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                 //
  20                 // Points to Mono's GetNamespaces method, an
  21                 // optimization when running on Mono to fetch all the
  22                 // namespaces in an assembly
  23                 //
  24                 static MethodInfo get_namespaces_method;
  25
  26                 protected readonly string alias_name;
  27                 protected Assembly [] referenced_assemblies;
  28
  29                 Hashtable all_namespaces;
  30
  31                 static RootNamespace ()
  32                 {
  33                         get_namespaces_method = typeof (Assembly).GetMethod ("GetNamespaces", BindingFlags.Instance | BindingFlags.NonPublic);
  34                 }
  35
  36                 public RootNamespace (string alias_name)
  37                         : base (null, String.Empty)
  38                 {
  39                         this.alias_name = alias_name;
  40                         referenced_assemblies = new Assembly [0];
  41
  42                         all_namespaces = new Hashtable ();
  43                         all_namespaces.Add ("", this);
  44                 }
  45
  46                 public void AddAssemblyReference (Assembly a)
  47                 {
  48                         foreach (Assembly assembly in referenced_assemblies) {
  49                                 if (a == assembly)
  50                                         return;
  51                         }
  52
  53                         int top = referenced_assemblies.Length;
  54                         Assembly [] n = new Assembly [top + 1];
  55                         referenced_assemblies.CopyTo (n, 0);
  56                         n [top] = a;
  57                         referenced_assemblies = n;
  58                 }
  59
  60                 public void ComputeNamespace (CompilerContext ctx, Type extensionType)
  61                 {
  62                         foreach (Assembly a in referenced_assemblies) {
  63                                 try {
  64                                         ComputeNamespaces (a, extensionType);
  65                                 } catch (TypeLoadException e) {
  66                                         ctx.Report.Error (11, Location.Null, e.Message);
  67                                 } catch (System.IO.FileNotFoundException) {
  68                                         ctx.Report.Error (12, Location.Null, "An assembly `{0}' is used without being referenced",
  69                                                 a.FullName);
  70                                 }
  71                         }
  72                 }
  73
  74                 public virtual Type LookupTypeReflection (CompilerContext ctx, string name, Location loc, bool must_be_unique)
  75                 {
  76                         // FIXME: Breaks dynamic
  77                         Assembly invocation_assembly = CodeGen.Assembly.Builder;
  78
  79                         Type found_type = null;
  80                         foreach (Assembly a in referenced_assemblies) {
  81                                 Type t = GetTypeInAssembly (invocation_assembly, a, name);
  82                                 if (t == null)
  83                                         continue;
  84
  85                                 if (!must_be_unique)
  86                                         return t;
  87
  88                                 if (found_type == null) {
  89                                         found_type = t;
  90                                         continue;
  91                                 }
  92
  93                                 // When type is forwarded
  94                                 if (t.Assembly == found_type.Assembly)
  95                                         continue;
  96
  97                                 ctx.Report.SymbolRelatedToPreviousError (found_type);
  98                                 ctx.Report.SymbolRelatedToPreviousError (t);
  99                                 if (loc.IsNull) {
 100                                         Error_AmbiguousPredefinedType (ctx, loc, name, found_type);
 101                                 } else {
 102                                         ctx.Report.Error (433, loc, "The imported type `{0}' is defined multiple times", name);
 103                                 }
 104
 105                                 return found_type;
 106                         }
 107
 108                         return found_type;
 109                 }
 110
 111                 //
 112                 // Returns the types starting with the given prefix
 113                 //
 114                 public ICollection CompletionGetTypesStartingWith (string prefix)
 115                 {
 116                         Hashtable result = null;
 117
 118                         foreach (Assembly a in referenced_assemblies){
 119                                 Type [] mtypes = a.GetTypes ();
 120
 121                                 foreach (Type t in mtypes){
 122                                         string f = t.FullName;
 123
 124                                         if (f.StartsWith (prefix) && (result == null || !result.Contains (f))){
 125                                                 if (result == null)
 126                                                         result = new Hashtable ();
 127
 128                                                 result [f] = f;
 129                                         }
 130                                 }
 131                         }
 132                         return result == null ? result : result.Keys;
 133                 }
 134
 135                 protected static void Error_AmbiguousPredefinedType (CompilerContext ctx, Location loc, string name, Type type)
 136                 {
 137                         ctx.Report.Warning (1685, 1, loc,
 138                                 "The predefined type `{0}' is ambiguous. Using definition from `{1}'",
 139                                 name, type.Assembly.FullName);
 140                 }
 141
 142                 public void RegisterNamespace (Namespace child)
 143                 {
 144                         if (child != this)
 145                                 all_namespaces.Add (child.Name, child);
 146                 }
 147
 148                 public bool IsNamespace (string name)
 149                 {
 150                         return all_namespaces.Contains (name);
 151                 }
 152
 153                 protected void RegisterNamespace (string dotted_name)
 154                 {
 155                         if (dotted_name != null && dotted_name.Length != 0 && ! IsNamespace (dotted_name))
 156                                 GetNamespace (dotted_name, true);
 157                 }
 158
 159                 void RegisterExtensionMethodClass (Type t)
 160                 {
 161                         string n = t.Namespace;
 162                         Namespace ns = n == null ? GlobalRootNamespace.Instance : (Namespace) all_namespaces[n];
 163                         if (ns == null)
 164                                 ns = GetNamespace (n, true);
 165
 166                         ns.RegisterExternalExtensionMethodClass (t);
 167                 }
 168
 169                 void ComputeNamespaces (Assembly assembly, Type extensionType)
 170                 {
 171                         bool contains_extension_methods = extensionType != null && assembly.IsDefined (extensionType, false);
 172
 173                         if (get_namespaces_method != null) {
 174                                 string [] namespaces = (string []) get_namespaces_method.Invoke (assembly, null);
 175                                 foreach (string ns in namespaces)
 176                                         RegisterNamespace (ns);
 177
 178                                 if (!contains_extension_methods)
 179                                         return;
 180                         }
 181
 182                         foreach (Type t in assembly.GetTypes ()) {
