**** Merged r40699 from MCS ****

[mono.git] / mcs / gmcs / class.cs

//
// class.cs: Class and Struct handlers
//
// Authors: Miguel de Icaza (miguel@gnu.org)
//          Martin Baulig (martin@ximian.com)
//          Marek Safar (marek.safar@seznam.cz)
//
// Licensed under the terms of the GNU GPL
//
// (C) 2001, 2002, 2003 Ximian, Inc (http://www.ximian.com)
// (C) 2004 Novell, Inc
//
//
//  2002-10-11  Miguel de Icaza  <miguel@ximian.com>
//
//      * class.cs: Following the comment from 2002-09-26 to AddMethod, I
//      have fixed a remaining problem: not every AddXXXX was adding a
//      fully qualified name.  
//
//      Now everyone registers a fully qualified name in the DeclSpace as
//      being defined instead of the partial name.  
//
//      Downsides: we are slower than we need to be due to the excess
//      copies and the names being registered this way.  
//
//      The reason for this is that we currently depend (on the corlib
//      bootstrap for instance) that types are fully qualified, because
//      we dump all the types in the namespace, and we should really have
//      types inserted into the proper namespace, so we can only store the
//      basenames in the defined_names array.
//
//
#define CACHE
using System;
using System.Text;
using System.Collections;
using System.Collections.Specialized;
using System.Reflection;
using System.Reflection.Emit;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Security;
using System.Security.Permissions;
using System.Xml;

using Mono.CompilerServices.SymbolWriter;

namespace Mono.CSharp {

        public enum Kind {
                Root,
                Struct,
                Class,
                Interface
        }

        /// <summary>
        ///   This is the base class for structs and classes.  
        /// </summary>
        public abstract class TypeContainer : DeclSpace, IMemberContainer {

                public class MemberCoreArrayList: ArrayList
                {
                        /// <summary>
                        ///   Defines the MemberCore objects that are in this array
                        /// </summary>
                        public virtual void DefineContainerMembers ()
                        {
                                foreach (MemberCore mc in this) {
                                        mc.Define ();
                                }
                        }

                        public virtual void Emit ()
                        {
                                foreach (MemberCore mc in this)
                                        mc.Emit ();
                        }
                }

                public class MethodArrayList: MemberCoreArrayList
                {
                        [Flags]
                        enum CachedMethods {
                                Equals                  = 1,
                                GetHashCode             = 1 << 1
                        }
 
                        CachedMethods cached_method;
                        TypeContainer container;

                        public MethodArrayList (TypeContainer container)
                        {
                                this.container = container;
                        }
 
                        /// <summary>
                        /// Method container contains Equals method
                        /// </summary>
                        public bool HasEquals {
                                set {
                                        cached_method |= CachedMethods.Equals;
                                }
 
                                get {
                                        return (cached_method & CachedMethods.Equals) != 0;
                                }
                        }
 
                        /// <summary>
                        /// Method container contains GetHashCode method
                        /// </summary>
                        public bool HasGetHashCode {
                                set {
                                        cached_method |= CachedMethods.GetHashCode;
                                }
 
                                get {
                                        return (cached_method & CachedMethods.GetHashCode) != 0;
                                }
                        }
 
                        public override void DefineContainerMembers ()
                        {
                                base.DefineContainerMembers ();
 
                                if ((RootContext.WarningLevel >= 3) && HasEquals && !HasGetHashCode) {
                                        Report.Warning (659, container.Location, "'{0}' overrides Object.Equals(object) but does not override Object.GetHashCode()", container.GetSignatureForError ());
                                }
                        }
 
                }

                public sealed class IndexerArrayList: MemberCoreArrayList
                {
                        /// <summary>
                        /// The indexer name for this container
                        /// </summary>
                        public string IndexerName = DefaultIndexerName;

                        bool seen_normal_indexers = false;

                        TypeContainer container;

                        public IndexerArrayList (TypeContainer container)
                        {
                                this.container = container;
                        }

                        /// <summary>
                        /// Defines the indexers, and also verifies that the IndexerNameAttribute in the
                        /// class is consistent.  Either it is `Item' or it is the name defined by all the
                        /// indexers with the `IndexerName' attribute.
                        ///
                        /// Turns out that the IndexerNameAttribute is applied to each indexer,
                        /// but it is never emitted, instead a DefaultMember attribute is attached
                        /// to the class.
                        /// </summary>
                        public override void DefineContainerMembers()
                        {
                                base.DefineContainerMembers ();

                                string class_indexer_name = null;

                                //
                                // If there's both an explicit and an implicit interface implementation, the
                                // explicit one actually implements the interface while the other one is just
                                // a normal indexer.  See bug #37714.
                                //

                                // Invariant maintained by AddIndexer(): All explicit interface indexers precede normal indexers
                                foreach (Indexer i in this) {
                                        if (i.InterfaceType != null) {
                                                if (seen_normal_indexers)
                                                        throw new Exception ("Internal Error: 'Indexers' array not sorted properly.");
                                                continue;
                                        }

                                        seen_normal_indexers = true;

                                        if (class_indexer_name == null) {
                                                class_indexer_name = i.ShortName;
                                                continue;
                                        }

                                        if (i.ShortName != class_indexer_name)
                                                Report.Error (668, i.Location, "Two indexers have different names; the IndexerName attribute must be used with the same name on every indexer within a type");
                                }

                                if (class_indexer_name != null)
                                        IndexerName = class_indexer_name;
                        }

                        public override void Emit ()
                        {
                                base.Emit ();

                                if (!seen_normal_indexers)
                                        return;

                                CustomAttributeBuilder cb = new CustomAttributeBuilder (TypeManager.default_member_ctor, new string [] { IndexerName });
                                container.TypeBuilder.SetCustomAttribute (cb);
                        }
                }

                public class OperatorArrayList: MemberCoreArrayList
                {
                        TypeContainer container;

                        public OperatorArrayList (TypeContainer container)
                        {
                                this.container = container;
                        }

                        //
                        // Operator pair checking
                        //
                        class OperatorEntry
                        {
                                public int flags;
                                public Type ret_type;
                                public Type type1, type2;
                                public Operator op;
                                public Operator.OpType ot;
                                
                                public OperatorEntry (int f, Operator o)
                                {
                                        flags = f;

                                        ret_type = o.OperatorMethod.ReturnType;
                                        Type [] pt = o.OperatorMethod.ParameterTypes;
                                        type1 = pt [0];
                                        type2 = pt [1];
                                        op = o;
                                        ot = o.OperatorType;
                                }

                                public override int GetHashCode ()
                                {       
                                        return ret_type.GetHashCode ();
                                }

                                public override bool Equals (object o)
                                {
                                        OperatorEntry other = (OperatorEntry) o;

                                        if (other.ret_type != ret_type)
                                                return false;
                                        if (other.type1 != type1)
                                                return false;
                                        if (other.type2 != type2)
                                                return false;
                                        return true;
                                }
                        }
                                
                        //
                        // Checks that some operators come in pairs:
                        //  == and !=
                        // > and <
                        // >= and <=
                        // true and false
                        //
                        // They are matched based on the return type and the argument types
                        //
                        void CheckPairedOperators ()
                        {
                                Hashtable pairs = new Hashtable (null, null);
                                Operator true_op = null;
                                Operator false_op = null;
                                bool has_equality_or_inequality = false;
                                
                                // Register all the operators we care about.
                                foreach (Operator op in this){
                                        int reg = 0;
                                        
                                        switch (op.OperatorType){
                                        case Operator.OpType.Equality:
                                                reg = 1;
                                                has_equality_or_inequality = true;
                                                break;
                                        case Operator.OpType.Inequality:
                                                reg = 2;
                                                has_equality_or_inequality = true;
                                                break;

                                        case Operator.OpType.True:
                                                true_op = op;
                                                break;
                                        case Operator.OpType.False:
                                                false_op = op;
                                                break;
                                                
                                        case Operator.OpType.GreaterThan:
                                                reg = 1; break;
                                        case Operator.OpType.LessThan:
                                                reg = 2; break;
                                                
                                        case Operator.OpType.GreaterThanOrEqual:
                                                reg = 1; break;
                                        case Operator.OpType.LessThanOrEqual:
                                                reg = 2; break;
                                        }
                                        if (reg == 0)
                                                continue;

                                        OperatorEntry oe = new OperatorEntry (reg, op);

                                        object o = pairs [oe];
                                        if (o == null)
                                                pairs [oe] = oe;
                                        else {
                                                oe = (OperatorEntry) o;
                                                oe.flags |= reg;
                                        }
                                }

                                if (true_op != null){
                                        if (false_op == null)
                                                Report.Error (216, true_op.Location, "operator true requires a matching operator false");
                                } else if (false_op != null)
                                        Report.Error (216, false_op.Location, "operator false requires a matching operator true");
                                
                                //
                                // Look for the mistakes.
                                //
                                foreach (DictionaryEntry de in pairs){
                                        OperatorEntry oe = (OperatorEntry) de.Key;

                                        if (oe.flags == 3)
                                                continue;

                                        string s = "";
                                        switch (oe.ot){
                                        case Operator.OpType.Equality:
                                                s = "!=";
                                                break;
                                        case Operator.OpType.Inequality: 
                                                s = "==";
                                                break;
                                        case Operator.OpType.GreaterThan: 
                                                s = "<";
                                                break;
                                        case Operator.OpType.LessThan:
                                                s = ">";
                                                break;
                                        case Operator.OpType.GreaterThanOrEqual:
                                                s = "<=";
                                                break;
                                        case Operator.OpType.LessThanOrEqual:
                                                s = ">=";
                                                break;
                                        }
                                        Report.Error (216, oe.op.Location,
                                                        "The operator `" + oe.op + "' requires a matching operator `" + s + "' to also be defined");
                                }

                                if (has_equality_or_inequality && (RootContext.WarningLevel > 2)) {
                                        if (container.Methods == null || !container.Methods.HasEquals)
                                                Report.Warning (660, container.Location, "'{0}' defines operator == or operator != but does not override Object.Equals(object o)", container.GetSignatureForError ());
 
                                        if (container.Methods == null || !container.Methods.HasGetHashCode)
                                                Report.Warning (661, container.Location, "'{0}' defines operator == or operator != but does not override Object.GetHashCode()", container.GetSignatureForError ());
                                }
                        }

                        public override void DefineContainerMembers ()
                        {
                                base.DefineContainerMembers ();
                                CheckPairedOperators ();
                        }
                }


                // Whether this is a struct, class or interface
                public readonly Kind Kind;

                // Holds a list of classes and structures
                ArrayList types;

                // Holds the list of properties
                MemberCoreArrayList properties;

                // Holds the list of enumerations
                MemberCoreArrayList enums;

                // Holds the list of delegates
                MemberCoreArrayList delegates;
                
                // Holds the list of constructors
                protected MemberCoreArrayList instance_constructors;

                // Holds the list of fields
                MemberCoreArrayList fields;

                // Holds a list of fields that have initializers
                protected ArrayList initialized_fields;

                // Holds a list of static fields that have initializers
                protected ArrayList initialized_static_fields;

                // Holds the list of constants
                MemberCoreArrayList constants;

                // Holds the list of
                MemberCoreArrayList interfaces;

                // Holds the methods.
                MethodArrayList methods;

                // Holds the events
                protected MemberCoreArrayList events;

                // Holds the indexers
                IndexerArrayList indexers;

                // Holds the operators
                MemberCoreArrayList operators;

                // Holds the iterators
                ArrayList iterators;

                // Holds the parts of a partial class;
                ArrayList parts;

                //
                // Pointers to the default constructor and the default static constructor
                //
                protected Constructor default_constructor;
                protected Constructor default_static_constructor;

                //
                // Whether we have at least one non-static field
                //
                bool have_nonstatic_fields = false;
                
                //
                // This one is computed after we can distinguish interfaces
                // from classes from the arraylist `type_bases' 
                //
                string base_class_name;
                TypeExpr base_type;

                ArrayList type_bases;

                bool members_defined;
                bool members_defined_ok;

                // The interfaces we implement.
                protected Type[] ifaces;
                protected Type ptype;

                // The base member cache and our member cache
                MemberCache base_cache;
                MemberCache member_cache;

                public const string DefaultIndexerName = "Item";

                Type GenericType;

                public TypeContainer (NamespaceEntry ns, TypeContainer parent, MemberName name,
                                      Attributes attrs, Kind kind, Location l)
                        : base (ns, parent, name, attrs, l)
                {
                        this.Kind = kind;

                        types = new ArrayList ();

                        base_class_name = null;
                }

                public bool AddToMemberContainer (MemberCore symbol)
                {
                        return AddToContainer (symbol, String.Concat (Name, '.', symbol.Name), symbol.Name);
                }

                bool AddToTypeContainer (DeclSpace ds)
                {
                        return AddToContainer (ds, ds.Name, ds.Basename);
                }

                public void AddConstant (Const constant)
                {
                        if (!AddToMemberContainer (constant))
                                return;

                        if (constants == null)
                                constants = new MemberCoreArrayList ();

                        constants.Add (constant);
                }

                public void AddEnum (Mono.CSharp.Enum e)
                {
                        if (!AddToTypeContainer (e))
                                return;

                        if (enums == null)
                                enums = new MemberCoreArrayList ();

                        enums.Add (e);
                }
                
                public void AddClassOrStruct (TypeContainer c)
                {
                        if (!AddToTypeContainer (c))
                                return;

                        types.Add (c);
                }

                public void AddDelegate (Delegate d)
                {
                        if (!AddToTypeContainer (d))
                                return;

                        if (delegates == null)
                                delegates = new MemberCoreArrayList ();
                        
                        delegates.Add (d);
                }

                public void AddMethod (Method method)
                {
                        if (!AddToMemberContainer (method))
                                return;

                        if (methods == null)
                                methods = new MethodArrayList (this);

                        if (method.Name.IndexOf ('.') != -1)
                                methods.Insert (0, method);
                        else 
                                methods.Add (method);
                }

                public void AddConstructor (Constructor c)
                {
                        if (c.Name != Basename) {
                                Report.Error (1520, c.Location, "Class, struct, or interface method must have a return type");
                        }

                        bool is_static = (c.ModFlags & Modifiers.STATIC) != 0;
                        
                        if (is_static){
                                if (default_static_constructor != null) {
                                        Report.SymbolRelatedToPreviousError (default_static_constructor);
                                        Report.Error (111, c.Location, "Type '{0}' already defines a member " +
                                                      "called '{1}' with the same parameter types", Name, c.Name);
                                        return;
                                }

                                default_static_constructor = c;
                        } else {
                                if (c.IsDefault ()){
                                        if (default_constructor != null) {
                                                Report.SymbolRelatedToPreviousError (default_constructor);
                                                Report.Error (111, c.Location, "Type '{0}' already defines a member " +
                                                      "called '{1}' with the same parameter types", Name, c.Name);
                                                return;
                                        }
                                        default_constructor = c;
                                }
                                
                                if (instance_constructors == null)
                                        instance_constructors = new MemberCoreArrayList ();
                                
                                instance_constructors.Add (c);
                        }
                }
                
                public void AddInterface (TypeContainer iface)
                {
                        if (!AddToTypeContainer (iface))
                                return;

                        if (interfaces == null) {
                                interfaces = new MemberCoreArrayList ();
                        }

                        interfaces.Add (iface);
                }

                public void AddField (FieldMember field)
                {
                        if (!AddToMemberContainer (field))
                                return;

                        if (fields == null)
                                fields = new MemberCoreArrayList ();
                        
                        fields.Add (field);
                        
                        if (field.HasInitializer){
                                if ((field.ModFlags & Modifiers.STATIC) != 0){
                                        if (initialized_static_fields == null)
                                                initialized_static_fields = new ArrayList ();

                                        initialized_static_fields.Add (field);

                                } else {
                                        if (initialized_fields == null)
                                                initialized_fields = new ArrayList ();
                                
                                        initialized_fields.Add (field);
                                }
                        }

                        if ((field.ModFlags & Modifiers.STATIC) == 0)
                                have_nonstatic_fields = true;
                }

                public void AddProperty (Property prop)
                {
                        if (!AddToMemberContainer (prop) || 
                                !AddToMemberContainer (prop.Get) || !AddToMemberContainer (prop.Set))
                                return;

                        if (properties == null)
                                properties = new MemberCoreArrayList ();

                        if (prop.Name.IndexOf ('.') != -1)
                                properties.Insert (0, prop);
                        else
                                properties.Add (prop);
                }

                public void AddEvent (Event e)
                {
                        if (!AddToMemberContainer (e))
                                return;

                        if (e is EventProperty) {
                                if (!AddToMemberContainer (e.Add))
                                        return;

                                if (!AddToMemberContainer (e.Remove))
                                        return;
                        }

                        if (events == null)
                                events = new MemberCoreArrayList ();

                        events.Add (e);
                }

                /// <summary>
                /// Indexer has special handling in constrast to other AddXXX because the name can be driven by IndexerNameAttribute
                /// </summary>
                public void AddIndexer (Indexer i)
                {
                        if (indexers == null)
                                indexers = new IndexerArrayList (this);

                        if (i.IsExplicitImpl)
                                indexers.Insert (0, i);
                        else
                                indexers.Add (i);
                }

                public void AddOperator (Operator op)
                {
                        if (!AddToMemberContainer (op))
                                return;

                        if (operators == null)
                                operators = new OperatorArrayList (this);

                        operators.Add (op);
                }

                public void AddIterator (Iterator i)
                {
                        if (iterators == null)
                                iterators = new ArrayList ();

                        iterators.Add (i);
                }

                public void AddType (TypeContainer tc)
                {
                        types.Add (tc);
                }

                public void AddPart (ClassPart part)
                {
                        if (parts == null)
                                parts = new ArrayList ();

