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 // Copyright 2011 Xamarin Inc
  11 //
  12 using System;
  13 using System.Collections.Generic;
  14 using System.Linq;
  15 using Mono.CompilerServices.SymbolWriter;
  16
  17 namespace Mono.CSharp {
  18
  19         public class RootNamespace : Namespace {
  20
  21                 readonly string alias_name;
  22                 readonly Dictionary<string, Namespace> all_namespaces;
  23
  24                 public RootNamespace (string alias_name)
  25                         : base ()
  26                 {
  27                         this.alias_name = alias_name;
  28                         RegisterNamespace (this);
  29
  30                         all_namespaces = new Dictionary<string, Namespace> ();
  31                         all_namespaces.Add ("", this);
  32                 }
  33
  34                 public string Alias {
  35                         get {
  36                                 return alias_name;
  37                         }
  38                 }
  39
  40                 public static void Error_GlobalNamespaceRedefined (Report report, Location loc)
  41                 {
  42                         report.Error (1681, loc, "The global extern alias cannot be redefined");
  43                 }
  44
  45                 //
  46                 // For better error reporting where we try to guess missing using directive
  47                 //
  48                 public List<string> FindTypeNamespaces (IMemberContext ctx, string name, int arity)
  49                 {
  50                         List<string> res = null;
  51
  52                         foreach (var ns in all_namespaces) {
  53                                 var type = ns.Value.LookupType (ctx, name, arity, LookupMode.Normal, Location.Null);
  54                                 if (type != null) {
  55                                         if (res == null)
  56                                                 res = new List<string> ();
  57
  58                                         res.Add (ns.Key);
  59                                 }
  60                         }
  61
  62                         return res;
  63                 }
  64
  65                 //
  66                 // For better error reporting where compiler tries to guess missing using directive
  67                 //
  68                 public List<string> FindExtensionMethodNamespaces (IMemberContext ctx, string name, int arity)
  69                 {
  70                         List<string> res = null;
  71
  72                         foreach (var ns in all_namespaces) {
  73                                 var methods = ns.Value.LookupExtensionMethod (ctx, name, arity);
  74                                 if (methods != null) {
  75                                         if (res == null)
  76                                                 res = new List<string> ();
  77
  78                                         res.Add (ns.Key);
  79                                 }
  80                         }
  81
  82                         return res;
  83                 }
  84
  85                 public void RegisterNamespace (Namespace child)
  86                 {
  87                         if (child != this)
  88                                 all_namespaces.Add (child.Name, child);
  89                 }
  90
  91                 public override string GetSignatureForError ()
  92                 {
  93                         return alias_name + "::";
  94                 }
  95         }
  96
  97         public sealed class GlobalRootNamespace : RootNamespace
  98         {
  99                 public GlobalRootNamespace ()
 100                         : base ("global")
 101                 {
 102                 }
 103         }
 104
 105         //
 106         // Namespace cache for imported and compiled namespaces
 107         //
 108         public class Namespace
 109         {
 110                 readonly Namespace parent;
 111                 string fullname;
 112                 protected Dictionary<string, Namespace> namespaces;
 113                 protected Dictionary<string, IList<TypeSpec>> types;
 114                 List<TypeSpec> extension_method_types;
 115                 Dictionary<string, TypeSpec> cached_types;
 116                 bool cls_checked;
 117
 118                 /// <summary>
 119                 ///   Constructor Takes the current namespace and the
 120                 ///   name.  This is bootstrapped with parent == null
 121                 ///   and name = ""
 122                 /// </summary>
 123                 public Namespace (Namespace parent, string name)
 124                         : this ()
 125                 {
 126                         if (name == null)
 127                                 throw new ArgumentNullException ("name");
 128
 129                         this.parent = parent;
 130
 131                         string pname = parent != null ? parent.fullname : null;
 132
 133                         if (pname == null)
 134                                 fullname = name;
 135                         else
 136                                 fullname = pname + "." + name;
 137
 138                         while (parent.parent != null)
 139                                 parent = parent.parent;
 140
 141                         var root = parent as RootNamespace;
 142                         if (root == null)
 143                                 throw new InternalErrorException ("Root namespaces must be created using RootNamespace");
 144
 145                         root.RegisterNamespace (this);
 146                 }
 147
 148                 protected Namespace ()
 149                 {
 150                         namespaces = new Dictionary<string, Namespace> ();
 151                         cached_types = new Dictionary<string, TypeSpec> ();
 152                 }
 153
 154                 #region Properties
 155
 156                 /// <summary>
 157                 ///   The qualified name of the current namespace
 158                 /// </summary>
 159                 public string Name {
 160                         get { return fullname; }
 161                 }
 162
 163                 /// <summary>
 164                 ///   The parent of this namespace, used by the parser to "Pop"
 165                 ///   the current namespace declaration
 166                 /// </summary>
 167                 public Namespace Parent {
 168                         get { return parent; }
 169                 }
 170
 171                 #endregion
 172
 173                 public Namespace AddNamespace (MemberName name)
 174                 {
 175                         var ns_parent = name.Left == null ? this : AddNamespace (name.Left);
 176                         return ns_parent.TryAddNamespace (name.Basename);
 177                 }
 178
 179                 Namespace TryAddNamespace (string name)
 180                 {
 181                         Namespace ns;
 182
 183                         if (!namespaces.TryGetValue (name, out ns)) {
 184                                 ns = new Namespace (this, name);
 185                                 namespaces.Add (name, ns);
 186                         }
 187
 188                         return ns;
 189                 }
 190
 191                 public bool TryGetNamespace (string name, out Namespace ns)
 192                 {
 193                         return namespaces.TryGetValue (name, out ns);
 194                 }
 195
 196                 // TODO: Replace with CreateNamespace where MemberName is created for the method call
 197                 public Namespace GetNamespace (string name, bool create)
 198                 {
 199                         int pos = name.IndexOf ('.');
 200
 201                         Namespace ns;
 202                         string first;
 203                         if (pos >= 0)
 204                                 first = name.Substring (0, pos);
 205                         else
 206                                 first = name;
 207
 208                         if (!namespaces.TryGetValue (first, out ns)) {
 209                                 if (!create)
