2007-12-06 Atsushi Enomoto <atsushi@ximian.com>
[mono.git] / mcs / mcs / decl.cs
index 0de61e2a1d3efbdeb05fc0c7679d29a2505f1eb7..a1bc891970e176b6417f403139b01b736a9f0520 100644 (file)
@@ -19,7 +19,7 @@ using System.Globalization;
 using System.Reflection.Emit;
 using System.Reflection;
 
-#if BOOTSTRAP_WITH_OLDLIB
+#if BOOTSTRAP_WITH_OLDLIB || NET_2_1
 using XmlElement = System.Object;
 #else
 using System.Xml;
@@ -51,7 +51,8 @@ namespace Mono.CSharp {
                                    TypeArguments args, Location loc)
                        : this (left, name, is_double_colon, loc)
                {
-                       this.TypeArguments = args;
+                       if (args != null && args.Count > 0)
+                               this.TypeArguments = args;
                }
 
                public MemberName (string name)
@@ -78,8 +79,8 @@ namespace Mono.CSharp {
                        : this (left, name, false, args, loc)
                { }
 
-               public MemberName (string alias, string name, Location loc)
-                       : this (new MemberName (alias, loc), name, true, loc)
+               public MemberName (string alias, string name, TypeArguments args, Location loc)
+                       : this (new MemberName (alias, loc), name, true, args, loc)
                { }
 
                public MemberName (MemberName left, MemberName right)
@@ -131,26 +132,17 @@ namespace Mono.CSharp {
 
                public Expression GetTypeExpression ()
                {
-#if GMCS_SOURCE
-                       if (IsUnbound) {
-                               if (!CheckUnbound (Location))
-                                       return null;
-
-                               return new UnboundTypeExpression (this, Location);
-                       }
-#endif
-
                        if (Left == null) {
                                if (TypeArguments != null)
                                        return new SimpleName (Basename, TypeArguments, Location);
-                               else
+                               
                                return new SimpleName (Name, Location);
                        }
 
                        if (is_double_colon) {
                                if (Left.Left != null)
                                        throw new InternalErrorException ("The left side of a :: should be an identifier");
-                               return new QualifiedAliasMember (Left.Name, Name, Location);
+                               return new QualifiedAliasMember (Left.Name, Basename, Location);
                        }
 
                        Expression lexpr = Left.GetTypeExpression ();
@@ -243,10 +235,12 @@ namespace Mono.CSharp {
 
                public int CountTypeArguments {
                        get {
-                               if (TypeArguments == null)
-                                       return 0;
-                               else
+                               if (TypeArguments != null)
                                        return TypeArguments.Count;
+                               else if (Left != null)
+                                       return Left.CountTypeArguments; 
+                               else
+                                       return 0;
                        }
                }
 
@@ -262,29 +256,6 @@ namespace Mono.CSharp {
                {
                        return name + "`" + count;
                }
-
-               protected bool IsUnbound {
-                       get {
-                               if ((Left != null) && Left.IsUnbound)
-                                       return true;
-                               else if (TypeArguments == null)
-                                       return false;
-                               else
-                                       return TypeArguments.IsUnbound;
-                       }
-               }
-
-               protected bool CheckUnbound (Location loc)
-               {
-                       if ((Left != null) && !Left.CheckUnbound (loc))
-                               return false;
-                       if ((TypeArguments != null) && !TypeArguments.IsUnbound) {
-                               Report.Error (1031, loc, "Type expected");
-                               return false;
-                       }
-
-                       return true;
-               }
        }
 
        /// <summary>
@@ -314,9 +285,19 @@ namespace Mono.CSharp {
                /// <summary>
                ///   Modifier flags that the user specified in the source code
                /// </summary>
-               public int ModFlags;
+               private int mod_flags;
+               public int ModFlags {
+                       set {
+                               mod_flags = value;
+                               if ((value & Modifiers.COMPILER_GENERATED) != 0)
+                                       caching_flags = Flags.IsUsed | Flags.IsAssigned;
+                       }
+                       get {
+                               return mod_flags;
+                       }
+               }
 
-               public readonly DeclSpace Parent;
+               public /*readonly*/ DeclSpace Parent;
 
                /// <summary>
                ///   Location where this declaration happens
@@ -348,10 +329,11 @@ namespace Mono.CSharp {
                        ClsCompliantAttributeTrue = 1 << 7,                     // Type has CLSCompliant (true)
                        Excluded_Undetected = 1 << 8,           // Conditional attribute has not been detected yet
                        Excluded = 1 << 9,                                      // Method is conditional
-                       TestMethodDuplication = 1 << 10,                // Test for duplication must be performed
+                       MethodOverloadsExist = 1 << 10,         // Test for duplication must be performed
                        IsUsed = 1 << 11,
                        IsAssigned = 1 << 12,                           // Field is assigned
-                       HasExplicitLayout       = 1 << 13
+                       HasExplicitLayout       = 1 << 13,
+                       PartialDefinitionExists = 1 << 14       // Set when corresponding partial method definition exists
                }
 