                        parts.Add (part);
                }

                public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
                {
                        if (a.Type == TypeManager.default_member_type) {
                                if (Indexers != null) {
                                        Report.Error (646, a.Location,
                                                      "Cannot specify the DefaultMember attribute on" +
                                                      " a type containing an indexer");
                                        return;
                                }
                        }
                        
                        base.ApplyAttributeBuilder (a, cb);
               } 

                public override AttributeTargets AttributeTargets {
                        get {
                                switch (Kind) {
                                case Kind.Class:
                                        return AttributeTargets.Class;
                                case Kind.Struct:
                                        return AttributeTargets.Struct;
                                case Kind.Interface:
                                        return AttributeTargets.Interface;
                                default:
                                        throw new NotSupportedException ();
                                }
                        }
                }

                public ArrayList Types {
                        get {
                                return types;
                        }
                }

                public MethodArrayList Methods {
                        get {
                                return methods;
                        }
                }

                public ArrayList Constants {
                        get {
                                return constants;
                        }
                }

                public ArrayList Interfaces {
                        get {
                                return interfaces;
                        }
                }

                public ArrayList Iterators {
                        get {
                                return iterators;
                        }
                }
                
                public string Base {
                        get {
                                return base_class_name;
                        }
                }
                
                public ArrayList Bases {
                        get {
                                return type_bases;
                        }

                        set {
                                type_bases = value;
                        }
                }

                public ArrayList Fields {
                        get {
                                return fields;
                        }
                }

                public ArrayList InstanceConstructors {
                        get {
                                return instance_constructors;
                        }
                }

                public ArrayList Properties {
                        get {
                                return properties;
                        }
                }

                public ArrayList Events {
                        get {
                                return events;
                        }
                }
                
                public ArrayList Enums {
                        get {
                                return enums;
                        }
                }

                public ArrayList Indexers {
                        get {
                                return indexers;
                        }
                }

                public ArrayList Operators {
                        get {
                                return operators;
                        }
                }

                public ArrayList Delegates {
                        get {
                                return delegates;
                        }
                }
                
                public ArrayList Parts {
                        get {
                                return parts;
                        }
                }

                public virtual TypeAttributes TypeAttr {
                        get {
                                return Modifiers.TypeAttr (ModFlags, this);
                        }
                }

                public string IndexerName {
                        get {
                                return indexers == null ? DefaultIndexerName : indexers.IndexerName;
                        }
                }

                //
                // Emits the instance field initializers
                //
                public bool EmitFieldInitializers (EmitContext ec)
                {
                        ArrayList fields;
                        Expression instance_expr;
                        
                        if (ec.IsStatic){
                                fields = initialized_static_fields;
                                instance_expr = null;
                        } else {
                                fields = initialized_fields;
                                instance_expr = new This (Location.Null).Resolve (ec);
                        }

                        if (fields == null)
                                return true;

                        foreach (Field f in fields){
                                Expression e = f.GetInitializerExpression (ec);
                                if (e == null)
                                        return false;

                                Location l = f.Location;
                                FieldExpr fe = new FieldExpr (f.FieldBuilder, l);
                                fe.InstanceExpression = instance_expr;
                                fe.IsFieldInitializer = true;

                                ExpressionStatement a = new Assign (fe, e, l);

                                a = a.ResolveStatement (ec);
                                if (a == null)
                                        return false;

                                a.EmitStatement (ec);
                        }

                        return true;
                }
                
                //
                // Defines the default constructors
                //
                protected void DefineDefaultConstructor (bool is_static)
                {
                        Constructor c;

                        // The default constructor is public
                        // If the class is abstract, the default constructor is protected
                        // The default static constructor is private

                        int mods = Modifiers.PUBLIC;
                        if (is_static)
                                mods = Modifiers.STATIC | Modifiers.PRIVATE;
                        else if ((ModFlags & Modifiers.ABSTRACT) != 0)
                                mods = Modifiers.PROTECTED;

                        c = new Constructor (this, Basename, mods, Parameters.EmptyReadOnlyParameters,
                                             new ConstructorBaseInitializer (
                                                     null, Parameters.EmptyReadOnlyParameters,
                                                     Location),
                                             Location);
                        
                        AddConstructor (c);
                        
                        c.Block = new ToplevelBlock (null, Location);
                        
                }

                /// <remarks>
                ///  The pending methods that need to be implemented
                //   (interfaces or abstract methods)
                /// </remarks>
                public PendingImplementation Pending;

                public abstract void Register ();

                public abstract PendingImplementation GetPendingImplementations ();

                TypeExpr[] GetPartialBases (out TypeExpr base_class, out bool error)
                {
                        ArrayList ifaces = new ArrayList ();

                        base_class = null;
                        Location base_loc = Location.Null;

                        foreach (ClassPart part in parts) {
                                TypeExpr new_base_class;
                                TypeExpr[] new_ifaces;

                                new_ifaces = part.GetClassBases (out new_base_class, out error);
                                if (error)
                                        return null;

                                if ((base_class != null) && (new_base_class != null) &&
                                    !base_class.Equals (new_base_class)) {
                                        Report.Error (263, part.Location,
                                                      "Partial declarations of `{0}' must " +
                                                      "not specify different base classes",
                                                      Name);

                                        if (!Location.IsNull (base_loc))
                                                Report.LocationOfPreviousError (base_loc);

                                        error = true;
                                        return null;
                                }

                                if ((base_class == null) && (new_base_class != null)) {
                                        base_class = new_base_class;
                                        base_loc = part.Location;
                                }

                                if (new_ifaces == null)
                                        continue;

                                foreach (TypeExpr iface in new_ifaces) {
                                        bool found = false;
                                        foreach (TypeExpr old_iface in ifaces) {
                                                if (old_iface.Equals (iface)) {
                                                        found = true;
                                                        break;
                                                }
                                        }

                                        if (!found)
                                                ifaces.Add (iface);
                                }
                        }

                        error = false;

                        TypeExpr[] retval = new TypeExpr [ifaces.Count];
                        ifaces.CopyTo (retval, 0);
                        return retval;
                }

                TypeExpr[] GetNormalBases (out TypeExpr base_class, out bool error)
                {
                        base_class = null;

                        int count = Bases.Count;
                        int start = 0, i, j;

                        if (Kind == Kind.Class){
                                TypeExpr name = ResolveBaseTypeExpr (
                                        (Expression) Bases [0], false, Location);

                                if (name == null){
                                        error = true;
                                        return null;
                                }

                                if (!name.IsInterface) {
                                        // base_class could be a class, struct, enum, delegate.
                                        // This is validated in GetClassBases.
                                        base_class = name;
                                        start = 1;
                                }
                        }

                        TypeExpr [] ifaces = new TypeExpr [count-start];
                        
                        for (i = start, j = 0; i < count; i++, j++){
                                TypeExpr resolved = ResolveBaseTypeExpr ((Expression) Bases [i], false, Location);
                                if (resolved == null) {
                                        error = true;
                                        return null;
                                }
                                
                                ifaces [j] = resolved;
                        }

                        error = false;
                        return ifaces;
                }

                /// <summary>
                ///   This function computes the Base class and also the
                ///   list of interfaces that the class or struct @c implements.
                ///   
                ///   The return value is an array (might be null) of
                ///   interfaces implemented (as Types).
                ///   
                ///   The @base_class argument is set to the base object or null
                ///   if this is `System.Object'. 
                /// </summary>
                TypeExpr [] GetClassBases (out TypeExpr base_class, out bool error)
                {
                        int i;

                        error = false;

                        TypeExpr[] ifaces;

                        if (parts != null)
                                ifaces = GetPartialBases (out base_class, out error);
                        else if (Bases == null){
                                base_class = null;
                                return null;
                        } else
                                ifaces = GetNormalBases (out base_class, out error);

                        if (error)
                                return null;

                        if ((base_class != null) && (Kind == Kind.Class)){
                                if (base_class is TypeParameterExpr){
                                        Report.Error (
                                                689, base_class.Location,
                                                "Type parameter `{0}' can not be used as a " +
                                                "base class or interface", base_class.Name);
                                        error = true;
                                        return null;
                                }

                                if (IsGeneric && base_class.IsAttribute){
                                        Report.Error (
                                                698, base_class.Location,
                                                "A generic type cannot derive from `{0}' " +
                                                "because it is an attribute class",
                                                base_class.Name);
                                        error = true;
                                        return null;
                                }

                                if (base_class.Type.IsArray || base_class.Type.IsPointer) {
                                        Report.Error (1521, base_class.Location, "Invalid base type");
                                        error = true;
                                        return null;
                                }

                                if (base_class.IsSealed){
                                        error = true;
                                        Report.SymbolRelatedToPreviousError (base_class.Type);
                                        if (base_class.Type.IsAbstract) {
                                                Report.Error (709, Location, "'{0}': Cannot derive from static class", GetSignatureForError ());
                                        } else {
                                                Report.Error (509, Location, "'{0}': Cannot derive from sealed class", GetSignatureForError ());
                                        }
                                        return null;
                                }

                                if (!base_class.CanInheritFrom ()){
                                        Report.Error (644, Location,
                                                      "`{0}' cannot inherit from special class `{1}'",
                                                      Name, base_class.Name);
                                        error = true;
                                        return null;
                                }

                                if (!base_class.AsAccessible (this, ModFlags)) {
                                        Report.SymbolRelatedToPreviousError (base_class.Type);
                                        Report.Error (60, Location, "Inconsistent accessibility: base class '{0}' is less accessible than class '{1}'", 
                                                TypeManager.CSharpName (base_class.Type), GetSignatureForError ());
                                }
                        }

                        if (base_class != null)
                                base_class_name = base_class.Name;

                        if (ifaces == null)
                                return null;

                        int count = ifaces != null ? ifaces.Length : 0;

                        for (i = 0; i < count; i++) {
                                TypeExpr iface = (TypeExpr) ifaces [i];

                                if (!iface.IsInterface) {
                                        error = true;
                                        if (Kind != Kind.Class) {
                                                string what = Kind == Kind.Struct ? "Struct" : "Interface";
                                                
                                                Report.Error (527, Location,
                                                              "In {0} `{1}', type `{2}' is not "+
                                                              "an interface", what, Name, iface.Name);
                                        }
                                        else if (base_class != null)
                                                Report.Error (1721, Location,
                                                              "In Class `{0}', `{1}' is not an interface, and a base class has already been defined",
                                                              Name, iface.Name);
                                        else {
                                                Report.Error (1722, Location,
                                                              "In Class `{0}', `{1}' is not " +
                                                              "an interface, a base class must be listed first", Name, iface.Name);
                                        }
                                        continue;
                                }
  
                                for (int x = 0; x < i; x++) {
                                        if (iface.Equals (ifaces [x])) {
                                                Report.Error (528, Location,
                                                              "`{0}' is already listed in " +
                                                              "interface list", iface.Name);
                                                error = true;
                                        }
                                }

                                if ((Kind == Kind.Interface) &&
                                    !iface.AsAccessible (Parent, ModFlags)) {
                                        Report.Error (61, Location,
                                                      "Inconsistent accessibility: base " +
                                                      "interface `{0}' is less accessible " +
                                                      "than interface `{1}'", iface.Name,
                                                      Name);
                                        error = true;
                                }
                        }

                        if (error)
                                return null;

                        return ifaces;
                }

                bool CheckGenericInterfaces (Type[] ifaces)
                {
                        ArrayList already_checked = new ArrayList ();

                        for (int i = 0; i < ifaces.Length; i++) {
                                Type iface = ifaces [i];
                                foreach (Type t in already_checked) {
                                        if (iface == t)
                                                continue;

                                        Type[] infered = new Type [CountTypeParameters];
                                        if (!TypeManager.MayBecomeEqualGenericInstances (iface, t, infered, null))
                                                continue;

                                        Report.Error (
                                                695, Location,
                                                "`{0}' cannot implement both `{1}' and `{2}' " +
                                                "because they may unify for some type " +
                                                "parameter substitutions",
                                                TypeManager.GetFullName (TypeBuilder),
                                                iface, t);
                                        return false;
                                }

                                already_checked.Add (iface);
                        }

                        return true;
                }

                bool error = false;
                
                //
                // Defines the type in the appropriate ModuleBuilder or TypeBuilder.
                //
                public override TypeBuilder DefineType ()
                {
                        if (error)
                                return null;

                        if (TypeBuilder != null)
                                return TypeBuilder;

                        ec = new EmitContext (this, Mono.CSharp.Location.Null, null, null, ModFlags);

                        TypeAttributes type_attributes = TypeAttr;

                        try {
                                if (IsTopLevel){
                                        if (TypeManager.NamespaceClash (Name, Location)) {
                                                error = true;
                                                return null;
                                        }

                                        ModuleBuilder builder = CodeGen.Module.Builder;
                                        TypeBuilder = builder.DefineType (
                                                Name, type_attributes, null, null);
                                } else {
                                        TypeBuilder builder;
                                        if (Parent.TypeBuilder != null)
                                                builder = Parent.TypeBuilder;
                                        else
                                                builder = Parent.DefineType ();

                                        if (builder == null) {
                                                error = true;
                                                return null;
                                        }
                                
                                        TypeBuilder = builder.DefineNestedType (
                                                MemberName.Basename, type_attributes,
                                                null, null);
                                }
                        }
                        catch (ArgumentException) {
                                Report.RuntimeMissingSupport (Location, "static classes");
                                return null;
                        }

                        TypeManager.AddUserType (Name, TypeBuilder, this);

                        TypeExpr current_type = null;

                        if (IsGeneric) {
                                string[] param_names = new string [TypeParameters.Length];
                                for (int i = 0; i < TypeParameters.Length; i++)
                                        param_names [i] = TypeParameters [i].Name;

                                GenericTypeParameterBuilder[] gen_params;
                                gen_params = TypeBuilder.DefineGenericParameters (param_names);

                                int offset = CountTypeParameters - CurrentTypeParameters.Length;
                                for (int i = offset; i < gen_params.Length; i++)
                                        CurrentTypeParameters [i - offset].Define (gen_params [i]);

                                foreach (TypeParameter type_param in CurrentTypeParameters) {
                                        if (!type_param.Resolve (this)) {
                                                error = true;
                                                return null;
                                        }
                                }

                                for (int i = offset; i < gen_params.Length; i++)
                                        CurrentTypeParameters [i - offset].DefineConstraints ();

                                current_type = new ConstructedType (Name, TypeParameters, Location);

                                foreach (TypeParameter type_param in TypeParameters) {
                                        if (!type_param.DefineType (ec)) {
                                                error = true;
                                                return null;
                                        }
                                }

                                if (!CheckConstraints (ec)) {
                                        error = true;
                                        return null;
                                }
                        }

                        if ((Kind == Kind.Struct) && TypeManager.value_type == null)
                                throw new Exception ();

                        TypeExpr[] iface_exprs = GetClassBases (out base_type, out error);
                        if (error)
                                return null;

                        if (base_type == null) {
                                if (Kind == Kind.Class){
                                        if (RootContext.StdLib)
                                                base_type = TypeManager.system_object_expr;
                                        else if (Name != "System.Object")
                                                base_type = TypeManager.system_object_expr;
                                } else if (Kind == Kind.Struct){
                                        //
                                        // If we are compiling our runtime,
                                        // and we are defining ValueType, then our
                                        // base is `System.Object'.
                                        //
                                        if (!RootContext.StdLib && Name == "System.ValueType")
                                                base_type = TypeManager.system_object_expr;
                                        else if (Kind == Kind.Struct)
                                                base_type = TypeManager.system_valuetype_expr;
                                }
                        }

                        if (base_type != null) {
                                base_type = base_type.ResolveAsTypeTerminal (ec);
                                if (base_type == null) {
                                        error = true;
                                        return null;
                                }

                                ptype = base_type.Type;
                        }

                        if (!CheckRecursiveDefinition ()) {
                                error = true;
                                return null;
                        }

                        if (ptype != null)
                                TypeBuilder.SetParent (ptype);

                        //
                        // Structs with no fields need to have at least one byte.
                        // The right thing would be to set the PackingSize in a DefineType
                        // but there are no functions that allow interfaces *and* the size to
                        // be specified.
                        //

                        if ((Kind == Kind.Struct) && !have_nonstatic_fields){
                                TypeBuilder.DefineField ("$PRIVATE$", TypeManager.byte_type,
                                                         FieldAttributes.Private);
                        }

                        // add interfaces that were not added at type creation
                        if (iface_exprs != null) {
                                // FIXME: I think this should be ...ExpandInterfaces (Parent.EmitContext, ...).
                                //        However, if Parent == RootContext.Tree.Types, its NamespaceEntry will be null.
                                ifaces = TypeManager.ExpandInterfaces (ec, iface_exprs);
                                if (ifaces == null) {
                                        error = true;
                                        return null;
                                }

                                foreach (Type itype in ifaces)
                                        TypeBuilder.AddInterfaceImplementation (itype);

                                if (!CheckGenericInterfaces (ifaces)) {
                                        error = true;
                                        return null;
                                }

                                TypeManager.RegisterBuilder (TypeBuilder, ifaces);
                        }

                        if (IsGeneric) {
                                foreach (TypeParameter type_param in TypeParameters)
                                        if (!type_param.CheckDependencies (ec)) {
                                                error = true;
                                                return null;
                                        }
                        }

                        if (current_type != null) {
                                current_type = current_type.ResolveAsTypeTerminal (ec);
                                if (current_type == null) {
                                        error = true;
                                        return null;
                                }

