                 Report.SymbolRelatedToPreviousError (best_candidate);
4303                                 Report.Error (121, loc, "The call is ambiguous between the following methods or properties: `{0}' and `{1}'",
4304                                         TypeManager.CSharpSignature (ambiguous), TypeManager.CSharpSignature (best_candidate));
4305                                 return this;
4306                         }
4307
4308                         //
4309                         // If the method is a virtual function, pick an override closer to the LHS type.
4310                         //
4311                         if (!IsBase && best_candidate.IsVirtual) {
4312                                 if (TypeManager.IsOverride (best_candidate))
4313                                         throw new InternalErrorException (
4314                                                 "Should not happen.  An 'override' method took part in overload resolution: " + best_candidate);
4315
4316                                 if (candidate_overrides != null) {
4317                                         Type[] gen_args = null;
4318                                         bool gen_override = false;
4319                                         if (TypeManager.IsGenericMethod (best_candidate))
4320                                                 gen_args = TypeManager.GetGenericArguments (best_candidate);
4321
4322                                         foreach (MethodBase candidate in candidate_overrides) {
4323                                                 if (TypeManager.IsGenericMethod (candidate)) {
4324                                                         if (gen_args == null)
4325                                                                 continue;
4326
4327                                                         if (gen_args.Length != TypeManager.GetGenericArguments (candidate).Length)
4328                                                                 continue;
4329                                                 } else {
4330                                                         if (gen_args != null)
4331                                                                 continue;
4332                                                 }
4333
4334                                                 if (IsOverride (candidate, best_candidate)) {
4335                                                         gen_override = true;
4336                                                         best_candidate = candidate;
4337                                                 }
4338                                         }
4339
4340                                         if (gen_override && gen_args != null) {
4341 #if GMCS_SOURCE
4342                                                 best_candidate = ((MethodInfo) best_candidate).MakeGenericMethod (gen_args);
4343 #endif
4344                                         }
4345                                 }
4346                         }
4347
4348                         //
4349                         // And now check if the arguments are all
4350                         // compatible, perform conversions if
4351                         // necessary etc. and return if everything is
4352                         // all right
4353                         //
4354                         if (!VerifyArgumentsCompat (ec, ref Arguments, arg_count, best_candidate,
4355                                 method_params, may_fail, loc))
4356                                 return null;
4357
4358                         if (best_candidate == null)
4359                                 return null;
4360
4361                         MethodBase the_method = TypeManager.DropGenericMethodArguments (best_candidate);
4362 #if GMCS_SOURCE
4363                         if (the_method.IsGenericMethodDefinition &&
4364                             !ConstraintChecker.CheckConstraints (ec, the_method, best_candidate, loc))
4365                                 return null;
4366 #endif
4367
4368                         IMethodData data = TypeManager.GetMethod (the_method);
4369                         if (data != null)
4370                                 data.SetMemberIsUsed ();
4371
4372                         return this;
4373                 }
4374
4375                 public override void SetTypeArguments (TypeArguments ta)
4376                 {
4377                         type_arguments = ta;
4378                 }
4379
4380                 public bool VerifyArgumentsCompat (EmitContext ec, ref ArrayList arguments,
4381                                                           int arg_count, MethodBase method,
4382                                                           bool chose_params_expanded,
4383                                                           bool may_fail, Location loc)
4384                 {
4385                         ParameterData pd = TypeManager.GetParameterData (method);
4386
4387                         int errors = Report.Errors;
4388                         Parameter.Modifier p_mod = 0;
4389                         Type pt = null;
4390                         int a_idx = 0, a_pos = 0;
4391                         Argument a = null;
4392                         ArrayList params_initializers = null;
4393
4394                         for (; a_idx < arg_count; a_idx++, ++a_pos) {
4395                                 a = (Argument) arguments [a_idx];
4396                                 if (p_mod != Parameter.Modifier.PARAMS) {
4397                                         p_mod = pd.ParameterModifier (a_idx);
4398                                         pt = pd.ParameterType (a_idx);
4399
4400                                         if (p_mod == Parameter.Modifier.ARGLIST) {
4401                                                 if (a.Type != TypeManager.runtime_argument_handle_type)
4402                                                         break;
4403                                                 continue;
4404                                         }
4405
4406                                         if (pt.IsPointer && !ec.InUnsafe) {
4407                                                 if (may_fail)
4408                                                         return false;
4409
4410                                                 UnsafeError (loc);
4411                                         }
4412
4413                                         if (p_mod == Parameter.Modifier.PARAMS) {
4414                                                 if (chose_params_expanded) {
4415                                                         params_initializers = new ArrayList (arg_count - a_idx);
4416                                                         pt = TypeManager.GetElementType (pt);
4417                                                 }
4418                                         } else if (p_mod != 0) {
4419                                                 pt = TypeManager.GetElementType (pt);
4420                                         }
4421                                 }
4422
4423                                 //
4424                                 // Types have to be identical when ref or out modifer is used
4425                                 //
4426                                 if (a.Modifier != 0 || (p_mod & ~Parameter.Modifier.PARAMS) != 0) {
4427                                         if ((p_mod & ~Parameter.Modifier.PARAMS) != a.Modifier)
4428                                                 break;
4429
4430                                         if (!TypeManager.IsEqual (a.Expr.Type, pt))
4431                                                 break;
4432
4433                                         continue;
4434                                 }
4435
4436                                 Expression conv;
4437                                 if (TypeManager.IsEqual (a.Type, pt)) {
4438                                         conv = a.Expr;
4439                                 } else {
4440                                         conv = Convert.ImplicitConversion (ec, a.Expr, pt, loc);
4441                                         if (conv == null)
4442                                                 break;
4443                                 }
4444
4445                                 //
4446                                 // Convert params arguments to an array initializer
4447                                 //
4448                                 if (params_initializers != null) {
4449                                         // we choose to use 'a.Expr' rather than 'conv' so that
4450                                         // we don't hide the kind of expression we have (esp. CompoundAssign.Helper)
4451                                         params_initializers.Add (a.Expr);
4452                                         arguments.RemoveAt (a_idx--);
4453                                         --arg_count;
4454                                         continue;
4455                                 }
4456
4457                                 // Update the argument with the implicit conversion
4458                                 a.Expr = conv;
4459                         }
4460
4461                         //
4462                         // Fill not provided arguments required by params modifier
4463                         //
4464                         if (params_initializers == null && pd.HasParams && arg_count < pd.Count && a_idx + 1 == pd.Count) {
4465                                 if (arguments == null)
4466                                         arguments = new ArrayList (1);
4467
4468                                 pt = pd.Types [GetApplicableParametersCount (method, pd) - 1];