                /// <summary>
@@ -372,6 +354,39 @@ namespace Mono.CSharp {
                        member_name = new_name;
                        cached_name = null;
                }
+               
+               protected bool CheckAbstractAndExtern (bool has_block)
+               {
+                       if (Parent.PartialContainer.Kind == Kind.Interface)
+                               return true;
+
+                       if (has_block) {
+                               if ((ModFlags & Modifiers.EXTERN) != 0) {
+                                       Report.Error (179, Location, "`{0}' cannot declare a body because it is marked extern",
+                                               GetSignatureForError ());
+                                       return false;
+                               }
+
+                               if ((ModFlags & Modifiers.ABSTRACT) != 0) {
+                                       Report.Error (500, Location, "`{0}' cannot declare a body because it is marked abstract",
+                                               GetSignatureForError ());
+                                       return false;
+                               }
+                       } else {
+                               if ((ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN | Modifiers.PARTIAL)) == 0) {
+                                       if (RootContext.Version >= LanguageVersion.LINQ && this is Property.PropertyMethod) {
+                                               Report.Error (840, Location, "`{0}' must have a body because it is not marked abstract or extern. The property can be automatically implemented when you define both accessors",
+                                                             GetSignatureForError ());
+                                       } else {
+                                               Report.Error (501, Location, "`{0}' must have a body because it is not marked abstract, extern, or partial",
+                                                             GetSignatureForError ());
+                                       }
+                                       return false;
+                               }
+                       }
+
+                       return true;
+               }               
 
                public abstract bool Define ();
 
@@ -516,6 +531,10 @@ namespace Mono.CSharp {
                                        return value;
                                }
                        }
+                       
+                       // It's null for TypeParameter
+                       if (Parent == null)
+                               return false;                   
 
                        if (Parent.GetClsCompliantAttributeValue ()) {
                                caching_flags |= Flags.ClsCompliantAttributeTrue;
@@ -529,14 +548,17 @@ namespace Mono.CSharp {
                /// </summary>
                protected bool HasClsCompliantAttribute {
                        get {
+                               if ((caching_flags & Flags.HasCompliantAttribute_Undetected) != 0)
+                                       GetClsCompliantAttributeValue ();
+                               
                                return (caching_flags & Flags.HasClsCompliantAttribute) != 0;
                        }
                }
 
                /// <summary>
-               /// It helps to handle error 102 & 111 detection
+               /// Returns true when a member supports multiple overloads (methods, indexers, etc)
                /// </summary>
-               public virtual bool MarkForDuplicationCheck ()
+               public virtual bool EnableOverloadChecks (MemberCore overload)
                {
                        return false;
                }
@@ -550,7 +572,7 @@ namespace Mono.CSharp {
                protected virtual bool VerifyClsCompliance ()
                {
                        if (!IsClsComplianceRequired ()) {
-                               if (HasClsCompliantAttribute && RootContext.WarningLevel >= 2) {
+                               if (HasClsCompliantAttribute && Report.WarningLevel >= 2) {
                                        if (!IsExposedFromAssembly ())
                                                Report.Warning (3019, 2, Location, "CLS compliance checking will not be performed on `{0}' because it is not visible from outside this assembly", GetSignatureForError ());
                                        if (!CodeGen.Assembly.IsClsCompliant)
@@ -732,7 +754,7 @@ namespace Mono.CSharp {
                                return true;
                        }
 
-                       if (symbol.MarkForDuplicationCheck () && mc.MarkForDuplicationCheck ())
+                       if (symbol.EnableOverloadChecks (mc))
                                return true;
 
                        Report.SymbolRelatedToPreviousError (mc);
@@ -766,6 +788,10 @@ namespace Mono.CSharp {
                {
                        return (MemberCore)defined_names [name];
                }
+
+               public bool IsStaticClass {
+                       get { return (ModFlags & Modifiers.STATIC) != 0; }
+               }
                
                // 
                // root_types contains all the types.  All TopLevel types
@@ -805,7 +831,7 @@ namespace Mono.CSharp {
                ///  Should be overriten by the appropriate declaration space
                /// </remarks>
                public abstract TypeBuilder DefineType ();
-               
+
                /// <summary>
                ///   Define all members, but don't apply any attributes or do anything which may
                ///   access not-yet-defined classes.  This method also creates the MemberCache.
@@ -978,16 +1004,16 @@ namespace Mono.CSharp {
                                return AccessLevel.Internal;
                        
