mcs/mcs/namespace.cs

   1 //
   2 // namespace.cs: Tracks namespaces
   3 //
   4 // Author:
   5 //   Miguel de Icaza (miguel@ximian.com)
   6 //   Marek Safar (marek.safar@seznam.cz)
   7 //
   8 // Copyright 2001 Ximian, Inc.
   9 // Copyright 2003-2008 Novell, Inc.
  10 //
  11 using System;
  12 using System.Collections;
  13 using System.Collections.Specialized;
  14 using System.Reflection;
  15
  16 namespace Mono.CSharp {
  17
  18         public class RootNamespace : Namespace {
  19                 static MethodInfo get_namespaces_method;
  20
  21                 string alias_name;
  22                 Assembly referenced_assembly;
  23
  24                 Hashtable all_namespaces;
  25
  26                 static Hashtable root_namespaces;
  27                 public static GlobalRootNamespace Global;
  28
  29                 static RootNamespace ()
  30                 {
  31                         get_namespaces_method = typeof (Assembly).GetMethod ("GetNamespaces", BindingFlags.Instance | BindingFlags.NonPublic);
  32
  33                         Reset ();
  34                 }
  35
  36                 public static void Reset ()
  37                 {
  38                         root_namespaces = new Hashtable ();
  39                         Global = new GlobalRootNamespace ();
  40                         root_namespaces ["global"] = Global;
  41                 }
  42
  43                 protected RootNamespace (string alias_name, Assembly assembly)
  44                         : base (null, String.Empty)
  45                 {
  46                         this.alias_name = alias_name;
  47                         referenced_assembly = assembly;
  48
  49                         all_namespaces = new Hashtable ();
  50                         all_namespaces.Add ("", this);
  51
  52                         if (referenced_assembly != null)
  53                                 ComputeNamespaces (this.referenced_assembly);
  54                 }
  55
  56                 public static void DefineRootNamespace (string name, Assembly assembly)
  57                 {
  58                         if (name == "global") {
  59                                 NamespaceEntry.Error_GlobalNamespaceRedefined (Location.Null);
  60                                 return;
  61                         }
  62                         RootNamespace retval = GetRootNamespace (name);
  63                         if (retval == null || retval.referenced_assembly != assembly)
  64                                 root_namespaces [name] = new RootNamespace (name, assembly);
  65                 }
  66
  67                 public static RootNamespace GetRootNamespace (string name)
  68                 {
  69                         return (RootNamespace) root_namespaces [name];
  70                 }
  71
  72                 public virtual Type LookupTypeReflection (string name, Location loc)
  73                 {
  74                         return GetTypeInAssembly (referenced_assembly, name);
  75                 }
  76
  77                 public void RegisterNamespace (Namespace child)
  78                 {
  79                         if (child != this)
  80                                 all_namespaces.Add (child.Name, child);
  81                 }
  82
  83                 public bool IsNamespace (string name)
  84                 {
  85                         return all_namespaces.Contains (name);
  86                 }
  87
  88                 protected void RegisterNamespace (string dotted_name)
  89                 {
  90                         if (dotted_name != null && dotted_name.Length != 0 && ! IsNamespace (dotted_name))
  91                                 GetNamespace (dotted_name, true);
  92                 }
  93
  94                 void RegisterExtensionMethodClass (Type t)
  95                 {
  96                         string n = t.Namespace;
  97                         Namespace ns = n == null ? Global : (Namespace)all_namespaces [n];
  98                         if (ns == null)
  99                                 ns = GetNamespace (n, true);
 100
 101                         ns.RegisterExternalExtensionMethodClass (t);
 102                 }
 103
 104                 protected void ComputeNamespaces (Assembly assembly)
 105                 {
 106                         // How to test whether attribute exists without loading the assembly :-(
 107 #if NET_2_1
 108                         const string SystemCore = "System.Core, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e";
 109 #else
 110                         const string SystemCore = "System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089";
 111 #endif
 112                         if (TypeManager.extension_attribute_type == null &&
 113                                 assembly.FullName == SystemCore) {
 114                                 TypeManager.extension_attribute_type = assembly.GetType("System.Runtime.CompilerServices.ExtensionAttribute");
 115                         }
 116
 117                         bool contains_extension_methods = TypeManager.extension_attribute_type != null &&
 118                                         assembly.IsDefined(TypeManager.extension_attribute_type, false);
 119
 120                         if (get_namespaces_method != null && !contains_extension_methods) {
 121                                 string [] namespaces = (string []) get_namespaces_method.Invoke (assembly, null);
 122                                 foreach (string ns in namespaces)
 123                                         RegisterNamespace (ns);
 124                                 return;
 125                         }
 126
 127                         foreach (Type t in assembly.GetExportedTypes ()) {
 128                                 if ((t.Attributes & Class.StaticClassAttribute) == Class.StaticClassAttribute &&
 129                                         contains_extension_methods && t.IsDefined (TypeManager.extension_attribute_type, false))
 130                                         RegisterExtensionMethodClass (t);
 131                                 else
 132                                         RegisterNamespace (t.Namespace);
 133                         }
 134                 }
 135
 136                 protected static Type GetTypeInAssembly (Assembly assembly, string name)
 137                 {
 138                         Type t = assembly.GetType (name);
 139                         if (t == null)