                                CurrentType = current_type.Type;
                        }

                        //
                        // Finish the setup for the EmitContext
                        //
                        ec.ContainerType = TypeBuilder;

                        if ((base_type != null) && base_type.IsAttribute) {
                                RootContext.RegisterAttribute (this);
                        } else if (!(this is Iterator))
                                RootContext.RegisterOrder (this); 

                        if (!DefineNestedTypes ()) {
                                error = true;
                                return null;
                        }

                        return TypeBuilder;
                }

                protected virtual bool CheckConstraints (EmitContext ec)
                {
                        return true;
                }

                protected virtual bool DefineNestedTypes ()
                {
                        if (Interfaces != null) {
                                foreach (TypeContainer iface in Interfaces)
                                        if (iface.DefineType () == null)
                                                return false;
                        }
                        
                        if (Types != null) {
                                foreach (TypeContainer tc in Types)
                                        if (tc.DefineType () == null)
                                                return false;
                        }

                        if (Delegates != null) {
                                foreach (Delegate d in Delegates)
                                        if (d.DefineType () == null)
                                                return false;
                        }

                        if (Enums != null) {
                                foreach (Enum en in Enums)
                                        if (en.DefineType () == null)
                                                return false;
                        }

                        if (Parts != null) {
                                foreach (ClassPart part in Parts) {
                                        part.TypeBuilder = TypeBuilder;
                                        part.base_type = base_type;
                                        part.ec = new EmitContext (part, Mono.CSharp.Location.Null, null, null, ModFlags);
                                }
                        }

                        return true;
                }

                protected bool CheckRecursiveDefinition ()
                {
                        if (InTransit) {
                                Report.Error (146, Location,
                                              "Class definition is circular: `{0}'",
                                              GetSignatureForError ());
                                error = true;
                                return false;
                        }

                        InTransit = true;

                        Type parent = ptype;
                        if (parent != null) {
                                if (parent.IsGenericInstance)
                                        parent = parent.GetGenericTypeDefinition ();

                                TypeContainer ptc = TypeManager.LookupTypeContainer (parent);
                                if ((ptc != null) && !ptc.CheckRecursiveDefinition ())
                                        return false;
                        }

                        InTransit = false;
                        return true;
                }

                static void Error_KeywordNotAllowed (Location loc)
                {
                        Report.Error (1530, loc, "Keyword new not allowed for namespace elements");
                }

                /// <summary>
                ///   Populates our TypeBuilder with fields and methods
                /// </summary>
                public override bool DefineMembers (TypeContainer container)
                {
                        if (members_defined)
                                return members_defined_ok;

                        members_defined_ok = DoDefineMembers ();
                        members_defined = true;

                        return members_defined_ok;
                }

                protected virtual bool DoDefineMembers ()
                {
                        if (IsTopLevel) {
                                if ((ModFlags & Modifiers.NEW) != 0)
                                        Error_KeywordNotAllowed (Location);
                        } else {
                                // HACK: missing implemenation
                                // This is not fully functional. Better way how to handle this is to have recursive definition of containers
                                // instead of flat as we have now.
                                // Now we are not able to check inner attribute class because its parent had not been defined.

                                // TODO: remove this if
                                if (Parent.MemberCache != null) {
                                        MemberInfo conflict_symbol = Parent.MemberCache.FindMemberWithSameName (Basename, false, TypeBuilder);
                                        if (conflict_symbol == null) {
                                                if ((RootContext.WarningLevel >= 4) && ((ModFlags & Modifiers.NEW) != 0))
                                                        Report.Warning (109, Location, "The member '{0}' does not hide an inherited member. The new keyword is not required", GetSignatureForError ());
                                        } else {
                                                if ((ModFlags & Modifiers.NEW) == 0) {
                                                        Report.SymbolRelatedToPreviousError (conflict_symbol);
                                                        Report.Warning (108, Location, "The keyword new is required on '{0}' because it hides inherited member", GetSignatureForError ());
                                                }
                                        }
                                }
                        }

                        DefineContainerMembers (constants);
                        DefineContainerMembers (fields);

                        if ((Kind == Kind.Class) && !(this is ClassPart)){
                                if ((instance_constructors == null) &&
                                    !(this is StaticClass)) {
                                        if (default_constructor == null)
                                                DefineDefaultConstructor (false);
                                }

                                if (initialized_static_fields != null &&
                                    default_static_constructor == null)
                                        DefineDefaultConstructor (true);
                        }

                        if (Kind == Kind.Struct){
                                //
                                // Structs can not have initialized instance
                                // fields
                                //
                                if (initialized_static_fields != null &&
                                    default_static_constructor == null)
                                        DefineDefaultConstructor (true);

                                if (initialized_fields != null)
                                        ReportStructInitializedInstanceError ();
                        }

                        Pending = GetPendingImplementations ();

                        if (parts != null) {
                                foreach (ClassPart part in parts) {
                                        if (!part.DefineMembers (this))
                                                return false;
                                }
                        }
                        
                        //
                        // Constructors are not in the defined_names array
                        //
                        DefineContainerMembers (instance_constructors);

                        if (default_static_constructor != null)
                                default_static_constructor.Define ();

                        DefineContainerMembers (properties);
                        DefineContainerMembers (events);
                        DefineContainerMembers (indexers);
                        DefineContainerMembers (methods);
                        DefineContainerMembers (operators);
                        DefineContainerMembers (enums);
                        DefineContainerMembers (delegates);

                        if (CurrentType != null) {
                                GenericType = CurrentType;

                                ec.ContainerType = GenericType;
                        }


#if CACHE
                        if (!(this is ClassPart))
                                member_cache = new MemberCache (this);
#endif

                        if (parts != null) {
                                foreach (ClassPart part in parts)
                                        part.member_cache = member_cache;
                        }

                        if (iterators != null) {
                                foreach (Iterator iterator in iterators) {
                                        if (iterator.DefineType () == null)
                                                return false;
                                }

                                foreach (Iterator iterator in iterators) {
                                        if (!iterator.DefineMembers (this))
                                                return false;
                                }
                        }

                        return true;
                }

                void ReportStructInitializedInstanceError ()
                {
                        string n = TypeBuilder.FullName;
                        
                        foreach (Field f in initialized_fields){
                                Report.Error (
                                        573, Location,
                                        "`" + n + "." + f.Name + "': can not have " +
                                        "instance field initializers in structs");
                        }
                }

                protected virtual void DefineContainerMembers (MemberCoreArrayList mcal)
                {
                        if (mcal != null)
                                mcal.DefineContainerMembers ();
                }

                public override bool Define ()
                {
                        if (parts != null) {
                                foreach (ClassPart part in parts) {
                                        if (!part.Define ())
                                                return false;
                                }
                        }

                        return true;
                }

                public MemberInfo FindBaseMemberWithSameName (string name, bool ignore_methods)
                {
                        return BaseCache.FindMemberWithSameName (name, ignore_methods, null);
                }

                /// <summary>
                ///   This function is based by a delegate to the FindMembers routine
                /// </summary>
                static bool AlwaysAccept (MemberInfo m, object filterCriteria)
                {
                        return true;
                }

                /// <summary>
                ///   This filter is used by FindMembers, and we just keep
                ///   a global for the filter to `AlwaysAccept'
                /// </summary>
                static MemberFilter accepting_filter;

                
                static TypeContainer ()
                {
                        accepting_filter = new MemberFilter (AlwaysAccept);
                }
                
                public MethodInfo[] GetMethods ()
                {
                        ArrayList members = new ArrayList ();

                        DefineMembers (null);

                        if (methods != null) {
                                int len = methods.Count;
                                for (int i = 0; i < len; i++) {
                                        Method m = (Method) methods [i];

                                        members.Add (m.MethodBuilder);
                                }
                        }

                        if (operators != null) {
                                int len = operators.Count;
                                for (int i = 0; i < len; i++) {
                                        Operator o = (Operator) operators [i];

                                        members.Add (o.OperatorMethodBuilder);
                                }
                        }

                        if (properties != null) {
                                int len = properties.Count;
                                for (int i = 0; i < len; i++) {
                                        Property p = (Property) properties [i];

                                        if (p.GetBuilder != null)
                                                members.Add (p.GetBuilder);
                                        if (p.SetBuilder != null)
                                                members.Add (p.SetBuilder);
                                }
                        }
                                
                        if (indexers != null) {
                                int len = indexers.Count;
                                for (int i = 0; i < len; i++) {
                                        Indexer ix = (Indexer) indexers [i];

                                        if (ix.GetBuilder != null)
                                                members.Add (ix.GetBuilder);
                                        if (ix.SetBuilder != null)
                                                members.Add (ix.SetBuilder);
                                }
                        }

                        if (events != null) {
                                int len = events.Count;
                                for (int i = 0; i < len; i++) {
                                        Event e = (Event) events [i];

                                        if (e.AddBuilder != null)
                                                members.Add (e.AddBuilder);
                                        if (e.RemoveBuilder != null)
                                                members.Add (e.RemoveBuilder);
                                }
                        }

                        MethodInfo[] retMethods = new MethodInfo [members.Count];
                        members.CopyTo (retMethods, 0);
                        return retMethods;
                }
                
                // Indicated whether container has StructLayout attribute set Explicit
                public virtual bool HasExplicitLayout {
                        get {
                                return false;
                        }
                }
                
                /// <summary>
                ///   This method returns the members of this type just like Type.FindMembers would
                ///   Only, we need to use this for types which are _being_ defined because MS' 
                ///   implementation can't take care of that.
                /// </summary>
                //
                // FIXME: return an empty static array instead of null, that cleans up
                // some code and is consistent with some coding conventions I just found
                // out existed ;-)
                //
                //
                // Notice that in various cases we check if our field is non-null,
                // something that would normally mean that there was a bug elsewhere.
                //
                // The problem happens while we are defining p-invoke methods, as those
                // will trigger a FindMembers, but this happens before things are defined
                //
                // Since the whole process is a no-op, it is fine to check for null here.
                //
                public override MemberList FindMembers (MemberTypes mt, BindingFlags bf,
                                                        MemberFilter filter, object criteria)
                {
                        ArrayList members = null;

                        int modflags = 0;
                        if ((bf & BindingFlags.Public) != 0)
                                modflags |= Modifiers.PUBLIC | Modifiers.PROTECTED |
                                        Modifiers.INTERNAL;
                        if ((bf & BindingFlags.NonPublic) != 0)
                                modflags |= Modifiers.PRIVATE;

                        int static_mask = 0, static_flags = 0;
                        switch (bf & (BindingFlags.Static | BindingFlags.Instance)) {
                        case BindingFlags.Static:
                                static_mask = static_flags = Modifiers.STATIC;
                                break;

                        case BindingFlags.Instance:
                                static_mask = Modifiers.STATIC;
                                static_flags = 0;
                                break;

                        default:
                                static_mask = static_flags = 0;
                                break;
                        }

                        Timer.StartTimer (TimerType.TcFindMembers);

                        if (filter == null)
                                filter = accepting_filter; 

                        if ((mt & MemberTypes.Field) != 0) {
                                if (fields != null) {
                                        int len = fields.Count;
                                        for (int i = 0; i < len; i++) {
                                                FieldMember f = (FieldMember) fields [i];
                                                
                                                if ((f.ModFlags & modflags) == 0)
                                                        continue;
                                                if ((f.ModFlags & static_mask) != static_flags)
                                                        continue;

                                                FieldBuilder fb = f.FieldBuilder;
                                                if (fb != null && filter (fb, criteria) == true) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                        members.Add (fb);
                                        }
                                }
                                }

                                if (constants != null) {
                                        int len = constants.Count;
                                        for (int i = 0; i < len; i++) {
                                                Const con = (Const) constants [i];
                                                
                                                if ((con.ModFlags & modflags) == 0)
                                                        continue;
                                                if ((con.ModFlags & static_mask) != static_flags)
                                                        continue;

                                                FieldBuilder fb = con.FieldBuilder;
                                                if (fb == null) {
                                                        if (con.Define ())
                                                                fb = con.FieldBuilder;
                                                }
                                                if (fb != null && filter (fb, criteria) == true) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                        members.Add (fb);
                                        }
                                }
                        }
                        }

                        if ((mt & MemberTypes.Method) != 0) {
                                if (methods != null) {
                                        int len = methods.Count;
                                        for (int i = 0; i < len; i++) {
                                                Method m = (Method) methods [i];
                                                
                                                if ((m.ModFlags & modflags) == 0)
                                                        continue;
                                                if ((m.ModFlags & static_mask) != static_flags)
                                                        continue;
                                                
                                                MethodBuilder mb = m.MethodBuilder;

                                                if (mb != null && filter (mb, criteria) == true) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                        members.Add (mb);
                                        }
                                }
                                }

                                if (operators != null) {
                                        int len = operators.Count;
                                        for (int i = 0; i < len; i++) {
                                                Operator o = (Operator) operators [i];

                                                if ((o.ModFlags & modflags) == 0)
                                                        continue;
                                                if ((o.ModFlags & static_mask) != static_flags)
                                                        continue;
                                                
                                                MethodBuilder ob = o.OperatorMethodBuilder;
                                                if (ob != null && filter (ob, criteria) == true) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                        members.Add (ob);
                                        }
                                }
                                }

                                if (properties != null) {
                                        int len = properties.Count;
                                        for (int i = 0; i < len; i++) {
                                                Property p = (Property) properties [i];

                                                if ((p.ModFlags & modflags) == 0)
                                                        continue;
                                                if ((p.ModFlags & static_mask) != static_flags)
                                                        continue;
                                                
                                                MethodBuilder b;

                                                b = p.GetBuilder;
                                                if (b != null && filter (b, criteria) == true) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                        members.Add (b);
                                                }

                                                b = p.SetBuilder;
                                                if (b != null && filter (b, criteria) == true) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                        members.Add (b);
                                        }
                                }
                                }
                                
                                if (indexers != null) {
                                        int len = indexers.Count;
                                        for (int i = 0; i < len; i++) {
                                                Indexer ix = (Indexer) indexers [i];
                                
                                                if ((ix.ModFlags & modflags) == 0)
                                                        continue;
                                                if ((ix.ModFlags & static_mask) != static_flags)
                                                        continue;
                                                
                                                MethodBuilder b;

                                                b = ix.GetBuilder;
                                                if (b != null && filter (b, criteria) == true) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                        members.Add (b);
                                                }

                                                b = ix.SetBuilder;
                                                if (b != null && filter (b, criteria) == true) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                        members.Add (b);
                                        }
                                }
                        }
                        }

                        if ((mt & MemberTypes.Event) != 0) {
                                if (events != null) {
                                        int len = events.Count;
                                        for (int i = 0; i < len; i++) {
                                                Event e = (Event) events [i];
                                                
                                                if ((e.ModFlags & modflags) == 0)
                                                        continue;
                                                if ((e.ModFlags & static_mask) != static_flags)
                                                        continue;

                                                MemberInfo eb = e.EventBuilder;
                                                if (eb != null && filter (eb, criteria) == true) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                        members.Add (e.EventBuilder);
                                        }
                        }
                                }
                        }
                        
                        if ((mt & MemberTypes.Property) != 0){
                                if (properties != null) {
                                        int len = properties.Count;
                                        for (int i = 0; i < len; i++) {
                                                Property p = (Property) properties [i];
                                                
                                                if ((p.ModFlags & modflags) == 0)
                                                        continue;
                                                if ((p.ModFlags & static_mask) != static_flags)
                                                        continue;

                                                MemberInfo pb = p.PropertyBuilder;
                                                if (pb != null && filter (pb, criteria) == true) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                        members.Add (p.PropertyBuilder);
                                                }
                                        }
                                }

                                if (indexers != null) {
                                        int len = indexers.Count;
                                        for (int i = 0; i < len; i++) {
                                                Indexer ix = (Indexer) indexers [i];

                                                if ((ix.ModFlags & modflags) == 0)
                                                        continue;
                                                if ((ix.ModFlags & static_mask) != static_flags)
                                                        continue;

                                                MemberInfo ib = ix.PropertyBuilder;
                                                if (ib != null && filter (ib, criteria) == true) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                        members.Add (ix.PropertyBuilder);
                                                }
                                        }
                        }
                        }
                        
                        if ((mt & MemberTypes.NestedType) != 0) {
                                if (types != null) {
                                        int len = types.Count;
                                        for (int i = 0; i < len; i++) {
                                                TypeContainer t = (TypeContainer) types [i];
                                                
                                                if ((t.ModFlags & modflags) == 0)
                                                        continue;

                                                TypeBuilder tb = t.TypeBuilder;
                                                if (tb == null)
                                                        tb = t.DefineType ();

                                                if (tb != null && (filter (tb, criteria) == true)) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                                members.Add (tb);
                                        }
                                }
                                }

                                if (enums != null) {
                                        int len = enums.Count;
                                        for (int i = 0; i < len; i++) {
                                                Enum en = (Enum) enums [i];

                                                if ((en.ModFlags & modflags) == 0)
                                                        continue;

                                                TypeBuilder tb = en.TypeBuilder;
                                                if (tb != null && (filter (tb, criteria) == true)) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                        members.Add (tb);
                                        }
                                }
                                }
                                
                                if (delegates != null) {
                                        int len = delegates.Count;
                                        for (int i = 0; i < len; i++) {
                                                Delegate d = (Delegate) delegates [i];
                                
                                                if ((d.ModFlags & modflags) == 0)
                                                        continue;

                                                TypeBuilder tb = d.TypeBuilder;
                                                if (tb != null && (filter (tb, criteria) == true)) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                        members.Add (tb);
                                        }
                                }
                                }

                                if (interfaces != null) {
                                        int len = interfaces.Count;
                                        for (int i = 0; i < len; i++) {
                                                TypeContainer iface = (TypeContainer) interfaces [i];