4469                                 pt = TypeManager.GetElementType (pt);
4470                                 params_initializers = new ArrayList (0);
4471                         }
4472
4473                         if (a_idx == arg_count) {
4474                                 //
4475                                 // Append an array argument with all params arguments
4476                                 //
4477                                 if (params_initializers != null) {
4478                                         arguments.Add (new Argument (
4479                                                 new ArrayCreation (new TypeExpression (pt, loc), "[]",
4480                                                 params_initializers, loc).Resolve (ec)));
4481                                 }
4482                                 return true;
4483                         }
4484
4485                         if (!may_fail && Report.Errors == errors) {
4486                                 if (CustomErrorHandler != null)
4487                                         CustomErrorHandler.NoExactMatch (ec, best_candidate);
4488                                 else
4489                                         Error_InvalidArguments (ec, loc, a_pos, method, a, pd, pt);
4490                         }
4491                         return false;
4492                 }
4493         }
4494
4495         public class ConstantExpr : MemberExpr
4496         {
4497                 FieldInfo constant;
4498
4499                 public ConstantExpr (FieldInfo constant, Location loc)
4500                 {
4501                         this.constant = constant;
4502                         this.loc = loc;
4503                 }
4504
4505                 public override string Name {
4506                         get { throw new NotImplementedException (); }
4507                 }
4508
4509                 public override bool IsInstance {
4510                         get { return !IsStatic; }
4511                 }
4512
4513                 public override bool IsStatic {
4514                         get { return constant.IsStatic; }
4515                 }
4516
4517                 public override Type DeclaringType {
4518                         get { return constant.DeclaringType; }
4519                 }
4520
4521                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc, SimpleName original)
4522                 {
4523                         constant = TypeManager.GetGenericFieldDefinition (constant);
4524
4525                         IConstant ic = TypeManager.GetConstant (constant);
4526                         if (ic == null) {
4527                                 if (constant.IsLiteral) {
4528                                         ic = new ExternalConstant (constant);
4529                                 } else {
4530                                         ic = ExternalConstant.CreateDecimal (constant);
4531                                         // HACK: decimal field was not resolved as constant
4532                                         if (ic == null)
4533                                                 return new FieldExpr (constant, loc).ResolveMemberAccess (ec, left, loc, original);
4534                                 }
4535                                 TypeManager.RegisterConstant (constant, ic);
4536                         }
4537
4538                         return base.ResolveMemberAccess (ec, left, loc, original);
4539                 }
4540
4541                 public override Expression CreateExpressionTree (EmitContext ec)
4542                 {
4543                         throw new NotSupportedException ("ET");
4544                 }
4545
4546                 public override Expression DoResolve (EmitContext ec)
4547                 {
4548                         IConstant ic = TypeManager.GetConstant (constant);
4549                         if (ic.ResolveValue ()) {
4550                                 if (!ec.IsInObsoleteScope)
4551                                         ic.CheckObsoleteness (loc);
4552                         }
4553
4554                         return ic.CreateConstantReference (loc);
4555                 }
4556
4557                 public override void Emit (EmitContext ec)
4558                 {
4559                         throw new NotSupportedException ();
4560                 }
4561
4562                 public override string GetSignatureForError ()
4563                 {
4564                         return TypeManager.GetFullNameSignature (constant);
4565                 }
4566         }
4567
4568         /// <summary>
4569         ///   Fully resolved expression that evaluates to a Field
4570         /// </summary>
4571         public class FieldExpr : MemberExpr, IAssignMethod, IMemoryLocation, IVariable {
4572                 public readonly FieldInfo FieldInfo;
4573                 VariableInfo variable_info;
4574
4575                 LocalTemporary temp;
4576                 bool prepared;
4577                 bool in_initializer;
4578
4579                 public FieldExpr (FieldInfo fi, Location l, bool in_initializer):
4580                         this (fi, l)
4581                 {
4582                         this.in_initializer = in_initializer;
4583                 }
4584
4585                 public FieldExpr (FieldInfo fi, Location l)
4586                 {
4587                         FieldInfo = fi;
4588                         eclass = ExprClass.Variable;
4589                         type = TypeManager.TypeToCoreType (fi.FieldType);
4590                         loc = l;
4591                 }
4592
4593                 public override string Name {
4594                         get {
4595                                 return FieldInfo.Name;
4596                         }
4597                 }
4598
4599                 public override bool IsInstance {
4600                         get {
4601                                 return !FieldInfo.IsStatic;
4602                         }
4603                 }
4604
4605                 public override bool IsStatic {
4606                         get {
4607                                 return FieldInfo.IsStatic;
4608                         }
4609                 }
4610
4611                 public override Type DeclaringType {
4612                         get {
4613                                 return FieldInfo.DeclaringType;
4614                         }
4615                 }
4616
4617                 public override string GetSignatureForError ()
4618                 {
4619                         return TypeManager.GetFullNameSignature (FieldInfo);
4620                 }
4621
4622                 public VariableInfo VariableInfo {
4623                         get {
4624                                 return variable_info;
4625                         }
4626                 }
4627
4628                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
4629                                                                 SimpleName original)
4630                 {
4631                         FieldInfo fi = TypeManager.GetGenericFieldDefinition (FieldInfo);
4632                         Type t = fi.FieldType;
4633
4634                         if (t.IsPointer && !ec.InUnsafe) {
4635                                 UnsafeError (loc);
4636                         }
4637
4638                         return base.ResolveMemberAccess (ec, left, loc, original);
4639                 }
4640
4641                 public override Expression CreateExpressionTree (EmitContext ec)
4642                 {
4643                         Expression instance;
4644                         if (InstanceExpression == null) {
4645                                 instance = new NullLiteral (loc);
4646                         } else {
4647                                 instance = InstanceExpression.CreateExpressionTree (ec);
4648                         }
4649
4650                         ArrayList args = new ArrayList (2);
4651                         args.Add (new Argument (instance));
4652                         args.Add (new Argument (CreateTypeOfExpression ()));
4653                         return CreateExpressionFactoryCall ("Field", args);
4654                 }
4655
4656                 public Expression CreateTypeOfExpression ()
4657                 {
4658                         return new TypeOfField (FieldInfo, loc);
4659                 }
4660
4661                 override public Expression DoResolve (EmitContext ec)
4662                 {
4663                         return DoResolve (ec, false, false);
4664                 }
4665
4666                 Expression DoResolve (EmitContext ec, bool lvalue_instance, bool out_access)
4667                 {
4668                         if (!FieldInfo.IsStatic){
4669                                 if (InstanceExpression == null){
4670                                         //
4671                                         // This can happen when referencing an instance field using
4672                                         // a fully qualified type expression: TypeName.InstanceField = xxx
4673                                         //
4674                                         SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
4675                                         return null;
4676                                 }
4677
4678                                 // Resolve the field's instance expression while flow analysis is turned
4679                                 // off: when accessing a field "a.b", we must check whether the field
4680                                 // "a.b" is initialized, not whether the whole struct "a" is initialized.
