Nothing to see here
[mono.git] / mcs / mcs / namespace.cs
index 526c7ea420f2f3c7b1a56d126a7ed3d1dd24617a..2b3a3ac5d700df9c3bb1eb92407a9f6c1f700da0 100644 (file)
 //
 // Author:
 //   Miguel de Icaza (miguel@ximian.com)
+//   Marek Safar (marek.safar@seznam.cz)
 //
-// (C) 2001 Ximian, Inc.
+// Copyright 2001 Ximian, Inc.
+// Copyright 2003-2008 Novell, Inc.
 //
 using System;
 using System.Collections;
+using System.Collections.Specialized;
+using System.Reflection;
 
 namespace Mono.CSharp {
 
+       public class RootNamespace : Namespace {
+               //
+               // Points to Mono's GetNamespaces method, an
+               // optimization when running on Mono to fetch all the
+               // namespaces in an assembly
+               //
+               static MethodInfo get_namespaces_method;
+
+               string alias_name;
+               protected Assembly [] referenced_assemblies;
+
+               Hashtable all_namespaces;
+
+               static ListDictionary root_namespaces;
+               public static GlobalRootNamespace Global;
+               
+               static RootNamespace ()
+               {
+                       get_namespaces_method = typeof (Assembly).GetMethod ("GetNamespaces", BindingFlags.Instance | BindingFlags.NonPublic);
+
+                       Reset ();
+               }
+
+               public static void Reset ()
+               {
+                       root_namespaces = new ListDictionary ();
+                       Global = new GlobalRootNamespace ();
+                       root_namespaces ["global"] = Global;
+               }
+
+               protected RootNamespace (string alias_name)
+                       : base (null, String.Empty)
+               {
+                       this.alias_name = alias_name;
+                       referenced_assemblies = new Assembly [0];
+
+                       all_namespaces = new Hashtable ();
+                       all_namespaces.Add ("", this);
+               }
+
+               public void AddAssemblyReference (Assembly a)
+               {
+                       foreach (Assembly assembly in referenced_assemblies) {
+                               if (a == assembly)
+                                       return;
+                       }
+
+                       // How to test whether attribute exists without loading the assembly :-(
+#if NET_2_1
+                       const string SystemCore = "System.Core, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e"; 
+#else
+                       const string SystemCore = "System.Core, Version=3.5.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089"; 
+#endif
+                       if (TypeManager.extension_attribute_type == null &&
+                               a.FullName == SystemCore) {
+                               TypeManager.extension_attribute_type = a.GetType("System.Runtime.CompilerServices.ExtensionAttribute");
+                       }
+
+                       int top = referenced_assemblies.Length;
+                       Assembly [] n = new Assembly [top + 1];
+                       referenced_assemblies.CopyTo (n, 0);
+                       n [top] = a;
+                       referenced_assemblies = n;
+               }
+
+               public static void DefineRootNamespace (string alias, Assembly assembly)
+               {
+                       if (alias == "global") {
+                               NamespaceEntry.Error_GlobalNamespaceRedefined (Location.Null);
+                               return;
+                       }
+
+                       RootNamespace retval = GetRootNamespace (alias);
+                       if (retval == null) {
+                               retval = new RootNamespace (alias);
+                               root_namespaces.Add (alias, retval);
+                       }
+
+                       retval.AddAssemblyReference (assembly);
+               }
+
+               public static RootNamespace GetRootNamespace (string name)
+               {
+                       return (RootNamespace) root_namespaces [name];
+               }
+
+               public static void ComputeNamespaces ()
+               {
+                       foreach (RootNamespace rn in root_namespaces.Values) {
+                               foreach (Assembly a in rn.referenced_assemblies) {
+                                       try {
+                                               rn.ComputeNamespaces (a);
+                                       } catch (TypeLoadException e) {
+                                               Report.Error (11, Location.Null, e.Message);
+                                       } catch (System.IO.FileNotFoundException) {
+                                               Report.Error (12, Location.Null, "An assembly `{0}' is used without being referenced",
+                                                       a.FullName);
+                                       }
+                               }
+                       }
+               }
+
+               public virtual Type LookupTypeReflection (string name, Location loc)
+               {
+                       Type found_type = null;
+
+                       foreach (Assembly a in referenced_assemblies) {
+                               Type t = GetTypeInAssembly (a, name);
+                               if (t == null)
+                                       continue;
+
+                               if (found_type == null) {
+                                       found_type = t;
+                                       continue;
+                               }
+
+                               Report.SymbolRelatedToPreviousError (found_type);
+                               Report.SymbolRelatedToPreviousError (t);
+                               Report.Error (433, loc, "The imported type `{0}' is defined multiple times", name);
+
+                               return found_type;
+                       }
+
+                       return found_type;
+               }
+
+               public void RegisterNamespace (Namespace child)
+               {
+                       if (child != this)
+                               all_namespaces.Add (child.Name, child);
+               }
+
+               public bool IsNamespace (string name)
+               {
+                       return all_namespaces.Contains (name);
+               }
+
+               protected void RegisterNamespace (string dotted_name)
+               {
+                       if (dotted_name != null && dotted_name.Length != 0 && ! IsNamespace (dotted_name))
+                               GetNamespace (dotted_name, true);
+               }
+
+               void RegisterExtensionMethodClass (Type t)
+               {
+                       string n = t.Namespace;
+                       Namespace ns = n == null ? Global : (Namespace)all_namespaces [n];
+                       if (ns == null)
+                               ns = GetNamespace (n, true);
+                       ns.RegisterExternalExtensionMethodClass (t);
+               }
+
+               protected void ComputeNamespaces (Assembly assembly)
+               {
+                       bool contains_extension_methods = TypeManager.extension_attribute_type != null &&
+                                       assembly.IsDefined(TypeManager.extension_attribute_type, false);
+                       if (get_namespaces_method != null && !contains_extension_methods) {
+                               string [] namespaces = (string []) get_namespaces_method.Invoke (assembly, null);
+                               foreach (string ns in namespaces)
+                                       RegisterNamespace (ns);
+                               return;
+                       }
+  
+                       foreach (Type t in assembly.GetExportedTypes ()) {
+                               if ((t.Attributes & Class.StaticClassAttribute) == Class.StaticClassAttribute &&
+                                       contains_extension_methods && t.IsDefined (TypeManager.extension_attribute_type, false))
+                                       RegisterExtensionMethodClass (t);
+                               else
+                                       RegisterNamespace (t.Namespace);
+                       }
+               }
+
+               protected static Type GetTypeInAssembly (Assembly assembly, string name)
+               {
+                       Type t = assembly.GetType (name);
+                       if (t == null)
+                               return null;
+
+                       if (t.IsPointer)
+                               throw new InternalErrorException ("Use GetPointerType() to get a pointer");
+
+                       TypeAttributes ta = t.Attributes & TypeAttributes.VisibilityMask;
+                       if (ta == TypeAttributes.NestedPrivate)
+                               return null;
+
+                       if ((ta == TypeAttributes.NotPublic ||
+                            ta == TypeAttributes.NestedAssembly ||
+                            ta == TypeAttributes.NestedFamANDAssem) &&
+                           !TypeManager.IsThisOrFriendAssembly (t.Assembly))
+                               return null;
+
+                       return t;
+               }
+
+               public override string ToString ()
+               {
+                       return String.Format ("RootNamespace ({0}::)", alias_name);
+               }
+
+               public override string GetSignatureForError ()
+               {
+                       return alias_name + "::";
+               }
+       }
+
+       public class GlobalRootNamespace : RootNamespace {
+               Module [] modules;
+
+               public GlobalRootNamespace ()
+                       : base ("global")
+               {
+               }
+
+               public Assembly [] Assemblies {
+                   get { return referenced_assemblies; }
+               }
+
+               public Module [] Modules {
+                       get { return modules; }
+               }
+
+               public void AddModuleReference (Module m)
+               {
+                       int top = modules != null ? modules.Length : 0;
+                       Module [] n = new Module [top + 1];
+                       if (modules != null)
+                               modules.CopyTo (n, 0);
+                       n [top] = m;
+                       modules = n;
+
+                       if (m == CodeGen.Module.Builder)
+                               return;
+
+                       foreach (Type t in m.GetTypes ())
+                               RegisterNamespace (t.Namespace);
+               }
+
+               public override void Error_NamespaceDoesNotExist(DeclSpace ds, Location loc, string name)
+               {
+                       Report.Error (400, loc, "The type or namespace name `{0}' could not be found in the global namespace (are you missing an assembly reference?)",
+                               name);
+               }
+
+               public override Type LookupTypeReflection (string name, Location loc)
+               {
+                       Type found_type = base.LookupTypeReflection (name, loc);
+
+                       if (modules != null) {
+                               foreach (Module module in modules) {
+                                       Type t = module.GetType (name);
+                                       if (t == null)
+                                               continue;
+
+                                       if (found_type == null) {
+                                               found_type = t;
+                                               continue;
+                                       }
+
+                                       Report.SymbolRelatedToPreviousError (found_type);
+                                       if (loc.IsNull) {
+                                               DeclSpace ds = TypeManager.LookupDeclSpace (t);
+                                               Report.Warning (1685, 1, ds.Location, "The type `{0}' conflicts with the predefined type `{1}' and will be ignored",
+                                                       ds.GetSignatureForError (), TypeManager.CSharpName (found_type));
+                                               return found_type;
+                                       }
+                                       Report.SymbolRelatedToPreviousError (t);
+                                       Report.Warning (436, 2, loc, "The type `{0}' conflicts with the imported type `{1}'. Ignoring the imported type definition",
+                                               TypeManager.CSharpName (t), TypeManager.CSharpName (found_type));
+                                       return t;
+                               }
+                       }
+
+                       return found_type;
+               }
+       }
+
        /// <summary>
        ///   Keeps track of the namespaces defined in the C# code.
        ///
        ///   This is an Expression to allow it to be referenced in the
        ///   compiler parse/intermediate tree during name resolution.
        /// </summary>
-       public class Namespace : FullNamedExpression, IAlias {
-               static ArrayList all_namespaces;
-               static Hashtable namespaces_map;
+       public class Namespace : FullNamedExpression {
                
