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.Generic;
  13 using System.Linq;
  14
  15 namespace Mono.CSharp {
  16
  17         public class RootNamespace : Namespace {
  18
  19                 readonly string alias_name;
  20                 readonly Dictionary<string, Namespace> all_namespaces;
  21
  22                 public RootNamespace (string alias_name)
  23                         : base (null, String.Empty)
  24                 {
  25                         this.alias_name = alias_name;
  26
  27                         all_namespaces = new Dictionary<string, Namespace> ();
  28                         all_namespaces.Add ("", this);
  29                 }
  30
  31                 public string Alias {
  32                         get {
  33                                 return alias_name;
  34                         }
  35                 }
  36
  37                 public void RegisterNamespace (Namespace child)
  38                 {
  39                         if (child != this)
  40                                 all_namespaces.Add (child.Name, child);
  41                 }
  42
  43                 public bool IsNamespace (string name)
  44                 {
  45                         return all_namespaces.ContainsKey (name);
  46                 }
  47
  48                 protected void RegisterNamespace (string dotted_name)
  49                 {
  50                         if (dotted_name != null && dotted_name.Length != 0 && ! IsNamespace (dotted_name))
  51                                 GetNamespace (dotted_name, true);
  52                 }
  53
  54                 public override string GetSignatureForError ()
  55                 {
  56                         return alias_name + "::";
  57                 }
  58         }
  59
  60         public class GlobalRootNamespace : RootNamespace
  61         {
  62                 public GlobalRootNamespace ()
  63                         : base ("global")
  64                 {
  65                 }
  66
  67                 public override void Error_NamespaceDoesNotExist (Location loc, string name, int arity, IMemberContext ctx)
  68                 {
  69                         ctx.Module.Compiler.Report.Error (400, loc,
  70                                 "The type or namespace name `{0}' could not be found in the global namespace (are you missing an assembly reference?)",
  71                                 name);
  72                 }
  73         }
  74
  75         /// <summary>
  76         ///   Keeps track of the namespaces defined in the C# code.
  77         ///
  78         ///   This is an Expression to allow it to be referenced in the
  79         ///   compiler parse/intermediate tree during name resolution.
  80         /// </summary>
  81         public class Namespace : FullNamedExpression {
  82
  83                 Namespace parent;
  84                 string fullname;
  85                 protected Dictionary<string, Namespace> namespaces;
  86                 protected Dictionary<string, IList<TypeSpec>> types;
  87                 Dictionary<string, TypeExpr> cached_types;
  88                 RootNamespace root;
  89                 bool cls_checked;
  90
  91                 public readonly MemberName MemberName;
  92
  93                 /// <summary>
  94                 ///   Constructor Takes the current namespace and the
  95                 ///   name.  This is bootstrapped with parent == null
  96                 ///   and name = ""
  97                 /// </summary>
  98                 public Namespace (Namespace parent, string name)
  99                 {
 100                         // Expression members.
 101                         this.eclass = ExprClass.Namespace;
 102                         this.Type = InternalType.FakeInternalType;
 103                         this.loc = Location.Null;
 104
 105                         this.parent = parent;
 106
 107                         if (parent != null)
 108                                 this.root = parent.root;
 109                         else
 110                                 this.root = this as RootNamespace;
 111
 112                         if (this.root == null)
 113                                 throw new InternalErrorException ("Root namespaces must be created using RootNamespace");
 114
 115                         string pname = parent != null ? parent.fullname : "";
 116
 117                         if (pname == "")
 118                                 fullname = name;
 119                         else
 120                                 fullname = parent.fullname + "." + name;
 121
 122                         if (fullname == null)
 123                                 throw new InternalErrorException ("Namespace has a null fullname");
 124
 125                         if (parent != null && parent.MemberName != MemberName.Null)
 126                                 MemberName = new MemberName (parent.MemberName, name);
 127                         else if (name.Length == 0)
 128                                 MemberName = MemberName.Null;
 129                         else
 130                                 MemberName = new MemberName (name);
 131
 132                         namespaces = new Dictionary<string, Namespace> ();
 133                         cached_types = new Dictionary<string, TypeExpr> ();
 134
 135                         root.RegisterNamespace (this);
 136                 }
 137
 138                 #region Properties
 139
 140                 /// <summary>
 141                 ///   The qualified name of the current namespace
 142                 /// </summary>
 143                 public string Name {
 144                         get { return fullname; }
 145                 }
 146
 147                 /// <summary>
 148                 ///   The parent of this namespace, used by the parser to "Pop"
 149                 ///   the current namespace declaration
 150                 /// </summary>
 151                 public Namespace Parent {
 152                         get { return parent; }
 153                 }
 154
 155                 #endregion
 156
 157                 protected override Expression DoResolve (ResolveContext ec)
 158                 {
 159                         return this;
 160                 }
 161
 162                 public virtual void Error_NamespaceDoesNotExist (Location loc, string name, int arity, IMemberContext ctx)
 163                 {
 164                         FullNamedExpression retval = Lookup (ctx, name, -System.Math.Max (1, arity), loc);
 165                         if (retval != null) {
 166                                 Error_TypeArgumentsCannotBeUsed (ctx.Module.Compiler.Report, loc, retval.Type, arity);
 167                                 return;
 168                         }
 169
 170                         Namespace ns;
 171                         if (arity > 0 && namespaces.TryGetValue (name, out ns)) {
 172                                 ns.Error_TypeArgumentsCannotBeUsed (ctx.Module.Compiler.Report, loc, null, arity);
 173                                 return;
 174                         }
 175
 176                         ctx.Module.Compiler.Report.Error (234, loc,
 177                                 "The type or namespace name `{0}' does not exist in the namespace `{1}'. Are you missing an assembly reference?",
 178                                 name, GetSignatureForError ());
 179                 }
 180
 181                 public override string GetSignatureForError ()