                        // By now, it must be nested
-                       AccessLevel parentLevel = TypeEffectiveAccessLevel (t.DeclaringType);
+                       AccessLevel parent_level = TypeEffectiveAccessLevel (t.DeclaringType);
                        
                        if (t.IsNestedPublic)
-                               return parentLevel;
+                               return parent_level;
                        if (t.IsNestedAssembly)
-                               return parentLevel & AccessLevel.Internal;
+                               return parent_level & AccessLevel.Internal;
                        if (t.IsNestedFamily)
-                               return parentLevel & AccessLevel.Protected;
+                               return parent_level & AccessLevel.Protected;
                        if (t.IsNestedFamORAssem)
-                               return parentLevel & AccessLevel.ProtectedOrInternal;
+                               return parent_level & AccessLevel.ProtectedOrInternal;
                        if (t.IsNestedFamANDAssem)
                                throw new NotImplementedException ("NestedFamANDAssem not implemented, cant make this kind of type from c# anyways");
                        
@@ -1014,9 +1040,17 @@ namespace Mono.CSharp {
                        while (p.IsArray || p.IsPointer || p.IsByRef)
                                p = TypeManager.GetElementType (p);
 
-                       if (TypeManager.IsGenericParameter(p))
-                               return true; // FIXME
+#if GMCS_SOURCE
+                       if (p.IsGenericParameter)
+                               return true;
 
+                       if (TypeManager.IsGenericType (p)) {
+                               foreach (Type t in p.GetGenericArguments ()) {
+                                       if (!AsAccessible (t, flags))
+                                               return false;
+                               }
+                       }
+#endif
                        AccessLevel pAccess = TypeEffectiveAccessLevel (p);
                        AccessLevel mAccess = this.EffectiveAccessLevel &
                                GetAccessLevelFromModifiers (flags);
@@ -1031,34 +1065,65 @@ namespace Mono.CSharp {
 
                private Type LookupNestedTypeInHierarchy (string name)
                {
+                       Type t = null;
                        // if the member cache has been created, lets use it.
                        // the member cache is MUCH faster.
-                       if (MemberCache != null)
-                               return MemberCache.FindNestedType (name);
+                       if (MemberCache != null) {
+                               t = MemberCache.FindNestedType (name);
+                               if (t == null)
+                                       return null;
+                               
+                       //
+                       // FIXME: This hack is needed because member cache does not work
+                       // with nested base generic types, it does only type name copy and
+                       // not type construction
+                       //
+#if !GMCS_SOURCE
+                               return t;
+#endif                         
+                       }
 
                        // no member cache. Do it the hard way -- reflection
-                       Type t = null;
                        for (Type current_type = TypeBuilder;
                             current_type != null && current_type != TypeManager.object_type;
                             current_type = current_type.BaseType) {
-                               current_type = TypeManager.DropGenericTypeArguments (current_type);
-                               if (current_type is TypeBuilder) {
-                                       TypeContainer tc = current_type == TypeBuilder
-                                               ? PartialContainer
-                                               : TypeManager.LookupTypeContainer (current_type);
+
+                               Type ct = TypeManager.DropGenericTypeArguments (current_type);
+                               if (ct is TypeBuilder) {
+                                       TypeContainer tc = ct == TypeBuilder
+                                               ? PartialContainer : TypeManager.LookupTypeContainer (ct);
                                        if (tc != null)
                                                t = tc.FindNestedType (name);
                                } else {
-                                       t = TypeManager.GetNestedType (current_type, name);
+                                       t = TypeManager.GetNestedType (ct, name);
                                }
 
-                               if (t != null && CheckAccessLevel (t))
+                               if ((t == null) || !CheckAccessLevel (t))
+                                       continue;
+
+#if GMCS_SOURCE
+                               if (!TypeManager.IsGenericType (current_type))
                                        return t;
+
+                               Type[] args = TypeManager.GetTypeArguments (current_type);
+                               Type[] targs = TypeManager.GetTypeArguments (t);
+                               for (int i = 0; i < args.Length; i++)
+                                       targs [i] = args [i];
+
+                               t = t.MakeGenericType (targs);
+#endif
+
+                               return t;
                        }
 
                        return null;
                }
 
+               public virtual ExtensionMethodGroupExpr LookupExtensionMethod (Type extensionType, string name)
+               {
+                       return null;
+               }
+
                //
                // Public function used to locate types.
                //
@@ -1089,8 +1154,13 @@ namespace Mono.CSharp {
                ///   be used while the type is still being created since it doesn't use the cache
                ///   and relies on the filter doing the member name check.
                /// </remarks>
-               public abstract MemberList FindMembers (MemberTypes mt, BindingFlags bf,
-                                                       MemberFilter filter, object criteria);
+               ///
+               // [Obsolete ("Only MemberCache approach should be used")]
+               public virtual MemberList FindMembers (MemberTypes mt, BindingFlags bf,
+                                                       MemberFilter filter, object criteria)
+               {
+                       throw new NotSupportedException ();
+               }
 