                Namespace parent;
                string fullname;
-               ArrayList entries;
-               Hashtable namespaces;
-               Hashtable defined_names;
+               IDictionary namespaces;
+               IDictionary declspaces;
                Hashtable cached_types;
+               RootNamespace root;
+               ArrayList external_exmethod_classes;
 
                public readonly MemberName MemberName;
 
-               public static Namespace Root;
-
-               static Namespace ()
-               {
-                       Reset ();
-               }
-
-               public static void Reset ()
-               {
-                       all_namespaces = new ArrayList ();
-                       namespaces_map = new Hashtable ();
-
-                       Root = new Namespace (null, "");
-               }
-
                /// <summary>
                ///   Constructor Takes the current namespace and the
                ///   name.  This is bootstrapped with parent == null
@@ -54,34 +320,40 @@ namespace Mono.CSharp {
                {
                        // Expression members.
                        this.eclass = ExprClass.Namespace;
-                       this.Type = null;
+                       this.Type = typeof (Namespace);
                        this.loc = Location.Null;
 
                        this.parent = parent;
 
-                       string pname = parent != null ? parent.Name : "";
+                       if (parent != null)
+                               this.root = parent.root;
+                       else
+                               this.root = this as RootNamespace;
+
+                       if (this.root == null)
+                               throw new InternalErrorException ("Root namespaces must be created using RootNamespace");
+                       
+                       string pname = parent != null ? parent.fullname : "";
                                
                        if (pname == "")
                                fullname = name;
                        else
-                               fullname = parent.Name + "." + name;
+                               fullname = parent.fullname + "." + name;
+
+                       if (fullname == null)
+                               throw new InternalErrorException ("Namespace has a null fullname");
 
                        if (parent != null && parent.MemberName != MemberName.Null)
                                MemberName = new MemberName (parent.MemberName, name);
-                       else if (name == "")
+                       else if (name.Length == 0)
                                MemberName = MemberName.Null;
                        else
                                MemberName = new MemberName (name);
 
-                       entries = new ArrayList ();
-                       namespaces = new Hashtable ();
-                       defined_names = new Hashtable ();
+                       namespaces = new HybridDictionary ();
                        cached_types = new Hashtable ();
 
-                       all_namespaces.Add (this);
-                       if (namespaces_map.Contains (fullname))
-                               return;
-                       namespaces_map [fullname] = true;
+                       root.RegisterNamespace (this);
                }
 
                public override Expression DoResolve (EmitContext ec)
@@ -89,14 +361,54 @@ namespace Mono.CSharp {
                        return this;
                }
 