4681
4682                                 if (lvalue_instance) {
4683                                         using (ec.With (EmitContext.Flags.DoFlowAnalysis, false)) {
4684                                                 Expression right_side =
4685                                                         out_access ? EmptyExpression.LValueMemberOutAccess : EmptyExpression.LValueMemberAccess;
4686                                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, right_side, loc);
4687                                         }
4688                                 } else {
4689                                         ResolveFlags rf = ResolveFlags.VariableOrValue | ResolveFlags.DisableFlowAnalysis;
4690                                         InstanceExpression = InstanceExpression.Resolve (ec, rf);
4691                                 }
4692
4693                                 if (InstanceExpression == null)
4694                                         return null;
4695
4696                                 using (ec.Set (EmitContext.Flags.OmitStructFlowAnalysis)) {
4697                                         InstanceExpression.CheckMarshalByRefAccess (ec);
4698                                 }
4699                         }
4700
4701                         if (!in_initializer && !ec.IsInFieldInitializer) {
4702                                 ObsoleteAttribute oa;
4703                                 FieldBase f = TypeManager.GetField (FieldInfo);
4704                                 if (f != null) {
4705                                         if (!ec.IsInObsoleteScope)
4706                                                 f.CheckObsoleteness (loc);
4707
4708                                         // To be sure that type is external because we do not register generated fields
4709                                 } else if (!(FieldInfo.DeclaringType is TypeBuilder)) {
4710                                         oa = AttributeTester.GetMemberObsoleteAttribute (FieldInfo);
4711                                         if (oa != null)
4712                                                 AttributeTester.Report_ObsoleteMessage (oa, TypeManager.GetFullNameSignature (FieldInfo), loc);
4713                                 }
4714                         }
4715
4716                         AnonymousContainer am = ec.CurrentAnonymousMethod;
4717                         if (am != null){
4718                                 if (!FieldInfo.IsStatic){
4719                                         if (!am.IsIterator && (ec.TypeContainer is Struct)){
4720                                                 Report.Error (1673, loc,
4721                                                 "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",
4722                                                         "this");
4723                                                 return null;
4724                                         }
4725                                 }
4726                         }
4727
4728                         IFixedBuffer fb = AttributeTester.GetFixedBuffer (FieldInfo);
4729                         if (fb != null) {
4730                                 if (!ec.InFixedInitializer && ec.ContainerType.IsValueType) {
4731                                         Report.Error (1666, loc, "You cannot use fixed size buffers contained in unfixed expressions. Try using the fixed statement");
4732                                 }
4733
4734                                 if (InstanceExpression.eclass != ExprClass.Variable) {
4735                                         Report.SymbolRelatedToPreviousError (FieldInfo);
4736                                         Report.Error (1708, loc, "`{0}': Fixed size buffers can only be accessed through locals or fields",
4737                                                 TypeManager.GetFullNameSignature (FieldInfo));
4738                                 }
4739
4740                                 return new FixedBufferPtr (this, fb.ElementType, loc).Resolve (ec);
4741                         }
4742
4743                         // If the instance expression is a local variable or parameter.
4744                         IVariable var = InstanceExpression as IVariable;
4745                         if (var == null || var.VariableInfo == null)
4746                                 return this;
4747
4748                         VariableInfo vi = var.VariableInfo;
4749                         if (!vi.IsFieldAssigned (ec, FieldInfo.Name, loc))
4750                                 return null;
4751
4752                         variable_info = vi.GetSubStruct (FieldInfo.Name);
4753                         return this;
4754                 }
4755
4756                 static readonly int [] codes = {
4757                         191,    // instance, write access
4758                         192,    // instance, out access
4759                         198,    // static, write access
4760                         199,    // static, out access
4761                         1648,   // member of value instance, write access
4762                         1649,   // member of value instance, out access
4763                         1650,   // member of value static, write access
4764                         1651    // member of value static, out access
4765                 };
4766
4767                 static readonly string [] msgs = {
4768                         /*0191*/ "A readonly field `{0}' cannot be assigned to (except in a constructor or a variable initializer)",
4769                         /*0192*/ "A readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4770                         /*0198*/ "A static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4771                         /*0199*/ "A static readonly field `{0}' cannot be passed ref or out (except in a static constructor)",
4772                         /*1648*/ "Members of readonly field `{0}' cannot be modified (except in a constructor or a variable initializer)",
4773                         /*1649*/ "Members of readonly field `{0}' cannot be passed ref or out (except in a constructor)",
4774                         /*1650*/ "Fields of static readonly field `{0}' cannot be assigned to (except in a static constructor or a variable initializer)",
4775                         /*1651*/ "Fields of static readonly field `{0}' cannot be passed ref or out (except in a static constructor)"
4776                 };
4777
4778                 // The return value is always null.  Returning a value simplifies calling code.
4779                 Expression Report_AssignToReadonly (Expression right_side)
4780                 {
4781                         int i = 0;
4782                         if (right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4783                                 i += 1;
4784                         if (IsStatic)
4785                                 i += 2;
4786                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess)
4787                                 i += 4;
4788                         Report.Error (codes [i], loc, msgs [i], GetSignatureForError ());
4789
4790                         return null;
4791                 }
4792
4793                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
4794                 {
4795                         IVariable var = InstanceExpression as IVariable;
4796                         if (var != null && var.VariableInfo != null)
4797                                 var.VariableInfo.SetFieldAssigned (ec, FieldInfo.Name);
4798
4799                         bool lvalue_instance = !FieldInfo.IsStatic && FieldInfo.DeclaringType.IsValueType;
4800                         bool out_access = right_side == EmptyExpression.OutAccess || right_side == EmptyExpression.LValueMemberOutAccess;
4801
4802                         Expression e = DoResolve (ec, lvalue_instance, out_access);
4803
4804                         if (e == null)
4805                                 return null;
4806
4807                         FieldBase fb = TypeManager.GetField (FieldInfo);
4808                         if (fb != null)
4809                                 fb.SetAssigned ();
4810
4811                         if (FieldInfo.IsInitOnly) {
4812                                 // InitOnly fields can only be assigned in constructors or initializers
4813                                 if (!ec.IsInFieldInitializer && !ec.IsConstructor)
4814                                         return Report_AssignToReadonly (right_side);
4815
4816                                 if (ec.IsConstructor) {
4817                                         Type ctype = ec.TypeContainer.CurrentType;
4818                                         if (ctype == null)
4819                                                 ctype = ec.ContainerType;
4820
4821                                         // InitOnly fields cannot be assigned-to in a different constructor from their declaring type
4822                                         if (!TypeManager.IsEqual (ctype, FieldInfo.DeclaringType))
4823                                                 return Report_AssignToReadonly (right_side);
4824                                         // static InitOnly fields cannot be assigned-to in an instance constructor
4825                                         if (IsStatic && !ec.IsStatic)
4826                                                 return Report_AssignToReadonly (right_side);
4827                                         // instance constructors can't modify InitOnly fields of other instances of the same type
4828                                         if (!IsStatic && !(InstanceExpression is This))
4829                                                 return Report_AssignToReadonly (right_side);
4830                                 }
4831                         }
4832
4833                         if (right_side == EmptyExpression.OutAccess &&
4834                             !IsStatic && !(InstanceExpression is This) && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type)) {
4835                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4836                                 Report.Warning (197, 1, loc,
4837                                                 "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",
4838                                                 GetSignatureForError ());
4839                         }
4840
4841                         return this;
4842                 }
4843
4844                 bool is_marshal_by_ref ()
4845                 {
4846                         return !IsStatic && Type.IsValueType && TypeManager.mbr_type != null && TypeManager.IsSubclassOf (DeclaringType, TypeManager.mbr_type);
4847                 }
4848
4849                 public override void CheckMarshalByRefAccess (EmitContext ec)
4850                 {
4851                         if (is_marshal_by_ref () && !(InstanceExpression is This)) {
4852                                 Report.SymbolRelatedToPreviousError (DeclaringType);
4853                                 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",
4854                                                 GetSignatureForError ());
4855                         }
4856                 }
4857
4858                 public override int GetHashCode ()
4859                 {
4860                         return FieldInfo.GetHashCode ();
4861                 }
4862
4863                 public bool IsFixed {
4864                         get {
4865                                 IVariable variable = InstanceExpression as IVariable;
4866                                 // A variable of the form V.I is fixed when V is a fixed variable of a struct type.