 140                                 return null;
 141
 142                         if (t.IsPointer)
 143                                 throw new InternalErrorException ("Use GetPointerType() to get a pointer");
 144
 145                         TypeAttributes ta = t.Attributes & TypeAttributes.VisibilityMask;
 146                         if (ta == TypeAttributes.NestedPrivate)
 147                                 return null;
 148
 149                         if ((ta == TypeAttributes.NotPublic ||
 150                              ta == TypeAttributes.NestedAssembly ||
 151                              ta == TypeAttributes.NestedFamANDAssem) &&
 152                             !TypeManager.IsThisOrFriendAssembly (t.Assembly))
 153                                 return null;
 154
 155                         return t;
 156                 }
 157
 158                 public override string ToString ()
 159                 {
 160                         return String.Format ("RootNamespace ({0}::)", alias_name);
 161                 }
 162
 163                 public override string GetSignatureForError ()
 164                 {
 165                         return alias_name + "::";
 166                 }
 167         }
 168
 169         public class GlobalRootNamespace : RootNamespace {
 170                 Assembly [] assemblies;
 171                 Module [] modules;
 172
 173                 public GlobalRootNamespace ()
 174                         : base ("global", null)
 175                 {
 176                         assemblies = new Assembly [0];
 177                 }
 178
 179                 public Assembly [] Assemblies {
 180                         get { return assemblies; }
 181                 }
 182
 183                 public Module [] Modules {
 184                         get { return modules; }
 185                 }
 186
 187                 public void AddAssemblyReference (Assembly a)
 188                 {
 189                         foreach (Assembly assembly in assemblies) {
 190                                 if (a == assembly)
 191                                         return;
 192                         }
 193
 194                         int top = assemblies.Length;
 195                         Assembly [] n = new Assembly [top + 1];
 196                         assemblies.CopyTo (n, 0);
 197                         n [top] = a;
 198                         assemblies = n;
 199
 200                         ComputeNamespaces (a);
 201                 }
 202
 203                 public void AddModuleReference (Module m)
 204                 {
 205                         int top = modules != null ? modules.Length : 0;
 206                         Module [] n = new Module [top + 1];
 207                         if (modules != null)
 208                                 modules.CopyTo (n, 0);
 209                         n [top] = m;
 210                         modules = n;
 211
 212                         if (m == CodeGen.Module.Builder)
 213                                 return;
 214
 215                         foreach (Type t in m.GetTypes ())
 216                                 RegisterNamespace (t.Namespace);
 217                 }
 218
 219                 public override void Error_NamespaceDoesNotExist(DeclSpace ds, Location loc, string name)
 220                 {
 221                         Report.Error (400, loc, "The type or namespace name `{0}' could not be found in the global namespace (are you missing an assembly reference?)",
 222                                 name);
 223                 }
 224
 225                 public override Type LookupTypeReflection (string name, Location loc)
 226                 {
 227                         Type found_type = null;
 228
 229                         foreach (Assembly a in assemblies) {
 230                                 Type t = GetTypeInAssembly (a, name);
 231                                 if (t == null)
 232                                         continue;
 233
 234                                 if (found_type == null) {
 235                                         found_type = t;
 236                                         continue;
 237                                 }
 238
 239                                 Report.SymbolRelatedToPreviousError (found_type);
 240                                 Report.SymbolRelatedToPreviousError (t);
 241                                 Report.Error (433, loc, "The imported type `{0}' is defined multiple times", name);
 242
 243                                 return found_type;
 244                         }
 245
 246                         if (modules != null) {
 247                                 foreach (Module module in modules) {
 248                                         Type t = module.GetType (name);
 249                                         if (t == null)
 250                                                 continue;
 251
 252                                         if (found_type == null) {
 253                                                 found_type = t;
 254                                                 continue;
 255                                         }
 256
 257                                         Report.SymbolRelatedToPreviousError (found_type);
 258                                         if (loc.IsNull) {
 259                                                 DeclSpace ds = TypeManager.LookupDeclSpace (t);
 260                                                 Report.Warning (1685, 1, ds.Location, "The type `{0}' conflicts with the predefined type `{1}' and will be ignored",
 261                                                         ds.GetSignatureForError (), TypeManager.CSharpName (found_type));
 262                                                 return found_type;
 263                                         }
 264                                         Report.SymbolRelatedToPreviousError (t);
 265                                         Report.Warning (436, 2, loc, "The type `{0}' conflicts with the imported type `{1}'. Ignoring the imported type definition",
 266                                                 TypeManager.CSharpName (t), TypeManager.CSharpName (found_type));
 267                                         return t;
 268                                 }
 269                         }
 270
 271                         return found_type;
 272                 }
 273         }
 274
 275         /// <summary>
 276         ///   Keeps track of the namespaces defined in the C# code.