-               public override void Emit (EmitContext ec)
+               public virtual void Error_NamespaceDoesNotExist (DeclSpace ds, Location loc, string name)
+               {
+                       if (name.IndexOf ('`') > 0) {
+                               FullNamedExpression retval = Lookup (ds, SimpleName.RemoveGenericArity (name), loc);
+                               if (retval != null) {
+                                       Error_TypeArgumentsCannotBeUsed (retval.Type, loc);
+                                       return;
+                               }
+                       } else {
+                               Type t = LookForAnyGenericType (name);
+                               if (t != null) {
+                                       Error_InvalidNumberOfTypeArguments (t, loc);
+                                       return;
+                               }
+                       }
+
+                       Report.Error (234, loc, "The type or namespace name `{0}' does not exist in the namespace `{1}'. Are you missing an assembly reference?",
+                               name, GetSignatureForError ());
+               }
+
+               public static void Error_InvalidNumberOfTypeArguments (Type t, Location loc)
                {
-                       throw new InternalErrorException ("Expression tree referenced namespace " + fullname + " during Emit ()");
+                       Report.SymbolRelatedToPreviousError (t);
+                       Report.Error (305, loc, "Using the generic type `{0}' requires `{1}' type argument(s)",
+                               TypeManager.CSharpName(t), TypeManager.GetNumberOfTypeArguments(t).ToString());
                }
 
-               public static bool IsNamespace (string name)
+               public static void Error_TypeArgumentsCannotBeUsed (Type t, Location loc)
                {
-                       return namespaces_map [name] != null;
+                       Report.SymbolRelatedToPreviousError (t);
+                       Error_TypeArgumentsCannotBeUsed (loc, "type", TypeManager.CSharpName (t));
+               }
+
+               public static void Error_TypeArgumentsCannotBeUsed (MethodBase mi, Location loc)
+               {
+                       Report.SymbolRelatedToPreviousError (mi);
+                       Error_TypeArgumentsCannotBeUsed (loc, "method", TypeManager.CSharpSignature (mi));
+               }
+
+               static void Error_TypeArgumentsCannotBeUsed (Location loc, string type, string name)
+               {
+                       Report.Error(308, loc, "The non-generic {0} `{1}' cannot be used with the type arguments",
+                               type, name);
+               }
+
+               public override string GetSignatureForError ()
+               {
+                       return fullname;
                }
                
                public Namespace GetNamespace (string name, bool create)
@@ -125,23 +437,19 @@ namespace Mono.CSharp {
                        return ns;
                }
 
-               public static Namespace LookupNamespace (string name, bool create)
+               public bool HasDefinition (string name)
                {
-                       return Root.GetNamespace (name, create);
+                       return declspaces != null && declspaces [name] != null;
                }
 
-               public FullNamedExpression Lookup (DeclSpace ds, string name, Location loc)
+               TypeExpr LookupType (string name, Location loc)
                {
-                       Namespace ns = GetNamespace (name, false);
-                       if (ns != null)
-                               return ns;
+                       if (cached_types.Contains (name))
+                               return cached_types [name] as TypeExpr;
 
-                       TypeExpr te;
-                       if (cached_types.Contains (name)) {
-                               te = (TypeExpr) cached_types [name];
-                       } else {
-                               Type t;
-                               DeclSpace tdecl = defined_names [name] as DeclSpace;
+                       Type t = null;
+                       if (declspaces != null) {
+                               DeclSpace tdecl = declspaces [name] as DeclSpace;
                                if (tdecl != null) {
                                        //
                                        // Note that this is not:
@@ -154,49 +462,128 @@ namespace Mono.CSharp {
                                        //
                                        tdecl.DefineType ();
                                        t = tdecl.TypeBuilder;
-                               } else {
-                                       string lookup = this == Namespace.Root ? name : fullname + "." + name;
-                                       t = TypeManager.LookupTypeReflection (lookup);
+
+                                       if (RootContext.EvalMode){
+                                               // Replace the TypeBuilder with a System.Type, as
+                                               // Reflection.Emit fails otherwise (we end up pretty
+                                               // much with Random type definitions later on).
+                                               Type tt = t.Assembly.GetType (t.Name);
+                                               if (tt != null)
+                                                       t = tt;
+                                       }
                                }
-                               te = t == null ? null : new TypeExpression (t, Location.Null);
-                               cached_types [name] = te;
                        }
+                       string lookup = t != null ? t.FullName : (fullname.Length == 0 ? name : fullname + "." + name);
+                       Type rt = root.LookupTypeReflection (lookup, loc);
 
-                       if (te != null && ds != null && !ds.CheckAccessLevel (te.Type))
-                               return null;
+                       // HACK: loc.IsNull when the type is core type
+                       if (t == null || (rt != null && loc.IsNull))
+                               t = rt;
 
+                       TypeExpr te = t == null ? null : new TypeExpression (t, Location.Null);
+                       cached_types [name] = te;
                        return te;
                }
 
-               public void AddNamespaceEntry (NamespaceEntry entry)
+               ///
+               /// Used for better error reporting only
+               /// 
+               public Type LookForAnyGenericType (string typeName)
                {
-                       entries.Add (entry);
+                       if (declspaces == null)
+                               return null;
+
+                       typeName = SimpleName.RemoveGenericArity (typeName);
+
+                       foreach (DictionaryEntry de in declspaces) {
+                               string type_item = (string) de.Key;
+                               int pos = type_item.LastIndexOf ('`');
+                               if (pos == typeName.Length && String.Compare (typeName, 0, type_item, 0, pos) == 0)
+                                       return ((DeclSpace) de.Value).TypeBuilder;
+                       }
+                       return null;
                }
 
-               public void DefineName (string name, IAlias o)
+               public FullNamedExpression Lookup (DeclSpace ds, string name, Location loc)
                {
-                       defined_names.Add (name, o);
+                       if (namespaces.Contains (name))
+                               return (Namespace) namespaces [name];
+
+                       return LookupType (name, loc);
                }
 
