mcs/mcs/ecore.cs

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