 183                                 if ((t.Attributes & Class.StaticClassAttribute) == Class.StaticClassAttribute &&
 184                                         contains_extension_methods && t.IsDefined (extensionType, false))
 185                                         RegisterExtensionMethodClass (t);
 186
 187                                 if (get_namespaces_method == null)
 188                                         RegisterNamespace (t.Namespace);
 189                         }
 190                 }
 191
 192                 protected static Type GetTypeInAssembly (Assembly invocation, Assembly assembly, string name)
 193                 {
 194                         if (assembly == null)
 195                                 throw new ArgumentNullException ("assembly");
 196                         if (name == null)
 197                                 throw new ArgumentNullException ("name");
 198                         Type t = assembly.GetType (name);
 199                         if (t == null)
 200                                 return null;
 201
 202                         if (t.IsPointer)
 203                                 throw new InternalErrorException ("Use GetPointerType() to get a pointer");
 204
 205                         TypeAttributes ta = t.Attributes & TypeAttributes.VisibilityMask;
 206                         if (ta == TypeAttributes.NestedPrivate)
 207                                 return null;
 208
 209                         if ((ta == TypeAttributes.NotPublic ||
 210                              ta == TypeAttributes.NestedAssembly ||
 211                              ta == TypeAttributes.NestedFamANDAssem) &&
 212                             !TypeManager.IsThisOrFriendAssembly (invocation, t.Assembly))
 213                                 return null;
 214
 215                         return t;
 216                 }
 217
 218                 public override string ToString ()
 219                 {
 220                         return String.Format ("RootNamespace ({0}::)", alias_name);
 221                 }
 222
 223                 public override string GetSignatureForError ()
 224                 {
 225                         return alias_name + "::";
 226                 }
 227         }
 228
 229         public class GlobalRootNamespace : RootNamespace {
 230                 Module [] modules;
 231                 ListDictionary root_namespaces;
 232
 233                 public static GlobalRootNamespace Instance = new GlobalRootNamespace ();
 234
 235                 GlobalRootNamespace ()
 236                         : base ("global")
 237                 {
 238                         root_namespaces = new ListDictionary ();
 239                         root_namespaces.Add (alias_name, this);
 240                 }
 241
 242                 public static void Reset ()
 243                 {
 244                         Instance = new GlobalRootNamespace ();
 245                 }
 246
 247                 public Assembly [] Assemblies {
 248                     get { return referenced_assemblies; }
 249                 }
 250
 251                 public Module [] Modules {
 252                         get { return modules; }
 253                 }
 254
 255                 public void AddModuleReference (Module m)
 256                 {
 257                         int top = modules != null ? modules.Length : 0;
 258                         Module [] n = new Module [top + 1];
 259                         if (modules != null)
 260                                 modules.CopyTo (n, 0);
 261                         n [top] = m;
 262                         modules = n;
 263
 264                         if (m == RootContext.ToplevelTypes.Builder)
 265                                 return;
 266
 267                         foreach (Type t in m.GetTypes ())
 268                                 RegisterNamespace (t.Namespace);
 269                 }
 270
 271                 public void ComputeNamespaces (CompilerContext ctx)
 272                 {
 273                         //
 274                         // Do very early lookup because type is required when we cache
 275                         // imported extension types in ComputeNamespaces
 276                         //
 277                         Type extension_attribute_type = TypeManager.CoreLookupType (ctx, "System.Runtime.CompilerServices", "ExtensionAttribute", Kind.Class, false);
 278
 279                         foreach (RootNamespace rn in root_namespaces.Values) {
 280                                 rn.ComputeNamespace (ctx, extension_attribute_type);
 281                         }
 282                 }
 283
 284                 public void DefineRootNamespace (string alias, Assembly assembly, CompilerContext ctx)
 285                 {
 286                         if (alias == alias_name) {
 287                                 NamespaceEntry.Error_GlobalNamespaceRedefined (Location.Null, ctx.Report);
 288                                 return;
 289                         }
 290
 291                         RootNamespace retval = GetRootNamespace (alias);
 292                         if (retval == null) {
 293                                 retval = new RootNamespace (alias);
 294                                 root_namespaces.Add (alias, retval);
 295                         }
 296
 297                         retval.AddAssemblyReference (assembly);
 298                 }
 299
 300                 public override void Error_NamespaceDoesNotExist (Location loc, string name, IMemberContext ctx)
 301                 {
 302                         ctx.Compiler.Report.Error (400, loc,
 303                                 "The type or namespace name `{0}' could not be found in the global namespace (are you missing an assembly reference?)",
 304                                 name);
 305                 }
 306
 307                 public RootNamespace GetRootNamespace (string name)
 308                 {
 309                         return (RootNamespace) root_namespaces[name];
 310                 }
 311
 312                 public override Type LookupTypeReflection (CompilerContext ctx, string name, Location loc, bool must_be_unique)
 313                 {
 314                         Type found_type = base.LookupTypeReflection (ctx, name, loc, must_be_unique);
 315
 316                         if (modules != null) {
 317                                 foreach (Module module in modules) {
 318                                         Type t = module.GetType (name);
 319                                         if (t == null)
 320                                                 continue;
 321
 322                                         if (found_type == null) {
 323                                                 found_type = t;
 324                                                 continue;
 325                                         }
 326
 327                                         ctx.Report.SymbolRelatedToPreviousError (found_type);
 328                                         if (loc.IsNull) {
 329                                                 DeclSpace ds = TypeManager.LookupDeclSpace (t);
 330                                                 Error_AmbiguousPredefinedType (ctx, ds.Location, name, found_type);
 331                                                 return found_type;
 332                                         }
 333                                         ctx.Report.SymbolRelatedToPreviousError (t);
 334                                         ctx.Report.Warning (436, 2, loc, "The type `{0}' conflicts with the imported type `{1}'. Ignoring the imported type definition",
 335                                                 TypeManager.CSharpName (t), TypeManager.CSharpName (found_type));
 336                                         return t;
 337                                 }
 338                         }
 339
 340                         return found_type;
 341                 }
 342         }
 343
 344         /// <summary>
 345         ///   Keeps track of the namespaces defined in the C# code.