 210                                         return null;
 211
 212                                 ns = new Namespace (this, first);
 213                                 namespaces.Add (first, ns);
 214                         }
 215
 216                         if (pos >= 0)
 217                                 ns = ns.GetNamespace (name.Substring (pos + 1), create);
 218
 219                         return ns;
 220                 }
 221
 222                 public IList<TypeSpec> GetAllTypes (string name)
 223                 {
 224                         IList<TypeSpec> found;
 225                         if (types == null || !types.TryGetValue (name, out found))
 226                                 return null;
 227
 228                         return found;
 229                 }
 230
 231                 public virtual string GetSignatureForError ()
 232                 {
 233                         return fullname;
 234                 }
 235
 236                 public TypeSpec LookupType (IMemberContext ctx, string name, int arity, LookupMode mode, Location loc)
 237                 {
 238                         if (types == null)
 239                                 return null;
 240
 241                         TypeSpec best = null;
 242                         if (arity == 0 && cached_types.TryGetValue (name, out best)) {
 243                                 if (best != null || mode != LookupMode.IgnoreAccessibility)
 244                                         return best;
 245                         }
 246
 247                         IList<TypeSpec> found;
 248                         if (!types.TryGetValue (name, out found))
 249                                 return null;
 250
 251                         foreach (var ts in found) {
 252                                 if (ts.Arity == arity) {
 253                                         if (best == null) {
 254                                                 if ((ts.Modifiers & Modifiers.INTERNAL) != 0 && !ts.MemberDefinition.IsInternalAsPublic (ctx.Module.DeclaringAssembly) && mode != LookupMode.IgnoreAccessibility)
 255                                                         continue;
 256
 257                                                 best = ts;
 258                                                 continue;
 259                                         }
 260
 261                                         if (best.MemberDefinition.IsImported && ts.MemberDefinition.IsImported) {
 262                                                 if (ts.Kind == MemberKind.MissingType)
 263                                                         continue;
 264
 265                                                 if (best.Kind == MemberKind.MissingType) {
 266                                                         best = ts;
 267                                                         continue;
 268                                                 }
 269
 270                                                 if (mode == LookupMode.Normal) {
 271                                                         ctx.Module.Compiler.Report.SymbolRelatedToPreviousError (best);
 272                                                         ctx.Module.Compiler.Report.SymbolRelatedToPreviousError (ts);
 273                                                         ctx.Module.Compiler.Report.Error (433, loc, "The imported type `{0}' is defined multiple times", ts.GetSignatureForError ());
 274                                                 }
 275
 276                                                 break;
 277                                         }
 278
 279                                         if (best.MemberDefinition.IsImported)
 280                                                 best = ts;
 281
 282                                         if ((best.Modifiers & Modifiers.INTERNAL) != 0 && !best.MemberDefinition.IsInternalAsPublic (ctx.Module.DeclaringAssembly))
 283                                                 continue;
 284
 285                                         if (mode != LookupMode.Normal)
 286                                                 continue;
 287
 288                                         if (ts.MemberDefinition.IsImported) {
 289                                                 ctx.Module.Compiler.Report.SymbolRelatedToPreviousError (best);
 290                                                 ctx.Module.Compiler.Report.SymbolRelatedToPreviousError (ts);
 291                                         }
 292
 293                                         ctx.Module.Compiler.Report.Warning (436, 2, loc,
 294                                                 "The type `{0}' conflicts with the imported type of same name'. Ignoring the imported type definition",
 295                                                 best.GetSignatureForError ());
 296                                 }
 297
 298                                 //
 299                                 // Lookup for the best candidate with the closest arity match
 300                                 //
 301                                 if (arity < 0) {
 302                                         if (best == null) {
 303                                                 best = ts;
 304                                         } else if (System.Math.Abs (ts.Arity + arity) < System.Math.Abs (best.Arity + arity)) {
 305                                                 best = ts;
 306                                         }
 307                                 }
 308                         }
 309
 310                         // TODO MemberCache: Cache more
 311                         if (arity == 0 && mode == LookupMode.Normal)
 312                                 cached_types.Add (name, best);
 313
 314                         return best;
 315                 }
 316
 317                 public FullNamedExpression LookupTypeOrNamespace (IMemberContext ctx, string name, int arity, LookupMode mode, Location loc)
 318                 {
 319                         var texpr = LookupType (ctx, name, arity, mode, loc);
 320
 321                         Namespace ns;
 322                         if (arity == 0 && namespaces.TryGetValue (name, out ns)) {
 323                                 if (texpr == null)
 324                                         return new NamespaceExpression (ns, loc);
 325
 326                                 if (mode != LookupMode.Probing) {
 327                                         //ctx.Module.Compiler.Report.SymbolRelatedToPreviousError (texpr.Type);
 328                                         // ctx.Module.Compiler.Report.SymbolRelatedToPreviousError (ns.loc, "");
 329                                         ctx.Module.Compiler.Report.Warning (437, 2, loc,
 330                                                 "The type `{0}' conflicts with the imported namespace `{1}'. Using the definition found in the source file",
 331                                                 texpr.GetSignatureForError (), ns.GetSignatureForError ());
 332                                 }
 333
 334                                 if (texpr.MemberDefinition.IsImported)
 335                                         return new NamespaceExpression (ns, loc);
 336                         }
 337
 338                         if (texpr == null)
 339                                 return null;
 340
 341                         return new TypeExpression (texpr, loc);
 342                 }
 343
 344                 //
 345                 // Completes types with the given `prefix'
 346                 //
 347                 public IEnumerable<string> CompletionGetTypesStartingWith (string prefix)
 348                 {
 349                         if (types == null)
 350                                 return Enumerable.Empty<string> ();
 351
 352                         var res = from item in types
 353                                           where item.Key.StartsWith (prefix) && item.Value.Any (l => (l.Modifiers & Modifiers.PUBLIC) != 0)
 354                                           select item.Key;
 355
 356                         if (namespaces != null)