 277         ///
 278         ///   This is an Expression to allow it to be referenced in the
 279         ///   compiler parse/intermediate tree during name resolution.
 280         /// </summary>
 281         public class Namespace : FullNamedExpression {
 282
 283                 Namespace parent;
 284                 string fullname;
 285                 IDictionary namespaces;
 286                 IDictionary declspaces;
 287                 Hashtable cached_types;
 288                 RootNamespace root;
 289                 ArrayList external_exmethod_classes;
 290
 291                 public readonly MemberName MemberName;
 292
 293                 /// <summary>
 294                 ///   Constructor Takes the current namespace and the
 295                 ///   name.  This is bootstrapped with parent == null
 296                 ///   and name = ""
 297                 /// </summary>
 298                 public Namespace (Namespace parent, string name)
 299                 {
 300                         // Expression members.
 301                         this.eclass = ExprClass.Namespace;
 302                         this.Type = typeof (Namespace);
 303                         this.loc = Location.Null;
 304
 305                         this.parent = parent;
 306
 307                         if (parent != null)
 308                                 this.root = parent.root;
 309                         else
 310                                 this.root = this as RootNamespace;
 311
 312                         if (this.root == null)
 313                                 throw new InternalErrorException ("Root namespaces must be created using RootNamespace");
 314
 315                         string pname = parent != null ? parent.fullname : "";
 316
 317                         if (pname == "")
 318                                 fullname = name;
 319                         else
 320                                 fullname = parent.fullname + "." + name;
 321
 322                         if (fullname == null)
 323                                 throw new InternalErrorException ("Namespace has a null fullname");
 324
 325                         if (parent != null && parent.MemberName != MemberName.Null)
 326                                 MemberName = new MemberName (parent.MemberName, name);
 327                         else if (name.Length == 0)
 328                                 MemberName = MemberName.Null;
 329                         else
 330                                 MemberName = new MemberName (name);
 331
 332                         namespaces = new HybridDictionary ();
 333                         cached_types = new Hashtable ();
 334
 335                         root.RegisterNamespace (this);
 336                 }
 337
 338                 public override Expression DoResolve (EmitContext ec)
 339                 {
 340                         return this;
 341                 }
 342
 343                 public virtual void Error_NamespaceDoesNotExist (DeclSpace ds, Location loc, string name)
 344                 {
 345                         if (name.IndexOf ('`') > 0) {
 346                                 FullNamedExpression retval = Lookup (ds, SimpleName.RemoveGenericArity (name), loc);
 347                                 if (retval != null) {
 348                                         Error_TypeArgumentsCannotBeUsed (retval.Type, loc);
 349                                         return;
 350                                 }
 351                         } else {
 352                                 Type t = LookForAnyGenericType (name);
 353                                 if (t != null) {
 354                                         Error_InvalidNumberOfTypeArguments (t, loc);
 355                                         return;
 356                                 }
 357                         }
 358
 359                         Report.Error (234, loc, "The type or namespace name `{0}' does not exist in the namespace `{1}'. Are you missing an assembly reference?",
 360                                 name, GetSignatureForError ());
 361                 }
 362
 363                 public static void Error_InvalidNumberOfTypeArguments (Type t, Location loc)
 364                 {
 365                         Report.SymbolRelatedToPreviousError (t);
 366                         Report.Error (305, loc, "Using the generic type `{0}' requires `{1}' type argument(s)",
 367                                 TypeManager.CSharpName(t), TypeManager.GetNumberOfTypeArguments(t).ToString());
 368                 }
 369
 370                 public static void Error_TypeArgumentsCannotBeUsed (Type t, Location loc)
 371                 {
 372                         Report.SymbolRelatedToPreviousError (t);
 373                         Error_TypeArgumentsCannotBeUsed (loc, "type", TypeManager.CSharpName (t));
 374                 }
 375
 376                 public static void Error_TypeArgumentsCannotBeUsed (MethodBase mi, Location loc)
 377                 {
 378                         Report.SymbolRelatedToPreviousError (mi);
 379                         Error_TypeArgumentsCannotBeUsed (loc, "method", TypeManager.CSharpSignature (mi));
 380                 }
 381
 382                 static void Error_TypeArgumentsCannotBeUsed (Location loc, string type, string name)
 383                 {
 384                         Report.Error(308, loc, "The non-generic {0} `{1}' cannot be used with the type arguments",
 385                                 type, name);
 386                 }
 387
 388                 public override string GetSignatureForError ()
 389                 {
 390                         return fullname;
 391                 }
 392
 393                 public Namespace GetNamespace (string name, bool create)
 394                 {
 395                         int pos = name.IndexOf ('.');
 396
 397                         Namespace ns;
 398                         string first;
 399                         if (pos >= 0)
 400                                 first = name.Substring (0, pos);
 401                         else
 402                                 first = name;
 403
 404                         ns = (Namespace) namespaces [first];
 405                         if (ns == null) {
 406                                 if (!create)
 407                                         return null;
 408
 409                                 ns = new Namespace (this, first);
 410                                 namespaces.Add (first, ns);
 411                         }
 412
 413                         if (pos >= 0)
 414                                 ns = ns.GetNamespace (name.Substring (pos + 1), create);
 415
 416                         return ns;
 417                 }
 418
 419                 TypeExpr LookupType (string name, Location loc)
 420                 {
 421                         if (cached_types.Contains (name))
 422                                 return cached_types [name] as TypeExpr;
 423
 424                         Type t = null;
 425                         if (declspaces != null) {