 346         ///
 347         ///   This is an Expression to allow it to be referenced in the
 348         ///   compiler parse/intermediate tree during name resolution.
 349         /// </summary>
 350         public class Namespace : FullNamedExpression {
 351
 352                 Namespace parent;
 353                 string fullname;
 354                 IDictionary namespaces;
 355                 IDictionary declspaces;
 356                 Hashtable cached_types;
 357                 RootNamespace root;
 358                 ArrayList external_exmethod_classes;
 359
 360                 public readonly MemberName MemberName;
 361
 362                 /// <summary>
 363                 ///   Constructor Takes the current namespace and the
 364                 ///   name.  This is bootstrapped with parent == null
 365                 ///   and name = ""
 366                 /// </summary>
 367                 public Namespace (Namespace parent, string name)
 368                 {
 369                         // Expression members.
 370                         this.eclass = ExprClass.Namespace;
 371                         this.Type = typeof (Namespace);
 372                         this.loc = Location.Null;
 373
 374                         this.parent = parent;
 375
 376                         if (parent != null)
 377                                 this.root = parent.root;
 378                         else
 379                                 this.root = this as RootNamespace;
 380
 381                         if (this.root == null)
 382                                 throw new InternalErrorException ("Root namespaces must be created using RootNamespace");
 383
 384                         string pname = parent != null ? parent.fullname : "";
 385
 386                         if (pname == "")
 387                                 fullname = name;
 388                         else
 389                                 fullname = parent.fullname + "." + name;
 390
 391                         if (fullname == null)
 392                                 throw new InternalErrorException ("Namespace has a null fullname");
 393
 394                         if (parent != null && parent.MemberName != MemberName.Null)
 395                                 MemberName = new MemberName (parent.MemberName, name);
 396                         else if (name.Length == 0)
 397                                 MemberName = MemberName.Null;
 398                         else
 399                                 MemberName = new MemberName (name);
 400
 401                         namespaces = new HybridDictionary ();
 402                         cached_types = new Hashtable ();
 403
 404                         root.RegisterNamespace (this);
 405                 }
 406
 407                 protected override Expression DoResolve (ResolveContext ec)
 408                 {
 409                         return this;
 410                 }
 411
 412                 public virtual void Error_NamespaceDoesNotExist (Location loc, string name, IMemberContext ctx)
 413                 {
 414                         if (name.IndexOf ('`') > 0) {
 415                                 FullNamedExpression retval = Lookup (ctx.Compiler, SimpleName.RemoveGenericArity (name), loc);
 416                                 if (retval != null) {
 417                                         retval.Error_TypeArgumentsCannotBeUsed (ctx.Compiler.Report, loc);
 418                                         return;
 419                                 }
 420                         } else {
 421                                 Type t = LookForAnyGenericType (name);
 422                                 if (t != null) {
 423                                         Error_InvalidNumberOfTypeArguments (ctx.Compiler.Report, t, loc);
 424                                         return;
 425                                 }
 426                         }
 427
 428                         ctx.Compiler.Report.Error (234, loc,
 429                                 "The type or namespace name `{0}' does not exist in the namespace `{1}'. Are you missing an assembly reference?",
 430                                 name, GetSignatureForError ());
 431                 }
 432
 433                 public static void Error_InvalidNumberOfTypeArguments (Report report, Type t, Location loc)
 434                 {
 435                         report.SymbolRelatedToPreviousError (t);
 436                         report.Error (305, loc, "Using the generic type `{0}' requires `{1}' type argument(s)",
 437                                 TypeManager.CSharpName(t), TypeManager.GetNumberOfTypeArguments(t).ToString());
 438                 }
 439
 440                 public override string GetSignatureForError ()
 441                 {
 442                         return fullname;
 443                 }
 444
 445                 public Namespace GetNamespace (string name, bool create)
 446                 {
 447                         int pos = name.IndexOf ('.');
 448
 449                         Namespace ns;
 450                         string first;
 451                         if (pos >= 0)
 452                                 first = name.Substring (0, pos);
 453                         else
 454                                 first = name;
 455
 456                         ns = (Namespace) namespaces [first];
 457                         if (ns == null) {
 458                                 if (!create)
 459                                         return null;
 460
 461                                 ns = new Namespace (this, first);
 462                                 namespaces.Add (first, ns);
 463                         }
 464
 465                         if (pos >= 0)
 466                                 ns = ns.GetNamespace (name.Substring (pos + 1), create);
 467
 468                         return ns;
 469                 }
 470
 471                 public bool HasDefinition (string name)
 472                 {
 473                         return declspaces != null && declspaces [name] != null;
 474                 }
 475
 476                 TypeExpr LookupType (CompilerContext ctx, string name, Location loc)
 477                 {
 478                         if (cached_types.Contains (name))
 479                                 return cached_types [name] as TypeExpr;
 480
 481                         Type t = null;
 482                         if (declspaces != null) {
 483                                 DeclSpace tdecl = declspaces [name] as DeclSpace;
 484                                 if (tdecl != null) {
 485                                         //
 486                                         // Note that this is not:
 487                                         //
 488                                         //   t = tdecl.DefineType ()
 489                                         //
 490                                         // This is to make it somewhat more useful when a DefineType
 491                                         // fails due to problems in nested types (more useful in the sense
 492                                         // of fewer misleading error messages)
 493                                         //
 494                                         tdecl.DefineType ();
 495                                         t = tdecl.TypeBuilder;
 496
 497                                         if (RootContext.EvalMode){
 498                                                 // Replace the TypeBuilder with a System.Type, as
 499                                                 // Reflection.Emit fails otherwise (we end up pretty
 500                                                 // much with Random type definitions later on).