4867                                 // We defer the InstanceExpression check after the variable check to avoid a
4868                                 // separate null check on InstanceExpression.
4869                                 return variable != null && InstanceExpression.Type.IsValueType && variable.IsFixed;
4870                         }
4871                 }
4872
4873                 public override bool Equals (object obj)
4874                 {
4875                         FieldExpr fe = obj as FieldExpr;
4876                         if (fe == null)
4877                                 return false;
4878
4879                         if (FieldInfo != fe.FieldInfo)
4880                                 return false;
4881
4882                         if (InstanceExpression == null || fe.InstanceExpression == null)
4883                                 return true;
4884
4885                         return InstanceExpression.Equals (fe.InstanceExpression);
4886                 }
4887
4888                 public void Emit (EmitContext ec, bool leave_copy)
4889                 {
4890                         ILGenerator ig = ec.ig;
4891                         bool is_volatile = false;
4892
4893                         FieldBase f = TypeManager.GetField (FieldInfo);
4894                         if (f != null){
4895                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4896                                         is_volatile = true;
4897
4898                                 f.SetMemberIsUsed ();
4899                         }
4900
4901                         if (FieldInfo.IsStatic){
4902                                 if (is_volatile)
4903                                         ig.Emit (OpCodes.Volatile);
4904
4905                                 ig.Emit (OpCodes.Ldsfld, FieldInfo);
4906                         } else {
4907                                 if (!prepared)
4908                                         EmitInstance (ec, false);
4909
4910                                 IFixedBuffer ff = AttributeTester.GetFixedBuffer (FieldInfo);
4911                                 if (ff != null) {
4912                                         ig.Emit (OpCodes.Ldflda, FieldInfo);
4913                                         ig.Emit (OpCodes.Ldflda, ff.Element);
4914                                 } else {
4915                                         if (is_volatile)
4916                                                 ig.Emit (OpCodes.Volatile);
4917
4918                                         ig.Emit (OpCodes.Ldfld, FieldInfo);
4919                                 }
4920                         }
4921
4922                         if (leave_copy) {
4923                                 ec.ig.Emit (OpCodes.Dup);
4924                                 if (!FieldInfo.IsStatic) {
4925                                         temp = new LocalTemporary (this.Type);
4926                                         temp.Store (ec);
4927                                 }
4928                         }
4929                 }
4930
4931                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
4932                 {
4933                         FieldAttributes fa = FieldInfo.Attributes;
4934                         bool is_static = (fa & FieldAttributes.Static) != 0;
4935                         bool is_readonly = (fa & FieldAttributes.InitOnly) != 0;
4936                         ILGenerator ig = ec.ig;
4937
4938                         if (is_readonly && !ec.IsConstructor){
4939                                 Report_AssignToReadonly (source);
4940                                 return;
4941                         }
4942
4943                         prepared = prepare_for_load;
4944                         EmitInstance (ec, prepared);
4945
4946                         source.Emit (ec);
4947                         if (leave_copy) {
4948                                 ec.ig.Emit (OpCodes.Dup);
4949                                 if (!FieldInfo.IsStatic) {
4950                                         temp = new LocalTemporary (this.Type);
4951                                         temp.Store (ec);
4952                                 }
4953                         }
4954
4955                         FieldBase f = TypeManager.GetField (FieldInfo);
4956                         if (f != null){
4957                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0)
4958                                         ig.Emit (OpCodes.Volatile);
4959
4960                                 f.SetAssigned ();
4961                         }
4962
4963                         if (is_static)
4964                                 ig.Emit (OpCodes.Stsfld, FieldInfo);
4965                         else
4966                                 ig.Emit (OpCodes.Stfld, FieldInfo);
4967
4968                         if (temp != null) {
4969                                 temp.Emit (ec);
4970                                 temp.Release (ec);
4971                         }
4972                 }
4973
4974                 public override void Emit (EmitContext ec)
4975                 {
4976                         Emit (ec, false);
4977                 }
4978
4979                 public override void EmitSideEffect (EmitContext ec)
4980                 {
4981                         FieldBase f = TypeManager.GetField (FieldInfo);
4982                         bool is_volatile = f != null && (f.ModFlags & Modifiers.VOLATILE) != 0;
4983
4984                         if (is_volatile || is_marshal_by_ref ())
4985                                 base.EmitSideEffect (ec);
4986                 }
4987
4988                 public void AddressOf (EmitContext ec, AddressOp mode)
4989                 {
4990                         ILGenerator ig = ec.ig;
4991
4992                         FieldBase f = TypeManager.GetField (FieldInfo);
4993                         if (f != null){
4994                                 if ((f.ModFlags & Modifiers.VOLATILE) != 0){
4995                                         Report.Warning (420, 1, loc, "`{0}': A volatile field references will not be treated as volatile",
4996                                                         f.GetSignatureForError ());
4997                                 }
4998
4999                                 if ((mode & AddressOp.Store) != 0)
5000                                         f.SetAssigned ();
5001                                 if ((mode & AddressOp.Load) != 0)
5002                                         f.SetMemberIsUsed ();
5003                         }
5004
5005                         //
5006                         // Handle initonly fields specially: make a copy and then
5007                         // get the address of the copy.
5008                         //
5009                         bool need_copy;
5010                         if (FieldInfo.IsInitOnly){
5011                                 need_copy = true;
5012                                 if (ec.IsConstructor){
5013                                         if (FieldInfo.IsStatic){
5014                                                 if (ec.IsStatic)
5015                                                         need_copy = false;
5016                                         } else
5017                                                 need_copy = false;
5018                                 }
5019                         } else
5020                                 need_copy = false;
5021
5022                         if (need_copy){
5023                                 LocalBuilder local;
5024                                 Emit (ec);
5025                                 local = ig.DeclareLocal (type);
5026                                 ig.Emit (OpCodes.Stloc, local);
5027                                 ig.Emit (OpCodes.Ldloca, local);
5028                                 return;
5029                         }
5030
5031
5032                         if (FieldInfo.IsStatic){
5033                                 ig.Emit (OpCodes.Ldsflda, FieldInfo);
5034                         } else {
5035                                 if (!prepared)
5036                                         EmitInstance (ec, false);
5037                                 ig.Emit (OpCodes.Ldflda, FieldInfo);
5038                         }
5039                 }
5040         }
5041
5042
5043         /// <summary>
5044         ///   Expression that evaluates to a Property.  The Assign class
5045         ///   might set the `Value' expression if we are in an assignment.