 426                                 DeclSpace tdecl = declspaces [name] as DeclSpace;
 427                                 if (tdecl != null) {
 428                                         //
 429                                         // Note that this is not:
 430                                         //
 431                                         //   t = tdecl.DefineType ()
 432                                         //
 433                                         // This is to make it somewhat more useful when a DefineType
 434                                         // fails due to problems in nested types (more useful in the sense
 435                                         // of fewer misleading error messages)
 436                                         //
 437                                         tdecl.DefineType ();
 438                                         t = tdecl.TypeBuilder;
 439                                 }
 440                         }
 441                         string lookup = t != null ? t.FullName : (fullname.Length == 0 ? name : fullname + "." + name);
 442                         Type rt = root.LookupTypeReflection (lookup, loc);
 443
 444                         // HACK: loc.IsNull when the type is core type
 445                         if (t == null || (rt != null && loc.IsNull))
 446                                 t = rt;
 447
 448                         TypeExpr te = t == null ? null : new TypeExpression (t, Location.Null);
 449                         cached_types [name] = te;
 450                         return te;
 451                 }
 452
 453                 ///
 454                 /// Used for better error reporting only
 455                 ///
 456                 public Type LookForAnyGenericType (string typeName)
 457                 {
 458                         if (declspaces == null)
 459                                 return null;
 460
 461                         typeName = SimpleName.RemoveGenericArity (typeName);
 462
 463                         foreach (DictionaryEntry de in declspaces) {
 464                                 string type_item = (string) de.Key;
 465                                 int pos = type_item.LastIndexOf ('`');
 466                                 if (pos == typeName.Length && String.Compare (typeName, 0, type_item, 0, pos) == 0)
 467                                         return ((DeclSpace) de.Value).TypeBuilder;
 468                         }
 469                         return null;
 470                 }
 471
 472                 public FullNamedExpression Lookup (DeclSpace ds, string name, Location loc)
 473                 {
 474                         if (namespaces.Contains (name))
 475                                 return (Namespace) namespaces [name];
 476
 477                         return LookupType (name, loc);
 478                 }
 479
 480                 public void RegisterExternalExtensionMethodClass (Type type)
 481                 {
 482                         if (external_exmethod_classes == null)
 483                                 external_exmethod_classes = new ArrayList ();
 484
 485                         external_exmethod_classes.Add (type);
 486                 }
 487
 488                 ///
 489                 /// Looks for extension method in this namespace
 490                 ///
 491                 public ArrayList LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name)
 492                 {
 493                         ArrayList found = null;
 494
 495                         if (declspaces != null) {
 496                                 IEnumerator e = declspaces.Values.GetEnumerator ();
 497                                 e.Reset ();
 498                                 while (e.MoveNext ()) {
 499                                         Class c = e.Current as Class;
 500                                         if (c == null)
 501                                                 continue;
 502
 503                                         if (!c.IsStaticClass)
 504                                                 continue;
 505
 506                                         ArrayList res = c.MemberCache.FindExtensionMethods (extensionType, name, c != currentClass);
 507                                         if (res == null)
 508                                                 continue;
 509
 510                                         if (found == null)
 511                                                 found = res;
 512                                         else
 513                                                 found.AddRange (res);
 514                                 }
 515                         }
 516
 517                         if (external_exmethod_classes == null)
 518                                 return found;
 519
 520                         foreach (Type t in external_exmethod_classes) {
 521                                 MemberCache m = TypeHandle.GetMemberCache (t);
 522                                 ArrayList res = m.FindExtensionMethods (extensionType, name, true);
 523                                 if (res == null)
 524                                         continue;
 525
 526                                 if (found == null)
 527                                         found = res;
 528                                 else
 529                                         found.AddRange (res);
 530                         }
 531
 532                         return found;
 533                 }
 534
 535                 public void AddDeclSpace (string name, DeclSpace ds)
 536                 {
 537                         if (declspaces == null)
 538                                 declspaces = new HybridDictionary ();
 539                         declspaces.Add (name, ds);
 540                 }
 541
 542                 /// <summary>
 543                 ///   The qualified name of the current namespace
 544                 /// </summary>
 545                 public string Name {
 546                         get { return fullname; }
 547                 }
 548
 549                 /// <summary>
 550                 ///   The parent of this namespace, used by the parser to "Pop"
 551                 ///   the current namespace declaration
 552                 /// </summary>
 553                 public Namespace Parent {
 554                         get { return parent; }
 555                 }
 556         }
 557
 558         //
 559         // Namespace container as created by the parser
 560         //
 561         public class NamespaceEntry : IResolveContext {
 562
 563                 class UsingEntry {
 564                         readonly MemberName name;
 565                         Namespace resolved;
 566
 567                         public UsingEntry (MemberName name)
 568                         {
 569                                 this.name = name;
 570                         }
 571
 572                         public string GetSignatureForError ()
 573                         {
 574                                 return name.GetSignatureForError ();