 501                                                 Type tt = t.Assembly.GetType (t.Name);
 502                                                 if (tt != null)
 503                                                         t = tt;
 504                                         }
 505                                 }
 506                         }
 507                         string lookup = t != null ? t.FullName : (fullname.Length == 0 ? name : fullname + "." + name);
 508                         Type rt = root.LookupTypeReflection (ctx, lookup, loc, t == null);
 509
 510                         // HACK: loc.IsNull when the type is core type
 511                         if (t == null || (rt != null && loc.IsNull))
 512                                 t = rt;
 513
 514                         TypeExpr te = t == null ? null : new TypeExpression (t, Location.Null);
 515                         cached_types [name] = te;
 516                         return te;
 517                 }
 518
 519                 ///
 520                 /// Used for better error reporting only
 521                 ///
 522                 public Type LookForAnyGenericType (string typeName)
 523                 {
 524                         if (declspaces == null)
 525                                 return null;
 526
 527                         typeName = SimpleName.RemoveGenericArity (typeName);
 528
 529                         foreach (DictionaryEntry de in declspaces) {
 530                                 string type_item = (string) de.Key;
 531                                 int pos = type_item.LastIndexOf ('`');
 532                                 if (pos == typeName.Length && String.Compare (typeName, 0, type_item, 0, pos) == 0)
 533                                         return ((DeclSpace) de.Value).TypeBuilder;
 534                         }
 535                         return null;
 536                 }
 537
 538                 public FullNamedExpression Lookup (CompilerContext ctx, string name, Location loc)
 539                 {
 540                         if (namespaces.Contains (name))
 541                                 return (Namespace) namespaces [name];
 542
 543                         return LookupType (ctx, name, loc);
 544                 }
 545
 546                 //
 547                 // Completes types with the given `prefix' and stores the results in `result'
 548                 //
 549                 public void CompletionGetTypesStartingWith (string prefix, Hashtable result)
 550                 {
 551                         int l = fullname.Length + 1;
 552                         ICollection res = root.CompletionGetTypesStartingWith (fullname + "." + prefix);
 553
 554                         if (res == null)
 555                                 return;
 556
 557                         foreach (string match in res){
 558                                 string x = match.Substring (l);
 559
 560                                 // Turn reflection nested classes foo+bar into foo.bar
 561                                 x = x.Replace ('+', '.');
 562
 563                                 // Only get the first name element, no point in adding anything beyond the first dot.
 564                                 int p = x.IndexOf ('.');
 565                                 if (p != -1)
 566                                         x = x.Substring (0, p);
 567
 568                                 // Turn Foo`N into Foo<
 569                                 p = x.IndexOf ('`');
 570                                 if (p != -1)
 571                                         x = x.Substring (0, p) + "<";
 572
 573                                 if (!result.Contains (x))
 574                                         result [x] = x;
 575                         }
 576                 }
 577
 578                 public void RegisterExternalExtensionMethodClass (Type type)
 579                 {
 580                         // Ignore, extension methods cannot be nested
 581                         if (type.DeclaringType != null)
 582                                 return;
 583
 584                         // TODO: CodeGen.Assembly.Builder is global
 585                         if (type.IsNotPublic && !TypeManager.IsThisOrFriendAssembly (CodeGen.Assembly.Builder, type.Assembly))
 586                                 return;
 587
 588                         if (external_exmethod_classes == null)
 589                                 external_exmethod_classes = new ArrayList ();
 590
 591                         external_exmethod_classes.Add (type);
 592                 }
 593
 594                 ///
 595                 /// Looks for extension method in this namespace
 596                 ///
 597                 public ArrayList LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name)
 598                 {
 599                         ArrayList found = null;
 600
 601                         // TODO: problematic
 602                         var invocation_assembly = CodeGen.Assembly.Builder;
 603
 604                         if (declspaces != null) {
 605                                 IEnumerator e = declspaces.Values.GetEnumerator ();
 606                                 e.Reset ();
 607                                 while (e.MoveNext ()) {
 608                                         Class c = e.Current as Class;
 609                                         if (c == null)
 610                                                 continue;
 611
 612                                         if ((c.ModFlags & Modifiers.METHOD_EXTENSION) == 0)
 613                                                 continue;
 614
 615                                         ArrayList res = c.MemberCache.FindExtensionMethods (invocation_assembly, extensionType, name, c != currentClass);
 616                                         if (res == null)
 617                                                 continue;
 618
 619                                         if (found == null)
 620                                                 found = res;
 621                                         else
 622                                                 found.AddRange (res);
 623                                 }
 624                         }
 625
 626                         if (external_exmethod_classes == null)
 627                                 return found;
 628
 629                         foreach (Type t in external_exmethod_classes) {
 630                                 MemberCache m = TypeHandle.GetMemberCache (t);
 631                                 ArrayList res = m.FindExtensionMethods (invocation_assembly, extensionType, name, true);
 632                                 if (res == null)
 633                                         continue;
 634
 635                                 if (found == null)
 636                                         found = res;
 637                                 else
 638                                         found.AddRange (res);
 639                         }
 640
 641                         return found;
 642                 }
 643
 644                 public void AddDeclSpace (string name, DeclSpace ds)
 645                 {
 646                         if (declspaces == null)
 647                                 declspaces = new HybridDictionary ();
 648                         declspaces.Add (name, ds);
 649                 }
 650
 651                 public void RemoveDeclSpace (string name)
 652                 {
 653                         declspaces.Remove (name);
 654                 }
 655
 656                 /// <summary>
 657                 ///   The qualified name of the current namespace
 658                 /// </summary>
 659                 public string Name {
 660                         get { return fullname; }
 661                 }
 662
 663                 /// <summary>
 664                 ///   The parent of this namespace, used by the parser to "Pop"