 357                                 res = res.Concat (from item in namespaces where item.Key.StartsWith (prefix) select item.Key);
 358
 359                         return res;
 360                 }
 361
 362                 //
 363                 // Looks for extension method in this namespace
 364                 //
 365                 public List<MethodSpec> LookupExtensionMethod (IMemberContext invocationContext, string name, int arity)
 366                 {
 367                         if (extension_method_types == null)
 368                                 return null;
 369
 370                         List<MethodSpec> found = null;
 371                         for (int i = 0; i < extension_method_types.Count; ++i) {
 372                                 var ts = extension_method_types[i];
 373
 374                                 //
 375                                 // When the list was built we didn't know what members the type
 376                                 // contains
 377                                 //
 378                                 if ((ts.Modifiers & Modifiers.METHOD_EXTENSION) == 0) {
 379                                         if (extension_method_types.Count == 1) {
 380                                                 extension_method_types = null;
 381                                                 return found;
 382                                         }
 383
 384                                         extension_method_types.RemoveAt (i--);
 385                                         continue;
 386                                 }
 387
 388                                 var res = ts.MemberCache.FindExtensionMethods (invocationContext, name, arity);
 389                                 if (res == null)
 390                                         continue;
 391
 392                                 if (found == null) {
 393                                         found = res;
 394                                 } else {
 395                                         found.AddRange (res);
 396                                 }
 397                         }
 398
 399                         return found;
 400                 }
 401
 402                 public void AddType (ModuleContainer module, TypeSpec ts)
 403                 {
 404                         if (types == null) {
 405                                 types = new Dictionary<string, IList<TypeSpec>> (64);
 406                         }
 407
 408                         if (ts.IsClass && ts.Arity == 0) {
 409                                 var extension_method_allowed = ts.MemberDefinition.IsImported ? (ts.Modifiers & Modifiers.METHOD_EXTENSION) != 0 : (ts.IsStatic || ts.MemberDefinition.IsPartial);
 410                                 if (extension_method_allowed) {
 411                                         if (extension_method_types == null)
 412                                                 extension_method_types = new List<TypeSpec> ();
 413
 414                                         extension_method_types.Add (ts);
 415                                 }
 416                         }
 417
 418                         var name = ts.Name;
 419                         IList<TypeSpec> existing;
 420                         if (types.TryGetValue (name, out existing)) {
 421                                 TypeSpec better_type;
 422                                 TypeSpec found;
 423                                 if (existing.Count == 1) {
 424                                         found = existing[0];
 425                                         if (ts.Arity == found.Arity) {
 426                                                 better_type = IsImportedTypeOverride (module, ts, found);
 427                                                 if (better_type == found)
 428                                                         return;
 429
 430                                                 if (better_type != null) {
 431                                                         existing [0] = better_type;
 432                                                         return;
 433                                                 }
 434                                         }
 435
 436                                         existing = new List<TypeSpec> ();
 437                                         existing.Add (found);
 438                                         types[name] = existing;
 439                                 } else {
 440                                         for (int i = 0; i < existing.Count; ++i) {
 441                                                 found = existing[i];
 442                                                 if (ts.Arity != found.Arity)
 443                                                         continue;
 444
 445                                                 better_type = IsImportedTypeOverride (module, ts, found);
 446                                                 if (better_type == found)
 447                                                         return;
 448
 449                                                 if (better_type != null) {
 450                                                         existing.RemoveAt (i);
 451                                                         --i;
 452                                                         continue;
 453                                                 }
 454                                         }
 455                                 }
 456
 457                                 existing.Add (ts);
 458                         } else {
 459                                 types.Add (name, new TypeSpec[] { ts });
 460                         }
 461                 }
 462
 463                 //
 464                 // We import any types but in the situation there are same types
 465                 // but one has better visibility (either public or internal with friend)
 466                 // the less visible type is removed from the namespace cache
 467                 //
 468                 public static TypeSpec IsImportedTypeOverride (ModuleContainer module, TypeSpec ts, TypeSpec found)
 469                 {
 470                         var ts_accessible = (ts.Modifiers & Modifiers.PUBLIC) != 0 || ts.MemberDefinition.IsInternalAsPublic (module.DeclaringAssembly);
 471                         var found_accessible = (found.Modifiers & Modifiers.PUBLIC) != 0 || found.MemberDefinition.IsInternalAsPublic (module.DeclaringAssembly);
 472
 473                         if (ts_accessible && !found_accessible)
 474                                 return ts;
 475
 476                         // found is better always better for accessible or inaccessible ts
 477                         if (!ts_accessible)
 478                                 return found;
 479
 480                         return null;
 481                 }
 482
 483                 public void RemoveContainer (TypeContainer tc)
 484                 {
 485                         types.Remove (tc.Basename);
 486                         cached_types.Remove (tc.Basename);
 487                 }
 488
 489                 public void SetBuiltinType (BuiltinTypeSpec pts)
 490                 {
 491                         var found = types[pts.Name];
 492                         cached_types.Remove (pts.Name);
 493                         if (found.Count == 1) {
 494                                 types[pts.Name][0] = pts;
 495                         } else {
 496                                 throw new NotImplementedException ();
 497                         }
 498                 }
 499
 500                 public void VerifyClsCompliance ()
 501                 {
 502                         if (types == null || cls_checked)
 503                                 return;
 504
 505                         cls_checked = true;
 506
 507                         // TODO: This is quite ugly way to check for CLS compliance at namespace level
 508
 509                         var locase_types = new Dictionary<string, List<TypeSpec>> (StringComparer.OrdinalIgnoreCase);
 510                         foreach (var tgroup in types.Values) {
 511                                 foreach (var tm in tgroup) {