                /// <remarks>
                ///   If we have a MemberCache, return it.  This property may return null if the
@@ -1237,6 +1307,8 @@ namespace Mono.CSharp {
                        get {
                                if (!IsGeneric)
                                        throw new InvalidOperationException ();
+                               if ((PartialContainer != null) && (PartialContainer != this))
+                                       return PartialContainer.TypeParameters;
                                if (type_param_list == null)
                                        initialize_type_params ();
 
@@ -1248,6 +1320,8 @@ namespace Mono.CSharp {
                        get {
                                if (!IsGeneric)
                                        throw new InvalidOperationException ();
+                               if ((PartialContainer != null) && (PartialContainer != this))
+                                       return PartialContainer.CurrentTypeParameters;
                                if (type_params != null)
                                        return type_params;
                                else
@@ -1289,6 +1363,12 @@ namespace Mono.CSharp {
                        return null;
                }
 
+               // Used for error reporting only
+               public virtual Type LookupAnyGeneric (string typeName)
+               {
+                       return NamespaceEntry.NS.LookForAnyGenericType (typeName);
+               }
+
                public override string[] ValidAttributeTargets {
                        get { return attribute_targets; }
                }
@@ -1368,7 +1448,7 @@ namespace Mono.CSharp {
                        List = list;
                }
 
-               public static readonly MemberList Empty = new MemberList (new ArrayList ());
+               public static readonly MemberList Empty = new MemberList (new ArrayList (0));
 
                /// <summary>
                ///   Cast the MemberList into a MemberInfo[] array.
@@ -1536,13 +1616,6 @@ namespace Mono.CSharp {
                ///   this method is called multiple times with different BindingFlags.
                /// </remarks>
                MemberList GetMembers (MemberTypes mt, BindingFlags bf);
-
-               /// <summary>
-               ///   Return the container's member cache.
-               /// </summary>
-               MemberCache MemberCache {
-                       get;
-               }
        }
 
        /// <summary>
@@ -1586,7 +1659,7 @@ namespace Mono.CSharp {
                        Type type = container.Type;
                        if (!(type is TypeBuilder) && !type.IsInterface &&
                            // !(type.IsGenericType && (type.GetGenericTypeDefinition () is TypeBuilder)) &&
-                           !TypeManager.IsGenericType (type) &&
+                           !TypeManager.IsGenericType (type) && !TypeManager.IsGenericParameter (type) &&
                            (Container.BaseCache == null || Container.BaseCache.method_hash != null)) {
                                method_hash = new Hashtable ();
                                AddMethods (type);
@@ -1598,6 +1671,15 @@ namespace Mono.CSharp {
                        Timer.StopTimer (TimerType.CacheInit);
                }
 
+               public MemberCache (Type baseType, IMemberContainer container)
+               {
+                       this.Container = container;
+                       if (baseType == null)
+                               this.member_hash = new Hashtable ();
+                       else
+                               this.member_hash = SetupCache (TypeManager.LookupMemberCache (baseType));
+               }
+
                public MemberCache (Type[] ifaces)
                {
                        //
@@ -1614,23 +1696,63 @@ namespace Mono.CSharp {
                                AddCacheContents (TypeManager.LookupMemberCache (itype));
                }
 
+               public MemberCache (IMemberContainer container, Type base_class, Type[] ifaces)
+               {
+                       this.Container = container;
+
+                       // If we have a base class (we have a base class unless we're
+                       // TypeManager.object_type), we deep-copy its MemberCache here.
+                       if (Container.BaseCache != null)
+                               member_hash = SetupCache (Container.BaseCache);
+                       else
+                               member_hash = new Hashtable ();
+
+                       if (base_class != null)
+                               AddCacheContents (TypeManager.LookupMemberCache (base_class));
+                       if (ifaces != null) {
+                               foreach (Type itype in ifaces) {
+                                       MemberCache cache = TypeManager.LookupMemberCache (itype);
+                                       if (cache != null)
+                                               AddCacheContents (cache);
+                               }
+                       }
+               }
+
                /// <summary>
                ///   Bootstrap this member cache by doing a deep-copy of our base.
                /// </summary>
                static Hashtable SetupCache (MemberCache base_class)
                {
-                       Hashtable hash = new Hashtable ();
-
                        if (base_class == null)
-                               return hash;
+                               return new Hashtable ();
 
+                       Hashtable hash = new Hashtable (base_class.member_hash.Count);
                        IDictionaryEnumerator it = base_class.member_hash.GetEnumerator ();
                        while (it.MoveNext ()) {
-                               hash [it.Key] = ((ArrayList) it.Value).Clone ();
+                               hash.Add (it.Key, ((ArrayList) it.Value).Clone ());
                         }
                                 