 182                 {
 183                         return fullname;
 184                 }
 185
 186                 public Namespace GetNamespace (string name, bool create)
 187                 {
 188                         int pos = name.IndexOf ('.');
 189
 190                         Namespace ns;
 191                         string first;
 192                         if (pos >= 0)
 193                                 first = name.Substring (0, pos);
 194                         else
 195                                 first = name;
 196
 197                         if (!namespaces.TryGetValue (first, out ns)) {
 198                                 if (!create)
 199                                         return null;
 200
 201                                 ns = new Namespace (this, first);
 202                                 namespaces.Add (first, ns);
 203                         }
 204
 205                         if (pos >= 0)
 206                                 ns = ns.GetNamespace (name.Substring (pos + 1), create);
 207
 208                         return ns;
 209                 }
 210
 211                 public TypeExpr LookupType (IMemberContext ctx, string name, int arity, bool silent, Location loc)
 212                 {
 213                         if (types == null)
 214                                 return null;
 215
 216                         TypeExpr te;
 217                         if (arity == 0 && cached_types.TryGetValue (name, out te))
 218                                 return te;
 219
 220                         IList<TypeSpec> found;
 221                         if (!types.TryGetValue (name, out found))
 222                                 return null;
 223
 224                         TypeSpec best = null;
 225                         foreach (var ts in found) {
 226                                 if (ts.Arity == arity) {
 227                                         if (best == null) {
 228                                                 best = ts;
 229                                                 continue;
 230                                         }
 231
 232                                         var pts = best as BuildinTypeSpec;
 233                                         if (pts == null)
 234                                                 pts = ts as BuildinTypeSpec;
 235
 236                                         if (pts != null) {
 237                                                 ctx.Module.Compiler.Report.SymbolRelatedToPreviousError (best);
 238                                                 ctx.Module.Compiler.Report.SymbolRelatedToPreviousError (ts);
 239
 240                                                 // TODO: This should use different warning number but we want to be csc compatible
 241                                                 ctx.Module.Compiler.Report.Warning (1685, 1, loc,
 242                                                         "The predefined type `{0}.{1}' is redefined in the source code. Ignoring the local type definition",
 243                                                         pts.Namespace, pts.Name);
 244                                                 best = pts;
 245                                                 continue;
 246                                         }
 247
 248                                         if (best.MemberDefinition.IsImported && ts.MemberDefinition.IsImported) {
 249                                                 ctx.Module.Compiler.Report.SymbolRelatedToPreviousError (best);
 250                                                 ctx.Module.Compiler.Report.SymbolRelatedToPreviousError (ts);
 251                                                 if (silent) {
 252                                                         ctx.Module.Compiler.Report.Warning (1685, 1, loc,
 253                                                                 "The predefined type `{0}' is defined in multiple assemblies. Using definition from `{1}'",
 254                                                                 ts.GetSignatureForError (), best.MemberDefinition.DeclaringAssembly.Name);
 255                                                 } else {
 256                                                         ctx.Module.Compiler.Report.Error (433, loc, "The imported type `{0}' is defined multiple times", ts.GetSignatureForError ());
 257                                                 }
 258
 259                                                 break;
 260                                         }
 261
 262                                         if (best.MemberDefinition.IsImported)
 263                                                 best = ts;
 264
 265                                         if ((best.Modifiers & Modifiers.INTERNAL) != 0 && !best.MemberDefinition.IsInternalAsPublic (RootContext.ToplevelTypes.DeclaringAssembly))
 266                                                 continue;
 267
 268                                         if (silent)
 269                                                 continue;
 270
 271                                         if (ts.MemberDefinition.IsImported)
 272                                                 ctx.Module.Compiler.Report.SymbolRelatedToPreviousError (ts);
 273
 274                                         ctx.Module.Compiler.Report.Warning (436, 2, loc,
 275                                                 "The type `{0}' conflicts with the imported type of same name'. Ignoring the imported type definition",
 276                                                 best.GetSignatureForError ());
 277                                 }
 278
 279                                 //
 280                                 // Lookup for the best candidate with closest arity match
 281                                 //
 282                                 if (arity < 0) {
 283                                         if (best == null) {
 284                                                 best = ts;
 285                                         } else if (System.Math.Abs (ts.Arity + arity) < System.Math.Abs (best.Arity + arity)) {
 286                                                 best = ts;
 287                                         }
 288                                 }
 289                         }
 290
 291                         if (best == null)
 292                                 return null;
 293
 294                         if ((best.Modifiers & Modifiers.INTERNAL) != 0 && !best.MemberDefinition.IsInternalAsPublic (RootContext.ToplevelTypes.DeclaringAssembly))
 295                                 return null;
 296
 297                         te = new TypeExpression (best, Location.Null);
 298
 299                         // TODO MemberCache: Cache more
 300                         if (arity == 0 && !silent)
 301                                 cached_types.Add (name, te);
 302
 303                         return te;
 304                 }
 305
 306                 TypeSpec LookupType (string name, int arity)
 307                 {
 308                         if (types == null)
 309                                 return null;
 310
 311                         IList<TypeSpec> found;
 312                         if (types.TryGetValue (name, out found)) {
 313                                 TypeSpec best = null;
 314
 315                                 foreach (var ts in found) {
 316                                         if (ts.Arity == arity)
 317                                                 return ts;