 575                         }
 576
 577                         public Location Location {
 578                                 get { return name.Location; }
 579                         }
 580
 581                         public MemberName MemberName {
 582                                 get { return name; }
 583                         }
 584
 585                         public string Name {
 586                                 get { return GetSignatureForError (); }
 587                         }
 588
 589                         public Namespace Resolve (IResolveContext rc)
 590                         {
 591                                 if (resolved != null)
 592                                         return resolved;
 593
 594                                 FullNamedExpression fne = name.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 595                                 if (fne == null)
 596                                         return null;
 597
 598                                 resolved = fne as Namespace;
 599                                 if (resolved == null) {
 600                                         Report.SymbolRelatedToPreviousError (fne.Type);
 601                                         Report.Error (138, Location,
 602                                                 "`{0}' is a type not a namespace. A using namespace directive can only be applied to namespaces",
 603                                                 GetSignatureForError ());
 604                                 }
 605                                 return resolved;
 606                         }
 607                 }
 608
 609                 class UsingAliasEntry {
 610                         public readonly string Alias;
 611                         public Location Location;
 612
 613                         public UsingAliasEntry (string alias, Location loc)
 614                         {
 615                                 this.Alias = alias;
 616                                 this.Location = loc;
 617                         }
 618
 619                         public virtual FullNamedExpression Resolve (IResolveContext rc)
 620                         {
 621                                 FullNamedExpression fne = RootNamespace.GetRootNamespace (Alias);
 622                                 if (fne == null) {
 623                                         Report.Error (430, Location,
 624                                                 "The extern alias `{0}' was not specified in -reference option",
 625                                                 Alias);
 626                                 }
 627
 628                                 return fne;
 629                         }
 630                 }
 631
 632                 class LocalUsingAliasEntry : UsingAliasEntry {
 633                         Expression resolved;
 634                         MemberName value;
 635
 636                         public LocalUsingAliasEntry (string alias, MemberName name, Location loc)
 637                                 : base (alias, loc)
 638                         {
 639                                 this.value = name;
 640                         }
 641
 642                         public override FullNamedExpression Resolve (IResolveContext rc)
 643                         {
 644                                 if (resolved != null)
 645                                         return (FullNamedExpression)resolved;
 646
 647                                 resolved = value.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 648                                 if (resolved == null)
 649                                         return null;
 650
 651                                 // FIXME: This is quite wrong, the accessibility is not global
 652                                 if (resolved.Type != null) {
 653                                         TypeAttributes attr = resolved.Type.Attributes & TypeAttributes.VisibilityMask;
 654                                         if (attr == TypeAttributes.NestedPrivate || attr == TypeAttributes.NestedFamily ||
 655                                                 ((attr == TypeAttributes.NestedFamORAssem || attr == TypeAttributes.NestedAssembly) &&
 656                                                 TypeManager.LookupDeclSpace (resolved.Type) == null)) {
 657                                                 Expression.ErrorIsInaccesible (resolved.Location, resolved.GetSignatureForError ());
 658                                                 return null;
 659                                         }
 660                                 }
 661
 662                                 return (FullNamedExpression)resolved;
 663                         }
 664                 }
 665
 666                 Namespace ns;
 667                 NamespaceEntry parent, implicit_parent;
 668                 CompilationUnit file;
 669                 int symfile_id;
 670
 671                 // Namespace using import block
 672                 ArrayList using_aliases;
 673                 ArrayList using_clauses;
 674                 public bool DeclarationFound = false;
 675                 // End
 676
 677                 public readonly bool IsImplicit;
 678                 public readonly DeclSpace SlaveDeclSpace;
 679                 static readonly Namespace [] empty_namespaces = new Namespace [0];
 680                 Namespace [] namespace_using_table;
 681
 682                 static ArrayList entries = new ArrayList ();
 683
 684                 public static void Reset ()
 685                 {
 686                         entries = new ArrayList ();
 687                 }
 688
 689                 public NamespaceEntry (NamespaceEntry parent, CompilationUnit file, string name)
 690                 {
 691                         this.parent = parent;
 692                         this.file = file;
 693                         entries.Add (this);
 694
 695                         if (parent != null)
 696                                 ns = parent.NS.GetNamespace (name, true);
 697                         else if (name != null)
 698                                 ns = RootNamespace.Global.GetNamespace (name, true);
 699                         else
 700                                 ns = RootNamespace.Global;
 701                         SlaveDeclSpace = new RootDeclSpace (this);
 702                 }
 703
 704                 private NamespaceEntry (NamespaceEntry parent, CompilationUnit file, Namespace ns, bool slave)
 705                 {
 706                         this.parent = parent;
 707                         this.file = file;
 708                         this.IsImplicit = true;
 709                         this.ns = ns;
 710                         this.SlaveDeclSpace = slave ? new RootDeclSpace (this) : null;
 711                 }
 712
 713                 //
 714                 // According to section 16.3.1 (using-alias-directive), the namespace-or-type-name is
 715                 // resolved as if the immediately containing namespace body has no using-directives.