                                                if ((iface.ModFlags & modflags) == 0)
                                                        continue;

                                                TypeBuilder tb = iface.TypeBuilder;
                                                if (tb != null && (filter (tb, criteria) == true)) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                        members.Add (tb);
                                        }
                                }
                        }
                        }

                        if ((mt & MemberTypes.Constructor) != 0){
                                if (((bf & BindingFlags.Instance) != 0) && (instance_constructors != null)){
                                        int len = instance_constructors.Count;
                                        for (int i = 0; i < len; i++) {
                                                Constructor c = (Constructor) instance_constructors [i];
                                                
                                                ConstructorBuilder cb = c.ConstructorBuilder;
                                                if (cb != null && filter (cb, criteria) == true) {
                                                        if (members == null)
                                                                members = new ArrayList ();
                                                        
                                                                members.Add (cb);
                                        }
                                }
                                }

                                if (((bf & BindingFlags.Static) != 0) && (default_static_constructor != null)){
                                        ConstructorBuilder cb =
                                                default_static_constructor.ConstructorBuilder;
                                        
                                        if (cb != null && filter (cb, criteria) == true) {
                                                if (members == null)
                                                        members = new ArrayList ();
                                                
                                                members.Add (cb);
                                }
                        }
                        }

                        //
                        // Lookup members in base if requested.
                        //
                        if ((bf & BindingFlags.DeclaredOnly) == 0) {
                                if (TypeBuilder.BaseType != null) {
                                MemberList list = FindMembers (TypeBuilder.BaseType, mt, bf, filter, criteria);
                                if (list.Count > 0) {
                                        if (members == null)
                                                members = new ArrayList ();
                                        
                                members.AddRange (list);
                        }
                        }
                                
                        }

                        Timer.StopTimer (TimerType.TcFindMembers);

                        if (members == null)
                                return MemberList.Empty;
                        else
                        return new MemberList (members);
                }

                public override MemberCache MemberCache {
                        get {
                                return member_cache;
                        }
                }

                public static MemberList FindMembers (Type t, MemberTypes mt, BindingFlags bf,
                                                      MemberFilter filter, object criteria)
                {
                        DeclSpace ds = TypeManager.LookupDeclSpace (t);

                        if (ds != null)
                                return ds.FindMembers (mt, bf, filter, criteria);
                        else
                                return new MemberList (t.FindMembers (mt, bf, filter, criteria));
                }

                //
                // FindMethods will look for methods not only in the type `t', but in
                // any interfaces implemented by the type.
                //
                public static MethodInfo [] FindMethods (Type t, BindingFlags bf,
                                                         MemberFilter filter, object criteria)
                {
                        return null;
                }

                /// <summary>
                ///   Emits the values for the constants
                /// </summary>
                public void EmitConstants ()
                {
                        if (constants != null)
                                foreach (Const con in constants)
                                        con.Emit ();
                        return;
                }

                protected virtual void VerifyMembers (EmitContext ec)
                {
                        //
                        // Check for internal or private fields that were never assigned
                        //
                        if (RootContext.WarningLevel >= 4) {
                                if (fields != null){
                                        foreach (Field f in fields) {
                                                if ((f.ModFlags & Modifiers.Accessibility) != Modifiers.PRIVATE)
                                                        continue;
                                                
                                                if ((f.status & Field.Status.USED) == 0){
                                                        Report.Warning (169, f.Location, "The private field '{0}' is never used", f.GetSignatureForError ());
                                                        continue;
                                                }
                                                
                                                //
                                                // Only report 649 on level 4
                                                //
                                                if (RootContext.WarningLevel < 4)
                                                        continue;
                                                
                                                if ((f.status & Field.Status.ASSIGNED) != 0)
                                                        continue;
                                                
                                                Report.Warning (649, f.Location, "Field '{0}' is never assigned to, and will always have its default value '{1}'", f.GetSignatureForError (), "");
                                        }
                                }
                        }
                }

                /// <summary>
                ///   Emits the code, this step is performed after all
                ///   the types, enumerations, constructors
                /// </summary>
                public void EmitType ()
                {
                        if (OptAttributes != null)
                                OptAttributes.Emit (ec, this);

                        Emit ();

                        if (instance_constructors != null) {
                                if (TypeBuilder.IsSubclassOf (TypeManager.attribute_type) && RootContext.VerifyClsCompliance && IsClsCompliaceRequired (this)) {
                                        bool has_compliant_args = false;

                                        foreach (Constructor c in instance_constructors) {
                                                c.Emit ();

                                                if (has_compliant_args)
                                                        continue;

                                                has_compliant_args = c.HasCompliantArgs;
                                        }
                                        if (!has_compliant_args)
                                                Report.Error (3015, Location, "'{0}' has no accessible constructors which use only CLS-compliant types", GetSignatureForError ());
                                } else {
                                foreach (Constructor c in instance_constructors)
                                                c.Emit ();
                                }
                        }

                        EmitConstants ();

                        if (default_static_constructor != null)
                                default_static_constructor.Emit ();
                        
                        if (methods != null)
                                foreach (Method m in methods)
                                        m.Emit ();

                        if (operators != null)
                                foreach (Operator o in operators)
                                        o.Emit ();

                        if (properties != null)
                                foreach (Property p in properties)
                                        p.Emit ();

                        if (indexers != null){
                                indexers.Emit ();
                        }
                        
                        if (fields != null)
                                foreach (FieldMember f in fields)
                                        f.Emit ();

                        if (events != null){
                                foreach (Event e in Events)
                                        e.Emit ();
                        }

                        if (delegates != null) {
                                foreach (Delegate d in Delegates) {
                                        d.Emit ();
                                }
                        }

                        if (enums != null) {
                                foreach (Enum e in enums) {
                                        e.Emit ();
                                }
                        }

                        if (parts != null) {
                                foreach (ClassPart part in parts)
                                        part.EmitType ();
                        }

                        if ((Pending != null) && !(this is ClassPart))
                                if (Pending.VerifyPendingMethods ())
                                        return;

                        VerifyMembers (ec);

                        if (iterators != null)
                                foreach (Iterator iterator in iterators)
                                        iterator.EmitType ();
                        
//                      if (types != null)
//                              foreach (TypeContainer tc in types)
//                                      tc.Emit ();
                }
                
                public override void CloseType ()
                {
                        if ((caching_flags & Flags.CloseTypeCreated) != 0)
                                return;

                        try {
                                caching_flags |= Flags.CloseTypeCreated;
                                        TypeBuilder.CreateType ();
                        } catch (TypeLoadException){
                                //
                                // This is fine, the code still created the type
                                //
//                              Report.Warning (-20, "Exception while creating class: " + TypeBuilder.Name);
//                              Console.WriteLine (e.Message);
                        } catch {
                                Console.WriteLine ("In type: " + Name);
                                throw;
                        }
                        
                        if (Enums != null)
                                foreach (Enum en in Enums)
                                        en.CloseType ();

                        if (Types != null){
                                foreach (TypeContainer tc in Types)
                                        if (tc.Kind == Kind.Struct)
                                                tc.CloseType ();

                                foreach (TypeContainer tc in Types)
                                        if (tc.Kind != Kind.Struct)
                                                tc.CloseType ();
                        }

                        if (Delegates != null)
                                foreach (Delegate d in Delegates)
                                        d.CloseType ();

                        if (Iterators != null)
                                foreach (Iterator i in Iterators)
                                        i.CloseType ();
                        
                        types = null;
                        properties = null;
                        enums = null;
                        delegates = null;
                        fields = null;
                        initialized_fields = null;
                        initialized_static_fields = null;
                        constants = null;
                        interfaces = null;
                        methods = null;
                        events = null;
                        indexers = null;
                        operators = null;
                        iterators = null;
                        ec = null;
                        default_constructor = null;
                        default_static_constructor = null;
                        type_bases = null;
                        OptAttributes = null;
                        ifaces = null;
                        base_cache = null;
                        member_cache = null;
                }

                // TODO: make it obsolete and use GetSignatureForError
                public string MakeName (string n)
                {
                        return "`" + Name + "." + n + "'";
                }

                //
                // Performs the validation on a Method's modifiers (properties have
                // the same properties).
                //
                public bool MethodModifiersValid (MemberCore mc)
                {
                        const int vao = (Modifiers.VIRTUAL | Modifiers.ABSTRACT | Modifiers.OVERRIDE);
                        const int va = (Modifiers.VIRTUAL | Modifiers.ABSTRACT);
                        const int nv = (Modifiers.NEW | Modifiers.VIRTUAL);
                        bool ok = true;
                        int flags = mc.ModFlags;
                        
                        //
                        // At most one of static, virtual or override
                        //
                        if ((flags & Modifiers.STATIC) != 0){
                                if ((flags & vao) != 0){
                                        Report.Error (112, mc.Location, "static method '{0}' can not be marked as virtual, abstract or override",
                                                GetSignatureForError ());
                                        ok = false;
                                }
                        }

                        if (Kind == Kind.Struct){
                                if ((flags & va) != 0){
                                        Modifiers.Error_InvalidModifier (mc.Location, "virtual or abstract");
                                        ok = false;
                                }
                        }

                        if ((flags & Modifiers.OVERRIDE) != 0 && (flags & nv) != 0){
                                Report.Error (113, mc.Location, "'{0}' marked as override cannot be marked as new or virtual", mc.GetSignatureForError ());
                                ok = false;
                        }

                        //
                        // If the declaration includes the abstract modifier, then the
                        // declaration does not include static, virtual or extern
                        //
                        if ((flags & Modifiers.ABSTRACT) != 0){
                                if ((flags & Modifiers.EXTERN) != 0){
                                        Report.Error (
                                                180, mc.Location, "'{0}' can not be both abstract and extern", mc.GetSignatureForError ());
                                        ok = false;
                                }

                                if ((flags & Modifiers.SEALED) != 0) {
                                        Report.Error (502, mc.Location, "'{0}' cannot be both abstract and sealed", mc.GetSignatureForError ());
                                        ok = false;
                                }

                                if ((flags & Modifiers.VIRTUAL) != 0){
                                        Report.Error (503, mc.Location, "'{0}' can not be both abstract and virtual", mc.GetSignatureForError ());
                                        ok = false;
                                }

                                if ((ModFlags & Modifiers.ABSTRACT) == 0){
                                        Report.Error (513, mc.Location, "'{0}' is abstract but its container class is not", mc.GetSignatureForError ());
                                        ok = false;
                                }
                        }

                        if ((flags & Modifiers.PRIVATE) != 0){
                                if ((flags & vao) != 0){
                                        Report.Error (621, mc.Location, "'{0}' virtual or abstract members can not be private", mc.GetSignatureForError ());
                                        ok = false;
                                }
                        }

                        if ((flags & Modifiers.SEALED) != 0){
                                if ((flags & Modifiers.OVERRIDE) == 0){
                                        Report.Error (238, mc.Location, "'{0}' cannot be sealed because it is not an override", mc.GetSignatureForError ());
                                        ok = false;
                                }
                        }

                        return ok;
                }

                public bool UserDefinedStaticConstructor {
                        get {
                                return default_static_constructor != null;
                        }
                }

                public Constructor DefaultStaticConstructor {
                        get { return default_static_constructor; }
                }

                protected override bool VerifyClsCompliance (DeclSpace ds)
                {
                        if (!base.VerifyClsCompliance (ds))
                                return false;

                        VerifyClsName ();

                        if (IsGeneric) {
                                Report.Error (3024, Location, "'{0}': type parameters are not CLS-compliant",
                                              GetSignatureForError ());
                                return false;
                        }

                        Type base_type = TypeBuilder.BaseType;
                        if (base_type != null && !AttributeTester.IsClsCompliant (base_type)) {
                                Report.Error (3009, Location, "'{0}': base type '{1}' is not CLS-compliant", GetSignatureForError (), TypeManager.CSharpName (base_type));
                        }

                        if (!Parent.IsClsCompliaceRequired (ds)) {
                                Report.Error (3018, Location, "'{0}' cannot be marked as CLS-Compliant because it is a member of non CLS-Compliant type '{1}'", 
                                        GetSignatureForError (), Parent.GetSignatureForError ());
                        }
                        return true;
                }


                /// <summary>
                /// Checks whether container name is CLS Compliant
                /// </summary>
                void VerifyClsName ()
                {
                        Hashtable base_members = base_cache == null ? 
                                new Hashtable () :
                                base_cache.GetPublicMembers ();
                        Hashtable this_members = new Hashtable ();

                        foreach (DictionaryEntry entry in defined_names) {
                                MemberCore mc = (MemberCore)entry.Value;
                                if (!mc.IsClsCompliaceRequired (this))
                                        continue;

                                string name = (string)entry.Key;
                                string basename = name.Substring (name.LastIndexOf ('.') + 1);

                                string lcase = basename.ToLower (System.Globalization.CultureInfo.InvariantCulture);
                                object found = base_members [lcase];
                                if (found == null) {
                                        found = this_members [lcase];
                                        if (found == null) {
                                                this_members.Add (lcase, mc);
                                                continue;
                                        }
                                }

                                if ((mc.ModFlags & Modifiers.OVERRIDE) != 0)
                                        continue;                                       

                                if (found is MemberInfo) {
                                        if (basename == ((MemberInfo)found).Name)
                                                continue;
                                        Report.SymbolRelatedToPreviousError ((MemberInfo)found);
                                } else {
                                        Report.SymbolRelatedToPreviousError ((MemberCore) found);
                                }
                                Report.Error (3005, mc.Location, "Identifier '{0}' differing only in case is not CLS-compliant", mc.GetSignatureForError ());
                        }
                }


                /// <summary>
                ///   Performs checks for an explicit interface implementation.  First it
                ///   checks whether the `interface_type' is a base inteface implementation.
                ///   Then it checks whether `name' exists in the interface type.
                /// </summary>
                public virtual bool VerifyImplements (Type interface_type, string full,
                                                      string name, Location loc)
                {
                        bool found = false;

                        if (ifaces != null){
                                foreach (Type t in ifaces){
                                        if (t == interface_type){
                                                found = true;
                                                break;
                                        }
                                }
                        }
                        
                        if (!found){
                                Report.Error (540, loc, "`{0}': containing class does not implement interface `{1}'",
                                              full, interface_type.FullName);
                                return false;
                        }

                        return true;
                }

                protected override void VerifyObsoleteAttribute()
                {
                        CheckUsageOfObsoleteAttribute (TypeBuilder.BaseType);

                        if (ifaces == null)
                                return;

                        foreach (Type iface in ifaces) {
                                CheckUsageOfObsoleteAttribute (iface);
                        }
                }

                //
                // IMemberContainer
                //

                string IMemberContainer.Name {
                        get {
                                return Name;
                        }
                }

                Type IMemberContainer.Type {
                        get {
                                return TypeBuilder;
                        }
                }

                MemberCache IMemberContainer.MemberCache {
                        get {
                                return member_cache;
                        }
                }

                bool IMemberContainer.IsInterface {
                        get {
                                return Kind == Kind.Interface;
                        }
                }

                MemberList IMemberContainer.GetMembers (MemberTypes mt, BindingFlags bf)
                {
                        BindingFlags new_bf = bf | BindingFlags.DeclaredOnly;

                        if (GenericType != null)
                                return TypeManager.FindMembers (GenericType, mt, new_bf,
                                                                null, null);
                        else
                                return FindMembers (mt, new_bf, null, null);
                }

                //
                // Generates xml doc comments (if any), and if required,
                // handle warning report.
                //
                internal override void GenerateDocComment (DeclSpace ds)
                {
                        DocUtil.GenerateTypeDocComment (this, ds);
                }

                public override string DocCommentHeader {
                        get { return "T:"; }
                }

                public virtual MemberCache BaseCache {
                        get {
                                if (base_cache != null)
                                        return base_cache;
                                if (TypeBuilder.BaseType != null)
                                        base_cache = TypeManager.LookupMemberCache (TypeBuilder.BaseType);
                                if (TypeBuilder.IsInterface)
                                        base_cache = TypeManager.LookupBaseInterfacesCache (TypeBuilder);
                                return base_cache;
                        }
                }
                
        }

        public class PartialContainer : TypeContainer {

                public readonly Namespace Namespace;
                public readonly int OriginalModFlags;
                public readonly int AllowedModifiers;
                public readonly TypeAttributes DefaultTypeAttributes;

                static PartialContainer Create (NamespaceEntry ns, TypeContainer parent,
                                                MemberName member_name, int mod_flags, Kind kind,
                                                Location loc)
                {
                        PartialContainer pc;
                        string full_name = member_name.GetName (true);
                        DeclSpace ds = (DeclSpace) RootContext.Tree.Decls [full_name];
                        if (ds != null) {
                                pc = ds as PartialContainer;

                                if (pc == null) {
                                        Report.Error (
                                                260, ds.Location, "Missing partial modifier " +
                                                "on declaration of type `{0}'; another " +
                                                "partial implementation of this type exists",
                                                member_name.GetTypeName());

                                        Report.LocationOfPreviousError (loc);
                                        return null;
                                }

                                if (pc.Kind != kind) {
                                        Report.Error (
                                                261, loc, "Partial declarations of `{0}' " +
                                                "must be all classes, all structs or " +
                                                "all interfaces", member_name.GetTypeName ());
                                        return null;
                                }

                                if (pc.OriginalModFlags != mod_flags) {
                                        Report.Error (
                                                262, loc, "Partial declarations of `{0}' " +
                                                "have conflicting accessibility modifiers",
                                                member_name.GetTypeName ());
                                        return null;
                                }