 318
 319                                         //
 320                                         // Lookup for the best candidate with closest arity match
 321                                         //
 322                                         if (arity < 0) {
 323                                                 if (best == null) {
 324                                                         best = ts;
 325                                                 } else if (System.Math.Abs (ts.Arity + arity) < System.Math.Abs (best.Arity + arity)) {
 326                                                         best = ts;
 327                                                 }
 328                                         }
 329                                 }
 330
 331                                 return best;
 332                         }
 333
 334                         return null;
 335                 }
 336
 337                 public FullNamedExpression Lookup (IMemberContext ctx, string name, int arity, Location loc)
 338                 {
 339                         if (arity == 0 && namespaces.ContainsKey (name))
 340                                 return namespaces [name];
 341
 342                         return LookupType (ctx, name, arity, false, loc);
 343                 }
 344
 345                 //
 346                 // Completes types with the given `prefix'
 347                 //
 348                 public IEnumerable<string> CompletionGetTypesStartingWith (string prefix)
 349                 {
 350                         if (types == null)
 351                                 return Enumerable.Empty<string> ();
 352
 353                         var res = from item in types
 354                                           where item.Key.StartsWith (prefix) && item.Value.Any (l => (l.Modifiers & Modifiers.PUBLIC) != 0)
 355                                           select item.Key;
 356
 357                         if (namespaces != null)
 358                                 res = res.Concat (from item in namespaces where item.Key.StartsWith (prefix) select item.Key);
 359
 360                         return res;
 361                 }
 362
 363                 ///
 364                 /// Looks for extension method in this namespace
 365                 ///
 366                 public List<MethodSpec> LookupExtensionMethod (TypeSpec extensionType, TypeContainer invocationContext, string name, int arity)
 367                 {
 368                         if (types == null)
 369                                 return null;
 370
 371                         List<MethodSpec> found = null;
 372
 373                         // TODO: Add per namespace flag when at least 1 type has extension
 374
 375                         foreach (var tgroup in types.Values) {
 376                                 foreach (var ts in tgroup) {
 377                                         if ((ts.Modifiers & Modifiers.METHOD_EXTENSION) == 0)
 378                                                 continue;
 379
 380                                         var res = ts.MemberCache.FindExtensionMethods (invocationContext, extensionType, name, arity);
 381                                         if (res == null)
 382                                                 continue;
 383
 384                                         if (found == null) {
 385                                                 found = res;
 386                                         } else {
 387                                                 found.AddRange (res);
 388                                         }
 389                                 }
 390                         }
 391
 392                         return found;
 393                 }
 394
 395                 public void AddType (TypeSpec ts)
 396                 {
 397                         if (types == null) {
 398                                 types = new Dictionary<string, IList<TypeSpec>> (64);
 399                         }
 400
 401                         var name = ts.Name;
 402                         IList<TypeSpec> existing;
 403                         if (types.TryGetValue (name, out existing)) {
 404                                 TypeSpec better_type;
 405                                 TypeSpec found;
 406                                 if (existing.Count == 1) {
 407                                         found = existing[0];
 408                                         if (ts.Arity == found.Arity) {
 409                                                 better_type = IsImportedTypeOverride (ts, found);
 410                                                 if (better_type == found)
 411                                                         return;
 412
 413                                                 if (better_type != null) {
 414                                                         existing [0] = better_type;
 415                                                         return;
 416                                                 }
 417                                         }
 418
 419                                         existing = new List<TypeSpec> ();
 420                                         existing.Add (found);
 421                                         types[name] = existing;
 422                                 } else {
 423                                         for (int i = 0; i < existing.Count; ++i) {
 424                                                 found = existing[i];
 425                                                 if (ts.Arity != found.Arity)
 426                                                         continue;
 427
 428                                                 better_type = IsImportedTypeOverride (ts, found);
 429                                                 if (better_type == found)
 430                                                         return;
 431
 432                                                 if (better_type != null) {
 433                                                         existing.RemoveAt (i);
 434                                                         --i;
 435                                                         continue;
 436                                                 }
 437                                         }
 438                                 }
 439
 440                                 existing.Add (ts);
 441                         } else {
 442                                 types.Add (name, new TypeSpec[] { ts });
 443                         }
 444                 }
 445
 446                 //
 447                 // We import any types but in the situation there are same types
 448                 // but one has better visibility (either public or internal with friend)
 449                 // the less visible type is removed from the namespace cache
 450                 //
 451                 public static TypeSpec IsImportedTypeOverride (TypeSpec ts, TypeSpec found)
 452                 {
 453                         var ts_accessible = (ts.Modifiers & Modifiers.PUBLIC) != 0 || ts.MemberDefinition.IsInternalAsPublic (RootContext.ToplevelTypes.DeclaringAssembly);
 454                         var found_accessible = (found.Modifiers & Modifiers.PUBLIC) != 0 || found.MemberDefinition.IsInternalAsPublic (RootContext.ToplevelTypes.DeclaringAssembly);
 455
 456                         if (ts_accessible && !found_accessible)
 457                                 return ts;
 458