-               static public ArrayList UserDefinedNamespaces {
-                       get {
-                               return all_namespaces;
+               public void RegisterExternalExtensionMethodClass (Type type)
+               {
+                       if (external_exmethod_classes == null)
+                               external_exmethod_classes = new ArrayList ();
+
+                       external_exmethod_classes.Add (type);
+               }
+
+               /// 
+               /// Looks for extension method in this namespace
+               /// 
+               public ArrayList LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name)
+               {
+                       ArrayList found = null;
+
+                       if (declspaces != null) {
+                               IEnumerator e = declspaces.Values.GetEnumerator ();
+                               e.Reset ();
+                               while (e.MoveNext ()) {
+                                       Class c = e.Current as Class;
+                                       if (c == null)
+                                               continue;
+
+                                       if (!c.IsStaticClass)
+                                               continue;
+
+                                       ArrayList res = c.MemberCache.FindExtensionMethods (extensionType, name, c != currentClass);
+                                       if (res == null)
+                                               continue;
+
+                                       if (found == null)
+                                               found = res;
+                                       else
+                                               found.AddRange (res);
+                               }
                        }
+
+                       if (external_exmethod_classes == null)
+                               return found;
+
+                       foreach (Type t in external_exmethod_classes) {
+                               MemberCache m = TypeHandle.GetMemberCache (t);
+                               ArrayList res = m.FindExtensionMethods (extensionType, name, true);
+                               if (res == null)
+                                       continue;
+
+                               if (found == null)
+                                       found = res;
+                               else
+                                       found.AddRange (res);
+                       }
+
+                       return found;
                }
 
+               public void AddDeclSpace (string name, DeclSpace ds)
+               {
+                       if (declspaces == null)
+                               declspaces = new HybridDictionary ();
+                       declspaces.Add (name, ds);
+               }
+
+               public void RemoveDeclSpace (string name)
+               {
+                       declspaces.Remove (name);
+               }
+               
                /// <summary>
                ///   The qualified name of the current namespace
                /// </summary>
                public string Name {
-                       get {
-                               return fullname;
-                       }
-               }
-
-               public override string FullName {
-                       get {
-                               return fullname;
-                       }
+                       get { return fullname; }
                }
 
                /// <summary>
@@ -204,152 +591,244 @@ namespace Mono.CSharp {
                ///   the current namespace declaration
                /// </summary>
                public Namespace Parent {
-                       get {
-                               return parent;
-                       }
+                       get { return parent; }
                }
+       }
 
-               public static void DefineNamespaces (SymbolWriter symwriter)
-               {
-                       foreach (Namespace ns in all_namespaces) {
-                               foreach (NamespaceEntry entry in ns.entries)
-                                       entry.DefineNamespace (symwriter);
+       //
+       // Namespace container as created by the parser
+       //
+       public class NamespaceEntry : IResolveContext {
+
+               class UsingEntry {
+                       readonly MemberName name;
+                       Namespace resolved;
+                       
+                       public UsingEntry (MemberName name)
+                       {
+                               this.name = name;
                        }
-               }
 
-               /// <summary>
-               ///   Used to validate that all the using clauses are correct
-               ///   after we are finished parsing all the files.  
-               /// </summary>
-               public static void VerifyUsing ()
-               {
-                       foreach (Namespace ns in all_namespaces) {
-                               foreach (NamespaceEntry entry in ns.entries)
-                                       entry.VerifyUsing ();
+                       public string GetSignatureForError ()
+                       {
+                               return name.GetSignatureForError ();
                        }
-               }
 
-               public override string ToString ()
-               {
-                       if (this == Root)
-                               return "Namespace (<root>)";
-                       else
-                               return String.Format ("Namespace ({0})", Name);
-               }
+                       public Location Location {
+                               get { return name.Location; }
+                       }
 
-               bool IAlias.IsType {
-                       get { return false; }
-               }
+                       public MemberName MemberName {
+                               get { return name; }
+                       }
+                       
+                       public string Name {
+                               get { return GetSignatureForError (); }
+                       }
 
-               TypeExpr IAlias.ResolveAsType (EmitContext ec)
-               {
-                       throw new InvalidOperationException ();
-               }
-       }
+                       public Namespace Resolve (IResolveContext rc)
+                       {
+                               if (resolved != null)
+                                       return resolved;
 
-       public class NamespaceEntry
-       {
-               Namespace ns;
-               NamespaceEntry parent, implicit_parent;
-               SourceFile file;
-               int symfile_id;
-               Hashtable aliases;
-               ArrayList using_clauses;
-               public bool DeclarationFound = false;
+                               FullNamedExpression fne = name.GetTypeExpression ().ResolveAsTypeStep (rc, false);
+                               if (fne == null)
+                                       return null;
 
-               //
-               // This class holds the location where a using definition is
-               // done, and whether it has been used by the program or not.
-               //
-               // We use this to flag using clauses for namespaces that do not
-               // exist.
-               //
-               public class UsingEntry {
-                       public MemberName Name;
-                       public Expression Expr;
-                       public readonly NamespaceEntry NamespaceEntry;
-                       public readonly Location Location;
-                       
-                       public UsingEntry (NamespaceEntry entry, MemberName name, Location loc)
+                               resolved = fne as Namespace;
+                               if (resolved == null) {
+                                       Report.SymbolRelatedToPreviousError (fne.Type);
+                                       Report.Error (138, Location,
+                                               "`{0}' is a type not a namespace. A using namespace directive can only be applied to namespaces",
+                                               GetSignatureForError ());
+                               }
+                               return resolved;
+                       }
+
+                       public override string ToString ()
                        {
-                               Name = name;
-                               Expr = name.GetTypeExpression (loc);
-                               NamespaceEntry = entry;
-                               Location = loc;
+                               return Name;
                        }
+               }
 
-                       internal FullNamedExpression resolved;
+               class UsingAliasEntry {
+                       public readonly string Alias;
+                       public Location Location;
 
-                       public Namespace Resolve ()
+                       public UsingAliasEntry (string alias, Location loc)
                        {
-                               if (resolved != null)
-                                       return resolved as Namespace;
+                               this.Alias = alias;
+                               this.Location = loc;
+                       }
 
-                               DeclSpace root = RootContext.Tree.Types;
-                               root.NamespaceEntry = NamespaceEntry;
-                               resolved = Expr.ResolveAsTypeStep (root.EmitContext);
-                               root.NamespaceEntry = null;
+                       public virtual FullNamedExpression Resolve (IResolveContext rc)
+                       {
+                               FullNamedExpression fne = RootNamespace.GetRootNamespace (Alias);
+                               if (fne == null) {
+                                       Report.Error (430, Location,
+                                               "The extern alias `{0}' was not specified in -reference option",
+                                               Alias);
+                               }
 
-                               return resolved as Namespace;
+                               return fne;
                        }
-               }
 