 665                 ///   the current namespace declaration
 666                 /// </summary>
 667                 public Namespace Parent {
 668                         get { return parent; }
 669                 }
 670         }
 671
 672         //
 673         // Namespace container as created by the parser
 674         //
 675         public class NamespaceEntry : IMemberContext {
 676
 677                 class UsingEntry {
 678                         readonly MemberName name;
 679                         Namespace resolved;
 680
 681                         public UsingEntry (MemberName name)
 682                         {
 683                                 this.name = name;
 684                         }
 685
 686                         public string GetSignatureForError ()
 687                         {
 688                                 return name.GetSignatureForError ();
 689                         }
 690
 691                         public Location Location {
 692                                 get { return name.Location; }
 693                         }
 694
 695                         public MemberName MemberName {
 696                                 get { return name; }
 697                         }
 698
 699                         public string Name {
 700                                 get { return GetSignatureForError (); }
 701                         }
 702
 703                         public Namespace Resolve (IMemberContext rc)
 704                         {
 705                                 if (resolved != null)
 706                                         return resolved;
 707
 708                                 FullNamedExpression fne = name.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 709                                 if (fne == null)
 710                                         return null;
 711
 712                                 resolved = fne as Namespace;
 713                                 if (resolved == null) {
 714                                         rc.Compiler.Report.SymbolRelatedToPreviousError (fne.Type);
 715                                         rc.Compiler.Report.Error (138, Location,
 716                                                 "`{0}' is a type not a namespace. A using namespace directive can only be applied to namespaces",
 717                                                 GetSignatureForError ());
 718                                 }
 719                                 return resolved;
 720                         }
 721
 722                         public override string ToString ()
 723                         {
 724                                 return Name;
 725                         }
 726                 }
 727
 728                 class UsingAliasEntry {
 729                         public readonly string Alias;
 730                         public Location Location;
 731
 732                         public UsingAliasEntry (string alias, Location loc)
 733                         {
 734                                 this.Alias = alias;
 735                                 this.Location = loc;
 736                         }
 737
 738                         public virtual FullNamedExpression Resolve (IMemberContext rc)
 739                         {
 740                                 FullNamedExpression fne = GlobalRootNamespace.Instance.GetRootNamespace (Alias);
 741                                 if (fne == null) {
 742                                         rc.Compiler.Report.Error (430, Location,
 743                                                 "The extern alias `{0}' was not specified in -reference option",
 744                                                 Alias);
 745                                 }
 746
 747                                 return fne;
 748                         }
 749
 750                         public override string ToString ()
 751                         {
 752                                 return Alias;
 753                         }
 754
 755                 }
 756
 757                 class LocalUsingAliasEntry : UsingAliasEntry {
 758                         FullNamedExpression resolved;
 759                         MemberName value;
 760
 761                         public LocalUsingAliasEntry (string alias, MemberName name, Location loc)
 762                                 : base (alias, loc)
 763                         {
 764                                 this.value = name;
 765                         }
 766
 767                         public override FullNamedExpression Resolve (IMemberContext rc)
 768                         {
 769                                 if (resolved != null || value == null)
 770                                         return resolved;
 771
 772                                 if (rc == null)
 773                                         return null;
 774
 775                                 resolved = value.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 776                                 if (resolved == null) {
 777                                         value = null;
 778                                         return null;
 779                                 }
 780
 781                                 if (resolved is TypeExpr)
 782                                         resolved = resolved.ResolveAsBaseTerminal (rc, false);
 783
 784                                 return resolved;
 785                         }
 786
 787                         public override string ToString ()
 788                         {
 789                                 return String.Format ("{0} = {1}", Alias, value.GetSignatureForError ());
 790                         }
 791                 }
 792
 793                 Namespace ns;
 794                 NamespaceEntry parent, implicit_parent;
 795                 CompilationUnit file;
 796                 int symfile_id;
 797
 798                 // Namespace using import block
 799                 ArrayList using_aliases;
 800                 ArrayList using_clauses;
 801                 public bool DeclarationFound = false;
 802                 // End
 803
 804                 public readonly bool IsImplicit;
 805                 public readonly DeclSpace SlaveDeclSpace;
 806                 static readonly Namespace [] empty_namespaces = new Namespace [0];
 807                 Namespace [] namespace_using_table;
 808
 809                 static ArrayList entries = new ArrayList ();
 810
 811                 public static void Reset ()
 812                 {
 813                         entries = new ArrayList ();
 814                 }
 815
 816                 public NamespaceEntry (NamespaceEntry parent, CompilationUnit file, string name)
 817                 {
 818                         this.parent = parent;
 819                         this.file = file;
 820                         entries.Add (this);
 821
 822                         if (parent != null)
 823                                 ns = parent.NS.GetNamespace (name, true);
 824                         else if (name != null)
 825                                 ns = GlobalRootNamespace.Instance.GetNamespace (name, true);
 826                         else
 827                                 ns = GlobalRootNamespace.Instance;
 828                         SlaveDeclSpace = new RootDeclSpace (this);
 829                 }
 830
 831                 private NamespaceEntry (NamespaceEntry parent, CompilationUnit file, Namespace ns, bool slave)
 832                 {
 833                         this.parent = parent;
 834                         this.file = file;
 835                         this.IsImplicit = true;
 836                         this.ns = ns;
 837                         this.SlaveDeclSpace = slave ? new RootDeclSpace (this) : null;
 838                 }
 839
 840                 //
 841                 // Populates the Namespace with some using declarations, used by the
 842                 // eval mode.