 459                         // found is better always better for accessible or inaccessible ts
 460                         if (!ts_accessible)
 461                                 return found;
 462
 463                         return null;
 464                 }
 465
 466                 public void RemoveDeclSpace (string name)
 467                 {
 468                         types.Remove (name);
 469                         cached_types.Remove (name);
 470                 }
 471
 472                 public void ReplaceTypeWithPredefined (TypeSpec ts, BuildinTypeSpec pts)
 473                 {
 474                         var found = types [ts.Name];
 475                         cached_types.Remove (ts.Name);
 476                         if (found.Count == 1) {
 477                                 types[ts.Name][0] = pts;
 478                         } else {
 479                                 throw new NotImplementedException ();
 480                         }
 481                 }
 482
 483                 public void VerifyClsCompliance ()
 484                 {
 485                         if (types == null || cls_checked)
 486                                 return;
 487
 488                         cls_checked = true;
 489
 490                         // TODO: This is quite ugly way to check for CLS compliance at namespace level
 491
 492                         var locase_types = new Dictionary<string, List<TypeSpec>> (StringComparer.OrdinalIgnoreCase);
 493                         foreach (var tgroup in types.Values) {
 494                                 foreach (var tm in tgroup) {
 495                                         if ((tm.Modifiers & Modifiers.PUBLIC) == 0 || !tm.IsCLSCompliant ())
 496                                                 continue;
 497
 498                                         List<TypeSpec> found;
 499                                         if (!locase_types.TryGetValue (tm.Name, out found)) {
 500                                                 found = new List<TypeSpec> ();
 501                                                 locase_types.Add (tm.Name, found);
 502                                         }
 503
 504                                         found.Add (tm);
 505                                 }
 506                         }
 507
 508                         foreach (var locase in locase_types.Values) {
 509                                 if (locase.Count < 2)
 510                                         continue;
 511
 512                                 bool all_same = true;
 513                                 foreach (var notcompliant in locase) {
 514                                         all_same = notcompliant.Name == locase[0].Name;
 515                                         if (!all_same)
 516                                                 break;
 517                                 }
 518
 519                                 if (all_same)
 520                                         continue;
 521
 522                                 TypeContainer compiled = null;
 523                                 foreach (var notcompliant in locase) {
 524                                         if (!notcompliant.MemberDefinition.IsImported) {
 525                                                 if (compiled != null)
 526                                                         compiled.Compiler.Report.SymbolRelatedToPreviousError (compiled);
 527
 528                                                 compiled = notcompliant.MemberDefinition as TypeContainer;
 529                                         } else {
 530                                                 compiled.Compiler.Report.SymbolRelatedToPreviousError (notcompliant);
 531                                         }
 532                                 }
 533
 534                                 compiled.Compiler.Report.Warning (3005, 1, compiled.Location,
 535                                         "Identifier `{0}' differing only in case is not CLS-compliant", compiled.GetSignatureForError ());
 536                         }
 537                 }
 538         }
 539
 540         //
 541         // Namespace container as created by the parser
 542         //
 543         public class NamespaceEntry : IMemberContext {
 544
 545                 public class UsingEntry {
 546                         readonly MemberName name;
 547                         Namespace resolved;
 548
 549                         public UsingEntry (MemberName name)
 550                         {
 551                                 this.name = name;
 552                         }
 553
 554                         public string GetSignatureForError ()
 555                         {
 556                                 return name.GetSignatureForError ();
 557                         }
 558
 559                         public Location Location {
 560                                 get { return name.Location; }
 561                         }
 562
 563                         public MemberName MemberName {
 564                                 get { return name; }
 565                         }
 566
 567                         public string Name {
 568                                 get { return GetSignatureForError (); }
 569                         }
 570
 571                         public Namespace Resolve (IMemberContext rc)
 572                         {
 573                                 if (resolved != null)
 574                                         return resolved;
 575
 576                                 FullNamedExpression fne = name.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 577                                 if (fne == null)
 578                                         return null;
 579
 580                                 resolved = fne as Namespace;
 581                                 if (resolved == null) {
 582                                         rc.Module.Compiler.Report.SymbolRelatedToPreviousError (fne.Type);
 583                                         rc.Module.Compiler.Report.Error (138, Location,
 584                                                 "`{0}' is a type not a namespace. A using namespace directive can only be applied to namespaces",
 585                                                 GetSignatureForError ());
 586                                 }
 587                                 return resolved;
 588                         }
 589
 590                         public override string ToString ()
 591                         {
 592                                 return Name;
 593                         }
 594                 }
 595
 596                 public class UsingAliasEntry {
 597                         public readonly string Alias;
 598                         public Location Location;
 599
 600                         public UsingAliasEntry (string alias, Location loc)
 601                         {
 602                                 this.Alias = alias;
 603                                 this.Location = loc;
 604                         }
 605
 606                         public virtual FullNamedExpression Resolve (IMemberContext rc, bool local)
 607                         {
 608                                 FullNamedExpression fne = rc.Module.GetRootNamespace (Alias);
 609                                 if (fne == null) {
 610                                         rc.Module.Compiler.Report.Error (430, Location,
 611                                                 "The extern alias `{0}' was not specified in -reference option",