 716                 //
 717                 // Section 16.3.2 says that the same rule is applied when resolving the namespace-name
 718                 // in the using-namespace-directive.
 719                 //
 720                 // To implement these rules, the expressions in the using directives are resolved using
 721                 // the "doppelganger" (ghostly bodiless duplicate).
 722                 //
 723                 NamespaceEntry doppelganger;
 724                 NamespaceEntry Doppelganger {
 725                         get {
 726                                 if (!IsImplicit && doppelganger == null) {
 727                                         doppelganger = new NamespaceEntry (ImplicitParent, file, ns, true);
 728                                         doppelganger.using_aliases = using_aliases;
 729                                 }
 730                                 return doppelganger;
 731                         }
 732                 }
 733
 734                 public Namespace NS {
 735                         get { return ns; }
 736                 }
 737
 738                 public NamespaceEntry Parent {
 739                         get { return parent; }
 740                 }
 741
 742                 public NamespaceEntry ImplicitParent {
 743                         get {
 744                                 if (parent == null)
 745                                         return null;
 746                                 if (implicit_parent == null) {
 747                                         implicit_parent = (parent.NS == ns.Parent)
 748                                                 ? parent
 749                                                 : new NamespaceEntry (parent, file, ns.Parent, false);
 750                                 }
 751                                 return implicit_parent;
 752                         }
 753                 }
 754
 755                 /// <summary>
 756                 ///   Records a new namespace for resolving name references
 757                 /// </summary>
 758                 public void AddUsing (MemberName name, Location loc)
 759                 {
 760                         if (DeclarationFound){
 761                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 762                         }
 763
 764                         if (using_clauses == null) {
 765                                 using_clauses = new ArrayList ();
 766                         } else {
 767                                 foreach (UsingEntry old_entry in using_clauses) {
 768                                         if (name.Equals (old_entry.MemberName)) {
 769                                                 Report.SymbolRelatedToPreviousError (old_entry.Location, old_entry.GetSignatureForError ());
 770                                                 Report.Warning (105, 3, loc, "The using directive for `{0}' appeared previously in this namespace", name.GetSignatureForError ());
 771                                                 return;
 772                                         }
 773                                 }
 774                         }
 775
 776                         using_clauses.Add (new UsingEntry (name));
 777                 }
 778
 779                 public void AddUsingAlias (string alias, MemberName name, Location loc)
 780                 {
 781                         // TODO: This is parser bussines
 782                         if (DeclarationFound){
 783                                 Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 784                         }
 785
 786                         if (RootContext.Version != LanguageVersion.ISO_1 && alias == "global")
 787                                 Report.Warning (440, 2, loc, "An alias named `global' will not be used when resolving 'global::';" +
 788                                         " the global namespace will be used instead");
 789
 790                         AddUsingAlias (new LocalUsingAliasEntry (alias, name, loc));
 791                 }
 792
 793                 public void AddUsingExternalAlias (string alias, Location loc)
 794                 {
 795                         // TODO: Do this in parser
 796                         bool not_first = using_clauses != null || DeclarationFound;
 797                         if (using_aliases != null && !not_first) {
 798                                 foreach (UsingAliasEntry uae in using_aliases) {
 799                                         if (uae is LocalUsingAliasEntry) {
 800                                                 not_first = true;
 801                                                 break;
 802                                         }
 803                                 }
 804                         }
 805
 806                         if (not_first)
 807                                 Report.Error (439, loc, "An extern alias declaration must precede all other elements");
 808
 809                         if (alias == "global") {
 810                                 Error_GlobalNamespaceRedefined (loc);
 811                                 return;
 812                         }
 813
 814                         AddUsingAlias (new UsingAliasEntry (alias, loc));
 815                 }
 816
 817                 void AddUsingAlias (UsingAliasEntry uae)
 818                 {
 819                         if (using_aliases == null) {
 820                                 using_aliases = new ArrayList ();
 821                         } else {
 822                                 foreach (UsingAliasEntry entry in using_aliases) {
 823                                         if (uae.Alias == entry.Alias) {
 824                                                 Report.SymbolRelatedToPreviousError (uae.Location, uae.Alias);
 825                                                 Report.Error (1537, entry.Location, "The using alias `{0}' appeared previously in this namespace",
 826                                                         entry.Alias);
 827                                                 return;
 828                                         }
 829                                 }
 830                         }
 831
 832                         using_aliases.Add (uae);
 833                 }
 834
 835                 ///
 836                 /// Does extension methods look up to find a method which matches name and extensionType.