 512                                         if ((tm.Modifiers & Modifiers.PUBLIC) == 0 || !tm.IsCLSCompliant ())
 513                                                 continue;
 514
 515                                         List<TypeSpec> found;
 516                                         if (!locase_types.TryGetValue (tm.Name, out found)) {
 517                                                 found = new List<TypeSpec> ();
 518                                                 locase_types.Add (tm.Name, found);
 519                                         }
 520
 521                                         found.Add (tm);
 522                                 }
 523                         }
 524
 525                         foreach (var locase in locase_types.Values) {
 526                                 if (locase.Count < 2)
 527                                         continue;
 528
 529                                 bool all_same = true;
 530                                 foreach (var notcompliant in locase) {
 531                                         all_same = notcompliant.Name == locase[0].Name;
 532                                         if (!all_same)
 533                                                 break;
 534                                 }
 535
 536                                 if (all_same)
 537                                         continue;
 538
 539                                 TypeContainer compiled = null;
 540                                 foreach (var notcompliant in locase) {
 541                                         if (!notcompliant.MemberDefinition.IsImported) {
 542                                                 if (compiled != null)
 543                                                         compiled.Compiler.Report.SymbolRelatedToPreviousError (compiled);
 544
 545                                                 compiled = notcompliant.MemberDefinition as TypeContainer;
 546                                         } else {
 547                                                 compiled.Compiler.Report.SymbolRelatedToPreviousError (notcompliant);
 548                                         }
 549                                 }
 550
 551                                 compiled.Compiler.Report.Warning (3005, 1, compiled.Location,
 552                                         "Identifier `{0}' differing only in case is not CLS-compliant", compiled.GetSignatureForError ());
 553                         }
 554                 }
 555         }
 556
 557         public class CompilationSourceFile : NamespaceContainer
 558         {
 559                 readonly SourceFile file;
 560                 CompileUnitEntry comp_unit;
 561                 Dictionary<string, SourceFile> include_files;
 562                 Dictionary<string, bool> conditionals;
 563
 564                 public CompilationSourceFile (ModuleContainer parent, SourceFile sourceFile)
 565                         : this (parent)
 566                 {
 567                         this.file = sourceFile;
 568                 }
 569
 570                 public CompilationSourceFile (ModuleContainer parent)
 571                         : base (parent)
 572                 {
 573                 }
 574
 575                 public CompileUnitEntry SymbolUnitEntry {
 576                         get {
 577                                 return comp_unit;
 578                         }
 579                 }
 580
 581                 public string FileName {
 582                         get {
 583                                 return file.Name;
 584                         }
 585                 }
 586
 587                 public SourceFile SourceFile {
 588                         get {
 589                                 return file;
 590                         }
 591                 }
 592
 593                 public void AddIncludeFile (SourceFile file)
 594                 {
 595                         if (file == this.file)
 596                                 return;
 597
 598                         if (include_files == null)
 599                                 include_files = new Dictionary<string, SourceFile> ();
 600
 601                         if (!include_files.ContainsKey (file.FullPathName))
 602                                 include_files.Add (file.FullPathName, file);
 603                 }
 604
 605                 public void AddDefine (string value)
 606                 {
 607                         if (conditionals == null)
 608                                 conditionals = new Dictionary<string, bool> (2);
 609
 610                         conditionals[value] = true;
 611                 }
 612
 613                 public void AddUndefine (string value)
 614                 {
 615                         if (conditionals == null)
 616                                 conditionals = new Dictionary<string, bool> (2);
 617
 618                         conditionals[value] = false;
 619                 }
 620
 621                 public override void PrepareEmit ()
 622                 {
 623                         var sw = Module.DeclaringAssembly.SymbolWriter;
 624                         if (sw != null) {
 625                                 CreateUnitSymbolInfo (sw);
 626                         }
 627
 628                         base.PrepareEmit ();
 629                 }
 630
 631                 //
 632                 // Creates symbol file index in debug symbol file
 633                 //
 634                 void CreateUnitSymbolInfo (MonoSymbolFile symwriter)
 635                 {
 636                         var si = file.CreateSymbolInfo (symwriter);
 637                         comp_unit = new CompileUnitEntry (symwriter, si);
 638
 639                         if (include_files != null) {
 640                                 foreach (SourceFile include in include_files.Values) {
 641                                         si = include.CreateSymbolInfo (symwriter);
 642                                         comp_unit.AddFile (si);
 643                                 }
 644                         }
 645                 }
 646
 647                 public bool IsConditionalDefined (string value)
 648                 {
 649                         if (conditionals != null) {
 650                                 bool res;
 651                                 if (conditionals.TryGetValue (value, out res))
 652                                         return res;
 653
 654                                 // When conditional was undefined
 655                                 if (conditionals.ContainsKey (value))
 656                                         return false;
 657                         }
 658
 659                         return Compiler.Settings.IsConditionalSymbolDefined (value);
 660                 }
 661
 662                 public override void Accept (StructuralVisitor visitor)
 663                 {
 664                         visitor.Visit (this);
 665                 }
 666         }
 667
 668
 669         //
 670         // Namespace block as created by the parser
 671         //
 672         public class NamespaceContainer : TypeContainer, IMemberContext
 673         {
 674                 static readonly Namespace[] empty_namespaces = new Namespace[0];
 675
 676                 readonly Namespace ns;
 677
 678                 public new readonly NamespaceContainer Parent;
 679
 680                 List<UsingNamespace> clauses;
 681
 682                 // Used by parsed to check for parser errors
 683                 public bool DeclarationFound;
 684
 685                 Namespace[] namespace_using_table;
 686                 Dictionary<string, UsingAliasNamespace> aliases;
 687
 688                 public NamespaceContainer (MemberName name, NamespaceContainer parent)
 689                         : base (parent, name, null, MemberKind.Namespace)
 690                 {
 691                         this.Parent = parent;
 692                         this.ns = parent.NS.AddNamespace (name);
 693
 694                         containers = new List<TypeContainer> ();
 695                 }
 696
 697                 protected NamespaceContainer (ModuleContainer parent)