5046         ///
5047         ///   This is not an LValue because we need to re-write the expression, we
5048         ///   can not take data from the stack and store it.
5049         /// </summary>
5050         public class PropertyExpr : MemberExpr, IAssignMethod {
5051                 public readonly PropertyInfo PropertyInfo;
5052                 MethodInfo getter, setter;
5053                 bool is_static;
5054
5055                 bool resolved;
5056
5057                 LocalTemporary temp;
5058                 bool prepared;
5059
5060                 public PropertyExpr (Type container_type, PropertyInfo pi, Location l)
5061                 {
5062                         PropertyInfo = pi;
5063                         eclass = ExprClass.PropertyAccess;
5064                         is_static = false;
5065                         loc = l;
5066
5067                         type = TypeManager.TypeToCoreType (pi.PropertyType);
5068
5069                         ResolveAccessors (container_type);
5070                 }
5071
5072                 public override string Name {
5073                         get {
5074                                 return PropertyInfo.Name;
5075                         }
5076                 }
5077
5078                 public override bool IsInstance {
5079                         get {
5080                                 return !is_static;
5081                         }
5082                 }
5083
5084                 public override bool IsStatic {
5085                         get {
5086                                 return is_static;
5087                         }
5088                 }
5089
5090                 public override Expression CreateExpressionTree (EmitContext ec)
5091                 {
5092                         ArrayList args;
5093                         if (IsSingleDimensionalArrayLength ()) {
5094                                 args = new ArrayList (1);
5095                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5096                                 return CreateExpressionFactoryCall ("ArrayLength", args);
5097                         }
5098
5099                         if (is_base) {
5100                                 Error_BaseAccessInExpressionTree (loc);
5101                                 return null;
5102                         }
5103
5104                         args = new ArrayList (2);
5105                         if (InstanceExpression == null)
5106                                 args.Add (new Argument (new NullLiteral (loc)));
5107                         else
5108                                 args.Add (new Argument (InstanceExpression.CreateExpressionTree (ec)));
5109                         args.Add (new Argument (new TypeOfMethodInfo (getter, loc)));
5110                         return CreateExpressionFactoryCall ("Property", args);
5111                 }
5112
5113                 public Expression CreateSetterTypeOfExpression ()
5114                 {
5115                         return new TypeOfMethodInfo (setter, loc);
5116                 }
5117
5118                 public override Type DeclaringType {
5119                         get {
5120                                 return PropertyInfo.DeclaringType;
5121                         }
5122                 }
5123
5124                 public override string GetSignatureForError ()
5125                 {
5126                         return TypeManager.GetFullNameSignature (PropertyInfo);
5127                 }
5128
5129                 void FindAccessors (Type invocation_type)
5130                 {
5131                         const BindingFlags flags = BindingFlags.Public | BindingFlags.NonPublic |
5132                                 BindingFlags.Static | BindingFlags.Instance |
5133                                 BindingFlags.DeclaredOnly;
5134
5135                         Type current = PropertyInfo.DeclaringType;
5136                         for (; current != null; current = current.BaseType) {
5137                                 MemberInfo[] group = TypeManager.MemberLookup (
5138                                         invocation_type, invocation_type, current,
5139                                         MemberTypes.Property, flags, PropertyInfo.Name, null);
5140
5141                                 if (group == null)
5142                                         continue;
5143
5144                                 if (group.Length != 1)
5145                                         // Oooops, can this ever happen ?
5146                                         return;
5147
5148                                 PropertyInfo pi = (PropertyInfo) group [0];
5149
5150                                 if (getter == null)
5151                                         getter = pi.GetGetMethod (true);
5152
5153                                 if (setter == null)
5154                                         setter = pi.GetSetMethod (true);
5155
5156                                 MethodInfo accessor = getter != null ? getter : setter;
5157
5158                                 if (!accessor.IsVirtual)
5159                                         return;
5160                         }
5161                 }
5162
5163                 //
5164                 // We also perform the permission checking here, as the PropertyInfo does not
5165                 // hold the information for the accessibility of its setter/getter
5166                 //
5167                 // TODO: Refactor to use some kind of cache together with GetPropertyFromAccessor
5168                 void ResolveAccessors (Type container_type)
5169                 {
5170                         FindAccessors (container_type);
5171
5172                         if (getter != null) {
5173                                 MethodBase the_getter = TypeManager.DropGenericMethodArguments (getter);
5174                                 IMethodData md = TypeManager.GetMethod (the_getter);
5175                                 if (md != null)
5176                                         md.SetMemberIsUsed ();
5177
5178                                 is_static = getter.IsStatic;
5179                         }
5180
5181                         if (setter != null) {
5182                                 MethodBase the_setter = TypeManager.DropGenericMethodArguments (setter);
5183                                 IMethodData md = TypeManager.GetMethod (the_setter);
5184                                 if (md != null)
5185                                         md.SetMemberIsUsed ();
5186
5187                                 is_static = setter.IsStatic;
5188                         }
5189                 }
5190
5191                 bool InstanceResolve (EmitContext ec, bool lvalue_instance, bool must_do_cs1540_check)
5192                 {
5193                         if (is_static) {
5194                                 InstanceExpression = null;
5195                                 return true;
5196                         }
5197
5198                         if (InstanceExpression == null) {
5199                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5200                                 return false;
5201                         }
5202
5203                         InstanceExpression = InstanceExpression.DoResolve (ec);
5204                         if (lvalue_instance && InstanceExpression != null)
5205                                 InstanceExpression = InstanceExpression.ResolveLValue (ec, EmptyExpression.LValueMemberAccess, loc);
5206
5207                         if (InstanceExpression == null)
5208                                 return false;
5209
5210                         InstanceExpression.CheckMarshalByRefAccess (ec);
5211
5212                         if (must_do_cs1540_check && (InstanceExpression != EmptyExpression.Null) &&
5213                             !TypeManager.IsInstantiationOfSameGenericType (InstanceExpression.Type, ec.ContainerType) &&
5214                             !TypeManager.IsNestedChildOf (ec.ContainerType, InstanceExpression.Type) &&
5215                             !TypeManager.IsSubclassOf (InstanceExpression.Type, ec.ContainerType)) {
5216                                 Report.SymbolRelatedToPreviousError (PropertyInfo);
5217                                 Error_CannotAccessProtected (loc, PropertyInfo, InstanceExpression.Type, ec.ContainerType);
5218                                 return false;
5219                         }
5220
5221                         return true;
5222                 }
5223
5224                 void Error_PropertyNotFound (MethodInfo mi, bool getter)
5225                 {
5226                         // TODO: correctly we should compare arguments but it will lead to bigger changes
5227                         if (mi is MethodBuilder) {
5228                                 Error_TypeDoesNotContainDefinition (loc, PropertyInfo.DeclaringType, Name);
5229                                 return;
5230                         }
5231
5232                         StringBuilder sig = new StringBuilder (TypeManager.CSharpName (mi.DeclaringType));