 837                 /// Search starts from this namespace and continues hierarchically up to top level.
 838                 ///
 839                 public ExtensionMethodGroupExpr LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name, Location loc)
 840                 {
 841                         ArrayList candidates = null;
 842                         if (currentClass != null) {
 843                                 candidates = ns.LookupExtensionMethod (extensionType, currentClass, name);
 844                                 if (candidates != null)
 845                                         return new ExtensionMethodGroupExpr (candidates, this, extensionType, loc);
 846                         }
 847
 848                         foreach (Namespace n in GetUsingTable ()) {
 849                                 ArrayList a = n.LookupExtensionMethod (extensionType, null, name);
 850                                 if (a == null)
 851                                         continue;
 852
 853                                 if (candidates == null)
 854                                         candidates = a;
 855                                 else
 856                                         candidates.AddRange (a);
 857                         }
 858
 859                         if (candidates != null)
 860                                 return new ExtensionMethodGroupExpr (candidates, parent, extensionType, loc);
 861
 862                         if (parent == null)
 863                                 return null;
 864
 865                         //
 866                         // Inspect parent namespaces in namespace expression
 867                         //
 868                         Namespace parent_ns = ns.Parent;
 869                         do {
 870                                 candidates = parent_ns.LookupExtensionMethod (extensionType, null, name);
 871                                 if (candidates != null)
 872                                         return new ExtensionMethodGroupExpr (candidates, parent, extensionType, loc);
 873
 874                                 parent_ns = parent_ns.Parent;
 875                         } while (parent_ns != null);
 876
 877                         //
 878                         // Continue in parent scope
 879                         //
 880                         return parent.LookupExtensionMethod (extensionType, currentClass, name, loc);
 881                 }
 882
 883                 public FullNamedExpression LookupNamespaceOrType (DeclSpace ds, string name, Location loc, bool ignore_cs0104)
 884                 {
 885                         // Precondition: Only simple names (no dots) will be looked up with this function.
 886                         FullNamedExpression resolved = null;
 887                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent) {
 888                                 if ((resolved = curr_ns.Lookup (ds, name, loc, ignore_cs0104)) != null)
 889                                         break;
 890                         }
 891                         return resolved;
 892                 }
 893
 894                 static void Error_AmbiguousTypeReference (Location loc, string name, FullNamedExpression t1, FullNamedExpression t2)
 895                 {
 896                         Report.SymbolRelatedToPreviousError (t1.Type);
 897                         Report.SymbolRelatedToPreviousError (t2.Type);
 898                         Report.Error (104, loc, "`{0}' is an ambiguous reference between `{1}' and `{2}'",
 899                                 name, t1.GetSignatureForError (), t2.GetSignatureForError ());
 900                 }
 901
 902                 // Looks-up a alias named @name in this and surrounding namespace declarations
 903                 public FullNamedExpression LookupAlias (string name)
 904                 {
 905                         for (NamespaceEntry n = this; n != null; n = n.ImplicitParent) {
 906                                 if (n.using_aliases == null)
 907                                         continue;
 908
 909                                 foreach (UsingAliasEntry ue in n.using_aliases) {
 910                                         if (ue.Alias == name)
 911                                                 return ue.Resolve (Doppelganger);
 912                                 }
 913                         }
 914
 915                         return null;
 916                 }
 917
 918                 private FullNamedExpression Lookup (DeclSpace ds, string name, Location loc, bool ignore_cs0104)
 919                 {
 920                         //
 921                         // Check whether it's in the namespace.
 922                         //
 923                         FullNamedExpression fne = ns.Lookup (ds, name, loc);
 924                         if (fne != null)
 925                                 return fne;
 926
 927                         //
 928                         // Check aliases.
 929                         //
 930                         if (using_aliases != null) {
 931                                 foreach (UsingAliasEntry ue in using_aliases) {
 932                                         if (ue.Alias == name)
 933                                                 return ue.Resolve (Doppelganger);
 934                                 }
 935                         }
 936
 937                         if (IsImplicit)
 938                                 return null;
 939
 940                         //
 941                         // Check using entries.