 612                                                 Alias);
 613                                 }
 614
 615                                 return fne;
 616                         }
 617
 618                         public override string ToString ()
 619                         {
 620                                 return Alias;
 621                         }
 622
 623                 }
 624
 625                 class LocalUsingAliasEntry : UsingAliasEntry {
 626                         FullNamedExpression resolved;
 627                         MemberName value;
 628
 629                         public LocalUsingAliasEntry (string alias, MemberName name, Location loc)
 630                                 : base (alias, loc)
 631                         {
 632                                 this.value = name;
 633                         }
 634
 635                         public override FullNamedExpression Resolve (IMemberContext rc, bool local)
 636                         {
 637                                 if (resolved != null || value == null)
 638                                         return resolved;
 639
 640                                 if (local)
 641                                         return null;
 642
 643                                 resolved = value.GetTypeExpression ().ResolveAsTypeStep (rc, false);
 644                                 if (resolved == null) {
 645                                         value = null;
 646                                         return null;
 647                                 }
 648
 649                                 if (resolved is TypeExpr)
 650                                         resolved = resolved.ResolveAsTypeTerminal (rc, false);
 651
 652                                 return resolved;
 653                         }
 654
 655                         public override string ToString ()
 656                         {
 657                                 return String.Format ("{0} = {1}", Alias, value.GetSignatureForError ());
 658                         }
 659                 }
 660
 661                 Namespace ns;
 662                 NamespaceEntry parent, implicit_parent;
 663                 CompilationUnit file;
 664                 int symfile_id;
 665
 666                 // Namespace using import block
 667                 List<UsingAliasEntry> using_aliases;
 668                 List<UsingEntry> using_clauses;
 669                 public bool DeclarationFound;
 670                 // End
 671
 672                 public readonly bool IsImplicit;
 673                 public readonly TypeContainer SlaveDeclSpace;
 674                 static readonly Namespace [] empty_namespaces = new Namespace [0];
 675                 Namespace [] namespace_using_table;
 676                 ModuleContainer ctx;
 677
 678                 static List<NamespaceEntry> entries = new List<NamespaceEntry> ();
 679
 680                 public static void Reset ()
 681                 {
 682                         entries = new List<NamespaceEntry> ();
 683                 }
 684
 685                 public NamespaceEntry (ModuleContainer ctx, NamespaceEntry parent, CompilationUnit file, string name)
 686                 {
 687                         this.ctx = ctx;
 688                         this.parent = parent;
 689                         this.file = file;
 690                         entries.Add (this);
 691
 692                         if (parent != null)
 693                                 ns = parent.NS.GetNamespace (name, true);
 694                         else if (name != null)
 695                                 ns = ctx.GlobalRootNamespace.GetNamespace (name, true);
 696                         else
 697                                 ns = ctx.GlobalRootNamespace;
 698
 699                         SlaveDeclSpace = new RootDeclSpace (ctx, this);
 700                 }
 701
 702                 private NamespaceEntry (ModuleContainer ctx, NamespaceEntry parent, CompilationUnit file, Namespace ns, bool slave)
 703                 {
 704                         this.ctx = ctx;
 705                         this.parent = parent;
 706                         this.file = file;
 707                         this.IsImplicit = true;
 708                         this.ns = ns;
 709                         this.SlaveDeclSpace = slave ? new RootDeclSpace (ctx, this) : null;
 710                 }
 711
 712                 public List<UsingEntry> Usings {
 713                         get {
 714                                 return using_clauses;
 715                         }
 716                 }
 717
 718                 //
 719                 // Extracts the using alises and using clauses into a couple of
 720                 // arrays that might already have the same information;  Used by the
 721                 // C# Eval mode.
 722                 //
 723                 public void Extract (List<UsingAliasEntry> out_using_aliases, List<UsingEntry> out_using_clauses)
 724                 {
 725                         if (using_aliases != null){
 726                                 foreach (UsingAliasEntry uae in using_aliases){
 727                                         bool replaced = false;
 728
 729                                         for (int i = 0; i < out_using_aliases.Count; i++){
 730                                                 UsingAliasEntry out_uea = (UsingAliasEntry) out_using_aliases [i];
 731
 732                                                 if (out_uea.Alias == uae.Alias){
 733                                                         out_using_aliases [i] = uae;
 734                                                         replaced = true;
 735                                                         break;
 736                                                 }
 737                                         }
 738                                         if (!replaced)
 739                                                 out_using_aliases.Add (uae);
 740                                 }
 741                         }
 742
 743                         if (using_clauses != null){
 744                                 foreach (UsingEntry ue in using_clauses){
 745                                         bool found = false;
 746
 747                                         foreach (UsingEntry out_ue in out_using_clauses)
 748                                                 if (out_ue.Name == ue.Name){
 749                                                         found = true;
 750                                                         break;
 751                                                 }
 752                                         if (!found)
 753                                                 out_using_clauses.Add (ue);
 754                                 }
 755                         }
 756                 }
 757
 758                 //
 759                 // According to section 16.3.1 (using-alias-directive), the namespace-or-type-name is
 760                 // resolved as if the immediately containing namespace body has no using-directives.
 761                 //
 762                 // Section 16.3.2 says that the same rule is applied when resolving the namespace-name
 763                 // in the using-namespace-directive.
 764                 //
 765                 // To implement these rules, the expressions in the using directives are resolved using
 766                 // the "doppelganger" (ghostly bodiless duplicate).