                        return hash;
                }
+               
+               //
+               // Converts ModFlags to BindingFlags
+               //
+               static BindingFlags GetBindingFlags (int modifiers)
+               {
+                       BindingFlags bf;
+                       if ((modifiers & Modifiers.STATIC) != 0)
+                               bf = BindingFlags.Static;
+                       else
+                               bf = BindingFlags.Instance;
+
+                       if ((modifiers & Modifiers.PRIVATE) != 0)
+                               bf |= BindingFlags.NonPublic;
+                       else
+                               bf |= BindingFlags.Public;
+
+                       return bf;
+               }               
 
                /// <summary>
                ///   Add the contents of `cache' to the member_hash.
@@ -1683,6 +1805,46 @@ namespace Mono.CSharp {
                        AddMembers (mt, BindingFlags.Instance | BindingFlags.NonPublic, container);
                }
 
+               public void AddMember (MemberInfo mi, MemberCore mc)
+               {
+                       AddMember (mi.MemberType, GetBindingFlags (mc.ModFlags), Container, mi.Name, mi);
+               }
+
+               public void AddGenericMember (MemberInfo mi, MemberCore mc)
+               {
+                       AddMember (mi.MemberType, GetBindingFlags (mc.ModFlags), Container, mc.MemberName.Basename, mi);
+               }
+
+               public void AddNestedType (DeclSpace type)
+               {
+                       AddMember (MemberTypes.NestedType, GetBindingFlags (type.ModFlags), (IMemberContainer) type.Parent,
+                               type.TypeBuilder.Name, type.TypeBuilder);
+               }
+
+               public void AddInterface (MemberCache baseCache)
+               {
+                       if (baseCache.member_hash.Count > 0)
+                               AddCacheContents (baseCache);
+               }
+
+               void AddMember (MemberTypes mt, BindingFlags bf, IMemberContainer container,
+                               string name, MemberInfo member)
+               {
+                       // We use a name-based hash table of ArrayList's.
+                       ArrayList list = (ArrayList) member_hash [name];
+                       if (list == null) {
+                               list = new ArrayList ();
+                               member_hash.Add (name, list);
+                       }
+
+                       // When this method is called for the current class, the list will
+                       // already contain all inherited members from our base classes.
+                       // We cannot add new members in front of the list since this'd be an
+                       // expensive operation, that's why the list is sorted in reverse order
+                       // (ie. members from the current class are coming last).
+                       list.Add (new CacheEntry (container, member, mt, bf));
+               }
+
                /// <summary>
                ///   Add all members from class `container' with the requested MemberTypes and
                ///   BindingFlags to the cache.  This method is called multiple times with different
@@ -1695,23 +1857,13 @@ namespace Mono.CSharp {
                        foreach (MemberInfo member in members) {
                                string name = member.Name;
 
-                               int pos = name.IndexOf ('<');
-                               if (pos > 0)
-                                       name = name.Substring (0, pos);
+                               AddMember (mt, bf, container, name, member);
 
-                               // We use a name-based hash table of ArrayList's.
-                               ArrayList list = (ArrayList) member_hash [name];
-                               if (list == null) {
-                                       list = new ArrayList ();
-                                       member_hash.Add (name, list);
+                               if (member is MethodInfo) {
+                                       string gname = TypeManager.GetMethodName ((MethodInfo) member);
+                                       if (gname != name)
+                                               AddMember (mt, bf, container, gname, member);
                                }
-
-                               // When this method is called for the current class, the list will
-                               // already contain all inherited members from our base classes.
-                               // We cannot add new members in front of the list since this'd be an
-                               // expensive operation, that's why the list is sorted in reverse order
-                               // (ie. members from the current class are coming last).
-                               list.Add (new CacheEntry (container, member, mt, bf));
                        }
                }
 
@@ -1857,12 +2009,14 @@ namespace Mono.CSharp {
                        Property        = 0x200,
                        NestedType      = 0x400,
 
+                       NotExtensionMethod      = 0x800,
+
                        MaskType        = Constructor|Event|Field|Method|Property|NestedType
                }
 
                protected class CacheEntry {
                        public readonly IMemberContainer Container;
-                       public readonly EntryType EntryType;
+                       public EntryType EntryType;
                        public readonly MemberInfo Member;
 
                        public CacheEntry (IMemberContainer container, MemberInfo member,
@@ -1932,7 +2086,7 @@ namespace Mono.CSharp {
                {
                        if (using_global)
                                throw new Exception ();
-                       
+
                        bool declared_only = (bf & BindingFlags.DeclaredOnly) != 0;
                        bool method_search = mt == MemberTypes.Method;
                        // If we have a method cache and we aren't already doing a method-only search,
@@ -2080,14 +2234,9 @@ namespace Mono.CSharp {
                        return null;
                }
 