                                if (pc.IsGeneric) {
                                        if (pc.CountTypeParameters != member_name.CountTypeArguments) {
                                                Report.Error (
                                                        264, loc, "Partial declarations of `{0}' " +
                                                        "must have the same type parameter names in " +
                                                        "the same order", member_name.GetTypeName ());
                                                return null;
                                        }

                                        string[] pc_names = pc.MemberName.TypeArguments.GetDeclarations ();
                                        string[] names = member_name.TypeArguments.GetDeclarations ();

                                        for (int i = 0; i < pc.CountTypeParameters; i++) {
                                                if (pc_names [i] == names [i])
                                                        continue;

                                                Report.Error (
                                                        264, loc, "Partial declarations of `{0}' " +
                                                        "must have the same type parameter names in " +
                                                        "the same order", member_name.GetTypeName ());
                                                return null;
                                        }
                                }

                                return pc;
                        }

                        pc = new PartialContainer (ns, parent, member_name, mod_flags, kind, loc);
                        RootContext.Tree.RecordDecl (full_name, pc);
                        parent.AddType (pc);
                        pc.Register ();
                        // This is needed to define our type parameters; we define the constraints later.
                        pc.SetParameterInfo (null);
                        return pc;
                }

                public static ClassPart CreatePart (NamespaceEntry ns, TypeContainer parent,
                                                    MemberName name, int mod, Attributes attrs,
                                                    Kind kind, Location loc)
                {
                        PartialContainer pc = Create (ns, parent, name, mod, kind, loc);
                        if (pc == null) {
                                // An error occured; create a dummy container, but don't
                                // register it.
                                pc = new PartialContainer (ns, parent, name, mod, kind, loc);
                        }

                        ClassPart part = new ClassPart (ns, pc, mod, attrs, kind, loc);
                        pc.AddPart (part);
                        return part;
                }

                protected PartialContainer (NamespaceEntry ns, TypeContainer parent,
                                            MemberName name, int mod, Kind kind, Location l)
                        : base (ns, parent, name, null, kind, l)
                {
                        this.Namespace = ns.NS;

                        switch (kind) {
                        case Kind.Class:
                                AllowedModifiers = Class.AllowedModifiers;
                                DefaultTypeAttributes = Class.DefaultTypeAttributes;
                                break;

                        case Kind.Struct:
                                AllowedModifiers = Struct.AllowedModifiers;
                                DefaultTypeAttributes = Struct.DefaultTypeAttributes;
                                break;

                        case Kind.Interface:
                                AllowedModifiers = Interface.AllowedModifiers;
                                DefaultTypeAttributes = Interface.DefaultTypeAttributes;
                                break;

                        default:
                                throw new InvalidOperationException ();
                        }

                        int accmods;
                        if (parent.Parent == null)
                                accmods = Modifiers.INTERNAL;
                        else
                                accmods = Modifiers.PRIVATE;

                        this.ModFlags = Modifiers.Check (AllowedModifiers, mod, accmods, l);
                        this.OriginalModFlags = mod;
                }

                public override void Register ()
                {
                        if (Kind == Kind.Interface)
                                Parent.AddInterface (this);
                        else if (Kind == Kind.Class || Kind == Kind.Struct)
                                Parent.AddClassOrStruct (this);
                        else
                                throw new InvalidOperationException ();
                }

                public override PendingImplementation GetPendingImplementations ()
                {
                        return PendingImplementation.GetPendingImplementations (this);
                }

                ArrayList constraints_lists;

                public void UpdateConstraints (ArrayList constraints_list)
                {
                        //
                        // This is called for each ClassPart in a partial generic type declaration.
                        //
                        // If no constraints were specified for the part, just return.
                        // Otherwise, if we're called with constraints for the first time, they become
                        // the type's constraint.  If we're called with constraints again, we just
                        // store them somewhere so we can later check whether there are no conflicts.
                        //
                        if (constraints_list == null)
                                return;

                        if (constraints_lists != null) {
                                constraints_lists.Add (constraints_list);
                                return;
                        }

                        DoUpdateConstraints (null, constraints_list, false);

                        constraints_lists = new ArrayList ();
                }

                protected bool DoUpdateConstraints (EmitContext ec, ArrayList constraints_list, bool check)
                {
                        for (int i = 0; i < TypeParameters.Length; i++) {
                                string name = TypeParameters [i].Name;

                                Constraints constraints = null;
                                if (constraints_list != null) {
                                        foreach (Constraints constraint in constraints_list) {
                                                if (constraint.TypeParameter == name) {
                                                        constraints = constraint;
                                                        break;
                                                }
                                        }
                                }

                                if (!TypeParameters [i].UpdateConstraints (ec, constraints, check)) {
                                        Report.Error (265, Location, "Partial declarations of `{0}' have " +
                                                      "inconsistent constraints for type parameter `{1}'.",
                                                      MemberName.GetTypeName (), name);
                                        return false;
                                }
                        }

                        return true;
                }

                protected override bool CheckConstraints (EmitContext ec)
                {
                        if (constraints_lists == null)
                                return true;

                        //
                        // If constraints were specified in more than one part of a
                        // partial generic type definition, they must be identical.
                        //
                        // Note that we must resolve them and then compute the fully
                        // resolved types since different parts may have different
                        // `using' aliases.  See gen-129.cs for an example.

                        foreach (ArrayList constraints_list in constraints_lists) {
                                if (!DoUpdateConstraints (ec, constraints_list, true))
                                        return false;
                        }

                        return true;
                }

                public ClassPart AddPart (NamespaceEntry ns, int mod, Attributes attrs,
                                          Location l)
                {
                        ClassPart part = new ClassPart (ns, this, mod, attrs, Kind, l);
                        AddPart (part);
                        return part;
                }

                public override TypeAttributes TypeAttr {
                        get {
                                return base.TypeAttr | DefaultTypeAttributes;
                        }
                }
        }

        public class ClassPart : TypeContainer, IMemberContainer {
                public readonly PartialContainer PartialContainer;
                public readonly bool IsPartial;

                public ClassPart (NamespaceEntry ns, PartialContainer parent,
                                  int mod, Attributes attrs, Kind kind, Location l)
                        : base (ns, parent.Parent, parent.MemberName, attrs, kind, l)
                {
                        this.PartialContainer = parent;
                        this.IsPartial = true;

                        int accmods;
                        if (parent.Parent == null)
                                accmods = Modifiers.INTERNAL;
                        else
                                accmods = Modifiers.PRIVATE;

                        this.ModFlags = Modifiers.Check (
                                parent.AllowedModifiers, mod, accmods, l);
                }

                public override void Register ()
                {
                }

                public override PendingImplementation GetPendingImplementations ()
                {
                        return PartialContainer.Pending;
                }

                public override bool VerifyImplements (Type interface_type, string full,
                                                       string name, Location loc)
                {
                        return PartialContainer.VerifyImplements (
                                interface_type, full, name, loc);
                }

                public override void SetParameterInfo (ArrayList constraints_list)
                {
                        PartialContainer.UpdateConstraints (constraints_list);
                }

                public override MemberCache BaseCache {
                        get {
                                return PartialContainer.BaseCache;
                        }
                }
        }

        public abstract class ClassOrStruct : TypeContainer {
                bool hasExplicitLayout = false;
                ListDictionary declarative_security;

                public ClassOrStruct (NamespaceEntry ns, TypeContainer parent,
                                      MemberName name, Attributes attrs, Kind kind,
                                      Location l)
                        : base (ns, parent, name, attrs, kind, l)
                {
                }

                public override PendingImplementation GetPendingImplementations ()
                {
                        return PendingImplementation.GetPendingImplementations (this);
                }

                public override bool HasExplicitLayout {
                        get {
                                return hasExplicitLayout;
                                }
                        }

                protected override void VerifyMembers (EmitContext ec)
                {
                        base.VerifyMembers (ec);

                        if ((events != null) && (RootContext.WarningLevel >= 3)) {
                                foreach (Event e in events){
                                        if (e.status == 0)
                                                Report.Warning (67, e.Location, "The event '{0}' is never used", e.GetSignatureForError ());
                                }
                        }
                }

                public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
                {
                        if (a.Type.IsSubclassOf (TypeManager.security_attr_type) && a.CheckSecurityActionValidity (false)) {
                                if (declarative_security == null)
                                        declarative_security = new ListDictionary ();

                                a.ExtractSecurityPermissionSet (declarative_security);
                                return;
                        }

                        if (a.Type == TypeManager.struct_layout_attribute_type
                            && (LayoutKind) a.GetPositionalValue (0) == LayoutKind.Explicit)
                                hasExplicitLayout = true;

                        base.ApplyAttributeBuilder (a, cb);
                }

                public override void Emit()
                {
                        base.Emit ();

                        if (declarative_security != null) {
                                foreach (DictionaryEntry de in declarative_security) {
                                        TypeBuilder.AddDeclarativeSecurity ((SecurityAction)de.Key, (PermissionSet)de.Value);
                                }
                        }
                }

                public override void Register ()
                {
                        Parent.AddClassOrStruct (this);
                }
        }

        /// <summary>
        /// Class handles static classes declaration
        /// </summary>
        public sealed class StaticClass: Class {
                public StaticClass (NamespaceEntry ns, TypeContainer parent, MemberName name, int mod,
                                    Attributes attrs, Location l)
                        : base (ns, parent, name, mod, attrs, l)
                {
                        if (RootContext.Version == LanguageVersion.ISO_1) {
                                Report.FeatureIsNotStandardized (l, "static classes");
                                Environment.Exit (1);
                        }
                }

                protected override int AllowedModifiersProp {
                        get {
                                return Modifiers.NEW | Modifiers.PUBLIC | Modifiers.PROTECTED | Modifiers.INTERNAL | Modifiers.PRIVATE |
                                        Modifiers.STATIC | Modifiers.UNSAFE;
                        }
                }

                protected override void DefineContainerMembers (MemberCoreArrayList list)
                {
                        if (list == null)
                                return;

                        foreach (MemberCore m in list) {
                                if (m is Operator) {
                                        Report.Error (715, m.Location, "'{0}': static classes cannot contain user-defined operators", m.GetSignatureForError (this));
                                        continue;
                                }

                                if ((m.ModFlags & Modifiers.STATIC) != 0 || m is Enum || m is Delegate)
                                        continue;

                                if (m is Constructor) {
                                        Report.Error (710, m.Location, "'{0}': Static classes cannot have instance constructors", GetSignatureForError ());
                                        continue;
                                }

                                if (m is Destructor) {
                                        Report.Error (711, m.Location, "'{0}': Static class cannot contain destructor", GetSignatureForError ());
                                        continue;
                                }
                                Report.Error (708, m.Location, "'{0}': cannot declare instance members in a static class", m.GetSignatureForError (this));
                        }

                        base.DefineContainerMembers (list);
                }

                public override TypeBuilder DefineType()
                {
                        if ((ModFlags & (Modifiers.SEALED | Modifiers.STATIC)) == (Modifiers.SEALED | Modifiers.STATIC)) {
                                Report.Error (441, Location, "'{0}': a class cannot be both static and sealed", GetSignatureForError ());
                                return null;
                        }

                        TypeBuilder tb = base.DefineType ();
                        if (tb == null)
                                return null;

                        if ((ptype != null) && (ptype != TypeManager.object_type)) {
                                Report.Error (
                                        713, Location,
                                        "Static class '{0}' cannot derive from type '{1}'. " +
                                        "Static classes must derive from object",
                                        GetSignatureForError (), ptype);
                                return null;
                        }

                        if (ifaces != null) {
                                foreach (Type t in ifaces)
                                        Report.SymbolRelatedToPreviousError (t);
                                Report.Error (
                                        714, Location,
                                        "'{0}': static classes cannot implement interfaces",
                                        GetSignatureForError ());
                        }
                        return tb;
                }

                public override TypeAttributes TypeAttr {
                        get {
                                return base.TypeAttr | TypeAttributes.Abstract | TypeAttributes.Sealed;
                        }
                }
        }

        public class Class : ClassOrStruct {
                // TODO: remove this and use only AllowedModifiersProp to fix partial classes bugs
                public const int AllowedModifiers =
                        Modifiers.NEW |
                        Modifiers.PUBLIC |
                        Modifiers.PROTECTED |
                        Modifiers.INTERNAL |
                        Modifiers.PRIVATE |
                        Modifiers.ABSTRACT |
                        Modifiers.SEALED |
                        Modifiers.UNSAFE;

                // Information in the case we are an attribute type
                AttributeUsageAttribute attribute_usage;

                public Class (NamespaceEntry ns, TypeContainer parent, MemberName name, int mod,
                              Attributes attrs, Location l)
                        : base (ns, parent, name, attrs, Kind.Class, l)
                {
                        this.ModFlags = mod;
                        attribute_usage = new AttributeUsageAttribute (AttributeTargets.All);
                }

                virtual protected int AllowedModifiersProp {
                        get {
                                return AllowedModifiers;
                        }
                }

                public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
                {
                        if (a.UsageAttribute != null) {
                                if (ptype != TypeManager.attribute_type &&
                                    !ptype.IsSubclassOf (TypeManager.attribute_type) &&
                                    TypeBuilder.FullName != "System.Attribute") {
                                        Report.Error (641, a.Location, "Attribute '{0}' is only valid on classes derived from System.Attribute", a.Name);
                                }
                                attribute_usage = a.UsageAttribute;
                        }

                        base.ApplyAttributeBuilder (a, cb);
                }

                public AttributeUsageAttribute AttributeUsage {
                        get {
                                return attribute_usage;
                        }
                }

                public const TypeAttributes DefaultTypeAttributes =
                        TypeAttributes.AutoLayout | TypeAttributes.Class;

                public override TypeBuilder DefineType()
                {
                        if ((ModFlags & Modifiers.ABSTRACT) == Modifiers.ABSTRACT && (ModFlags & (Modifiers.SEALED | Modifiers.STATIC)) != 0) {
                                Report.Error (418, Location, "'{0}': an abstract class cannot be sealed or static", GetSignatureForError ());
                                return null;
                        }

                        int accmods = Parent.Parent == null ? Modifiers.INTERNAL : Modifiers.PRIVATE;
                        ModFlags = Modifiers.Check (AllowedModifiersProp, ModFlags, accmods, Location);

                        return base.DefineType ();
                }

                //
                // FIXME: How do we deal with the user specifying a different
                // layout?
                //
                public override TypeAttributes TypeAttr {
                        get {
                                return base.TypeAttr | DefaultTypeAttributes;
                        }
                }
        }

        public class Struct : ClassOrStruct {
                // <summary>
                //   Modifiers allowed in a struct declaration
                // </summary>
                public const int AllowedModifiers =
                        Modifiers.NEW       |
                        Modifiers.PUBLIC    |
                        Modifiers.PROTECTED |
                        Modifiers.INTERNAL  |
                        Modifiers.UNSAFE    |
                        Modifiers.PRIVATE;

                public Struct (NamespaceEntry ns, TypeContainer parent, MemberName name,
                               int mod, Attributes attrs, Location l)
                        : base (ns, parent, name, attrs, Kind.Struct, l)
                {
                        int accmods;
                        
                        if (parent.Parent == null)
                                accmods = Modifiers.INTERNAL;
                        else
                                accmods = Modifiers.PRIVATE;
                        
                        this.ModFlags = Modifiers.Check (AllowedModifiers, mod, accmods, l);

                        this.ModFlags |= Modifiers.SEALED;
                }

                public const TypeAttributes DefaultTypeAttributes =
                        TypeAttributes.SequentialLayout |
                        TypeAttributes.Sealed |
                        TypeAttributes.BeforeFieldInit;

                //
                // FIXME: Allow the user to specify a different set of attributes
                // in some cases (Sealed for example is mandatory for a class,
                // but what SequentialLayout can be changed
                //
                public override TypeAttributes TypeAttr {
                        get {
                                return base.TypeAttr | DefaultTypeAttributes;
                        }
                }
        }

        /// <summary>
        ///   Interfaces
        /// </summary>
        public class Interface : TypeContainer, IMemberContainer {
                /// <summary>
                ///   Modifiers allowed in a class declaration
                /// </summary>
                public const int AllowedModifiers =
                        Modifiers.NEW       |
                        Modifiers.PUBLIC    |
                        Modifiers.PROTECTED |
                        Modifiers.INTERNAL  |
                        Modifiers.UNSAFE    |
                        Modifiers.PRIVATE;

                public Interface (NamespaceEntry ns, TypeContainer parent, MemberName name,
                                  int mod, Attributes attrs, Location l)
                        : base (ns, parent, name, attrs, Kind.Interface, l)
                {
                        int accmods;

                        if (parent.Parent == null)
                                accmods = Modifiers.INTERNAL;
                        else
                                accmods = Modifiers.PRIVATE;

                        this.ModFlags = Modifiers.Check (AllowedModifiers, mod, accmods, l);
                }

                public override void Register ()
                {
                        Parent.AddInterface (this);
                }

                public override PendingImplementation GetPendingImplementations ()
                {
                        return null;
                }

                public const TypeAttributes DefaultTypeAttributes =
                                        TypeAttributes.AutoLayout |
                                        TypeAttributes.Abstract |
                                        TypeAttributes.Interface;

                public override TypeAttributes TypeAttr {
                        get {
                                return base.TypeAttr | DefaultTypeAttributes;
                        }
                }
        }

        public abstract class MethodCore : MemberBase {
                public readonly Parameters Parameters;
                public readonly GenericMethod GenericMethod;
                public readonly DeclSpace ds;
                protected ToplevelBlock block;
                
                //
                // Parameters, cached for semantic analysis.
                //
                protected InternalParameters parameter_info;
                protected Type [] parameter_types;

                // Whether this is an operator method.
                public bool IsOperator;