 767                 //
 768                 NamespaceEntry doppelganger;
 769                 NamespaceEntry Doppelganger {
 770                         get {
 771                                 if (!IsImplicit && doppelganger == null) {
 772                                         doppelganger = new NamespaceEntry (ctx, ImplicitParent, file, ns, true);
 773                                         doppelganger.using_aliases = using_aliases;
 774                                 }
 775                                 return doppelganger;
 776                         }
 777                 }
 778
 779                 public Namespace NS {
 780                         get { return ns; }
 781                 }
 782
 783                 public NamespaceEntry Parent {
 784                         get { return parent; }
 785                 }
 786
 787                 public NamespaceEntry ImplicitParent {
 788                         get {
 789                                 if (parent == null)
 790                                         return null;
 791                                 if (implicit_parent == null) {
 792                                         implicit_parent = (parent.NS == ns.Parent)
 793                                                 ? parent
 794                                                 : new NamespaceEntry (ctx, parent, file, ns.Parent, false);
 795                                 }
 796                                 return implicit_parent;
 797                         }
 798                 }
 799
 800                 /// <summary>
 801                 ///   Records a new namespace for resolving name references
 802                 /// </summary>
 803                 public void AddUsing (MemberName name, Location loc)
 804                 {
 805                         if (DeclarationFound){
 806                                 Compiler.Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 807                         }
 808
 809                         if (using_clauses == null) {
 810                                 using_clauses = new List<UsingEntry> ();
 811                         } else {
 812                                 foreach (UsingEntry old_entry in using_clauses) {
 813                                         if (name.Equals (old_entry.MemberName)) {
 814                                                 Compiler.Report.SymbolRelatedToPreviousError (old_entry.Location, old_entry.GetSignatureForError ());
 815                                                 Compiler.Report.Warning (105, 3, loc, "The using directive for `{0}' appeared previously in this namespace", name.GetSignatureForError ());
 816                                                 return;
 817                                         }
 818                                 }
 819                         }
 820
 821                         using_clauses.Add (new UsingEntry (name));
 822                 }
 823
 824                 public void AddUsingAlias (string alias, MemberName name, Location loc)
 825                 {
 826                         // TODO: This is parser bussines
 827                         if (DeclarationFound){
 828                                 Compiler.Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
 829                         }
 830
 831                         AddUsingAlias (new LocalUsingAliasEntry (alias, name, loc));
 832                 }
 833
 834                 public void AddUsingExternalAlias (string alias, Location loc, Report Report)
 835                 {
 836                         // TODO: Do this in parser
 837                         bool not_first = using_clauses != null || DeclarationFound;
 838                         if (using_aliases != null && !not_first) {
 839                                 foreach (UsingAliasEntry uae in using_aliases) {
 840                                         if (uae is LocalUsingAliasEntry) {
 841                                                 not_first = true;
 842                                                 break;
 843                                         }
 844                                 }
 845                         }
 846
 847                         if (not_first)
 848                                 Report.Error (439, loc, "An extern alias declaration must precede all other elements");
 849
 850                         if (alias == "global") {
 851                                 Error_GlobalNamespaceRedefined (loc, Report);
 852                                 return;
 853                         }
 854
 855                         AddUsingAlias (new UsingAliasEntry (alias, loc));
 856                 }
 857
 858                 void AddUsingAlias (UsingAliasEntry uae)
 859                 {
 860                         if (using_aliases == null) {
 861                                 using_aliases = new List<UsingAliasEntry> ();
 862                         } else {
 863                                 foreach (UsingAliasEntry entry in using_aliases) {
 864                                         if (uae.Alias == entry.Alias) {
 865                                                 Compiler.Report.SymbolRelatedToPreviousError (uae.Location, uae.Alias);
 866                                                 Compiler.Report.Error (1537, entry.Location, "The using alias `{0}' appeared previously in this namespace",
 867                                                         entry.Alias);
 868                                                 return;
 869                                         }
 870                                 }
 871                         }
 872
 873                         using_aliases.Add (uae);
 874                 }
 875
 876                 ///
 877                 /// Does extension methods look up to find a method which matches name and extensionType.
 878                 /// Search starts from this namespace and continues hierarchically up to top level.
 879                 ///
 880                 public IList<MethodSpec> LookupExtensionMethod (TypeSpec extensionType, string name, int arity, ref NamespaceEntry scope)
 881                 {
 882                         List<MethodSpec> candidates = null;
 883                         foreach (Namespace n in GetUsingTable ()) {
 884                                 var a = n.LookupExtensionMethod (extensionType, RootContext.ToplevelTypes, name, arity);
 885                                 if (a == null)
 886                                         continue;
 887
 888                                 if (candidates == null)
 889                                         candidates = a;
 890                                 else
 891                                         candidates.AddRange (a);
 892                         }
 893
 894                         scope = parent;
 895                         if (candidates != null)
 896                                 return candidates;
 897
 898                         if (parent == null)
 899                                 return null;
 900
 901                         //
 902                         // Inspect parent namespaces in namespace expression
 903                         //
 904                         Namespace parent_ns = ns.Parent;
 905                         do {
 906                                 candidates = parent_ns.LookupExtensionMethod (extensionType, RootContext.ToplevelTypes, name, arity);
 907                                 if (candidates != null)
 908                                         return candidates;
 909
 910                                 parent_ns = parent_ns.Parent;
 911                         } while (parent_ns != null);
 912
 913                         //
 914                         // Continue in parent scope
 915                         //
 916                         return parent.LookupExtensionMethod (extensionType, name, arity, ref scope);
 917                 }
 918
 919                 public FullNamedExpression LookupNamespaceOrType (string name, int arity, Location loc, bool ignore_cs0104)
 920                 {
 921                         // Precondition: Only simple names (no dots) will be looked up with this function.