5233                         sig.Append ('.');
5234                         ParameterData iparams = TypeManager.GetParameterData (mi);
5235                         sig.Append (getter ? "get_" : "set_");
5236                         sig.Append (Name);
5237                         sig.Append (iparams.GetSignatureForError ());
5238
5239                         Report.SymbolRelatedToPreviousError (mi);
5240                         Report.Error (1546, loc, "Property `{0}' is not supported by the C# language. Try to call the accessor method `{1}' directly",
5241                                 Name, sig.ToString ());
5242                 }
5243
5244                 public bool IsAccessibleFrom (Type invocation_type, bool lvalue)
5245                 {
5246                         bool dummy;
5247                         MethodInfo accessor = lvalue ? setter : getter;
5248                         if (accessor == null && lvalue)
5249                                 accessor = getter;
5250                         return accessor != null && IsAccessorAccessible (invocation_type, accessor, out dummy);
5251                 }
5252
5253                 bool IsSingleDimensionalArrayLength ()
5254                 {
5255                         if (DeclaringType != TypeManager.array_type || getter == null || Name != "Length")
5256                                 return false;
5257
5258                         string t_name = InstanceExpression.Type.Name;
5259                         int t_name_len = t_name.Length;
5260                         return t_name_len > 2 && t_name [t_name_len - 2] == '[' && t_name [t_name_len - 3] != ']';
5261                 }
5262
5263                 override public Expression DoResolve (EmitContext ec)
5264                 {
5265                         if (resolved)
5266                                 return this;
5267
5268                         if (getter != null){
5269                                 if (TypeManager.GetParameterData (getter).Count != 0){
5270                                         Error_PropertyNotFound (getter, true);
5271                                         return null;
5272                                 }
5273                         }
5274
5275                         if (getter == null){
5276                                 //
5277                                 // The following condition happens if the PropertyExpr was
5278                                 // created, but is invalid (ie, the property is inaccessible),
5279                                 // and we did not want to embed the knowledge about this in
5280                                 // the caller routine.  This only avoids double error reporting.
5281                                 //
5282                                 if (setter == null)
5283                                         return null;
5284
5285                                 if (InstanceExpression != EmptyExpression.Null) {
5286                                         Report.Error (154, loc, "The property or indexer `{0}' cannot be used in this context because it lacks the `get' accessor",
5287                                                 TypeManager.GetFullNameSignature (PropertyInfo));
5288                                         return null;
5289                                 }
5290                         }
5291
5292                         bool must_do_cs1540_check = false;
5293                         if (getter != null &&
5294                             !IsAccessorAccessible (ec.ContainerType, getter, out must_do_cs1540_check)) {
5295                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (getter) as PropertyBase.PropertyMethod;
5296                                 if (pm != null && pm.HasCustomAccessModifier) {
5297                                         Report.SymbolRelatedToPreviousError (pm);
5298                                         Report.Error (271, loc, "The property or indexer `{0}' cannot be used in this context because the get accessor is inaccessible",
5299                                                 TypeManager.CSharpSignature (getter));
5300                                 }
5301                                 else {
5302                                         Report.SymbolRelatedToPreviousError (getter);
5303                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (getter));
5304                                 }
5305                                 return null;
5306                         }
5307
5308                         if (!InstanceResolve (ec, false, must_do_cs1540_check))
5309                                 return null;
5310
5311                         //
5312                         // Only base will allow this invocation to happen.
5313                         //
5314                         if (IsBase && getter.IsAbstract) {
5315                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5316                                 return null;
5317                         }
5318
5319                         if (PropertyInfo.PropertyType.IsPointer && !ec.InUnsafe){
5320                                 UnsafeError (loc);
5321                                 return null;
5322                         }
5323
5324                         resolved = true;
5325
5326                         return this;
5327                 }
5328
5329                 override public Expression DoResolveLValue (EmitContext ec, Expression right_side)
5330                 {
5331                         if (right_side == EmptyExpression.OutAccess) {
5332                                 if (ec.CurrentBlock.Toplevel.GetTransparentIdentifier (PropertyInfo.Name) != null) {
5333                                         Report.Error (1939, loc, "A range variable `{0}' may not be passes as `ref' or `out' parameter",
5334                                             PropertyInfo.Name);
5335                                 } else {
5336                                         Report.Error (206, loc, "A property or indexer `{0}' may not be passed as `ref' or `out' parameter",
5337                                               GetSignatureForError ());
5338                                 }
5339                                 return null;
5340                         }
5341
5342                         if (right_side == EmptyExpression.LValueMemberAccess || right_side == EmptyExpression.LValueMemberOutAccess) {
5343                                 Error_CannotModifyIntermediateExpressionValue (ec);
5344                         }
5345
5346                         if (setter == null){
5347                                 //
5348                                 // The following condition happens if the PropertyExpr was
5349                                 // created, but is invalid (ie, the property is inaccessible),
5350                                 // and we did not want to embed the knowledge about this in
5351                                 // the caller routine.  This only avoids double error reporting.
5352                                 //
5353                                 if (getter == null)
5354                                         return null;
5355                                 Report.Error (200, loc, "Property or indexer `{0}' cannot be assigned to (it is read only)",
5356                                               GetSignatureForError ());
5357                                 return null;
5358                         }
5359
5360                         if (TypeManager.GetParameterData (setter).Count != 1){
5361                                 Error_PropertyNotFound (setter, false);
5362                                 return null;
5363                         }
5364
5365                         bool must_do_cs1540_check;
5366                         if (!IsAccessorAccessible (ec.ContainerType, setter, out must_do_cs1540_check)) {
5367                                 PropertyBase.PropertyMethod pm = TypeManager.GetMethod (setter) as PropertyBase.PropertyMethod;
5368                                 if (pm != null && pm.HasCustomAccessModifier) {
5369                                         Report.SymbolRelatedToPreviousError (pm);
5370                                         Report.Error (272, loc, "The property or indexer `{0}' cannot be used in this context because the set accessor is inaccessible",
5371                                                 TypeManager.CSharpSignature (setter));
5372                                 }
5373                                 else {
5374                                         Report.SymbolRelatedToPreviousError (setter);
5375                                         ErrorIsInaccesible (loc, TypeManager.CSharpSignature (setter));
5376                                 }
5377                                 return null;
5378                         }
5379
5380                         if (!InstanceResolve (ec, PropertyInfo.DeclaringType.IsValueType, must_do_cs1540_check))
5381                                 return null;
5382
5383                         //
5384                         // Only base will allow this invocation to happen.