                //
                // The method we're overriding if this is an override method.
                //
                protected MethodInfo base_method = null;

                static string[] attribute_targets = new string [] { "method", "return" };

                public MethodCore (TypeContainer parent, GenericMethod generic,
                                   Expression type, int mod, int allowed_mod, bool is_iface,
                                   MemberName name, Attributes attrs, Parameters parameters,
                                   Location loc)
                        : base (parent, type, mod, allowed_mod, Modifiers.PRIVATE, name,
                                attrs, loc)
                {
                        Parameters = parameters;
                        IsInterface = is_iface;
                        this.GenericMethod = generic;

                        if (generic != null)
                                ds = generic;
                        else
                                ds = parent;
                }
                
                //
                //  Returns the System.Type array for the parameters of this method
                //
                public Type [] ParameterTypes {
                        get {
                                return parameter_types;
                        }
                }

                public InternalParameters ParameterInfo
                {
                        get {
                                return parameter_info;
                        }
                }
                
                public ToplevelBlock Block {
                        get {
                                return block;
                        }

                        set {
                                block = value;
                        }
                }

                protected override bool CheckBase ()
                {
                        if (!base.CheckBase ())
                                return false;
                        
                        // Check whether arguments were correct.
                        if (!DoDefineParameters ())
                                return false;

                        if ((caching_flags & Flags.TestMethodDuplication) != 0 && !CheckForDuplications ())
                                return false;

                        if (IsExplicitImpl)
                                return true;

                        // Is null for System.Object while compiling corlib and base interfaces
                        if (Parent.BaseCache == null) {
                                if ((RootContext.WarningLevel >= 4) && ((ModFlags & Modifiers.NEW) != 0)) {
                                        Report.Warning (109, Location, "The member '{0}' does not hide an inherited member. The new keyword is not required", GetSignatureForError (Parent));
                                }
                                return true;
                        }

                        Type base_ret_type = null;
                        base_method = FindOutBaseMethod (Parent, ref base_ret_type);

                        // method is override
                        if (base_method != null) {

                                if (!CheckMethodAgainstBase ())
                                        return false;

                                if ((ModFlags & Modifiers.NEW) == 0) {
                                        if (MemberType != TypeManager.TypeToCoreType (base_ret_type)) {
                                                Report.SymbolRelatedToPreviousError (base_method);
                                                Report.Error (508, Location, GetSignatureForError (Parent) + ": cannot " +
                                                        "change return type when overriding inherited member");
                                                return false;
                                        }
                                } else {
                                        if (base_method.IsAbstract && !IsInterface) {
                                                Report.SymbolRelatedToPreviousError (base_method);
                                                Report.Error (533, Location, "'{0}' hides inherited abstract member", GetSignatureForError (Parent));
                                                return false;
                                        }
                                }

                                if (base_method.IsSpecialName && !(this is PropertyBase)) {
                                        Report.Error (561, Location, "'{0}': cannot override '{1}' because it is a special compiler-generated method", GetSignatureForError (Parent), TypeManager.GetFullNameSignature (base_method));
                                        return false;
                                }

                                if (RootContext.WarningLevel > 2) {
                                        if (Name == "Equals" && parameter_types.Length == 1 && parameter_types [0] == TypeManager.object_type)
                                                Parent.Methods.HasEquals = true;
                                        else if (Name == "GetHashCode" && parameter_types.Length == 0)
                                                Parent.Methods.HasGetHashCode = true;
                                }

                                if ((ModFlags & Modifiers.OVERRIDE) != 0) {
                                        ObsoleteAttribute oa = AttributeTester.GetMethodObsoleteAttribute (base_method);
                                        if (oa != null) {
                                                EmitContext ec = new EmitContext (this.Parent, this.Parent, Location, null, null, ModFlags, false);
                                                if (OptAttributes == null || !OptAttributes.Contains (TypeManager.obsolete_attribute_type, ec)) {
                                                        Report.SymbolRelatedToPreviousError (base_method);
                                                        Report.Warning (672, 1, Location, "Member '{0}' overrides obsolete member. Add the Obsolete attribute to '{0}'", GetSignatureForError (Parent));
                                                }
                                        }
                                }
                                return true;
                        }

                        MemberInfo conflict_symbol = Parent.FindBaseMemberWithSameName (Name, !(this is Property));
                        if ((ModFlags & Modifiers.OVERRIDE) != 0) {
                                if (conflict_symbol != null) {
                                        Report.SymbolRelatedToPreviousError (conflict_symbol);
                                        if (this is PropertyBase)
                                                Report.Error (544, Location, "'{0}': cannot override because '{1}' is not a property", GetSignatureForError (Parent), TypeManager.GetFullNameSignature (conflict_symbol));
                                        else
                                                Report.Error (505, Location, "'{0}': cannot override because '{1}' is not a method", GetSignatureForError (Parent), TypeManager.GetFullNameSignature (conflict_symbol));
                                } else
                                Report.Error (115, Location, "'{0}': no suitable methods found to override", GetSignatureForError (Parent));
                                return false;
                        }

                        if (conflict_symbol == null) {
                                if ((RootContext.WarningLevel >= 4) && ((ModFlags & Modifiers.NEW) != 0)) {
                                        Report.Warning (109, Location, "The member '{0}' does not hide an inherited member. The new keyword is not required", GetSignatureForError (Parent));
                                }
                                return true;
                        }

                        if ((ModFlags & Modifiers.NEW) == 0) {
                                if (this is Method && conflict_symbol is MethodBase)
                                        return true;

                                Report.SymbolRelatedToPreviousError (conflict_symbol);
                                Report.Warning (108, Location, "The keyword new is required on '{0}' because it hides inherited member", GetSignatureForError (Parent));
                        }

                        return true;
                }


                //
                // Performs various checks on the MethodInfo `mb' regarding the modifier flags
                // that have been defined.
                //
                // `name' is the user visible name for reporting errors (this is used to
                // provide the right name regarding method names and properties)
                //
                bool CheckMethodAgainstBase ()
                {
                        bool ok = true;

                        // TODO: replace with GetSignatureForError 
                        string name = base_method.DeclaringType.Name + "." + base_method.Name;

                        if ((ModFlags & Modifiers.OVERRIDE) != 0){
                                if (!(base_method.IsAbstract || base_method.IsVirtual)){
                                        Report.Error (
                                                506, Location, Parent.MakeName (Name) +
                                                ": cannot override inherited member `" +
                                                name + "' because it is not " +
                                                "virtual, abstract or override");
                                        ok = false;
                                }
                                
                                // Now we check that the overriden method is not final
                                
                                if (base_method.IsFinal) {
                                        // This happens when implementing interface methods.
                                        if (base_method.IsHideBySig && base_method.IsVirtual) {
                                                Report.Error (
                                                        506, Location, Parent.MakeName (Name) +
                                                        ": cannot override inherited member `" +
                                                        name + "' because it is not " +
                                                        "virtual, abstract or override");
                                        } else
                                                Report.Error (239, Location, Parent.MakeName (Name) + " : cannot " +
                                                              "override inherited member `" + name +
                                                              "' because it is sealed.");
                                        ok = false;
                                }
                                //
                                // Check that the permissions are not being changed
                                //
                                MethodAttributes thisp = flags & MethodAttributes.MemberAccessMask;
                                MethodAttributes base_classp = base_method.Attributes & MethodAttributes.MemberAccessMask;

                                if (!CheckAccessModifiers (thisp, base_classp, base_method)) {
                                        Error_CannotChangeAccessModifiers (Parent, base_method, name);
                                        ok = false;
                                }
                        }

                        if ((ModFlags & (Modifiers.NEW | Modifiers.OVERRIDE)) == 0 && Name != "Finalize") {
                                ModFlags |= Modifiers.NEW;
                                Report.SymbolRelatedToPreviousError (base_method);
                                if (!IsInterface && (base_method.IsVirtual || base_method.IsAbstract)) {
                                        if (RootContext.WarningLevel >= 2)
                                                Report.Warning (114, Location, "'{0}' hides inherited member '{1}'. To make the current member override that implementation, add the override keyword. Otherwise add the new keyword", GetSignatureForError (Parent), TypeManager.CSharpSignature (base_method));
                                } else
                                        Report.Warning (108, Location, "The keyword new is required on '{0}' because it hides inherited member", GetSignatureForError (Parent));
                        }

                        return ok;
                }
                
                protected bool CheckAccessModifiers (MethodAttributes thisp, MethodAttributes base_classp, MethodInfo base_method)
                {
                        if ((base_classp & MethodAttributes.FamORAssem) == MethodAttributes.FamORAssem){
                                //
                                // when overriding protected internal, the method can be declared
                                // protected internal only within the same assembly
                                //

                                if ((thisp & MethodAttributes.FamORAssem) == MethodAttributes.FamORAssem){
                                        if (Parent.TypeBuilder.Assembly != base_method.DeclaringType.Assembly){
                                                //
                                                // assemblies differ - report an error
                                                //
                                                
                                                return false;
                                        } else if (thisp != base_classp) {
                                                //
                                                // same assembly, but other attributes differ - report an error
                                                //
                                                
                                                return false;
                                        };
                                } else if ((thisp & MethodAttributes.Family) != MethodAttributes.Family) {
                                        //
                                        // if it's not "protected internal", it must be "protected"
                                        //

                                        return false;
                                } else if (Parent.TypeBuilder.Assembly == base_method.DeclaringType.Assembly) {
                                        //
                                        // protected within the same assembly - an error
                                        //
                                        return false;
                                } else if ((thisp & ~(MethodAttributes.Family | MethodAttributes.FamORAssem)) != 
                                           (base_classp & ~(MethodAttributes.Family | MethodAttributes.FamORAssem))) {
                                        //
                                        // protected ok, but other attributes differ - report an error
                                        //
                                        return false;
                                }
                                return true;
                        } else {
                                return (thisp == base_classp);
                        }
                }
                
                void Error_CannotChangeAccessModifiers (TypeContainer parent, MethodInfo base_method, string name)
                {
                        //
                        // FIXME: report the old/new permissions?
                        //
                        Report.Error (
                                507, Location, parent.MakeName (Name) +
                                ": can't change the access modifiers when overriding inherited " +
                                "member `" + name + "'");
                }

                protected static string Error722 {
                        get {
                                return "'{0}': static types cannot be used as return types";
                        }
                }

                /// <summary>
                /// For custom member duplication search in a container
                /// </summary>
                protected abstract bool CheckForDuplications ();

                /// <summary>
                /// Gets base method and its return type
                /// </summary>
                protected abstract MethodInfo FindOutBaseMethod (TypeContainer container, ref Type base_ret_type);

                protected virtual bool DoDefineParameters ()
                {
                        EmitContext ec = ds.EmitContext;
                        if (ec == null)
                                throw new InternalErrorException ("DoDefineParameters invoked too early");

                        bool old_unsafe = ec.InUnsafe;
                        ec.InUnsafe = InUnsafe;
                        // Check if arguments were correct
                        parameter_types = Parameters.GetParameterInfo (ec);
                        ec.InUnsafe = old_unsafe;

                        if ((parameter_types == null) ||
                            !CheckParameters (ds, parameter_types))
                                return false;

                        TypeParameter[] tparam = ds.IsGeneric ? ds.TypeParameters : null;
                        parameter_info = new InternalParameters (parameter_types, Parameters, tparam);

                        Parameter array_param = Parameters.ArrayParameter;
                        if ((array_param != null) &&
                            (!array_param.ParameterType.IsArray ||
                             (array_param.ParameterType.GetArrayRank () != 1))) {
                                Report.Error (225, Location, "params parameter has to be a single dimensional array");
                                return false;
                        }

                        return true;
                }

                void error_425 (Type old, Type t, string name)
                {
                        Report.Error (425, Location,
                                      "The constraints of type parameter `{0}' " +
                                      "of method `{1}' must match the constraints for " +
                                      "type parameter `{2}' of method `{3}'",
                                      TypeManager.CSharpName (old), Name,
                                      TypeManager.CSharpName (t), name);
                }

                protected override bool CheckGenericOverride (MethodInfo method, string name)
                {
                        ParameterData pd = TypeManager.GetParameterData (method);

                        for (int i = 0; i < ParameterTypes.Length; i++) {
                                GenericConstraints ogc = pd.GenericConstraints (i);
                                GenericConstraints gc = ParameterInfo.GenericConstraints (i);

                                if ((gc == null) && (ogc == null))
                                        continue;

                                Type ot = pd.ParameterType (i);
                                Type t = ParameterTypes [i];

                                if (!((gc != null) && (ogc != null))) {
                                        error_425 (ot, t, name);
                                        return false;
                                }

                                if ((gc.Attributes != ogc.Attributes) ||
                                    (gc.HasClassConstraint != ogc.HasClassConstraint)) {
                                        error_425 (ot, t, name);
                                        return false;
                                }

                                if (ogc.HasClassConstraint &&
                                    !ogc.ClassConstraint.Equals (gc.ClassConstraint)) {
                                        error_425 (ot, t, name);
                                        return false;
                                }

                                Type[] oct = ogc.InterfaceConstraints;
                                Type[] ct = gc.InterfaceConstraints;

                                if (oct.Length != ct.Length) {
                                        error_425 (ot, t, name);
                                        return false;
                                }

                                for (int j = 0; j < oct.Length; j++)
                                        if (!oct [j].Equals (ct [j])) {
                                                error_425 (ot, t, name);
                                                return false;
                                        }
                        }

                        return true;
                }

                public override string[] ValidAttributeTargets {
                        get {
                                return attribute_targets;
                        }
                }

                protected override bool VerifyClsCompliance (DeclSpace ds)
                {
                        if (!base.VerifyClsCompliance (ds)) {
                                if ((ModFlags & Modifiers.ABSTRACT) != 0 && IsExposedFromAssembly (ds) && ds.IsClsCompliaceRequired (ds)) {
                                        Report.Error (3011, Location, "'{0}': only CLS-compliant members can be abstract", GetSignatureForError ());
                                }
                                return false;
                        }

                        if (Parameters.HasArglist) {
                                Report.Error (3000, Location, "Methods with variable arguments are not CLS-compliant");
                        }

                        if (!AttributeTester.IsClsCompliant (MemberType)) {
                                if (this is PropertyBase)
                                        Report.Error (3003, Location, "Type of `{0}' is not CLS-compliant",
                                                      GetSignatureForError ());
                                else
                                        Report.Error (3002, Location, "Return type of '{0}' is not CLS-compliant",
                                                      GetSignatureForError ());
                        }

                        AttributeTester.AreParametersCompliant (Parameters.FixedParameters, Location);

                        return true;
                }

                bool MayUnify (MethodCore first, MethodCore second)
                {
                        int a_type_params = 0;
                        if (first.GenericMethod != null)
                                a_type_params = first.GenericMethod.CountTypeParameters;

                        int b_type_params = 0;
                        if (second.GenericMethod != null)
                                b_type_params = second.GenericMethod.CountTypeParameters;

                        if (a_type_params != b_type_params)
                                return false;

                        Type[] class_infered, method_infered;
                        if (Parent.CountTypeParameters > 0)
                                class_infered = new Type [Parent.CountTypeParameters];
                        else
                                class_infered = null;

                        if (a_type_params > 0)
                                method_infered = new Type [a_type_params];
                        else
                                method_infered = null;

                        return TypeManager.MayBecomeEqualGenericInstances (
                                first.ParameterTypes, second.ParameterTypes, class_infered, method_infered);
                }

                protected bool IsDuplicateImplementation (MethodCore method)
                {
                        if ((method == this) ||
                            (method.MemberName.GetTypeName () != MemberName.GetTypeName ()))
                                return false;

                        Type[] param_types = method.ParameterTypes;
                        if (param_types == null)
                                return false;

                        if (param_types.Length != ParameterTypes.Length)
                                return false;

                        bool equal = true;
                        bool may_unify = MayUnify (this, method);

                        for (int i = 0; i < param_types.Length; i++) {
                                if (param_types [i] != ParameterTypes [i])
                                        equal = false;
                        }

                        // TODO: make operator compatible with MethodCore to avoid this
                        if (this is Operator && method is Operator) {
                                if (MemberType != method.MemberType)
                                        equal = may_unify = false;
                        }

                        if (equal) {
                                //
                                // Try to report 663: method only differs on out/ref
                                //
                                ParameterData info = ParameterInfo;
                                ParameterData other_info = method.ParameterInfo;
                                for (int i = 0; i < info.Count; i++){
                                        if (info.ParameterModifier (i) != other_info.ParameterModifier (i)){
                                                Report.Error (663, Location,
                                                              "Overload method only differs " +
                                                              "in parameter modifier");
                                                return false;
                                        }
                                }

                                Report.SymbolRelatedToPreviousError (method);
                                Report.Error (111, Location, "Type '{0}' already defines a member called '{1}' with the same parameter types", Parent.Name, Name);
                                return true;
                        } else if (may_unify) {
                                Report.Error (408, Location,
                                              "`{0}' cannot define overload members that " +
                                              "may unify for some type parameter substitutions",
                                              Parent.MemberName);
                                return true;
                        }

                        return false;
                }

                //
                // Returns a string that represents the signature for this 
                // member which should be used in XML documentation.
                //
                public override string GetDocCommentName (DeclSpace ds)
                {
                        return DocUtil.GetMethodDocCommentName (this, ds);
                }

                //
                // Raised (and passed an XmlElement that contains the comment)
                // when GenerateDocComment is writing documentation expectedly.
                //
                // FIXME: with a few effort, it could be done with XmlReader,
                // that means removal of DOM use.
                //
                internal override void OnGenerateDocComment (DeclSpace ds, XmlElement el)
                {
                        DocUtil.OnMethodGenerateDocComment (this, ds, el);
                }