 922                         FullNamedExpression resolved = null;
 923                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent) {
 924                                 if ((resolved = curr_ns.Lookup (name, arity, loc, ignore_cs0104)) != null)
 925                                         break;
 926                         }
 927
 928                         return resolved;
 929                 }
 930
 931                 public IList<string> CompletionGetTypesStartingWith (string prefix)
 932                 {
 933                         IEnumerable<string> all = Enumerable.Empty<string> ();
 934
 935                         for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent){
 936                                 foreach (Namespace using_ns in GetUsingTable ()){
 937                                         if (prefix.StartsWith (using_ns.Name)){
 938                                                 int ld = prefix.LastIndexOf ('.');
 939                                                 if (ld != -1){
 940                                                         string rest = prefix.Substring (ld+1);
 941
 942                                                         all = all.Concat (using_ns.CompletionGetTypesStartingWith (rest));
 943                                                 }
 944                                         }
 945                                         all = all.Concat (using_ns.CompletionGetTypesStartingWith (prefix));
 946                                 }
 947                         }
 948
 949                         return all.Distinct ().ToList ();
 950                 }
 951
 952                 // Looks-up a alias named @name in this and surrounding namespace declarations
 953                 public FullNamedExpression LookupNamespaceAlias (string name)
 954                 {
 955                         for (NamespaceEntry n = this; n != null; n = n.ImplicitParent) {
 956                                 if (n.using_aliases == null)
 957                                         continue;
 958
 959                                 foreach (UsingAliasEntry ue in n.using_aliases) {
 960                                         if (ue.Alias == name)
 961                                                 return ue.Resolve (Doppelganger ?? this, Doppelganger == null);
 962                                 }
 963                         }
 964
 965                         return null;
 966                 }
 967
 968                 private FullNamedExpression Lookup (string name, int arity, Location loc, bool ignore_cs0104)
 969                 {
 970                         //
 971                         // Check whether it's in the namespace.
 972                         //
 973                         FullNamedExpression fne = ns.Lookup (this, name, arity, loc);
 974
 975                         //
 976                         // Check aliases.
 977                         //
 978                         if (using_aliases != null && arity == 0) {
 979                                 foreach (UsingAliasEntry ue in using_aliases) {
 980                                         if (ue.Alias == name) {
 981                                                 if (fne != null) {
 982                                                         if (Doppelganger != null) {
 983                                                                 // TODO: Namespace has broken location
 984                                                                 //Report.SymbolRelatedToPreviousError (fne.Location, null);
 985                                                                 Compiler.Report.SymbolRelatedToPreviousError (ue.Location, null);
 986                                                                 Compiler.Report.Error (576, loc,
 987                                                                         "Namespace `{0}' contains a definition with same name as alias `{1}'",
 988                                                                         GetSignatureForError (), name);
 989                                                         } else {
 990                                                                 return fne;
 991                                                         }
 992                                                 }
 993
 994                                                 return ue.Resolve (Doppelganger ?? this, Doppelganger == null);
 995                                         }
 996                                 }
 997                         }
 998
 999                         if (fne != null) {
1000                                 if (!((fne.Type.Modifiers & Modifiers.INTERNAL) != 0 && !fne.Type.MemberDefinition.IsInternalAsPublic (RootContext.ToplevelTypes.DeclaringAssembly)))
1001                                         return fne;
1002                         }
1003
1004                         if (IsImplicit)
1005                                 return null;
1006
1007                         //
1008                         // Check using entries.
1009                         //
1010                         FullNamedExpression match = null;
1011                         foreach (Namespace using_ns in GetUsingTable ()) {
1012                                 // A using directive imports only types contained in the namespace, it
1013                                 // does not import any nested namespaces
1014                                 fne = using_ns.LookupType (this, name, arity, false, loc);
1015                                 if (fne == null)
1016                                         continue;
1017
1018                                 if (match == null) {
1019                                         match = fne;
1020                                         continue;
1021                                 }
1022
1023                                 // Prefer types over namespaces
1024                                 var texpr_fne = fne as TypeExpr;
1025                                 var texpr_match = match as TypeExpr;
1026                                 if (texpr_fne != null && texpr_match == null) {
1027                                         match = fne;
1028                                         continue;
1029                                 } else if (texpr_fne == null) {
1030                                         continue;
1031                                 }
1032
1033                                 if (ignore_cs0104)
1034                                         return match;
1035
1036                                 // It can be top level accessibility only
1037                                 var better = Namespace.IsImportedTypeOverride (texpr_match.Type, texpr_fne.Type);
1038                                 if (better == null) {
1039                                         Compiler.Report.SymbolRelatedToPreviousError (texpr_match.Type);
1040                                         Compiler.Report.SymbolRelatedToPreviousError (texpr_fne.Type);
1041                                         Compiler.Report.Error (104, loc, "`{0}' is an ambiguous reference between `{1}' and `{2}'",
1042                                                 name, texpr_match.GetSignatureForError (), texpr_fne.GetSignatureForError ());
1043                                         return match;
1044                                 }
1045
1046                                 if (better == texpr_fne.Type)