-               public MemberInfo FindBaseEvent (Type invocationType, string name)
+               public MemberInfo FindBaseEvent (Type invocation_type, string name)
                {
-                       ArrayList applicable;
-                       if (method_hash != null)
-                               applicable = (ArrayList) method_hash [name];
-                       else
-                               applicable = (ArrayList) member_hash [name];
-                       
+                       ArrayList applicable = (ArrayList) member_hash [name];
                        if (applicable == null)
                                return null;
 
@@ -2106,16 +2255,62 @@ namespace Mono.CSharp {
 
                        return null;
                }
+
+               //
+               // Looks for extension methods with defined name and extension type
+               //
+               public ArrayList FindExtensionMethods (Type extensionType, string name, bool publicOnly)
+               {
+                       ArrayList entries;
+                       if (method_hash != null)
+                               entries = (ArrayList)method_hash [name];
+                       else
+                               entries = (ArrayList)member_hash [name];
+
+                       if (entries == null)
+                               return null;
+
+                       EntryType entry_type = EntryType.Static | EntryType.Method | EntryType.NotExtensionMethod;
+                       if (publicOnly) {
+                               entry_type |= EntryType.Public;
+                       }
+                       EntryType found_entry_type = entry_type & ~EntryType.NotExtensionMethod;
+
+                       ArrayList candidates = null;
+                       foreach (CacheEntry entry in entries) {
+                               if ((entry.EntryType & entry_type) == found_entry_type) {
+                                       MethodBase mb = (MethodBase)entry.Member;
+
+                                       IMethodData md = TypeManager.GetMethod (mb);
+                                       ParameterData pd = md == null ?
+                                               TypeManager.GetParameterData (mb) : md.ParameterInfo;
+
+                                       Type ex_type = pd.ExtensionMethodType;
+                                       if (ex_type == null) {
+                                               entry.EntryType |= EntryType.NotExtensionMethod;
+                                               continue;
+                                       }
+
+                                       //if (implicit conversion between ex_type and extensionType exist) {
+                                               if (candidates == null)
+                                                       candidates = new ArrayList (2);
+                                               candidates.Add (mb);
+                                       //}
+                               }
+                       }
+
+                       return candidates;
+               }
                
                //
-               // This finds the method or property for us to override. invocationType is the type where
+               // This finds the method or property for us to override. invocation_type is the type where
                // the override is going to be declared, name is the name of the method/property, and
-               // paramTypes is the parameters, if any to the method or property
+               // param_types is the parameters, if any to the method or property
                //
                // Because the MemberCache holds members from this class and all the base classes,
                // we can avoid tons of reflection stuff.
                //
-               public MemberInfo FindMemberToOverride (Type invocationType, string name, Type [] paramTypes, GenericMethod genericMethod, bool is_property)
+               public MemberInfo FindMemberToOverride (Type invocation_type, string name, Type [] param_types, GenericMethod generic_method, bool is_property)
                {
                        ArrayList applicable;
                        if (method_hash != null && !is_property)
@@ -2137,7 +2332,7 @@ namespace Mono.CSharp {
                                PropertyInfo pi = null;
                                MethodInfo mi = null;
                                FieldInfo fi = null;
-                               Type [] cmpAttrs = null;
+                               Type [] cmp_attrs = null;
                                
                                if (is_property) {
                                        if ((entry.EntryType & EntryType.Field) != 0) {
@@ -2145,14 +2340,14 @@ namespace Mono.CSharp {
 
                                                // TODO: For this case we ignore member type
                                                //fb = TypeManager.GetField (fi);
-                                               //cmpAttrs = new Type[] { fb.MemberType };
+                                               //cmp_attrs = new Type[] { fb.MemberType };
                                        } else {
                                                pi = (PropertyInfo) entry.Member;
-                                               cmpAttrs = TypeManager.GetArgumentTypes (pi);
+                                               cmp_attrs = TypeManager.GetArgumentTypes (pi);
                                        }
                                } else {
                                        mi = (MethodInfo) entry.Member;
-                                       cmpAttrs = TypeManager.GetParameterData (mi).Types;
+                                       cmp_attrs = TypeManager.GetParameterData (mi).Types;
                                }
 
                                if (fi != null) {
@@ -2166,8 +2361,8 @@ namespace Mono.CSharp {
                                                // A private method is Ok if we are a nested subtype.
                                                // The spec actually is not very clear about this, see bug 52458.
                                                //
-                                               if (!invocationType.Equals (entry.Container.Type) &&
-                                                   !TypeManager.IsNestedChildOf (invocationType, entry.Container.Type))
+                                               if (!invocation_type.Equals (entry.Container.Type) &&
+                                                   !TypeManager.IsNestedChildOf (invocation_type, entry.Container.Type))
                                                        continue;
                                                break;
                                        case FieldAttributes.FamANDAssem:
@@ -2185,14 +2380,14 @@ namespace Mono.CSharp {
                                //
                                // Check the arguments
                                //
-                               if (cmpAttrs.Length != paramTypes.Length)
+                               if (cmp_attrs.Length != param_types.Length)
                                        continue;
        