-               public class AliasEntry {
-                       public readonly string Name;
-                       public readonly Expression Alias;
-                       public readonly NamespaceEntry NamespaceEntry;
-                       public readonly Location Location;
-                       
-                       public AliasEntry (NamespaceEntry entry, string name, MemberName alias, Location loc)
+                       public override string ToString ()
                        {
-                               Name = name;
-                               Alias = alias.GetTypeExpression (loc);
-                               NamespaceEntry = entry;
-                               Location = loc;
+                               return Alias;
                        }
+                       
+               }
 
-                       FullNamedExpression resolved;
+               class LocalUsingAliasEntry : UsingAliasEntry {
+                       Expression resolved;
+                       MemberName value;
 
-                       public FullNamedExpression Resolve ()
+                       public LocalUsingAliasEntry (string alias, MemberName name, Location loc)
+                               : base (alias, loc)
                        {
-                               if (resolved != null)
-                                       return resolved;
+                               this.value = name;
+                       }
 
-                               DeclSpace root = RootContext.Tree.Types;
-                               root.NamespaceEntry = NamespaceEntry;
-                               resolved = Alias.ResolveAsTypeStep (root.EmitContext);
-                               root.NamespaceEntry = null;
+                       public override FullNamedExpression Resolve (IResolveContext rc)
+                       {
+                               if (resolved != null || value == null)
+                                       return (FullNamedExpression)resolved;
 
-                               return resolved;
+                               resolved = value.GetTypeExpression ().ResolveAsTypeStep (rc, false);
+                               if (resolved == null) {
+                                       value = null;
+                                       return null;
+                               }
+
+                               // FIXME: This is quite wrong, the accessibility is not global
+                               if (resolved.Type != null) {
+                                       TypeAttributes attr = resolved.Type.Attributes & TypeAttributes.VisibilityMask;
+                                       if (attr == TypeAttributes.NestedPrivate || attr == TypeAttributes.NestedFamily ||
+                                               ((attr == TypeAttributes.NestedFamORAssem || attr == TypeAttributes.NestedAssembly) && 
+                                               TypeManager.LookupDeclSpace (resolved.Type) == null)) {
+                                               Expression.ErrorIsInaccesible (resolved.Location, resolved.GetSignatureForError ());
+                                               return null;
+                                       }
+                               }
+
+                               return (FullNamedExpression)resolved;
+                       }
+
+                       public override string ToString ()
+                       {
+                               return String.Format ("{0} = {1}", Alias, value.GetSignatureForError ());
                        }
                }
 
-               public NamespaceEntry (NamespaceEntry parent, SourceFile file, string name, Location loc)
+               Namespace ns;
+               NamespaceEntry parent, implicit_parent;
+               CompilationUnit file;
+               int symfile_id;
+
+               // Namespace using import block
+               ArrayList using_aliases;
+               ArrayList using_clauses;
+               public bool DeclarationFound = false;
+               // End
+
+               public readonly bool IsImplicit;
+               public readonly DeclSpace SlaveDeclSpace;
+               static readonly Namespace [] empty_namespaces = new Namespace [0];
+               Namespace [] namespace_using_table;
+
+               static ArrayList entries = new ArrayList ();
+
+               public static void Reset ()
+               {
+                       entries = new ArrayList ();
+               }
+
+               public NamespaceEntry (NamespaceEntry parent, CompilationUnit file, string name)
                {
                        this.parent = parent;
                        this.file = file;
-                       this.IsImplicit = false;
-                       this.ID = ++next_id;
+                       entries.Add (this);
 
                        if (parent != null)
                                ns = parent.NS.GetNamespace (name, true);
                        else if (name != null)
-                               ns = Namespace.LookupNamespace (name, true);
+                               ns = RootNamespace.Global.GetNamespace (name, true);
                        else
-                               ns = Namespace.Root;
-                       ns.AddNamespaceEntry (this);
+                               ns = RootNamespace.Global;
+                       SlaveDeclSpace = new RootDeclSpace (this);
                }
 
-
-               private NamespaceEntry (NamespaceEntry parent, SourceFile file, Namespace ns)
+               private NamespaceEntry (NamespaceEntry parent, CompilationUnit file, Namespace ns, bool slave)
                {
                        this.parent = parent;
                        this.file = file;
                        this.IsImplicit = true;
-                       this.ID = ++next_id;
                        this.ns = ns;
+                       this.SlaveDeclSpace = slave ? new RootDeclSpace (this) : null;
+               }
+
+               //
+               // Populates the Namespace with some using declarations, used by the
+               // eval mode. 
+               //
+               public void Populate (ArrayList source_using_aliases, ArrayList source_using_clauses)
+               {
+                       foreach (UsingAliasEntry uae in source_using_aliases){
+                               if (using_aliases == null)
+                                       using_aliases = new ArrayList ();
+                               
+                               using_aliases.Add (uae);
+                       }
+
+                       foreach (UsingEntry ue in source_using_clauses){
+                               if (using_clauses == null)
+                                       using_clauses = new ArrayList ();
+                               
+                               using_clauses.Add (ue);
+                       }
                }
 
+               //
+               // Extracts the using alises and using clauses into a couple of
+               // arrays that might already have the same information;  Used by the
+               // C# Eval mode.
+               //
+               public void Extract (ArrayList out_using_aliases, ArrayList out_using_clauses)
+               {
+                       if (using_aliases != null){
+                               foreach (UsingAliasEntry uae in using_aliases){
+                                       bool replaced = false;
+                                       
+                                       for (int i = 0; i < out_using_aliases.Count; i++){
+                                               UsingAliasEntry out_uea = (UsingAliasEntry) out_using_aliases [i];
+                                               
+                                               if (out_uea.Alias == uae.Alias){
+                                                       out_using_aliases [i] = uae;
+                                                       replaced = true;
+                                                       break;
+                                               }
+                                       }
+                                       if (!replaced)
+                                               out_using_aliases.Add (uae);
+                               }
+                       }
+
+                       if (using_clauses != null){
+                               foreach (UsingEntry ue in using_clauses){
+                                       bool found = false;
+                                       
+                                       foreach (UsingEntry out_ue in out_using_clauses)
+                                               if (out_ue.Name == ue.Name){
+                                                       found = true;
+                                                       break;
+                                               }
+                                       if (!found)
+                                               out_using_clauses.Add (ue);
+                               }
+                       }
+               }
+               
                //
                // According to section 16.3.1 (using-alias-directive), the namespace-or-type-name is
                // resolved as if the immediately containing namespace body has no using-directives.
@@ -363,26 +842,20 @@ namespace Mono.CSharp {
                NamespaceEntry doppelganger;
                NamespaceEntry Doppelganger {
                        get {
-                               if (!IsImplicit && doppelganger == null)
-                                       doppelganger = new NamespaceEntry (ImplicitParent, file, ns);
+                               if (!IsImplicit && doppelganger == null) {
+                                       doppelganger = new NamespaceEntry (ImplicitParent, file, ns, true);
+                                       doppelganger.using_aliases = using_aliases;
+                               }
                                return doppelganger;
                        }
                }
 