                //
                //   Represents header string for documentation comment.
                //
                public override string DocCommentHeader {
                        get { return "M:"; }
                }

                protected override void VerifyObsoleteAttribute()
                {
                        base.VerifyObsoleteAttribute ();

                        if (parameter_types == null)
                                return;

                        foreach (Type type in parameter_types) {
                                CheckUsageOfObsoleteAttribute (type);
                        }
                }
        }

        public class SourceMethod : ISourceMethod
        {
                TypeContainer container;
                MethodBase builder;

                protected SourceMethod (TypeContainer container, MethodBase builder,
                                        ISourceFile file, Location start, Location end)
                {
                        this.container = container;
                        this.builder = builder;
                        
                        CodeGen.SymbolWriter.OpenMethod (
                                file, this, start.Row, 0, end.Row, 0);
                }

                public string Name {
                        get { return builder.Name; }
                }

                public int NamespaceID {
                        get { return container.NamespaceEntry.SymbolFileID; }
                }

                public int Token {
                        get {
                                if (builder is MethodBuilder)
                                        return ((MethodBuilder) builder).GetToken ().Token;
                                else if (builder is ConstructorBuilder)
                                        return ((ConstructorBuilder) builder).GetToken ().Token;
                                else
                                        throw new NotSupportedException ();
                        }
                }

                public void CloseMethod ()
                {
                        if (CodeGen.SymbolWriter != null)
                                CodeGen.SymbolWriter.CloseMethod ();
                }

                public static SourceMethod Create (TypeContainer parent,
                                                   MethodBase builder, Block block)
                {
                        if (CodeGen.SymbolWriter == null)
                                return null;
                        if (block == null)
                                return null;

                        Location start_loc = block.StartLocation;
                        if (Location.IsNull (start_loc))
                                return null;

                        Location end_loc = block.EndLocation;
                        if (Location.IsNull (end_loc))
                                return null;

                        ISourceFile file = start_loc.SourceFile;
                        if (file == null)
                                return null;

                        return new SourceMethod (
                                parent, builder, file, start_loc, end_loc);
                }
        }

        public class Method : MethodCore, IIteratorContainer, IMethodData {
                public MethodBuilder MethodBuilder;
                public MethodData MethodData;
                ReturnParameter return_attributes;
                ListDictionary declarative_security;

                /// <summary>
                ///   Modifiers allowed in a class declaration
                /// </summary>
                const int AllowedModifiers =
                        Modifiers.NEW |
                        Modifiers.PUBLIC |
                        Modifiers.PROTECTED |
                        Modifiers.INTERNAL |
                        Modifiers.PRIVATE |
                        Modifiers.STATIC |
                        Modifiers.VIRTUAL |
                        Modifiers.SEALED |
                        Modifiers.OVERRIDE |
                        Modifiers.ABSTRACT |
                        Modifiers.UNSAFE |
                        Modifiers.METHOD_YIELDS | 
                        Modifiers.EXTERN;

                const int AllowedInterfaceModifiers =
                        Modifiers.NEW | Modifiers.UNSAFE;

                //
                // return_type can be "null" for VOID values.
                //
                public Method (TypeContainer parent, GenericMethod generic,
                               Expression return_type, int mod, bool is_iface,
                               MemberName name, Parameters parameters, Attributes attrs,
                               Location l)
                        : base (parent, generic, return_type, mod,
                                is_iface ? AllowedInterfaceModifiers : AllowedModifiers,
                                is_iface, name, attrs, parameters, l)
                {
                }

                public override AttributeTargets AttributeTargets {
                        get {
                                return AttributeTargets.Method;
                        }
                }
                
                public override string GetSignatureForError()
                {
                        if (MethodBuilder == null) {
                                return GetSignatureForError (Parent);
                        }
                        return TypeManager.CSharpSignature (MethodBuilder);
                }

                /// <summary>
                /// Use this method when MethodBuilder is null
                /// </summary>
                public override string GetSignatureForError (TypeContainer tc)
                {
                        // TODO: get params from somewhere
                        if (parameter_info == null)
                                return base.GetSignatureForError (tc);

                        // TODO: move to parameters
                        System.Text.StringBuilder args = new System.Text.StringBuilder ();
                        if (parameter_info.Parameters.FixedParameters != null) {
                                for (int i = 0; i < parameter_info.Parameters.FixedParameters.Length; ++i) {
                                        Parameter p = parameter_info.Parameters.FixedParameters [i];
                                        args.Append (p.GetSignatureForError ());

                                        if (i < parameter_info.Parameters.FixedParameters.Length - 1)
                                                args.Append (',');
                                }
                        }

                        return String.Concat (base.GetSignatureForError (tc), "(", args.ToString (), ")");
                }

                void DuplicateEntryPoint (MethodInfo b, Location location)
                {
                        Report.Error (
                                17, location,
                                "Program `" + CodeGen.FileName +
                                "'  has more than one entry point defined: `" +
                                TypeManager.CSharpSignature(b) + "'");
                }

                public bool IsEntryPoint (MethodBuilder b, InternalParameters pinfo)
                {
                        if (b.ReturnType != TypeManager.void_type &&
                            b.ReturnType != TypeManager.int32_type)
                                return false;

                        if (pinfo.Count == 0)
                                return true;

                        if (pinfo.Count > 1)
                                return false;

                        Type t = pinfo.ParameterType(0);
                        if (t.IsArray &&
                            (t.GetArrayRank() == 1) &&
                            (TypeManager.GetElementType(t) == TypeManager.string_type) &&
                            (pinfo.ParameterModifier(0) == Parameter.Modifier.NONE))
                                return true;
                        else
                                return false;
                }

                public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
                {
                        if (a.Target == AttributeTargets.ReturnValue) {
                                if (return_attributes == null)
                                        return_attributes = new ReturnParameter (MethodBuilder, Location);

                                return_attributes.ApplyAttributeBuilder (a, cb);
                                return;
                        }

                        if (a.Type == TypeManager.methodimpl_attr_type && a.IsInternalCall) {
                                MethodBuilder.SetImplementationFlags (MethodImplAttributes.InternalCall | MethodImplAttributes.Runtime);
                        }

                        if (a.Type == TypeManager.dllimport_type) {
                                const int extern_static = Modifiers.EXTERN | Modifiers.STATIC;
                                if ((ModFlags & extern_static) != extern_static) {
                                        Report.Error (601, a.Location, "The DllImport attribute must be specified on a method marked `static' and `extern'");
                                }

                                return;
                        }

                        if (a.Type.IsSubclassOf (TypeManager.security_attr_type) && a.CheckSecurityActionValidity (false)) {
                                if (declarative_security == null)
                                        declarative_security = new ListDictionary ();
                                a.ExtractSecurityPermissionSet (declarative_security);
                                return;
                        }

                        if (a.Type == TypeManager.conditional_attribute_type) {
                                if (IsOperator || IsExplicitImpl) {
                                        Report.Error (577, Location, "Conditional not valid on '{0}' because it is a destructor, operator, or explicit interface implementation", GetSignatureForError ());
                                        return;
                                }

                                if (ReturnType != TypeManager.void_type) {
                                        Report.Error (578, Location, "Conditional not valid on '{0}' because its return new ErrorData ( type is not void", GetSignatureForError ());
                                        return;
                                }

                                if ((ModFlags & Modifiers.OVERRIDE) != 0) {
                                        Report.Error (243, Location, "Conditional not valid on '{0}' because it is an override method", GetSignatureForError ());
                                        return;
                                }

                                if (IsInterface) {
                                        Report.Error (582, Location, "Conditional not valid on interface members");
                                        return;
                                }

                                if (MethodData.IsImplementing) {
                                        Report.Error (629, Location, "Conditional member '{0}' cannot implement interface member", GetSignatureForError ());
                                        return;
                                }

                                for (int i = 0; i < parameter_info.Count; ++i) {
                                        if ((parameter_info.ParameterModifier (i) & Parameter.Modifier.OUT) != 0) {
                                                Report.Error (685, Location, "Conditional method '{0}' cannot have an out parameter", GetSignatureForError ());
                                                return;
                                        }
                                }
                        }

                        MethodBuilder.SetCustomAttribute (cb);
                }

                protected override bool CheckForDuplications ()
                {
                        ArrayList ar = Parent.Methods;
                        if (ar != null) {
                                int arLen = ar.Count;
                                        
                                for (int i = 0; i < arLen; i++) {
                                        Method m = (Method) ar [i];
                                        if (IsDuplicateImplementation (m))
                                                return false;
                                }
                        }

                        ar = Parent.Properties;
                        if (ar != null) {
                                for (int i = 0; i < ar.Count; ++i) {
                                        PropertyBase pb = (PropertyBase) ar [i];
                                        if (pb.AreAccessorsDuplicateImplementation (this))
                                                return false;
                                }
                        }

                        ar = Parent.Indexers;
                        if (ar != null) {
                                for (int i = 0; i < ar.Count; ++i) {
                                        PropertyBase pb = (PropertyBase) ar [i];
                                        if (pb.AreAccessorsDuplicateImplementation (this))
                                                return false;
                                }
                        }

                        ar = Parent.Events;
                        if (ar != null) {
                                for (int i = 0; i < ar.Count; ++i) {
                                        Event ev = (Event) ar [i];
                                        if (ev.AreAccessorsDuplicateImplementation (this))
                                                return false;
                                }
                        }

                        return true;
                }

                //
                // Creates the type
                //
                public override bool Define ()
                {
                        if (!DoDefineBase ())
                                return false;

                        MethodBuilder mb = null;
                        if (GenericMethod != null) {
                                string mname = MemberName.GetMethodName ();
                                mb = Parent.TypeBuilder.DefineGenericMethod (mname, flags);
                                if (!GenericMethod.Define (mb, ReturnType))
                                        return false;
                        }

                        if (!DoDefine (ds))
                                return false;

                        if (!CheckBase ())
                                return false;

                        if (IsOperator)
                                flags |= MethodAttributes.SpecialName | MethodAttributes.HideBySig;

                        MethodData = new MethodData (this, ParameterInfo, ModFlags, flags,
                                                     this, mb, GenericMethod, base_method);

                        if (!MethodData.Define (Parent))
                                return false;

                        //
                        // Setup iterator if we are one
                        //
                        if ((ModFlags & Modifiers.METHOD_YIELDS) != 0){
                                Iterator iterator = new Iterator (
                                        Parent, Name, MemberType, ParameterTypes,
                                        ParameterInfo, ModFlags, block, Location);

                                if (!iterator.DefineIterator ())
                                        return false;

                                block = iterator.Block;
                        }

                        MethodBuilder = MethodData.MethodBuilder;

                        //
                        // This is used to track the Entry Point,
                        //
                        if (Name == "Main" &&
                            ((ModFlags & Modifiers.STATIC) != 0) && RootContext.NeedsEntryPoint && 
                            (RootContext.MainClass == null ||
                             RootContext.MainClass == Parent.TypeBuilder.FullName)){
                                if (IsEntryPoint (MethodBuilder, ParameterInfo)) {
                                        if (RootContext.EntryPoint == null) {
                                                if (Parent.IsGeneric){
                                                        Report.Error (-201, Location,
                                                                      "Entry point can not be defined in a generic class");
                                                }
                                                
                                                RootContext.EntryPoint = MethodBuilder;
                                                RootContext.EntryPointLocation = Location;
                                        } else {
                                                DuplicateEntryPoint (RootContext.EntryPoint, RootContext.EntryPointLocation);
                                                DuplicateEntryPoint (MethodBuilder, Location);
                                        }
                                } else {
                                        if (RootContext.WarningLevel >= 4)
                                                Report.Warning (28, Location, "'{0}' has the wrong signature to be an entry point", TypeManager.CSharpSignature(MethodBuilder) );
                                }
                        }

                        if (MemberType.IsAbstract && MemberType.IsSealed) {
                                Report.Error (722, Location, Error722, TypeManager.CSharpName (MemberType));
                                return false;
                        }

                        return true;
                }

                //
                // Emits the code
                // 
                public override void Emit ()
                {
                        MethodData.Emit (Parent, this);
                        base.Emit ();

                        if (declarative_security != null) {
                                foreach (DictionaryEntry de in declarative_security) {
                                        MethodBuilder.AddDeclarativeSecurity ((SecurityAction)de.Key, (PermissionSet)de.Value);
                                }
                        }

                        Block = null;
                        MethodData = null;
                }

                protected override MethodInfo FindOutBaseMethod (TypeContainer container, ref Type base_ret_type)
                {
                        MethodInfo mi = (MethodInfo) container.BaseCache.FindMemberToOverride (
                                container.TypeBuilder, Name, ParameterTypes, false);

                        if (mi == null)
                                return null;

                        base_ret_type = mi.ReturnType;
                        return mi;
                }
        
                public override bool MarkForDuplicationCheck ()
                {
                        caching_flags |= Flags.TestMethodDuplication;
                        return true;
                }

                protected override bool VerifyClsCompliance(DeclSpace ds)
                {
                        if (!base.VerifyClsCompliance (ds))
                                return false;

                        if (parameter_types.Length > 0) {
                                ArrayList al = (ArrayList)ds.MemberCache.Members [Name];
                                if (al.Count > 1)
                                        ds.MemberCache.VerifyClsParameterConflict (al, this, MethodBuilder);
                        }

                        return true;
                }


                void IIteratorContainer.SetYields ()
                {
                        ModFlags |= Modifiers.METHOD_YIELDS;
                }

                #region IMethodData Members

                public CallingConventions CallingConventions {
                        get {
                                CallingConventions cc = Parameters.GetCallingConvention ();
                                if (Parameters.HasArglist)
                                        block.HasVarargs = true;

                                if (!IsInterface)
                                        if ((ModFlags & Modifiers.STATIC) == 0)
                                                cc |= CallingConventions.HasThis;

                                // FIXME: How is `ExplicitThis' used in C#?
                        
                                return cc;
                        }
                }

                public Type ReturnType {
                        get {
                                return MemberType;
                        }
                }

                public MemberName MethodName {
                        get {
                                return MemberName;
                        }
                }

                public new Location Location {
                        get {
                                return base.Location;
                        }
                }

                public EmitContext CreateEmitContext (TypeContainer tc, ILGenerator ig)
                {
                        return new EmitContext (
                                tc, ds, Location, ig, ReturnType, ModFlags, false);
                }

                public ObsoleteAttribute GetObsoleteAttribute ()
                {
                        return GetObsoleteAttribute (ds);
                }

                /// <summary>
                /// Returns true if method has conditional attribute and the conditions is not defined (method is excluded).
                /// </summary>
                public bool IsExcluded (EmitContext ec)
                {
                        if ((caching_flags & Flags.Excluded_Undetected) == 0)
                                return (caching_flags & Flags.Excluded) != 0;

                        caching_flags &= ~Flags.Excluded_Undetected;

                        if (base_method == null) {
                                if (OptAttributes == null)
                                        return false;

                                Attribute[] attrs = OptAttributes.SearchMulti (TypeManager.conditional_attribute_type, ec);

                                if (attrs == null)
                                        return false;

                                foreach (Attribute a in attrs) {
                                        string condition = a.GetConditionalAttributeValue (Parent.EmitContext);
                                        if (RootContext.AllDefines.Contains (condition))
                                                return false;
                                }

                                caching_flags |= Flags.Excluded;
                                return true;
                        }

                        IMethodData md = TypeManager.GetMethod (base_method);
                        if (md == null) {
                                if (AttributeTester.IsConditionalMethodExcluded (base_method)) {
                                        caching_flags |= Flags.Excluded;
                                        return true;
                                }
                                return false;
                        }

                        if (md.IsExcluded (ec)) {
                                caching_flags |= Flags.Excluded;
                                return true;
                        }
                        return false;
                }

                GenericMethod IMethodData.GenericMethod {
                        get {
                                return GenericMethod;
                        }
                }

                #endregion
        }

        public abstract class ConstructorInitializer {
                ArrayList argument_list;
                protected ConstructorInfo base_constructor;
                Parameters parameters;
                Location loc;
                
                public ConstructorInitializer (ArrayList argument_list, Parameters parameters,
                                               Location loc)
                {
                        this.argument_list = argument_list;
                        this.parameters = parameters;
                        this.loc = loc;
                }

                public ArrayList Arguments {
                        get {
                                return argument_list;
                        }
                }

                public bool Resolve (ConstructorBuilder caller_builder, EmitContext ec)
                {
                        Expression base_constructor_group;
                        Type t;

                        ec.CurrentBlock = new ToplevelBlock (Block.Flags.Implicit, parameters, loc);

                        if (argument_list != null){
                                foreach (Argument a in argument_list){
                                        if (!a.Resolve (ec, loc))
                                                return false;
                                }
                        }
                        ec.CurrentBlock = null;

                        if (this is ConstructorBaseInitializer) {
                                if (ec.ContainerType.BaseType == null)
                                        return true;

                                t = ec.ContainerType.BaseType;
                                if (ec.ContainerType.IsValueType) {
                                        Report.Error (522, loc,
                                                "structs cannot call base class constructors");
                                        return false;
                                }
                        } else
                                t = ec.ContainerType;

                        base_constructor_group = Expression.MemberLookup (
                                ec, t, ".ctor", MemberTypes.Constructor,
                                BindingFlags.Public | BindingFlags.Instance | BindingFlags.DeclaredOnly,
                                loc);
                        
                        if (base_constructor_group == null){
                                base_constructor_group = Expression.MemberLookup (
                                        ec, t, ".ctor", MemberTypes.Constructor,
                                        BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.DeclaredOnly,
                                        loc);