 843                 //
 844                 public void Populate (ArrayList source_using_aliases, ArrayList source_using_clauses)
 845                 {
 846                         foreach (UsingAliasEntry uae in source_using_aliases){
 847                                 if (using_aliases == null)
 848                                         using_aliases = new ArrayList ();
 849
 850                                 using_aliases.Add (uae);
 851                         }
 852
 853                         foreach (UsingEntry ue in source_using_clauses){
 854                                 if (using_clauses == null)
 855                                         using_clauses = new ArrayList ();
 856
 857                                 using_clauses.Add (ue);
 858                         }
 859                 }
 860
 861                 //
 862                 // Extracts the using alises and using clauses into a couple of
 863                 // arrays that might already have the same information;  Used by the
 864                 // C# Eval mode.
 865                 //
 866                 public void Extract (ArrayList out_using_aliases, ArrayList out_using_clauses)
 867                 {
 868                         if (using_aliases != null){
 869                                 foreach (UsingAliasEntry uae in using_aliases){
 870                                         bool replaced = false;
 871
 872                                         for (int i = 0; i < out_using_aliases.Count; i++){
 873                                                 UsingAliasEntry out_uea = (UsingAliasEntry) out_using_aliases [i];
 874
 875                                                 if (out_uea.Alias == uae.Alias){
 876                                                         out_using_aliases [i] = uae;
 877                                                         replaced = true;
 878                                                         break;
 879                                                 }
 880                                         }
 881                                         if (!replaced)
 882                                                 out_using_aliases.Add (uae);
 883                                 }
 884                         }
 885
 886                         if (using_clauses != null){
 887                                 foreach (UsingEntry ue in using_clauses){
 888                                         bool found = false;
 889
 890                                         foreach (UsingEntry out_ue in out_using_clauses)
 891                                                 if (out_ue.Name == ue.Name){
 892                                                         found = true;
 893                                                         break;
 894                                                 }
 895                                         if (!found)
 896                                                 out_using_clauses.Add (ue);
 897                                 }
 898                         }
 899                 }
 900
 901                 //
 902                 // According to section 16.3.1 (using-alias-directive), the namespace-or-type-name is
 903                 // resolved as if the immediately containing namespace body has no using-directives.
 904                 //
 905                 // Section 16.3.2 says that the same rule is applied when resolving the namespace-name
 906                 // in the using-namespace-directive.
 907                 //
 908                 // To implement these rules, the expressions in the using directives are resolved using
 909                 // the "doppelganger" (ghostly bodiless duplicate).
 910                 //
 911                 NamespaceEntry doppelganger;
 912                 NamespaceEntry Doppelganger {
 913                         get {
 914                                 if (!IsImplicit && doppelganger == null) {
 915                                         doppelganger = new NamespaceEntry (ImplicitParent, file, ns, true);
 916                                         doppelganger.using_aliases = using_aliases;
 917                                 }
 918                                 return doppelganger;
 919                         }
 920                 }
 921
 922                 public Namespace NS {
 923                         get { return ns; }
 924                 }
 925
 926                 public NamespaceEntry Parent {
 927                         get { return parent; }
 928                 }
 929
 930                 public NamespaceEntry ImplicitParent {
 931                         get {
 932                                 if (parent == null)
 933                                         return null;
 934                                 if (implicit_parent == null) {
 935                                         implicit_parent = (parent.NS == ns.Parent)
 936                                                 ? parent
 937                                                 : new NamespaceEntry (parent, file, ns.Parent, false);
 938                                 }
 939                                 return implicit_parent;
 940                         }
 941                 }
 942
 943                 /// <summary>
 944                 ///   Records a new namespace for resolving name references
 945                 /// </summary>
 946                 public void AddUsing (MemberName name, Location loc)
 947                 {
 948                         if (DeclarationFound){
 949                                 Compiler.Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 950                         }
 951
 952                         if (using_clauses == null) {
 953                                 using_clauses = new ArrayList ();
 954                         } else {
 955                                 foreach (UsingEntry old_entry in using_clauses) {
 956                                         if (name.Equals (old_entry.MemberName)) {
 957                                                 Compiler.Report.SymbolRelatedToPreviousError (old_entry.Location, old_entry.GetSignatureForError ());
 958                                                 Compiler.Report.Warning (105, 3, loc, "The using directive for `{0}' appeared previously in this namespace", name.GetSignatureForError ());
 959                                                 return;
 960                                         }
 961                                 }
 962                         }
 963
 964                         using_clauses.Add (new UsingEntry (name));
 965                 }
 966
 967                 public void AddUsingAlias (string alias, MemberName name, Location loc)
 968                 {
 969                         // TODO: This is parser bussines
 970                         if (DeclarationFound){
 971                                 Compiler.Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 972                         }
 973
 974                         if (RootContext.Version != LanguageVersion.ISO_1 && alias == "global")
 975                                 Compiler.Report.Warning (440, 2, loc, "An alias named `global' will not be used when resolving 'global::';" +
 976                                         " the global namespace will be used instead");
 977
 978                         AddUsingAlias (new LocalUsingAliasEntry (alias, name, loc));
 979                 }
 980
 981                 public void AddUsingExternalAlias (string alias, Location loc, Report Report)
 982                 {
 983                         // TODO: Do this in parser
 984                         bool not_first = using_clauses != null || DeclarationFound;
 985                         if (using_aliases != null && !not_first) {
 986                                 foreach (UsingAliasEntry uae in using_aliases) {
 987                                         if (uae is LocalUsingAliasEntry) {
 988                                                 not_first = true;
 989                                                 break;
 990                                         }
 991                                 }
 992                         }
 993
 994                         if (not_first)
 995                                 Report.Error (439, loc, "An extern alias declaration must precede all other elements");
 996
 997                         if (alias == "global") {
 998                                 Error_GlobalNamespaceRedefined (loc, Report);
 999                                 return;
1000                         }
1001
1002                         AddUsingAlias (new UsingAliasEntry (alias, loc));
1003                 }
1004
1005                 void AddUsingAlias (UsingAliasEntry uae)
1006                 {
1007                         if (using_aliases == null) {
1008                                 using_aliases = new ArrayList ();
1009                         } else {
1010                                 foreach (UsingAliasEntry entry in using_aliases) {
1011                                         if (uae.Alias == entry.Alias) {
1012                                                 Compiler.Report.SymbolRelatedToPreviousError (uae.Location, uae.Alias);
1013                                                 Compiler.Report.Error (1537, entry.Location, "The using alias `{0}' appeared previously in this namespace",
1014                                                         entry.Alias);
1015                                                 return;
1016                                         }
1017                                 }
1018                         }
1019
1020                         using_aliases.Add (uae);
1021                 }
1022
1023                 ///
1024                 /// Does extension methods look up to find a method which matches name and extensionType.