-               static int next_id = 0;
-               public readonly int ID;
-               public readonly bool IsImplicit;
-
                public Namespace NS {
-                       get {
-                               return ns;
-                       }
+                       get { return ns; }
                }
 
                public NamespaceEntry Parent {
-                       get {
-                               return parent;
-                       }
+                       get { return parent; }
                }
 
                public NamespaceEntry ImplicitParent {
@@ -392,118 +865,170 @@ namespace Mono.CSharp {
                                if (implicit_parent == null) {
                                        implicit_parent = (parent.NS == ns.Parent)
                                                ? parent
-                                               : new NamespaceEntry (parent, file, ns.Parent);
+                                               : new NamespaceEntry (parent, file, ns.Parent, false);
                                }
                                return implicit_parent;
                        }
                }
 
-               public void DefineName (string name, IAlias o)
-               {
-                       ns.DefineName (name, o);
-               }
-
                /// <summary>
                ///   Records a new namespace for resolving name references
                /// </summary>
-               public void Using (MemberName name, Location loc)
+               public void AddUsing (MemberName name, Location loc)
                {
                        if (DeclarationFound){
-                               Report.Error (1529, loc, "A using clause must precede all other namespace elements");
-                               return;
+                               Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
                        }
 
-                       if (name.Equals (ns.MemberName))
-                               return;
-                       
-                       if (using_clauses == null)
+                       if (using_clauses == null) {
                                using_clauses = new ArrayList ();
-
-                       foreach (UsingEntry old_entry in using_clauses) {
-                               if (name.Equals (old_entry.Name)) {
-                                       if (RootContext.WarningLevel >= 3)
-                                               Report.Warning (105, loc, "The using directive for '{0}' appeared previously in this namespace", name);
-                                       return;
+                       } else {
+                               foreach (UsingEntry old_entry in using_clauses) {
+                                       if (name.Equals (old_entry.MemberName)) {
+                                               Report.SymbolRelatedToPreviousError (old_entry.Location, old_entry.GetSignatureForError ());
+                                               Report.Warning (105, 3, loc, "The using directive for `{0}' appeared previously in this namespace", name.GetSignatureForError ());
+                                               return;
+                                       }
                                }
                        }
 
-
-                       UsingEntry ue = new UsingEntry (Doppelganger, name, loc);
-                       using_clauses.Add (ue);
+                       using_clauses.Add (new UsingEntry (name));
                }
 
-               public void UsingAlias (string name, MemberName alias, Location loc)
+               public void AddUsingAlias (string alias, MemberName name, Location loc)
                {
+                       // TODO: This is parser bussines
                        if (DeclarationFound){
-                               Report.Error (1529, loc, "A using clause must precede all other namespace elements");
-                               return;
+                               Report.Error (1529, loc, "A using clause must precede all other namespace elements except extern alias declarations");
                        }
 
-                       if (aliases == null)
-                               aliases = new Hashtable ();
-                       
-                       if (aliases.Contains (name)){
-                               AliasEntry ae = (AliasEntry)aliases [name];
-                               Report.SymbolRelatedToPreviousError (ae.Location, ae.Name);
-                               Report.Error (1537, loc, "The using alias `" + name +
-                                             "' appeared previously in this namespace");
+                       if (RootContext.Version != LanguageVersion.ISO_1 && alias == "global")
+                               Report.Warning (440, 2, loc, "An alias named `global' will not be used when resolving 'global::';" +
+                                       " the global namespace will be used instead");
+
+                       AddUsingAlias (new LocalUsingAliasEntry (alias, name, loc));
+               }
+
+               public void AddUsingExternalAlias (string alias, Location loc)
+               {
+                       // TODO: Do this in parser
+                       bool not_first = using_clauses != null || DeclarationFound;
+                       if (using_aliases != null && !not_first) {
+                               foreach (UsingAliasEntry uae in using_aliases) {
+                                       if (uae is LocalUsingAliasEntry) {
+                                               not_first = true;
+                                               break;
+                                       }
+                               }
+                       }
+
+                       if (not_first)
+                               Report.Error (439, loc, "An extern alias declaration must precede all other elements");
+
+                       if (alias == "global") {
+                               Error_GlobalNamespaceRedefined (loc);
                                return;
                        }
 
-                       aliases [name] = new AliasEntry (Doppelganger, name, alias, loc);
+                       AddUsingAlias (new UsingAliasEntry (alias, loc));
                }
 
-               public FullNamedExpression LookupAlias (string alias)
+               void AddUsingAlias (UsingAliasEntry uae)
                {
-                       AliasEntry entry = null;
-                       if (aliases != null)
-                               entry = (AliasEntry) aliases [alias];
+                       if (using_aliases == null) {
+                               using_aliases = new ArrayList ();
+                       } else {
+                               foreach (UsingAliasEntry entry in using_aliases) {
+                                       if (uae.Alias == entry.Alias) {
+                                               Report.SymbolRelatedToPreviousError (uae.Location, uae.Alias);
+                                               Report.Error (1537, entry.Location, "The using alias `{0}' appeared previously in this namespace",
+                                                       entry.Alias);
+                                               return;
+                                       }
+                               }
+                       }
 
-                       return entry == null ? null : entry.Resolve ();
+                       using_aliases.Add (uae);
                }
 
-               static readonly char [] dot_array = { '.' };
-
-               public FullNamedExpression LookupNamespaceOrType (DeclSpace ds, string name, Location loc, bool ignore_cs0104)
+               ///
+               /// Does extension methods look up to find a method which matches name and extensionType.
+               /// Search starts from this namespace and continues hierarchically up to top level.
+               ///
+               public ExtensionMethodGroupExpr LookupExtensionMethod (Type extensionType, ClassOrStruct currentClass, string name, Location loc)
                {
-                       FullNamedExpression resolved = null;
-                       string rest = null;
+                       ArrayList candidates = null;
+                       if (currentClass != null) {
+                               candidates = ns.LookupExtensionMethod (extensionType, currentClass, name);
+                               if (candidates != null)
+                                       return new ExtensionMethodGroupExpr (candidates, this, extensionType, loc);
+                       }
 