 942                         //
 943                         FullNamedExpression match = null;
 944                         foreach (Namespace using_ns in GetUsingTable ()) {
 945                                 match = using_ns.Lookup (ds, name, loc);
 946                                 if (match == null || !(match is TypeExpr))
 947                                         continue;
 948                                 if (fne != null) {
 949                                         if (!ignore_cs0104)
 950                                                 Error_AmbiguousTypeReference (loc, name, fne, match);
 951                                         return null;
 952                                 }
 953                                 fne = match;
 954                         }
 955
 956                         return fne;
 957                 }
 958
 959                 Namespace [] GetUsingTable ()
 960                 {
 961                         if (namespace_using_table != null)
 962                                 return namespace_using_table;
 963
 964                         if (using_clauses == null) {
 965                                 namespace_using_table = empty_namespaces;
 966                                 return namespace_using_table;
 967                         }
 968
 969                         ArrayList list = new ArrayList (using_clauses.Count);
 970
 971                         foreach (UsingEntry ue in using_clauses) {
 972                                 Namespace using_ns = ue.Resolve (Doppelganger);
 973                                 if (using_ns == null)
 974                                         continue;
 975
 976                                 list.Add (using_ns);
 977                         }
 978
 979                         namespace_using_table = (Namespace[])list.ToArray (typeof (Namespace));
 980                         return namespace_using_table;
 981                 }
 982
 983                 static readonly string [] empty_using_list = new string [0];
 984
 985                 public int SymbolFileID {
 986                         get {
 987                                 if (symfile_id == 0 && file.SourceFileEntry != null) {
 988                                         int parent_id = parent == null ? 0 : parent.SymbolFileID;
 989
 990                                         string [] using_list = empty_using_list;
 991                                         if (using_clauses != null) {
 992                                                 using_list = new string [using_clauses.Count];
 993                                                 for (int i = 0; i < using_clauses.Count; i++)
 994                                                         using_list [i] = ((UsingEntry) using_clauses [i]).MemberName.GetTypeName ();
 995                                         }
 996
 997                                         symfile_id = SymbolWriter.DefineNamespace (ns.Name, file.CompileUnitEntry, using_list, parent_id);
 998                                 }
 999                                 return symfile_id;
1000                         }
1001                 }
1002
1003                 static void MsgtryRef (string s)
1004                 {
1005                         Console.WriteLine ("    Try using -r:" + s);
1006                 }
1007
1008                 static void MsgtryPkg (string s)
1009                 {
1010                         Console.WriteLine ("    Try using -pkg:" + s);
1011                 }
1012
1013                 public static void Error_GlobalNamespaceRedefined (Location loc)
1014                 {
1015                         Report.Error (1681, loc, "You cannot redefine the global extern alias");
1016                 }
1017
1018                 public static void Error_NamespaceNotFound (Location loc, string name)
1019                 {
1020                         Report.Error (246, loc, "The type or namespace name `{0}' could not be found. Are you missing a using directive or an assembly reference?",
1021                                 name);
1022
1023                         switch (name) {
1024                         case "Gtk": case "GtkSharp":
1025                                 MsgtryPkg ("gtk-sharp");
1026                                 break;
1027
1028                         case "Gdk": case "GdkSharp":
1029                                 MsgtryPkg ("gdk-sharp");
1030                                 break;
1031
1032                         case "Glade": case "GladeSharp":
1033                                 MsgtryPkg ("glade-sharp");
1034                                 break;
1035
1036                         case "System.Drawing":
1037                         case "System.Web.Services":
1038                         case "System.Web":
1039                         case "System.Data":
1040                         case "System.Windows.Forms":
1041                                 MsgtryRef (name);
1042                                 break;
1043                         }
1044                 }
1045
1046                 /// <summary>
1047                 ///   Used to validate that all the using clauses are correct
1048                 ///   after we are finished parsing all the files.
1049                 /// </summary>
1050                 void VerifyUsing ()
1051                 {
1052                         if (using_aliases != null) {
1053                                 foreach (UsingAliasEntry ue in using_aliases)
1054                                         ue.Resolve (Doppelganger);
1055                         }
1056
1057                         if (using_clauses != null) {
1058                                 foreach (UsingEntry ue in using_clauses)
1059                                         ue.Resolve (Doppelganger);
1060                         }
1061                 }
1062
1063                 /// <summary>
1064                 ///   Used to validate that all the using clauses are correct
1065                 ///   after we are finished parsing all the files.
1066                 /// </summary>
1067                 static public void VerifyAllUsing ()
1068                 {
1069                         foreach (NamespaceEntry entry in entries)
1070                                 entry.VerifyUsing ();
1071                 }
1072
1073                 public string GetSignatureForError ()
1074                 {
1075                         return ns.GetSignatureForError ();
1076                 }
1077
1078                 public override string ToString ()
1079                 {
1080                         return ns.ToString ();
1081                 }
1082
1083                 #region IResolveContext Members
1084
1085                 public DeclSpace DeclContainer {
1086                         get { return SlaveDeclSpace; }
1087                 }
1088
1089                 public bool IsInObsoleteScope {
1090                         get { return SlaveDeclSpace.IsInObsoleteScope; }
1091                 }
1092
1093                 public bool IsInUnsafeScope {
1094                         get { return SlaveDeclSpace.IsInUnsafeScope; }
1095                 }
1096
1097                 public DeclSpace GenericDeclContainer {
1098                         get { return SlaveDeclSpace; }
1099                 }
1100
1101                 #endregion
1102         }
1103 }