 698                         : base (parent, null, null, MemberKind.Namespace)
 699                 {
 700                         ns = parent.GlobalRootNamespace;
 701                         containers = new List<TypeContainer> (2);
 702                 }
 703
 704                 #region Properties
 705
 706                 public override AttributeTargets AttributeTargets {
 707                         get {
 708                                 throw new NotSupportedException ();
 709                         }
 710                 }
 711
 712                 public override string DocCommentHeader {
 713                         get {
 714                                 throw new NotSupportedException ();
 715                         }
 716                 }
 717
 718                 public Namespace NS {
 719                         get {
 720                                 return ns;
 721                         }
 722                 }
 723
 724                 public List<UsingNamespace> Usings {
 725                         get {
 726                                 return clauses;
 727                         }
 728                 }
 729
 730                 public override string[] ValidAttributeTargets {
 731                         get {
 732                                 throw new NotSupportedException ();
 733                         }
 734                 }
 735
 736                 #endregion
 737
 738                 public void AddUsing (UsingNamespace un)
 739                 {
 740                         if (DeclarationFound){
 741                                 Compiler.Report.Error (1529, un.Location, "A using clause must precede all other namespace elements except extern alias declarations");
 742                         }
 743
 744                         if (clauses == null)
 745                                 clauses = new List<UsingNamespace> ();
 746
 747                         clauses.Add (un);
 748                 }
 749
 750                 public void AddUsing (UsingAliasNamespace un)
 751                 {
 752                         if (DeclarationFound){
 753                                 Compiler.Report.Error (1529, un.Location, "A using clause must precede all other namespace elements except extern alias declarations");
 754                         }
 755
 756                         AddAlias (un);
 757                 }
 758
 759                 void AddAlias (UsingAliasNamespace un)
 760                 {
 761                         if (clauses == null) {
 762                                 clauses = new List<UsingNamespace> ();
 763                         } else {
 764                                 foreach (var entry in clauses) {
 765                                         var a = entry as UsingAliasNamespace;
 766                                         if (a != null && a.Alias.Value == un.Alias.Value) {
 767                                                 Compiler.Report.SymbolRelatedToPreviousError (a.Location, "");
 768                                                 Compiler.Report.Error (1537, un.Location,
 769                                                         "The using alias `{0}' appeared previously in this namespace", un.Alias.Value);
 770                                         }
 771                                 }
 772                         }
 773
 774                         clauses.Add (un);
 775                 }
 776
 777                 public override void AddPartial (TypeDefinition next_part)
 778                 {
 779                         var existing = ns.LookupType (this, next_part.MemberName.Name, next_part.MemberName.Arity, LookupMode.Probing, Location.Null);
 780                         var td = existing != null ? existing.MemberDefinition as TypeDefinition : null;
 781                         AddPartial (next_part, td);
 782                 }
 783
 784                 public override void AddTypeContainer (TypeContainer tc)
 785                 {
 786                         string name = tc.Basename;
 787
 788                         var mn = tc.MemberName;
 789                         while (mn.Left != null) {
 790                                 mn = mn.Left;
 791                                 name = mn.Name;
 792                         }
 793
 794                         var names_container = Parent == null ? Module : (TypeContainer) this;
 795
 796                         MemberCore mc;
 797                         if (names_container.DefinedNames.TryGetValue (name, out mc)) {
 798                                 if (tc is NamespaceContainer && mc is NamespaceContainer) {
 799                                         AddTypeContainerMember (tc);
 800                                         return;
 801                                 }
 802
 803                                 Report.SymbolRelatedToPreviousError (mc);
 804                                 if ((mc.ModFlags & Modifiers.PARTIAL) != 0 && (tc is ClassOrStruct || tc is Interface)) {
 805                                         Error_MissingPartialModifier (tc);
 806                                 } else {
 807                                         Report.Error (101, tc.Location, "The namespace `{0}' already contains a definition for `{1}'",
 808                                                 GetSignatureForError (), mn.GetSignatureForError ());
 809                                 }
 810                         } else {
 811                                 names_container.DefinedNames.Add (name, tc);
 812
 813                                 var tdef = tc.PartialContainer;
 814                                 if (tdef != null) {
 815                                         //
 816                                         // Same name conflict in different namespace containers
 817                                         //
 818                                         var conflict = ns.GetAllTypes (name);
 819                                         if (conflict != null) {
 820                                                 foreach (var e in conflict) {
 821                                                         if (e.Arity == mn.Arity) {
 822                                                                 mc = (MemberCore) e.MemberDefinition;
 823                                                                 break;
 824                                                         }
 825                                                 }
 826                                         }
 827
 828                                         if (mc != null) {
 829                                                 Report.SymbolRelatedToPreviousError (mc);
 830                                                 Report.Error (101, tc.Location, "The namespace `{0}' already contains a definition for `{1}'",
 831                                                         GetSignatureForError (), mn.GetSignatureForError ());
 832                                         } else {
 833                                                 ns.AddType (Module, tdef.Definition);
 834                                         }
 835                                 }
 836                         }
 837
 838                         base.AddTypeContainer (tc);
 839                 }
 840
 841                 public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
 842                 {
 843                         throw new NotSupportedException ();
 844                 }
 845
 846                 public override void EmitContainer ()
 847                 {
 848                         VerifyClsCompliance ();
 849
 850                         base.EmitContainer ();
 851                 }
 852
 853                 public ExtensionMethodCandidates LookupExtensionMethod (IMemberContext invocationContext, TypeSpec extensionType, string name, int arity, int position)
 854                 {
 855                         //
 856                         // Here we try to resume the search for extension method at the point
 857                         // where the last bunch of candidates was found. It's more tricky than
 858                         // it seems as we have to check both namespace containers and namespace
 859                         // in correct order.