                                int j;
-                               for (j = 0; j < cmpAttrs.Length; ++j)
-                                       if (!TypeManager.IsEqual (paramTypes [j], cmpAttrs [j]))
+                               for (j = 0; j < cmp_attrs.Length; ++j)
+                                       if (!TypeManager.IsEqual (param_types [j], cmp_attrs [j]))
                                                break;
-                               if (j < cmpAttrs.Length)
+                               if (j < cmp_attrs.Length)
                                        continue;
 
                                //
@@ -2200,9 +2395,9 @@ namespace Mono.CSharp {
                                //
                                if (mi != null) {
                                        Type [] cmpGenArgs = TypeManager.GetGenericArguments (mi);
-                                       if (genericMethod == null && cmpGenArgs.Length != 0)
+                                       if (generic_method == null && cmpGenArgs.Length != 0)
                                                continue;
-                                       if (genericMethod != null && cmpGenArgs.Length != genericMethod.TypeParameters.Length)
+                                       if (generic_method != null && cmpGenArgs.Length != generic_method.TypeParameters.Length)
                                                continue;
                                }
 
@@ -2226,8 +2421,8 @@ namespace Mono.CSharp {
                                        // A private method is Ok if we are a nested subtype.
                                        // The spec actually is not very clear about this, see bug 52458.
                                        //
-                                       if (!invocationType.Equals (entry.Container.Type) &&
-                                           !TypeManager.IsNestedChildOf (invocationType, entry.Container.Type))
+                                       if (!invocation_type.Equals (entry.Container.Type) &&
+                                           !TypeManager.IsNestedChildOf (invocation_type, entry.Container.Type))
                                                continue;
                                        break;
                                case MethodAttributes.FamANDAssem:
@@ -2399,5 +2594,164 @@ namespace Mono.CSharp {
                                throw new NotImplementedException (result.ToString ());
                        }
                }
+
+               public bool CheckExistingMembersOverloads (MemberCore member, string name, Parameters parameters)
+               {
+                       ArrayList entries = (ArrayList)member_hash [name];
+                       if (entries == null)
+                               return true;
+
+                       int method_param_count = parameters.Count;
+                       for (int i = entries.Count - 1; i >= 0; --i) {
+                               CacheEntry ce = (CacheEntry) entries [i];
+
+                               if (ce.Container != member.Parent.PartialContainer)
+                                       return true;
+
+                               Type [] p_types;
+                               ParameterData pd = null;
+                               if ((ce.EntryType & EntryType.Property) != 0) {
+                                       p_types = TypeManager.GetArgumentTypes ((PropertyInfo) ce.Member);
+                               } else {
+                                       MethodBase mb = (MethodBase) ce.Member;
+#if GMCS_SOURCE                                        
+                                       // TODO: This is more like a hack, because we are adding generic methods
+                                       // twice with and without arity name
+                                       if (mb.IsGenericMethod && !member.MemberName.IsGeneric)
+                                               continue;
+#endif                                 
+                                       pd = TypeManager.GetParameterData (mb);
+                                       p_types = pd.Types;
+                               }
+
+                               if (p_types.Length != method_param_count)
+                                       continue;
+
+                               if (method_param_count > 0) {
+                                       int ii = method_param_count - 1;
+                                       Type type_a, type_b;
+                                       do {
+                                               type_a = parameters.ParameterType (ii);
+                                               type_b = p_types [ii];
+#if GMCS_SOURCE
+                                               if (type_a.IsGenericParameter && type_a.DeclaringMethod != null)
+                                                       type_a = null;
+
+                                               if (type_b.IsGenericParameter && type_b.DeclaringMethod != null)
+                                                       type_b = null;
+#endif
+                                       } while (type_a == type_b && ii-- != 0);
+
+                                       if (ii >= 0)
+                                               continue;
+
+                                       //
+                                       // Operators can differ in return type only
+                                       //
+                                       if (member is Operator) {
+                                               Operator op = TypeManager.GetMethod ((MethodBase) ce.Member) as Operator;
+                                               if (op != null && op.ReturnType != ((Operator) member).ReturnType)
+                                                       continue;
+                                       }
+
+                                       //
+                                       // Report difference in parameter modifiers only
+                                       //
+                                       if (pd != null && !(member is AbstractPropertyEventMethod)) {
+                                               ii = method_param_count;
+                                               while (ii-- != 0 && parameters.ParameterModifier (ii) == pd.ParameterModifier (ii) &&
+                                                       parameters.ExtensionMethodType == pd.ExtensionMethodType);
+
+                                               if (ii >= 0) {
+                                                       MethodCore mc = TypeManager.GetMethod ((MethodBase) ce.Member) as MethodCore;
+                                                       Report.SymbolRelatedToPreviousError (ce.Member);
+                                                       if ((member.ModFlags & Modifiers.PARTIAL) != 0 && (mc.ModFlags & Modifiers.PARTIAL) != 0) {
+                                                               if (parameters.HasParams || pd.HasParams) {