1025                 /// Search starts from this namespace and continues hierarchically up to top level.
1026                 ///
1027                 public ExtensionMethodGroupExpr LookupExtensionMethod (Type extensionType, string name, Location loc)
1028                 {
1029                         ArrayList candidates = null;
1030                         foreach (Namespace n in GetUsingTable ()) {
1031                                 ArrayList a = n.LookupExtensionMethod (extensionType, null, name);
1032                                 if (a == null)
1033                                         continue;
1034
1035                                 if (candidates == null)
1036                                         candidates = a;
1037                                 else
1038                                         candidates.AddRange (a);
1039                         }
1040
1041                         if (candidates != null)
1042                                 return new ExtensionMethodGroupExpr (candidates, parent, extensionType, loc);
1043
1044                         if (parent == null)
1045                                 return null;
1046
1047                         //
1048                         // Inspect parent namespaces in namespace expression
1049                         //
1050                         Namespace parent_ns = ns.Parent;
1051                         do {
1052                                 candidates = parent_ns.LookupExtensionMethod (extensionType, null, name);
1053                                 if (candidates != null)
1054                                         return new ExtensionMethodGroupExpr (candidates, parent, extensionType, loc);
1055
1056                                 parent_ns = parent_ns.Parent;
1057                         } while (parent_ns != null);
1058
1059                         //
1060                         // Continue in parent scope
1061                         //
1062                         return parent.LookupExtensionMethod (extensionType, name, loc);
1063                 }
1064
1065                 public FullNamedExpression LookupNamespaceOrType (string name, Location loc, bool ignore_cs0104)
1066                 {
1067                         // Precondition: Only simple names (no dots) will be looked up with this function.
1068                         FullNamedExpression resolved = null;
1069                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent) {
1070                                 if ((resolved = curr_ns.Lookup (name, loc, ignore_cs0104)) != null)
1071                                         break;
1072                         }
1073                         return resolved;
1074                 }
1075
1076                 public ICollection CompletionGetTypesStartingWith (string prefix)
1077                 {
1078                         Hashtable result = new Hashtable ();
1079
1080                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent){
1081                                 foreach (Namespace using_ns in GetUsingTable ()){
1082                                         if (prefix.StartsWith (using_ns.Name)){
1083                                                 int ld = prefix.LastIndexOf ('.');
1084                                                 if (ld != -1){
1085                                                         string rest = prefix.Substring (ld+1);
1086
1087                                                         using_ns.CompletionGetTypesStartingWith (rest, result);
1088                                                 }
1089                                         }
1090                                         using_ns.CompletionGetTypesStartingWith (prefix, result);
1091                                 }
1092                         }
1093
1094                         return result.Keys;
1095                 }
1096
1097                 void Error_AmbiguousTypeReference (Location loc, string name, FullNamedExpression t1, FullNamedExpression t2)
1098                 {
1099                         Compiler.Report.SymbolRelatedToPreviousError (t1.Type);
1100                         Compiler.Report.SymbolRelatedToPreviousError (t2.Type);
1101                         Compiler.Report.Error (104, loc, "`{0}' is an ambiguous reference between `{1}' and `{2}'",
1102                                 name, t1.GetSignatureForError (), t2.GetSignatureForError ());
1103                 }
1104
1105                 // Looks-up a alias named @name in this and surrounding namespace declarations
1106                 public FullNamedExpression LookupNamespaceAlias (string name)
1107                 {
1108                         for (NamespaceEntry n = this; n != null; n = n.ImplicitParent) {
1109                                 if (n.using_aliases == null)
1110                                         continue;
1111
1112                                 foreach (UsingAliasEntry ue in n.using_aliases) {
1113                                         if (ue.Alias == name)
1114                                                 return ue.Resolve (Doppelganger);
1115                                 }
1116                         }
1117
1118                         return null;
1119                 }
1120
1121                 private FullNamedExpression Lookup (string name, Location loc, bool ignore_cs0104)
1122                 {
1123                         //
1124                         // Check whether it's in the namespace.
1125                         //
1126                         FullNamedExpression fne = ns.Lookup (Compiler, name, loc);
1127
1128                         //
1129                         // Check aliases.
1130                         //
1131                         if (using_aliases != null) {
1132                                 foreach (UsingAliasEntry ue in using_aliases) {
1133                                         if (ue.Alias == name) {
1134                                                 if (fne != null) {
1135                                                         if (Doppelganger != null) {
1136                                                                 // TODO: Namespace has broken location
1137                                                                 //Report.SymbolRelatedToPreviousError (fne.Location, null);
1138                                                                 Compiler.Report.SymbolRelatedToPreviousError (ue.Location, null);
1139                                                                 Compiler.Report.Error (576, loc,
1140                                                                         "Namespace `{0}' contains a definition with same name as alias `{1}'",
1141                                                                         GetSignatureForError (), name);
1142                                                         } else {
1143                                                                 return fne;
1144                                                         }
1145                                                 }
1146
1147                                                 return ue.Resolve (Doppelganger);
1148                                         }
1149                                 }
1150                         }
1151
1152                         if (fne != null)
1153                                 return fne;
1154
1155                         if (IsImplicit)
1156                                 return null;
1157
1158                         //
1159                         // Check using entries.