5385                         //
5386                         if (IsBase && setter.IsAbstract){
5387                                 Error_CannotCallAbstractBase (TypeManager.GetFullNameSignature (PropertyInfo));
5388                                 return null;
5389                         }
5390
5391                         return this;
5392                 }
5393
5394                 public override void Emit (EmitContext ec)
5395                 {
5396                         Emit (ec, false);
5397                 }
5398
5399                 public void Emit (EmitContext ec, bool leave_copy)
5400                 {
5401                         //
5402                         // Special case: length of single dimension array property is turned into ldlen
5403                         //
5404                         if (IsSingleDimensionalArrayLength ()) {
5405                                 if (!prepared)
5406                                         EmitInstance (ec, false);
5407                                 ec.ig.Emit (OpCodes.Ldlen);
5408                                 ec.ig.Emit (OpCodes.Conv_I4);
5409                                 return;
5410                         }
5411
5412                         Invocation.EmitCall (ec, IsBase, InstanceExpression, getter, null, loc, prepared, false);
5413
5414                         if (leave_copy) {
5415                                 ec.ig.Emit (OpCodes.Dup);
5416                                 if (!is_static) {
5417                                         temp = new LocalTemporary (this.Type);
5418                                         temp.Store (ec);
5419                                 }
5420                         }
5421                 }
5422
5423                 //
5424                 // Implements the IAssignMethod interface for assignments
5425                 //
5426                 public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
5427                 {
5428                         Expression my_source = source;
5429
5430                         if (prepare_for_load) {
5431                                 prepared = true;
5432                                 source.Emit (ec);
5433
5434                                 if (leave_copy) {
5435                                         ec.ig.Emit (OpCodes.Dup);
5436                                         if (!is_static) {
5437                                                 temp = new LocalTemporary (this.Type);
5438                                                 temp.Store (ec);
5439                                         }
5440                                 }
5441                         } else if (leave_copy) {
5442                                 source.Emit (ec);
5443                                 temp = new LocalTemporary (this.Type);
5444                                 temp.Store (ec);
5445                                 my_source = temp;
5446                         }
5447
5448                         ArrayList args = new ArrayList (1);
5449                         args.Add (new Argument (my_source, Argument.AType.Expression));
5450
5451                         Invocation.EmitCall (ec, IsBase, InstanceExpression, setter, args, loc, false, prepared);
5452
5453                         if (temp != null) {
5454                                 temp.Emit (ec);
5455                                 temp.Release (ec);
5456                         }
5457                 }
5458         }
5459
5460         /// <summary>
5461         ///   Fully resolved expression that evaluates to an Event
5462         /// </summary>
5463         public class EventExpr : MemberExpr {
5464                 public readonly EventInfo EventInfo;
5465
5466                 bool is_static;
5467                 MethodInfo add_accessor, remove_accessor;
5468
5469                 public EventExpr (EventInfo ei, Location loc)
5470                 {
5471                         EventInfo = ei;
5472                         this.loc = loc;
5473                         eclass = ExprClass.EventAccess;
5474
5475                         add_accessor = TypeManager.GetAddMethod (ei);
5476                         remove_accessor = TypeManager.GetRemoveMethod (ei);
5477                         if (add_accessor.IsStatic || remove_accessor.IsStatic)
5478                                 is_static = true;
5479
5480                         if (EventInfo is MyEventBuilder){
5481                                 MyEventBuilder eb = (MyEventBuilder) EventInfo;
5482                                 type = eb.EventType;
5483                                 eb.SetUsed ();
5484                         } else
5485                                 type = EventInfo.EventHandlerType;
5486                 }
5487
5488                 public override string Name {
5489                         get {
5490                                 return EventInfo.Name;
5491                         }
5492                 }
5493
5494                 public override bool IsInstance {
5495                         get {
5496                                 return !is_static;
5497                         }
5498                 }
5499
5500                 public override bool IsStatic {
5501                         get {
5502                                 return is_static;
5503                         }
5504                 }
5505
5506                 public override Type DeclaringType {
5507                         get {
5508                                 return EventInfo.DeclaringType;
5509                         }
5510                 }
5511
5512                 void Error_AssignmentEventOnly ()
5513                 {
5514                         Report.Error (79, loc, "The event `{0}' can only appear on the left hand side of `+=' or `-=' operator",
5515                                 GetSignatureForError ());
5516                 }
5517
5518                 public override MemberExpr ResolveMemberAccess (EmitContext ec, Expression left, Location loc,
5519                                                                 SimpleName original)
5520                 {
5521                         //
5522                         // If the event is local to this class, we transform ourselves into a FieldExpr
5523                         //
5524
5525                         if (EventInfo.DeclaringType == ec.ContainerType ||
5526                             TypeManager.IsNestedChildOf(ec.ContainerType, EventInfo.DeclaringType)) {
5527                                 EventField mi = TypeManager.GetEventField (EventInfo);
5528
5529                                 if (mi != null) {
5530                                         if (!ec.IsInObsoleteScope)
5531                                                 mi.CheckObsoleteness (loc);
5532
5533                                         if ((mi.ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0 && !ec.IsInCompoundAssignment)
5534                                                 Error_AssignmentEventOnly ();
5535
5536                                         FieldExpr ml = new FieldExpr (mi.FieldBuilder, loc);
5537
5538                                         InstanceExpression = null;
5539
5540                                         return ml.ResolveMemberAccess (ec, left, loc, original);
5541                                 }
5542                         }
5543
5544                         if (left is This && !ec.IsInCompoundAssignment)
5545                                 Error_AssignmentEventOnly ();
5546
5547                         return base.ResolveMemberAccess (ec, left, loc, original);
5548                 }
5549
5550                 bool InstanceResolve (EmitContext ec, bool must_do_cs1540_check)
5551                 {
5552                         if (is_static) {
5553                                 InstanceExpression = null;
5554                                 return true;
5555                         }
5556
5557                         if (InstanceExpression == null) {
5558                                 SimpleName.Error_ObjectRefRequired (ec, loc, GetSignatureForError ());
5559                                 return false;
5560                         }
5561
5562                         InstanceExpression = InstanceExpression.DoResolve (ec);
5563                         if (InstanceExpression == null)
5564                                 return false;
5565
5566                         if (IsBase && add_accessor.IsAbstract) {
5567                                 Error_CannotCallAbstractBase(TypeManager.CSharpSignature(add_accessor));
5568                                 return false;
5569                         }
5570
5571                         //
5572                         // This is using the same mechanism as the CS1540 check in PropertyExpr.
5573                         // However, in the Event case, we reported a CS0122 instead.