-                       // If name is of the form `N.I', first lookup `N', then search a member `I' in it.
-                       int pos = name.IndexOf ('.');
-                       if (pos >= 0) {
-                               rest = name.Substring (pos + 1);
-                               name = name.Substring (0, pos);
+                       foreach (Namespace n in GetUsingTable ()) {
+                               ArrayList a = n.LookupExtensionMethod (extensionType, null, name);
+                               if (a == null)
+                                       continue;
+
+                               if (candidates == null)
+                                       candidates = a;
+                               else
+                                       candidates.AddRange (a);
                        }
 
+                       if (candidates != null)
+                               return new ExtensionMethodGroupExpr (candidates, parent, extensionType, loc);
+
+                       if (parent == null)
+                               return null;
+
+                       //
+                       // Inspect parent namespaces in namespace expression
+                       //
+                       Namespace parent_ns = ns.Parent;
+                       do {
+                               candidates = parent_ns.LookupExtensionMethod (extensionType, null, name);
+                               if (candidates != null)
+                                       return new ExtensionMethodGroupExpr (candidates, parent, extensionType, loc);
+
+                               parent_ns = parent_ns.Parent;
+                       } while (parent_ns != null);
+
+                       //
+                       // Continue in parent scope
+                       //
+                       return parent.LookupExtensionMethod (extensionType, currentClass, name, loc);
+               }
+
+               public FullNamedExpression LookupNamespaceOrType (DeclSpace ds, string name, Location loc, bool ignore_cs0104)
+               {
+                       // Precondition: Only simple names (no dots) will be looked up with this function.
+                       FullNamedExpression resolved = null;
                        for (NamespaceEntry curr_ns = this; curr_ns != null; curr_ns = curr_ns.ImplicitParent) {
                                if ((resolved = curr_ns.Lookup (ds, name, loc, ignore_cs0104)) != null)
                                        break;
                        }
+                       return resolved;
+               }
 
-                       if (resolved == null || rest == null)
-                               return resolved;
-
-                       // Now handle the rest of the the name.
-                       string [] elements = rest.Split (dot_array);
-                       int count = elements.Length;
-                       int i = 0;
-                       while (i < count && resolved != null && resolved is Namespace) {
-                               Namespace ns = resolved as Namespace;
-                               resolved = ns.Lookup (ds, elements [i++], loc);
-                       }
+               static void Error_AmbiguousTypeReference (Location loc, string name, FullNamedExpression t1, FullNamedExpression t2)
+               {
+                       Report.SymbolRelatedToPreviousError (t1.Type);
+                       Report.SymbolRelatedToPreviousError (t2.Type);
+                       Report.Error (104, loc, "`{0}' is an ambiguous reference between `{1}' and `{2}'",
+                               name, t1.GetSignatureForError (), t2.GetSignatureForError ());
+               }
 
-                       if (resolved == null || resolved is Namespace)
-                               return resolved;
+               // Looks-up a alias named @name in this and surrounding namespace declarations
+               public FullNamedExpression LookupAlias (string name)
+               {
+                       for (NamespaceEntry n = this; n != null; n = n.ImplicitParent) {
+                               if (n.using_aliases == null)
+                                       continue;
 
-                       Type t = ((TypeExpr) resolved).Type;
-                       
-                       while (t != null) {
-                               if (ds != null && !ds.CheckAccessLevel (t))
-                                       break;
-                               if (i == count)
-                                       return new TypeExpression (t, Location.Null);
-                               t = TypeManager.GetNestedType (t, elements [i++]);
+                               foreach (UsingAliasEntry ue in n.using_aliases) {
+                                       if (ue.Alias == name)
+                                               return ue.Resolve (Doppelganger);
+                               }
                        }
 
                        return null;
@@ -511,99 +1036,100 @@ namespace Mono.CSharp {
 
                private FullNamedExpression Lookup (DeclSpace ds, string name, Location loc, bool ignore_cs0104)
                {
-                       // Precondition: Only simple names (no dots) will be looked up with this function.
-
                        //
                        // Check whether it's in the namespace.
                        //
-                       FullNamedExpression o = NS.Lookup (ds, name, loc);
-                       if (o != null)
-                               return o;
-
-                       if (IsImplicit)
-                               return null;
+                       FullNamedExpression fne = ns.Lookup (ds, name, loc);
 
                        //
-                       // Check aliases.
+                       // Check aliases. 
                        //
-                       o = LookupAlias (name);
-                       if (o != null)
-                               return o;
+                       if (using_aliases != null) {
+                               foreach (UsingAliasEntry ue in using_aliases) {
+                                       if (ue.Alias == name) {
+                                               if (fne != null) {
+                                                       if (Doppelganger != null) {
+                                                               // TODO: Namespace has broken location
+                                                               //Report.SymbolRelatedToPreviousError (fne.Location, null);
+                                                               Report.SymbolRelatedToPreviousError (ue.Location, null);
+                                                               Report.Error (576, loc,
+                                                                       "Namespace `{0}' contains a definition with same name as alias `{1}'",
+                                                                       GetSignatureForError (), name);
+                                                       } else {
+                                                               return fne;
+                                                       }
+                                               }
+
+                                               return ue.Resolve (Doppelganger);
+                                       }
+                               }
+                       }
+
+                       if (fne != null)
+                               return fne;
+
+                       if (IsImplicit)
+                               return null;
 
                        //
                        // Check using entries.
                        //
-                       FullNamedExpression t = null, match = null;
+                       FullNamedExpression match = null;
                        foreach (Namespace using_ns in GetUsingTable ()) {
                                match = using_ns.Lookup (ds, name, loc);
-                               if ((match != null) && (match is TypeExpr)) {
-                                       if (t != null) {
-                                               if (!ignore_cs0104)
-                                                       DeclSpace.Error_AmbiguousTypeReference (loc, name, t.FullName, match.FullName);
-                                               
-                                               return null;
-                                       } else {
-                                               t = match;
-                                       }
+                               if (match == null || !(match is TypeExpr))
+                                       continue;
+                               if (fne != null) {
+                                       if (!ignore_cs0104)
+                                               Error_AmbiguousTypeReference (loc, name, fne, match);
+                                       return null;
                                }
+                               fne = match;
                        }
 