+                                                                       Report.Error (758, member.Location,
+                                                                               "A partial method declaration and partial method implementation cannot differ on use of `params' modifier");
+                                                               } else {
+                                                                       Report.Error (755, member.Location,
+                                                                               "A partial method declaration and partial method implementation must be both an extension method or neither");
+                                                               }
+                                                       } else {
+                                                               Report.Error (663, member.Location,
+                                                                       "An overloaded method `{0}' cannot differ on use of parameter modifiers only",
+                                                                       member.GetSignatureForError ());
+                                                       }
+                                                       return false;
+                                               }
+                                       }
+                               }
+
+                               if ((ce.EntryType & EntryType.Method) != 0) {
+                                       Method method_a = member as Method;
+                                       Method method_b = TypeManager.GetMethod ((MethodBase) ce.Member) as Method;
+                                       if (method_a != null && method_b != null && (method_a.ModFlags & method_b.ModFlags & Modifiers.PARTIAL) != 0) {
+                                               const int partial_modifiers = Modifiers.STATIC | Modifiers.UNSAFE;
+                                               if (method_a.IsPartialDefinition == method_b.IsPartialImplementation) {
+                                                       if ((method_a.ModFlags & partial_modifiers) == (method_b.ModFlags & partial_modifiers) ||
+                                                               method_a.Parent.IsInUnsafeScope && method_b.Parent.IsInUnsafeScope) {
+                                                               if (method_a.IsPartialImplementation) {
+                                                                       method_a.SetPartialDefinition (method_b);
+                                                                       entries.RemoveAt (i);
+                                                               } else {
+                                                                       method_b.SetPartialDefinition (method_a);
+                                                               }
+                                                               continue;
+                                                       }
+
+                                                       if ((method_a.ModFlags & Modifiers.STATIC) != (method_b.ModFlags & Modifiers.STATIC)) {
+                                                               Report.SymbolRelatedToPreviousError (ce.Member);
+                                                               Report.Error (763, member.Location,
+                                                                       "A partial method declaration and partial method implementation must be both `static' or neither");
+                                                       }
+
+                                                       Report.SymbolRelatedToPreviousError (ce.Member);
+                                                       Report.Error (764, member.Location,
+                                                               "A partial method declaration and partial method implementation must be both `unsafe' or neither");
+                                                       return false;
+                                               }
+
+                                               Report.SymbolRelatedToPreviousError (ce.Member);
+                                               if (method_a.IsPartialDefinition) {
+                                                       Report.Error (756, member.Location, "A partial method `{0}' declaration is already defined",
+                                                               member.GetSignatureForError ());
+                                               }
+
+                                               Report.Error (757, member.Location, "A partial method `{0}' implementation is already defined",
+                                                       member.GetSignatureForError ());
+                                               return false;
+                                       }
+
+                                       Report.SymbolRelatedToPreviousError (ce.Member);
+                                       IMethodData duplicate_member = TypeManager.GetMethod ((MethodBase) ce.Member);
+                                       if (member is Operator && duplicate_member is Operator) {
+                                               Report.Error (557, member.Location, "Duplicate user-defined conversion in type `{0}'",
+                                                       member.Parent.GetSignatureForError ());
+                                               return false;
+                                       }
+
+                                       bool is_reserved_a = member is AbstractPropertyEventMethod || member is Operator;
+                                       bool is_reserved_b = duplicate_member is AbstractPropertyEventMethod || duplicate_member is Operator;
+
+                                       if (is_reserved_a || is_reserved_b) {
+                                               Report.Error (82, member.Location, "A member `{0}' is already reserved",
+                                                       is_reserved_a ?
+                                                       TypeManager.GetFullNameSignature (ce.Member) :
+                                                       member.GetSignatureForError ());
+                                               return false;
+                                       }
+                               } else {
+                                       Report.SymbolRelatedToPreviousError (ce.Member);
+                               }
+                               
+                               Report.Error (111, member.Location,
+                                       "A member `{0}' is already defined. Rename this member or use different parameter types",
+                                       member.GetSignatureForError ());
+                               return false;
+                       }
+
+                       return true;
+               }
        }
 }