 860                         //
 861                         // Consider:
 862                         //
 863                         // namespace A {
 864                         //      using N1;
 865                         //  namespace B.C.D {
 866                         //              <our first search found candidates in A.B.C.D
 867                         //  }
 868                         // }
 869                         //
 870                         // In the example above namespace A.B.C.D, A.B.C and A.B have to be
 871                         // checked before we hit A.N1 using
 872                         //
 873                         ExtensionMethodCandidates candidates;
 874                         var container = this;
 875                         do {
 876                                 candidates = container.LookupExtensionMethodCandidates (invocationContext, name, arity, ref position);
 877                                 if (candidates != null || container.MemberName == null)
 878                                         return candidates;
 879
 880                                 var container_ns = container.ns.Parent;
 881                                 var mn = container.MemberName.Left;
 882                                 int already_checked = position - 2;
 883                                 while (already_checked-- > 0) {
 884                                         mn = mn.Left;
 885                                         container_ns = container_ns.Parent;
 886                                 }
 887
 888                                 while (mn != null) {
 889                                         ++position;
 890
 891                                         var methods = container_ns.LookupExtensionMethod (invocationContext, name, arity);
 892                                         if (methods != null) {
 893                                                 return new ExtensionMethodCandidates (invocationContext, methods, container, position);
 894                                         }
 895
 896                                         mn = mn.Left;
 897                                         container_ns = container_ns.Parent;
 898                                 }
 899
 900                                 position = 0;
 901                                 container = container.Parent;
 902                         } while (container != null);
 903
 904                         return null;
 905                 }
 906
 907                 ExtensionMethodCandidates LookupExtensionMethodCandidates (IMemberContext invocationContext, string name, int arity, ref int position)
 908                 {
 909                         List<MethodSpec> candidates = null;
 910
 911                         if (position == 0) {
 912                                 ++position;
 913
 914                                 candidates = ns.LookupExtensionMethod (invocationContext, name, arity);
 915                                 if (candidates != null) {
 916                                         return new ExtensionMethodCandidates (invocationContext, candidates, this, position);
 917                                 }
 918                         }
 919
 920                         if (position == 1) {
 921                                 ++position;
 922
 923                                 foreach (Namespace n in namespace_using_table) {
 924                                         var a = n.LookupExtensionMethod (invocationContext, name, arity);
 925                                         if (a == null)
 926                                                 continue;
 927
 928                                         if (candidates == null)
 929                                                 candidates = a;
 930                                         else
 931                                                 candidates.AddRange (a);
 932                                 }
 933
 934                                 if (candidates != null)
 935                                         return new ExtensionMethodCandidates (invocationContext, candidates, this, position);
 936                         }
 937
 938                         return null;
 939                 }
 940
 941                 public override FullNamedExpression LookupNamespaceOrType (string name, int arity, LookupMode mode, Location loc)
 942                 {
 943                         //
 944                         // Only simple names (no dots) will be looked up with this function
 945                         //
 946                         FullNamedExpression resolved;
 947                         for (NamespaceContainer container = this; container != null; container = container.Parent) {
 948                                 resolved = container.Lookup (name, arity, mode, loc);
 949                                 if (resolved != null || container.MemberName == null)
 950                                         return resolved;
 951
 952                                 var container_ns = container.ns.Parent;
 953                                 var mn = container.MemberName.Left;
 954                                 while (mn != null) {
 955                                         resolved = container_ns.LookupTypeOrNamespace (this, name, arity, mode, loc);
 956                                         if (resolved != null)
 957                                                 return resolved;
 958
 959                                         mn = mn.Left;
 960                                         container_ns = container_ns.Parent;
 961                                 }
 962                         }
 963
 964                         return null;
 965                 }
 966
 967                 public override void GetCompletionStartingWith (string prefix, List<string> results)
 968                 {
 969                         if (Usings == null)
 970                                 return;
 971
 972                         foreach (var un in Usings) {
 973                                 if (un.Alias != null)
 974                                         continue;
 975
 976                                 var name = un.NamespaceExpression.Name;
 977                                 if (name.StartsWith (prefix))
 978                                         results.Add (name);
 979                         }
 980
 981
 982                         IEnumerable<string> all = Enumerable.Empty<string> ();
 983
 984                         foreach (Namespace using_ns in namespace_using_table) {
 985                                 if (prefix.StartsWith (using_ns.Name)) {
 986                                         int ld = prefix.LastIndexOf ('.');
 987                                         if (ld != -1) {
 988                                                 string rest = prefix.Substring (ld + 1);
 989
 990                                                 all = all.Concat (using_ns.CompletionGetTypesStartingWith (rest));
 991                                         }
 992                                 }
 993                                 all = all.Concat (using_ns.CompletionGetTypesStartingWith (prefix));
 994                         }
 995
 996                         results.AddRange (all);
 997
 998                         base.GetCompletionStartingWith (prefix, results);
 999                 }
1000
1001
1002                 //
1003                 // Looks-up a alias named @name in this and surrounding namespace declarations
1004                 //
1005                 public FullNamedExpression LookupExternAlias (string name)
1006                 {
1007                         if (aliases == null)
1008                                 return null;
1009
1010                         UsingAliasNamespace uan;
1011                         if (aliases.TryGetValue (name, out uan) && uan is UsingExternAlias)
1012                                 return uan.ResolvedExpression;
1013
1014                         return null;
1015                 }
1016
1017                 //
1018                 // Looks-up a alias named @name in this and surrounding namespace declarations
1019                 //
1020                 public override FullNamedExpression LookupNamespaceAlias (string name)
1021                 {
1022                         for (NamespaceContainer n = this; n != null; n = n.Parent) {
1023                                 if (n.aliases == null)
1024                                         continue;
1025
1026                                 UsingAliasNamespace uan;
1027                                 if (n.aliases.TryGetValue (name, out uan))
1028                                         return uan.ResolvedExpression;
1029                         }
1030
1031                         return null;
1032                 }
1033
1034                 FullNamedExpression Lookup (string name, int arity, LookupMode mode, Location loc)
1035                 {
1036                         //
1037                         // Check whether it's in the namespace.
1038                         //
1039                         FullNamedExpression fne = ns.LookupTypeOrNamespace (this, name, arity, mode, loc);
1040
1041                         //
1042                         // Check aliases.
1043                         //
1044                         if (aliases != null && arity == 0) {
1045                                 UsingAliasNamespace uan;
1046                                 if (aliases.TryGetValue (name, out uan)) {
1047                                         if (fne != null && mode != LookupMode.Probing) {
1048                                                 // TODO: Namespace has broken location
1049                                                 //Report.SymbolRelatedToPreviousError (fne.Location, null);
1050                                                 Compiler.Report.SymbolRelatedToPreviousError (uan.Location, null);
1051                                                 Compiler.Report.Error (576, loc,
1052                                                         "Namespace `{0}' contains a definition with same name as alias `{1}'",
1053                                                         GetSignatureForError (), name);
1054                                         }
1055
1056                                         return uan.ResolvedExpression;
1057                                 }
1058                         }
1059
1060                         if (fne != null)
1061                                 return fne;
1062
1063                         //
1064                         // Lookup can be called before the namespace is defined from different namespace using alias clause
1065                         //
1066                         if (namespace_using_table == null) {
1067                                 DoDefineNamespace ();
1068                         }
1069
1070                         //
1071                         // Check using entries.