5574                         //
5575                         if (must_do_cs1540_check && InstanceExpression != EmptyExpression.Null &&
5576                             InstanceExpression.Type != ec.ContainerType &&
5577                             TypeManager.IsSubclassOf (ec.ContainerType, InstanceExpression.Type)) {
5578                                 Report.SymbolRelatedToPreviousError (EventInfo);
5579                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5580                                 return false;
5581                         }
5582
5583                         return true;
5584                 }
5585
5586                 public bool IsAccessibleFrom (Type invocation_type)
5587                 {
5588                         bool dummy;
5589                         return IsAccessorAccessible (invocation_type, add_accessor, out dummy) &&
5590                                 IsAccessorAccessible (invocation_type, remove_accessor, out dummy);
5591                 }
5592
5593                 public override Expression CreateExpressionTree (EmitContext ec)
5594                 {
5595                         throw new NotSupportedException ("ET");
5596                 }
5597
5598                 public override Expression DoResolveLValue (EmitContext ec, Expression right_side)
5599                 {
5600                         // contexts where an LValue is valid have already devolved to FieldExprs
5601                         Error_CannotAssign ();
5602                         return null;
5603                 }
5604
5605                 public override Expression DoResolve (EmitContext ec)
5606                 {
5607                         bool must_do_cs1540_check;
5608                         if (!(IsAccessorAccessible (ec.ContainerType, add_accessor, out must_do_cs1540_check) &&
5609                               IsAccessorAccessible (ec.ContainerType, remove_accessor, out must_do_cs1540_check))) {
5610                                 Report.SymbolRelatedToPreviousError (EventInfo);
5611                                 ErrorIsInaccesible (loc, TypeManager.CSharpSignature (EventInfo));
5612                                 return null;
5613                         }
5614
5615                         if (!InstanceResolve (ec, must_do_cs1540_check))
5616                                 return null;
5617
5618                         if (!ec.IsInCompoundAssignment) {
5619                                 Error_CannotAssign ();
5620                                 return null;
5621                         }
5622
5623                         return this;
5624                 }
5625
5626                 public override void Emit (EmitContext ec)
5627                 {
5628                         Error_CannotAssign ();
5629                 }
5630
5631                 public void Error_CannotAssign ()
5632                 {
5633                         Report.Error (70, loc,
5634                                 "The event `{0}' can only appear on the left hand side of += or -= when used outside of the type `{1}'",
5635                                 GetSignatureForError (), TypeManager.CSharpName (EventInfo.DeclaringType));
5636                 }
5637
5638                 public override string GetSignatureForError ()
5639                 {
5640                         return TypeManager.CSharpSignature (EventInfo);
5641                 }
5642
5643                 public void EmitAddOrRemove (EmitContext ec, bool is_add, Expression source)
5644                 {
5645                         ArrayList args = new ArrayList (1);
5646                         args.Add (new Argument (source, Argument.AType.Expression));
5647                         Invocation.EmitCall (ec, IsBase, InstanceExpression, is_add ? add_accessor : remove_accessor, args, loc);
5648                 }
5649         }
5650
5651         public class TemporaryVariable : Expression, IMemoryLocation
5652         {
5653                 LocalInfo li;
5654                 Variable var;
5655
5656                 public TemporaryVariable (Type type, Location loc)
5657                 {
5658                         this.type = type;
5659                         this.loc = loc;
5660                         eclass = ExprClass.Value;
5661                 }
5662
5663                 public override Expression CreateExpressionTree (EmitContext ec)
5664                 {
5665                         throw new NotSupportedException ("ET");
5666                 }
5667
5668                 public override Expression DoResolve (EmitContext ec)
5669                 {
5670                         if (li != null)
5671                                 return this;
5672
5673                         TypeExpr te = new TypeExpression (type, loc);
5674                         li = ec.CurrentBlock.AddTemporaryVariable (te, loc);
5675                         if (!li.Resolve (ec))
5676                                 return null;
5677
5678                         if (ec.MustCaptureVariable (li)) {
5679                                 ScopeInfo scope = li.Block.CreateScopeInfo ();
5680                                 var = scope.AddLocal (li);
5681                                 type = var.Type;
5682                         }
5683
5684                         return this;
5685                 }
5686
5687                 public Variable Variable {
5688                         get { return var != null ? var : li.Variable; }
5689                 }
5690
5691                 public override void Emit (EmitContext ec)
5692                 {
5693                         Variable.EmitInstance (ec);
5694                         Variable.Emit (ec);
5695                 }
5696
5697                 public void EmitLoadAddress (EmitContext ec)
5698                 {
5699                         Variable.EmitInstance (ec);
5700                         Variable.EmitAddressOf (ec);
5701                 }
5702
5703                 public void Store (EmitContext ec, Expression right_side)
5704                 {
5705                         Variable.EmitInstance (ec);
5706                         right_side.Emit (ec);
5707                         Variable.EmitAssign (ec);
5708                 }
5709
5710                 public void EmitThis (EmitContext ec)
5711                 {
5712                         Variable.EmitInstance (ec);
5713                 }
5714
5715                 public void EmitStore (EmitContext ec)
5716                 {
5717                         Variable.EmitAssign (ec);
5718                 }
5719
5720                 public void AddressOf (EmitContext ec, AddressOp mode)
5721                 {
5722                         EmitLoadAddress (ec);
5723                 }
5724         }
5725
5726         ///
5727         /// Handles `var' contextual keyword; var becomes a keyword only
5728         /// if no type called var exists in a variable scope
5729         ///
5730         public class VarExpr : SimpleName
5731         {
5732                 // Used for error reporting only
5733                 ArrayList initializer;
5734
5735                 public VarExpr (Location loc)
5736                         : base ("var", loc)
5737                 {
5738                 }
5739
5740                 public ArrayList VariableInitializer {
5741                         set {
5742                                 this.initializer = value;
5743                         }
5744                 }
5745
5746                 public bool InferType (EmitContext ec, Expression right_side)
5747                 {
5748                         if (type != null)
5749                                 throw new InternalErrorException ("An implicitly typed local variable could not be redefined");
5750
5751                         type = right_side.Type;
5752                         if (type == TypeManager.null_type || type == TypeManager.void_type || type == TypeManager.anonymous_method_type) {
5753                                 Report.Error (815, loc, "An implicitly typed local variable declaration cannot be initialized with `{0}'",
5754                                               right_side.GetSignatureForError ());
5755                                 return false;
5756                         }
5757
5758                         eclass = ExprClass.Variable;
5759                         return true;
5760                 }
5761
5762                 protected override void Error_TypeOrNamespaceNotFound (IResolveContext ec)
5763                 {
5764                         Report.Error (825, loc, "The contextual keyword `var' may only appear within a local variable declaration");
5765                 }
5766
5767                 public override TypeExpr ResolveAsContextualType (IResolveContext rc, bool silent)
5768                 {
5769                         TypeExpr te = base.ResolveAsContextualType (rc, true);
5770                         if (te != null)
5771                                 return te;
5772
5773                         if (initializer == null)
5774                                 return null;
5775
5776                         if (initializer.Count > 1) {
5777                                 Location loc = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [1]).Location;
5778                                 Report.Error (819, loc, "An implicitly typed local variable declaration cannot include multiple declarators");
5779                                 initializer = null;
5780                                 return null;
5781                         }
5782
5783                         Expression variable_initializer = ((Mono.CSharp.CSharpParser.VariableDeclaration)initializer [0]).expression_or_array_initializer;
5784                         if (variable_initializer == null) {
5785                                 Report.Error (818, loc, "An implicitly typed local variable declarator must include an initializer");
5786                                 return null;
5787                         }
5788
5789                         return null;
5790                 }
5791         }
5792 }