1047                                         match = texpr_fne;
1048                         }
1049
1050                         return match;
1051                 }
1052
1053                 Namespace [] GetUsingTable ()
1054                 {
1055                         if (namespace_using_table != null)
1056                                 return namespace_using_table;
1057
1058                         if (using_clauses == null) {
1059                                 namespace_using_table = empty_namespaces;
1060                                 return namespace_using_table;
1061                         }
1062
1063                         var list = new List<Namespace> (using_clauses.Count);
1064
1065                         foreach (UsingEntry ue in using_clauses) {
1066                                 Namespace using_ns = ue.Resolve (Doppelganger);
1067                                 if (using_ns == null)
1068                                         continue;
1069
1070                                 list.Add (using_ns);
1071                         }
1072
1073                         namespace_using_table = list.ToArray ();
1074                         return namespace_using_table;
1075                 }
1076
1077                 static readonly string [] empty_using_list = new string [0];
1078
1079                 public int SymbolFileID {
1080                         get {
1081                                 if (symfile_id == 0 && file.SourceFileEntry != null) {
1082                                         int parent_id = parent == null ? 0 : parent.SymbolFileID;
1083
1084                                         string [] using_list = empty_using_list;
1085                                         if (using_clauses != null) {
1086                                                 using_list = new string [using_clauses.Count];
1087                                                 for (int i = 0; i < using_clauses.Count; i++)
1088                                                         using_list [i] = ((UsingEntry) using_clauses [i]).MemberName.GetName ();
1089                                         }
1090
1091                                         symfile_id = SymbolWriter.DefineNamespace (ns.Name, file.CompileUnitEntry, using_list, parent_id);
1092                                 }
1093                                 return symfile_id;
1094                         }
1095                 }
1096
1097                 static void MsgtryRef (string s)
1098                 {
1099                         Console.WriteLine ("    Try using -r:" + s);
1100                 }
1101
1102                 static void MsgtryPkg (string s)
1103                 {
1104                         Console.WriteLine ("    Try using -pkg:" + s);
1105                 }
1106
1107                 public static void Error_GlobalNamespaceRedefined (Location loc, Report Report)
1108                 {
1109                         Report.Error (1681, loc, "The global extern alias cannot be redefined");
1110                 }
1111
1112                 public static void Error_NamespaceNotFound (Location loc, string name, Report Report)
1113                 {
1114                         Report.Error (246, loc, "The type or namespace name `{0}' could not be found. Are you missing a using directive or an assembly reference?",
1115                                 name);
1116
1117                         switch (name) {
1118                         case "Gtk": case "GtkSharp":
1119                                 MsgtryPkg ("gtk-sharp");
1120                                 break;
1121
1122                         case "Gdk": case "GdkSharp":
1123                                 MsgtryPkg ("gdk-sharp");
1124                                 break;
1125
1126                         case "Glade": case "GladeSharp":
1127                                 MsgtryPkg ("glade-sharp");
1128                                 break;
1129
1130                         case "System.Drawing":
1131                         case "System.Web.Services":
1132                         case "System.Web":
1133                         case "System.Data":
1134                         case "System.Windows.Forms":
1135                                 MsgtryRef (name);
1136                                 break;
1137                         }
1138                 }
1139
1140                 /// <summary>
1141                 ///   Used to validate that all the using clauses are correct
1142                 ///   after we are finished parsing all the files.
1143                 /// </summary>
1144                 void VerifyUsing ()
1145                 {
1146                         if (using_aliases != null) {
1147                                 foreach (UsingAliasEntry ue in using_aliases)
1148                                         ue.Resolve (Doppelganger, Doppelganger == null);
1149                         }
1150
1151                         if (using_clauses != null) {
1152                                 foreach (UsingEntry ue in using_clauses)
1153                                         ue.Resolve (Doppelganger);
1154                         }
1155                 }
1156
1157                 /// <summary>
1158                 ///   Used to validate that all the using clauses are correct
1159                 ///   after we are finished parsing all the files.
1160                 /// </summary>
1161                 static public void VerifyAllUsing ()
1162                 {
1163                         foreach (NamespaceEntry entry in entries)
1164                                 entry.VerifyUsing ();
1165                 }
1166
1167                 public string GetSignatureForError ()
1168                 {
1169                         return ns.GetSignatureForError ();
1170                 }
1171
1172                 public override string ToString ()
1173                 {
1174                         return ns.ToString ();
1175                 }
1176
1177                 #region IMemberContext Members
1178
1179                 public CompilerContext Compiler {
1180                         get { return ctx.Compiler; }
1181                 }
1182
1183                 public TypeSpec CurrentType {
1184                         get { return SlaveDeclSpace.CurrentType; }
1185                 }
1186
1187                 public MemberCore CurrentMemberDefinition {
1188                         get { return SlaveDeclSpace.CurrentMemberDefinition; }
1189                 }
1190
1191                 public TypeParameter[] CurrentTypeParameters {
1192                         get { return SlaveDeclSpace.CurrentTypeParameters; }
1193                 }
1194
1195                 // FIXME: It's false for expression types
1196                 public bool HasUnresolvedConstraints {
1197                         get { return true; }
1198                 }
1199
1200                 public bool IsObsolete {
1201                         get { return SlaveDeclSpace.IsObsolete; }
1202                 }
1203
1204                 public bool IsUnsafe {
1205                         get { return SlaveDeclSpace.IsUnsafe; }
1206                 }
1207
1208                 public bool IsStatic {
1209                         get { return SlaveDeclSpace.IsStatic; }
1210                 }
1211
1212                 public ModuleContainer Module {
1213                         get { return ctx; }
1214                 }
1215
1216                 #endregion
1217         }
1218 }