1072                         //
1073                         FullNamedExpression match = null;
1074                         foreach (Namespace using_ns in namespace_using_table) {
1075                                 //
1076                                 // A using directive imports only types contained in the namespace, it
1077                                 // does not import any nested namespaces
1078                                 //
1079                                 var t = using_ns.LookupType (this, name, arity, mode, loc);
1080                                 if (t == null)
1081                                         continue;
1082
1083                                 fne = new TypeExpression (t, loc);
1084                                 if (match == null) {
1085                                         match = fne;
1086                                         continue;
1087                                 }
1088
1089                                 // Prefer types over namespaces
1090                                 var texpr_fne = fne as TypeExpr;
1091                                 var texpr_match = match as TypeExpr;
1092                                 if (texpr_fne != null && texpr_match == null) {
1093                                         match = fne;
1094                                         continue;
1095                                 } else if (texpr_fne == null) {
1096                                         continue;
1097                                 }
1098
1099                                 // It can be top level accessibility only
1100                                 var better = Namespace.IsImportedTypeOverride (Module, texpr_match.Type, texpr_fne.Type);
1101                                 if (better == null) {
1102                                         if (mode == LookupMode.Normal) {
1103                                                 Compiler.Report.SymbolRelatedToPreviousError (texpr_match.Type);
1104                                                 Compiler.Report.SymbolRelatedToPreviousError (texpr_fne.Type);
1105                                                 Compiler.Report.Error (104, loc, "`{0}' is an ambiguous reference between `{1}' and `{2}'",
1106                                                         name, texpr_match.GetSignatureForError (), texpr_fne.GetSignatureForError ());
1107                                         }
1108
1109                                         return match;
1110                                 }
1111
1112                                 if (better == texpr_fne.Type)
1113                                         match = texpr_fne;
1114                         }
1115
1116                         return match;
1117                 }
1118
1119                 protected override void DefineNamespace ()
1120                 {
1121                         if (namespace_using_table == null)
1122                                 DoDefineNamespace ();
1123
1124                         base.DefineNamespace ();
1125                 }
1126
1127                 void DoDefineNamespace ()
1128                 {
1129                         namespace_using_table = empty_namespaces;
1130
1131                         if (clauses != null) {
1132                                 var list = new List<Namespace> (clauses.Count);
1133                                 bool post_process_using_aliases = false;
1134
1135                                 for (int i = 0; i < clauses.Count; ++i) {
1136                                         var entry = clauses[i];
1137
1138                                         if (entry.Alias != null) {
1139                                                 if (aliases == null)
1140                                                         aliases = new Dictionary<string, UsingAliasNamespace> ();
1141
1142                                                 //
1143                                                 // Aliases are not available when resolving using section
1144                                                 // except extern aliases
1145                                                 //
1146                                                 if (entry is UsingExternAlias) {
1147                                                         entry.Define (this);
1148                                                         if (entry.ResolvedExpression != null)
1149                                                                 aliases.Add (entry.Alias.Value, (UsingExternAlias) entry);
1150
1151                                                         clauses.RemoveAt (i--);
1152                                                 } else {
1153                                                         post_process_using_aliases = true;
1154                                                 }
1155
1156                                                 continue;
1157                                         }
1158
1159                                         entry.Define (this);
1160
1161                                         //
1162                                         // It's needed for repl only, when using clause cannot be resolved don't hold it in
1163                                         // global list which is resolved for each evaluation
1164                                         //
1165                                         if (entry.ResolvedExpression == null) {
1166                                                 clauses.RemoveAt (i--);
1167                                                 continue;
1168                                         }
1169
1170                                         var using_ns = entry.ResolvedExpression as NamespaceExpression;
1171                                         if (using_ns == null)
1172                                                 continue;
1173
1174                                         if (list.Contains (using_ns.Namespace)) {
1175                                                 // Ensure we don't report the warning multiple times in repl
1176                                                 clauses.RemoveAt (i--);
1177
1178                                                 Compiler.Report.Warning (105, 3, entry.Location,
1179                                                         "The using directive for `{0}' appeared previously in this namespace", using_ns.GetSignatureForError ());
1180                                         } else {
1181                                                 list.Add (using_ns.Namespace);
1182                                         }
1183                                 }
1184
1185                                 namespace_using_table = list.ToArray ();
1186
1187                                 if (post_process_using_aliases) {
1188                                         for (int i = 0; i < clauses.Count; ++i) {
1189                                                 var entry = clauses[i];
1190                                                 if (entry.Alias != null) {
1191                                                         entry.Define (this);
1192                                                         if (entry.ResolvedExpression != null) {
1193                                                                 aliases.Add (entry.Alias.Value, (UsingAliasNamespace) entry);
1194                                                         }
1195
1196                                                         clauses.RemoveAt (i--);
1197                                                 }
1198                                         }
1199                                 }
1200                         }
1201                 }
1202
1203                 public void EnableRedefinition ()
1204                 {
1205                         is_defined = false;
1206                         namespace_using_table = null;
1207                 }
1208
1209                 internal override void GenerateDocComment (DocumentationBuilder builder)
1210                 {
1211                         if (containers != null) {
1212                                 foreach (var tc in containers)
1213                                         tc.GenerateDocComment (builder);
1214                         }
1215                 }
1216
1217                 public override string GetSignatureForError ()
1218                 {
1219                         return MemberName == null ? "global::" : base.GetSignatureForError ();
1220                 }
1221
1222                 public override void RemoveContainer (TypeContainer cont)
1223                 {
1224                         base.RemoveContainer (cont);
1225                         NS.RemoveContainer (cont);
1226                 }
1227
1228                 protected override bool VerifyClsCompliance ()
1229                 {
1230                         if (Module.IsClsComplianceRequired ()) {
1231                                 if (MemberName != null && MemberName.Name[0] == '_') {
1232                                         Warning_IdentifierNotCompliant ();
1233                                 }
1234
1235                                 ns.VerifyClsCompliance ();
1236                                 return true;
1237                         }
1238
1239                         return false;
1240                 }
1241
1242                 public override void Accept (StructuralVisitor visitor)
1243                 {
1244                         visitor.Visit (this);
1245                 }
1246         }
1247