1160                         //
1161                         FullNamedExpression match = null;
1162                         foreach (Namespace using_ns in GetUsingTable ()) {
1163                                 match = using_ns.Lookup (Compiler, name, loc);
1164                                 if (match == null || !(match is TypeExpr))
1165                                         continue;
1166                                 if (fne != null) {
1167                                         if (!ignore_cs0104)
1168                                                 Error_AmbiguousTypeReference (loc, name, fne, match);
1169                                         return null;
1170                                 }
1171                                 fne = match;
1172                         }
1173
1174                         return fne;
1175                 }
1176
1177                 Namespace [] GetUsingTable ()
1178                 {
1179                         if (namespace_using_table != null)
1180                                 return namespace_using_table;
1181
1182                         if (using_clauses == null) {
1183                                 namespace_using_table = empty_namespaces;
1184                                 return namespace_using_table;
1185                         }
1186
1187                         ArrayList list = new ArrayList (using_clauses.Count);
1188
1189                         foreach (UsingEntry ue in using_clauses) {
1190                                 Namespace using_ns = ue.Resolve (Doppelganger);
1191                                 if (using_ns == null)
1192                                         continue;
1193
1194                                 list.Add (using_ns);
1195                         }
1196
1197                         namespace_using_table = (Namespace[])list.ToArray (typeof (Namespace));
1198                         return namespace_using_table;
1199                 }
1200
1201                 static readonly string [] empty_using_list = new string [0];
1202
1203                 public int SymbolFileID {
1204                         get {
1205                                 if (symfile_id == 0 && file.SourceFileEntry != null) {
1206                                         int parent_id = parent == null ? 0 : parent.SymbolFileID;
1207
1208                                         string [] using_list = empty_using_list;
1209                                         if (using_clauses != null) {
1210                                                 using_list = new string [using_clauses.Count];
1211                                                 for (int i = 0; i < using_clauses.Count; i++)
1212                                                         using_list [i] = ((UsingEntry) using_clauses [i]).MemberName.GetName ();
1213                                         }
1214
1215                                         symfile_id = SymbolWriter.DefineNamespace (ns.Name, file.CompileUnitEntry, using_list, parent_id);
1216                                 }
1217                                 return symfile_id;
1218                         }
1219                 }
1220
1221                 static void MsgtryRef (string s)
1222                 {
1223                         Console.WriteLine ("    Try using -r:" + s);
1224                 }
1225
1226                 static void MsgtryPkg (string s)
1227                 {
1228                         Console.WriteLine ("    Try using -pkg:" + s);
1229                 }
1230
1231                 public static void Error_GlobalNamespaceRedefined (Location loc, Report Report)
1232                 {
1233                         Report.Error (1681, loc, "You cannot redefine the global extern alias");
1234                 }
1235
1236                 public static void Error_NamespaceNotFound (Location loc, string name, Report Report)
1237                 {
1238                         Report.Error (246, loc, "The type or namespace name `{0}' could not be found. Are you missing a using directive or an assembly reference?",
1239                                 name);
1240
1241                         switch (name) {
1242                         case "Gtk": case "GtkSharp":
1243                                 MsgtryPkg ("gtk-sharp");
1244                                 break;
1245
1246                         case "Gdk": case "GdkSharp":
1247                                 MsgtryPkg ("gdk-sharp");
1248                                 break;
1249
1250                         case "Glade": case "GladeSharp":
1251                                 MsgtryPkg ("glade-sharp");
1252                                 break;
1253
1254                         case "System.Drawing":
1255                         case "System.Web.Services":
1256                         case "System.Web":
1257                         case "System.Data":
1258                         case "System.Windows.Forms":
1259                                 MsgtryRef (name);
1260                                 break;
1261                         }
1262                 }
1263
1264                 /// <summary>
1265                 ///   Used to validate that all the using clauses are correct
1266                 ///   after we are finished parsing all the files.
1267                 /// </summary>
1268                 void VerifyUsing ()
1269                 {
1270                         if (using_aliases != null) {
1271                                 foreach (UsingAliasEntry ue in using_aliases)
1272                                         ue.Resolve (Doppelganger);
1273                         }
1274
1275                         if (using_clauses != null) {
1276                                 foreach (UsingEntry ue in using_clauses)
1277                                         ue.Resolve (Doppelganger);
1278                         }
1279                 }
1280
1281                 /// <summary>
1282                 ///   Used to validate that all the using clauses are correct
1283                 ///   after we are finished parsing all the files.
1284                 /// </summary>
1285                 static public void VerifyAllUsing ()
1286                 {
1287                         foreach (NamespaceEntry entry in entries)
1288                                 entry.VerifyUsing ();
1289                 }
1290
1291                 public string GetSignatureForError ()
1292                 {
1293                         return ns.GetSignatureForError ();
1294                 }
1295
1296                 public override string ToString ()
1297                 {
1298                         return ns.ToString ();
1299                 }
1300
1301                 #region IMemberContext Members
1302
1303                 public CompilerContext Compiler {
1304                         get { return RootContext.ToplevelTypes.Compiler; }
1305                 }
1306
1307                 public Type CurrentType {
1308                         get { return SlaveDeclSpace.CurrentType; }
1309                 }
1310
1311                 public TypeContainer CurrentTypeDefinition {
1312                         get { return SlaveDeclSpace.CurrentTypeDefinition; }
1313                 }
1314
1315                 public TypeParameter[] CurrentTypeParameters {
1316                         get { return SlaveDeclSpace.CurrentTypeParameters; }
1317                 }
1318
1319                 public bool IsObsolete {
1320                         get { return SlaveDeclSpace.IsObsolete; }
1321                 }
1322
1323                 public bool IsUnsafe {
1324                         get { return SlaveDeclSpace.IsUnsafe; }
1325                 }
1326
1327                 public bool IsStatic {
1328                         get { return SlaveDeclSpace.IsStatic; }
1329                 }
1330
1331                 #endregion
1332         }
1333 }