-                       return t;
+                       return fne;
                }
 
-               // Our cached computation.
-               Namespace [] namespace_using_table;
-               public Namespace[] GetUsingTable ()
+               Namespace [] GetUsingTable ()
                {
                        if (namespace_using_table != null)
                                return namespace_using_table;
 
                        if (using_clauses == null) {
-                               namespace_using_table = new Namespace [0];
+                               namespace_using_table = empty_namespaces;
                                return namespace_using_table;
                        }
 
                        ArrayList list = new ArrayList (using_clauses.Count);
 
                        foreach (UsingEntry ue in using_clauses) {
-                               Namespace using_ns = ue.Resolve ();
+                               Namespace using_ns = ue.Resolve (Doppelganger);
                                if (using_ns == null)
                                        continue;
 
                                list.Add (using_ns);
                        }
 
-                       namespace_using_table = new Namespace [list.Count];
-                       list.CopyTo (namespace_using_table, 0);
+                       namespace_using_table = (Namespace[])list.ToArray (typeof (Namespace));
                        return namespace_using_table;
                }
 
-               public void DefineNamespace (SymbolWriter symwriter)
-               {
-                       if (symfile_id != 0)
-                               return;
-                       if (parent != null)
-                               parent.DefineNamespace (symwriter);
-
-                       string[] using_list;
-                       if (using_clauses != null) {
-                               using_list = new string [using_clauses.Count];
-                               for (int i = 0; i < using_clauses.Count; i++)
-                                       using_list [i] = ((UsingEntry) using_clauses [i]).Name.ToString ();
-                       } else {
-                               using_list = new string [0];
-                       }
-
-                       int parent_id = parent != null ? parent.symfile_id : 0;
-                       if (file.SourceFileEntry == null)
-                               return;
-
-                       symfile_id = symwriter.DefineNamespace (
-                               ns.Name, file.SourceFileEntry, using_list, parent_id);
-               }
+               static readonly string [] empty_using_list = new string [0];
 
                public int SymbolFileID {
                        get {
+                               if (symfile_id == 0 && file.SourceFileEntry != null) {
+                                       int parent_id = parent == null ? 0 : parent.SymbolFileID;
+
+                                       string [] using_list = empty_using_list;
+                                       if (using_clauses != null) {
+                                               using_list = new string [using_clauses.Count];
+                                               for (int i = 0; i < using_clauses.Count; i++)
+                                                       using_list [i] = ((UsingEntry) using_clauses [i]).MemberName.GetTypeName ();
+                                       }
+
+                                       symfile_id = SymbolWriter.DefineNamespace (ns.Name, file.CompileUnitEntry, using_list, parent_id);
+                               }
                                return symfile_id;
                        }
                }
@@ -612,16 +1138,26 @@ namespace Mono.CSharp {
                {
                        Console.WriteLine ("    Try using -r:" + s);
                }
-               
+
                static void MsgtryPkg (string s)
                {
                        Console.WriteLine ("    Try using -pkg:" + s);
                }
 
-               protected void error246 (Location loc, string name)
+               public static void Error_GlobalNamespaceRedefined (Location loc)
+               {
+                       Report.Error (1681, loc, "You cannot redefine the global extern alias");
+               }
+
+               public static void Error_NamespaceNotFound (Location loc, string name)
                {
-                       Report.Error (246, loc, "The namespace `" + name +
-                                     "' can not be found (missing assembly reference?)");
+                       if (RootContext.EvalMode){
+                               // Do not report this, it might be an error on the eval side, and we are lax there.
+                               return;
+                       }
+                       
+                       Report.Error (246, loc, "The type or namespace name `{0}' could not be found. Are you missing a using directive or an assembly reference?",
+                               name);
 
                        switch (name) {
                        case "Gtk": case "GtkSharp":
@@ -650,40 +1186,57 @@ namespace Mono.CSharp {
                ///   Used to validate that all the using clauses are correct
                ///   after we are finished parsing all the files.  
                /// </summary>
-               public void VerifyUsing ()
+               void VerifyUsing ()
                {
-                       if (using_clauses != null){
-                               foreach (UsingEntry ue in using_clauses){
-                                       if (ue.Resolve () != null)
-                                               continue;
-
-                                       if (ue.resolved == null)
-                                               error246 (ue.Location, ue.Name.ToString ());
-                                       else
-                                               Report.Error (138, ue.Location, "The using keyword only lets you specify a namespace, " +
-                                                             "`" + ue.Name + "' is a class not a namespace.");
-
-                               }
+                       if (using_aliases != null) {
+                               foreach (UsingAliasEntry ue in using_aliases)
+                                       ue.Resolve (Doppelganger);
                        }
 
-                       if (aliases != null){
-                               foreach (DictionaryEntry de in aliases){
-                                       AliasEntry alias = (AliasEntry) de.Value;
+                       if (using_clauses != null) {
+                               foreach (UsingEntry ue in using_clauses)
+                                       ue.Resolve (Doppelganger);
+                       }
+               }
 
-                                       if (alias.Resolve () != null)
-                                               continue;
+               /// <summary>
+               ///   Used to validate that all the using clauses are correct
+               ///   after we are finished parsing all the files.  
+               /// </summary>
+               static public void VerifyAllUsing ()
+               {
+                       foreach (NamespaceEntry entry in entries)
+                               entry.VerifyUsing ();
+               }
 
-                                       error246 (alias.Location, alias.Alias.ToString ());
-                               }
-                       }
+               public string GetSignatureForError ()
+               {
+                       return ns.GetSignatureForError ();
                }
 
                public override string ToString ()
                {
-                       if (NS == Namespace.Root)
-                               return "NamespaceEntry (<root>)";
-                       else
-                               return String.Format ("NamespaceEntry ({0},{1},{2})", ns.Name, IsImplicit, ID);
+                       return ns.ToString ();
                }
+
+               #region IResolveContext Members
+
+               public DeclSpace DeclContainer {
+                       get { return SlaveDeclSpace; }
+               }
+
+               public bool IsInObsoleteScope {
+                       get { return SlaveDeclSpace.IsInObsoleteScope; }
+               }
+
+               public bool IsInUnsafeScope {
+                       get { return SlaveDeclSpace.IsInUnsafeScope; }
+               }
+
+               public DeclSpace GenericDeclContainer {
+                       get { return SlaveDeclSpace; }
+               }
+
+               #endregion
        }
 }