1248         public class UsingNamespace
1249         {
1250                 readonly ATypeNameExpression expr;
1251                 readonly Location loc;
1252                 protected FullNamedExpression resolved;
1253
1254                 public UsingNamespace (ATypeNameExpression expr, Location loc)
1255                 {
1256                         this.expr = expr;
1257                         this.loc = loc;
1258                 }
1259
1260                 #region Properties
1261
1262                 public virtual SimpleMemberName Alias {
1263                         get {
1264                                 return null;
1265                         }
1266                 }
1267
1268                 public Location Location {
1269                         get {
1270                                 return loc;
1271                         }
1272                 }
1273
1274                 public ATypeNameExpression NamespaceExpression  {
1275                         get {
1276                                 return expr;
1277                         }
1278                 }
1279
1280                 public FullNamedExpression ResolvedExpression {
1281                         get {
1282                                 return resolved;
1283                         }
1284                 }
1285
1286                 #endregion
1287
1288                 public string GetSignatureForError ()
1289                 {
1290                         return expr.GetSignatureForError ();
1291                 }
1292
1293                 public virtual void Define (NamespaceContainer ctx)
1294                 {
1295                         resolved = expr.ResolveAsTypeOrNamespace (ctx);
1296                         var ns = resolved as NamespaceExpression;
1297                         if (ns == null) {
1298                                 if (resolved != null) {
1299                                         ctx.Module.Compiler.Report.SymbolRelatedToPreviousError (resolved.Type);
1300                                         ctx.Module.Compiler.Report.Error (138, Location,
1301                                                 "`{0}' is a type not a namespace. A using namespace directive can only be applied to namespaces",
1302                                                 GetSignatureForError ());
1303                                 }
1304                         }
1305                 }
1306
1307                 public override string ToString()
1308                 {
1309                         return resolved.ToString();
1310                 }
1311         }
1312
1313         public class UsingExternAlias : UsingAliasNamespace
1314         {
1315                 public UsingExternAlias (SimpleMemberName alias, Location loc)
1316                         : base (alias, null, loc)
1317                 {
1318                 }
1319
1320                 public override void Define (NamespaceContainer ctx)
1321                 {
1322                         var ns = ctx.Module.GetRootNamespace (Alias.Value);
1323                         if (ns == null) {
1324                                 ctx.Module.Compiler.Report.Error (430, Location,
1325                                         "The extern alias `{0}' was not specified in -reference option",
1326                                         Alias.Value);
1327                                 return;
1328                         }
1329
1330                         resolved = new NamespaceExpression (ns, Location);
1331                 }
1332         }
1333
1334         public class UsingAliasNamespace : UsingNamespace
1335         {
1336                 readonly SimpleMemberName alias;
1337
1338                 public struct AliasContext : IMemberContext
1339                 {
1340                         readonly NamespaceContainer ns;
1341
1342                         public AliasContext (NamespaceContainer ns)
1343                         {
1344                                 this.ns = ns;
1345                         }
1346
1347                         public TypeSpec CurrentType {
1348                                 get {
1349                                         return null;
1350                                 }
1351                         }
1352
1353                         public TypeParameters CurrentTypeParameters {
1354                                 get {
1355                                         return null;
1356                                 }
1357                         }
1358
1359                         public MemberCore CurrentMemberDefinition {
1360                                 get {
1361                                         return null;
1362                                 }
1363                         }
1364
1365                         public bool IsObsolete {
1366                                 get {
1367                                         return false;
1368                                 }
1369                         }
1370
1371                         public bool IsUnsafe {
1372                                 get {
1373                                         throw new NotImplementedException ();
1374                                 }
1375                         }
1376
1377                         public bool IsStatic {
1378                                 get {
1379                                         throw new NotImplementedException ();
1380                                 }
1381                         }
1382
1383                         public ModuleContainer Module {
1384                                 get {
1385                                         return ns.Module;
1386                                 }
1387                         }
1388
1389                         public string GetSignatureForError ()
1390                         {
1391                                 throw new NotImplementedException ();
1392                         }
1393
1394                         public ExtensionMethodCandidates LookupExtensionMethod (TypeSpec extensionType, string name, int arity)
1395                         {
1396                                 return null;
1397                         }
1398
1399                         public FullNamedExpression LookupNamespaceOrType (string name, int arity, LookupMode mode, Location loc)
1400                         {
1401                                 var fne = ns.NS.LookupTypeOrNamespace (ns, name, arity, mode, loc);
1402                                 if (fne != null)
1403                                         return fne;
1404
1405                                 //
1406                                 // Only extern aliases are allowed in this context
1407                                 //
1408                                 fne = ns.LookupExternAlias (name);
1409                                 if (fne != null || ns.MemberName == null)
1410                                         return fne;
1411
1412                                 var container_ns = ns.NS.Parent;
1413                                 var mn = ns.MemberName.Left;
1414                                 while (mn != null) {
1415                                         fne = container_ns.LookupTypeOrNamespace (this, name, arity, mode, loc);
1416                                         if (fne != null)
1417                                                 return fne;
1418
1419                                         mn = mn.Left;
1420                                         container_ns = container_ns.Parent;
1421                                 }
1422
1423                                 if (ns.Parent != null)
1424                                         return ns.Parent.LookupNamespaceOrType (name, arity, mode, loc);
1425
1426                                 return null;
1427                         }
1428
1429                         public FullNamedExpression LookupNamespaceAlias (string name)
1430                         {
1431                                 return ns.LookupNamespaceAlias (name);
1432                         }
1433                 }
1434
1435                 public UsingAliasNamespace (SimpleMemberName alias, ATypeNameExpression expr, Location loc)
1436                         : base (expr, loc)
1437                 {
1438                         this.alias = alias;
1439                 }
1440
1441                 public override SimpleMemberName Alias {
1442                         get {
1443                                 return alias;
1444                         }
1445                 }
1446
1447                 public override void Define (NamespaceContainer ctx)
1448                 {
1449                         //
1450                         // The namespace-or-type-name of a using-alias-directive is resolved as if
1451                         // the immediately containing compilation unit or namespace body had no
1452                         // using-directives. A using-alias-directive may however be affected
1453                         // by extern-alias-directives in the immediately containing compilation
1454                         // unit or namespace body
1455                         //
1456                         // We achieve that by introducing alias-context which redirect any local
1457                         // namespace or type resolve calls to parent namespace
1458                         //
1459                         resolved = NamespaceExpression.ResolveAsTypeOrNamespace (new AliasContext (ctx));
1460                 }
1461         }
1462 }