                                if (base_constructor_group != null)
                                        Report.Error (
                                                112, loc, "`{0}.{1}' is inaccessible due to " +
                                                "its protection level", t.FullName, t.Name);
                                else
                                        Report.Error (
                                                1501, loc, "Can not find a constructor for " +
                                                "this argument list");
                                return false;
                        }
                        
                        base_constructor = (ConstructorInfo) Invocation.OverloadResolve (
                                ec, (MethodGroupExpr) base_constructor_group, argument_list,
                                false, loc);
                        
                        if (base_constructor == null){
                                Report.Error (1501, loc,
                                       "Can not find a constructor for this argument list");
                                return false;
                        }
                        
                        if (base_constructor == caller_builder){
                                Report.Error (516, String.Format ("Constructor `{0}' can not call itself", TypeManager.CSharpSignature (caller_builder)));
                                return false;
                        }
                        
                        return true;
                }

                public void Emit (EmitContext ec)
                {
                        if (base_constructor != null){
                                ec.Mark (loc, false);
                                if (ec.IsStatic)
                                        Invocation.EmitCall (ec, true, true, null, base_constructor, argument_list, loc);
                                else
                                        Invocation.EmitCall (ec, true, false, ec.GetThis (loc), base_constructor, argument_list, loc);
                        }
                }

                /// <summary>
                /// Method search for base ctor. (We do not cache it).
                /// </summary>
                Constructor GetOverloadedConstructor (TypeContainer tc)
                {
                        if (tc.InstanceConstructors == null)
                                return null;

                        foreach (Constructor c in tc.InstanceConstructors) {
                                if (Arguments == null) {
                                        if (c.ParameterTypes.Length == 0)
                                                return c;

                                        continue;
                                }

                                bool ok = true;

                                int count = c.ParameterInfo.Count;
                                if ((count > 0) &&
                                    c.ParameterInfo.ParameterModifier (count - 1) == Parameter.Modifier.PARAMS) {
                                        for (int i = 0; i < count-1; i++)
                                                if (c.ParameterTypes [i] != ((Argument)Arguments [i]).Type) {
                                                        ok = false;
                                                        break;
                                                }
                                } else {
                                        if (c.ParameterTypes.Length != Arguments.Count)
                                                continue;

                                        for (int i = 0; i < Arguments.Count; ++i)
                                                if (c.ParameterTypes [i] != ((Argument)Arguments [i]).Type) {
                                                        ok = false;
                                                        break;
                                                }
                                }

                                if (!ok)
                                        continue;

                                return c;
                        }

                        return null;
                }

                //TODO: implement caching when it will be necessary
                public virtual void CheckObsoleteAttribute (TypeContainer tc, Location loc)
                {
                        Constructor ctor = GetOverloadedConstructor (tc);
                        if (ctor == null)
                                return;

                        ObsoleteAttribute oa = ctor.GetObsoleteAttribute (tc);
                        if (oa == null)
                                return;

                        AttributeTester.Report_ObsoleteMessage (oa, ctor.GetSignatureForError (), loc);
                }
        }

        public class ConstructorBaseInitializer : ConstructorInitializer {
                public ConstructorBaseInitializer (ArrayList argument_list, Parameters pars, Location l) :
                        base (argument_list, pars, l)
                {
                }

                public override void CheckObsoleteAttribute(TypeContainer tc, Location loc) {
                        if (base_constructor == null)
                                return;

                        TypeContainer type_ds = TypeManager.LookupTypeContainer (tc.TypeBuilder.BaseType);
                        if (type_ds == null) {
                                ObsoleteAttribute oa = AttributeTester.GetMemberObsoleteAttribute (base_constructor);

                                if (oa != null)
                                        AttributeTester.Report_ObsoleteMessage (oa, TypeManager.CSharpSignature (base_constructor), loc);

                                return;
                        }

                        base.CheckObsoleteAttribute (type_ds, loc);
                }

        }

        public class ConstructorThisInitializer : ConstructorInitializer {
                public ConstructorThisInitializer (ArrayList argument_list, Parameters pars, Location l) :
                        base (argument_list, pars, l)
                {
                }
        }
        
        public class Constructor : MethodCore, IMethodData {
                public ConstructorBuilder ConstructorBuilder;
                public ConstructorInitializer Initializer;
                ListDictionary declarative_security;

                // <summary>
                //   Modifiers allowed for a constructor.
                // </summary>
                public const int AllowedModifiers =
                        Modifiers.PUBLIC |
                        Modifiers.PROTECTED |
                        Modifiers.INTERNAL |
                        Modifiers.STATIC |
                        Modifiers.UNSAFE |
                        Modifiers.EXTERN |              
                        Modifiers.PRIVATE;

                bool has_compliant_args = false;
                //
                // The spec claims that static is not permitted, but
                // my very own code has static constructors.
                //
                public Constructor (TypeContainer ds, string name, int mod, Parameters args,
                                    ConstructorInitializer init, Location l)
                        : base (ds, null, null, mod, AllowedModifiers, false,
                                new MemberName (name), null, args, l)
                {
                        Initializer = init;
                }

                public override string GetSignatureForError()
                {
                        if (ConstructorBuilder == null)
                                return GetSignatureForError (Parent);

                        return TypeManager.CSharpSignature (ConstructorBuilder);
                }

                public bool HasCompliantArgs {
                        get {
                                return has_compliant_args;
                        }
                }

                public override AttributeTargets AttributeTargets {
                        get {
                                return AttributeTargets.Constructor;
                        }
                }


                //
                // Returns true if this is a default constructor
                //
                public bool IsDefault ()
                {
                        if ((ModFlags & Modifiers.STATIC) != 0)
                                return  (Parameters.FixedParameters == null ? true : Parameters.Empty) &&
                                        (Parameters.ArrayParameter == null ? true : Parameters.Empty);
                        
                        else
                                return  (Parameters.FixedParameters == null ? true : Parameters.Empty) &&
                                        (Parameters.ArrayParameter == null ? true : Parameters.Empty) &&
                                        (Initializer is ConstructorBaseInitializer) &&
                                        (Initializer.Arguments == null);
                }

                public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
                {
                        if (a.Type.IsSubclassOf (TypeManager.security_attr_type) && a.CheckSecurityActionValidity (false)) {
                                if (declarative_security == null) {
                                        declarative_security = new ListDictionary ();
                                }
                                a.ExtractSecurityPermissionSet (declarative_security);
                                return;
                        }

                        ConstructorBuilder.SetCustomAttribute (cb);
                }

                protected override bool CheckForDuplications ()
                {
                        ArrayList ar = Parent.InstanceConstructors;
                        if (ar != null) {
                                int arLen = ar.Count;
                                        
                                for (int i = 0; i < arLen; i++) {
                                        Constructor m = (Constructor) ar [i];
                                        if (IsDuplicateImplementation (m))
                                                return false;
                                }
                        }
                        return true;
                }
                        
                protected override bool CheckBase ()
                {
                        // Check whether arguments were correct.
                        if (!DoDefineParameters ())
                                return false;
                        
                        // TODO: skip the rest for generated ctor
                        if ((ModFlags & Modifiers.STATIC) != 0)
                                return true;
                        
                        if (!CheckForDuplications ())
                                return false;

                        if (Parent.Kind == Kind.Struct) {
                                if (ParameterTypes.Length == 0) {
                                Report.Error (568, Location, 
                                        "Structs can not contain explicit parameterless " +
                                        "constructors");
                                return false;
                        }
                                
                                if ((ModFlags & Modifiers.PROTECTED) != 0) {
                                        Report.Error (666, Location, "Protected member in struct declaration");
                                                return false;
                                }
                        }
                        
                        if ((RootContext.WarningLevel >= 4) && ((Parent.ModFlags & Modifiers.SEALED) != 0 && (ModFlags & Modifiers.PROTECTED) != 0)) {
                                Report.Warning (628, Location, "'{0}': new protected member declared in sealed class", GetSignatureForError (Parent));
                        }
                        
                        return true;
                }
                
                //
                // Creates the ConstructorBuilder
                //
                public override bool Define ()
                {
                        MethodAttributes ca = (MethodAttributes.RTSpecialName |
                                               MethodAttributes.SpecialName);

                        if ((ModFlags & Modifiers.STATIC) != 0){
                                ca |= MethodAttributes.Static | MethodAttributes.Private;
                        } else {
                                ca |= MethodAttributes.HideBySig;

                                if ((ModFlags & Modifiers.PUBLIC) != 0)
                                        ca |= MethodAttributes.Public;
                                else if ((ModFlags & Modifiers.PROTECTED) != 0){
                                        if ((ModFlags & Modifiers.INTERNAL) != 0)
                                                ca |= MethodAttributes.FamORAssem;
                                        else 
                                                ca |= MethodAttributes.Family;
                                } else if ((ModFlags & Modifiers.INTERNAL) != 0)
                                        ca |= MethodAttributes.Assembly;
                                else if (IsDefault ())
                                        ca |= MethodAttributes.Public;
                                else
                                        ca |= MethodAttributes.Private;
                        }

                        // Check if arguments were correct.
                        if (!CheckBase ())
                                return false;

                        ConstructorBuilder = Parent.TypeBuilder.DefineConstructor (
                                ca, CallingConventions,
                                ParameterTypes);

                        if ((ModFlags & Modifiers.UNSAFE) != 0)
                                ConstructorBuilder.InitLocals = false;
                        
                        TypeManager.AddMethod (ConstructorBuilder, this);

                        //
                        // HACK because System.Reflection.Emit is lame
                        //
                        TypeManager.RegisterMethod (ConstructorBuilder, ParameterInfo, ParameterTypes);

                        return true;
                }

                //
                // Emits the code
                //
                public override void Emit ()
                {
                        EmitContext ec = CreateEmitContext (null, null);

                        //
                        // extern methods have no bodies
                        //
                        if ((ModFlags & Modifiers.EXTERN) != 0) {
                                if ((block != null) && ((ModFlags & Modifiers.EXTERN) != 0)) {
                                        Report.Error (
                                                179, Location, "External constructor `" +
                                                TypeManager.CSharpSignature (ConstructorBuilder) +
                                                "' can not have a body");
                                        return;
                                }
                        } else if (block == null) {
                                Report.Error (
                                        501, Location, "Constructor `" +
                                        TypeManager.CSharpSignature (ConstructorBuilder) +
                                        "' must declare a body since it is not marked extern");
                                return;
                        }

                        if ((ModFlags & Modifiers.STATIC) == 0){
                                if (Parent.Kind == Kind.Class && Initializer == null)
                                        Initializer = new ConstructorBaseInitializer (
                                                null, Parameters.EmptyReadOnlyParameters, Location);


                                //
                                // Spec mandates that Initializers will not have
                                // `this' access
                                //
                                ec.IsStatic = true;
                                if (Initializer != null && !Initializer.Resolve (ConstructorBuilder, ec))
                                        return;
                                ec.IsStatic = false;
                        }

                        Parameters.LabelParameters (ec, ConstructorBuilder, Location);
                        
                        SourceMethod source = SourceMethod.Create (
                                Parent, ConstructorBuilder, block);

                        //
                        // Classes can have base initializers and instance field initializers.
                        //
                        if (Parent.Kind == Kind.Class){
                                if ((ModFlags & Modifiers.STATIC) == 0){

                                        //
                                        // If we use a "this (...)" constructor initializer, then
                                        // do not emit field initializers, they are initialized in the other constructor
                                        //
                                        if (!(Initializer != null && Initializer is ConstructorThisInitializer))
                                                Parent.EmitFieldInitializers (ec);
                                }
                        }
                        if (Initializer != null) {
                                if (GetObsoleteAttribute (Parent) == null && Parent.GetObsoleteAttribute (Parent.Parent) == null)
                                        Initializer.CheckObsoleteAttribute (Parent, Location);
                                else
                                        ec.TestObsoleteMethodUsage = false;
                                Initializer.Emit (ec);
                        }
                        
                        if ((ModFlags & Modifiers.STATIC) != 0)
                                Parent.EmitFieldInitializers (ec);

                        if (OptAttributes != null) 
                                OptAttributes.Emit (ec, this);

                        // If this is a non-static `struct' constructor and doesn't have any
                        // initializer, it must initialize all of the struct's fields.
                        if ((Parent.Kind == Kind.Struct) &&
                            ((ModFlags & Modifiers.STATIC) == 0) && (Initializer == null))
                                Block.AddThisVariable (Parent, Location);

                        ec.EmitTopBlock (block, ParameterInfo, Location);

                        if (source != null)
                                source.CloseMethod ();

                        base.Emit ();

                        if (declarative_security != null) {
                                foreach (DictionaryEntry de in declarative_security) {
                                        ConstructorBuilder.AddDeclarativeSecurity ((SecurityAction)de.Key, (PermissionSet)de.Value);
                                }
                        }

                        block = null;
                }

                // Is never override
                protected override MethodInfo FindOutBaseMethod (TypeContainer container, ref Type base_ret_type)
                {
                        return null;
                }
                                                
                protected override bool VerifyClsCompliance (DeclSpace ds)
                {
                        if (!base.VerifyClsCompliance (ds) || !IsExposedFromAssembly (ds)) {
                                return false;
                        }

                        if (parameter_types.Length > 0) {
                                ArrayList al = (ArrayList)ds.MemberCache.Members [".ctor"];
                                if (al.Count > 3)
                                        ds.MemberCache.VerifyClsParameterConflict (al, this, ConstructorBuilder);
                                
                                if (ds.TypeBuilder.IsSubclassOf (TypeManager.attribute_type)) {
                                        foreach (Type param in parameter_types) {
                                                if (param.IsArray) {
                                                        return true;
                                }
                        }
                                }
                        }
                        has_compliant_args = true;
                                return true;
                }

                #region IMethodData Members

                public System.Reflection.CallingConventions CallingConventions {
                        get {
                                CallingConventions cc = Parameters.GetCallingConvention ();

                                if (Parent.Kind == Kind.Class)
                                        if ((ModFlags & Modifiers.STATIC) == 0)
                                                cc |= CallingConventions.HasThis;

                                // FIXME: How is `ExplicitThis' used in C#?
                        
                                return cc;
                                }
                        }
                        
                public new Location Location {
                        get {
                                return base.Location;
                        }
                }

                public MemberName MethodName {
                        get {
                                return MemberName;
                        }
                }
                        
                public Type ReturnType {
                        get {
                                return MemberType;
                        }
                }

                public EmitContext CreateEmitContext (TypeContainer tc, ILGenerator ig)
                {
                        ILGenerator ig_ = ConstructorBuilder.GetILGenerator ();
                        return new EmitContext (Parent, Location, ig_, null, ModFlags, true);
                        }

                public ObsoleteAttribute GetObsoleteAttribute ()
                {
                        return null;
                }

                public bool IsExcluded(EmitContext ec)
                {
                        return false;
                }

                GenericMethod IMethodData.GenericMethod {
                        get {
                                return null;
                        }
                }

                #endregion
        }

        /// <summary>
        /// Interface for MethodData class. Holds links to parent members to avoid member duplication.
        /// </summary>
        public interface IMethodData
        {
                CallingConventions CallingConventions { get; }
                Location Location { get; }
                MemberName MethodName { get; }
                Type[] ParameterTypes { get; }
                Type ReturnType { get; }
                GenericMethod GenericMethod { get; }

                Attributes OptAttributes { get; }
                ToplevelBlock Block { get; }

                EmitContext CreateEmitContext (TypeContainer tc, ILGenerator ig);
                ObsoleteAttribute GetObsoleteAttribute ();
                string GetSignatureForError (TypeContainer tc);
                bool IsExcluded (EmitContext ec);
                bool IsClsCompliaceRequired (DeclSpace ds);
        }

        //
        // Encapsulates most of the Method's state
        //
        public class MethodData {

                readonly IMethodData method;

                //
                // The return type of this method
                //
                public readonly GenericMethod GenericMethod;
                public readonly InternalParameters ParameterInfo;

                //
                // Are we implementing an interface ?
                //
                public bool IsImplementing = false;

                //
                // Protected data.
                //
                protected MemberBase member;
                protected int modifiers;
                protected MethodAttributes flags;
                protected Type declaring_type;
                protected MethodInfo parent_method;

                EmitContext ec;

                MethodBuilder builder = null;
                public MethodBuilder MethodBuilder {
                        get {
                                return builder;
                        }
                }

                public Type DeclaringType {
                        get {
                                return declaring_type;
                        }
                }

                public MethodData (MemberBase member, InternalParameters parameters,
                                   int modifiers, MethodAttributes flags, IMethodData method)
                {
                        this.member = member;
                        this.ParameterInfo = parameters;
                        this.modifiers = modifiers;
                        this.flags = flags;

                        this.method = method;
                }

                public MethodData (MemberBase member, InternalParameters parameters,
                                   int modifiers, MethodAttributes flags, 
                                   IMethodData method, MethodBuilder builder,
                                   GenericMethod generic, MethodInfo parent_method)
                        : this (member, parameters, modifiers, flags, method)
                {
                        this.builder = builder;
                        this.GenericMethod = generic;
                        this.parent_method = parent_method;
                }

                static string RemoveArity (string name)
                {
                        int start = 0;
                        StringBuilder sb = new StringBuilder ();
                        while (start < name.Length) {
                                int pos = name.IndexOf ('`', start);
                                if (pos < 0) {
                                        sb.Append (name.Substring (start));
                                        break;
                                }

                                sb.Append (name.Substring (start, pos-start));

                                pos++;
                                while ((pos < name.Length) && Char.IsNumber (name [pos]))
                                        pos++;

                                start = pos;
                        }

                        return sb.ToString ();
                }

                public bool Define (TypeContainer container)
                {
                        MethodInfo implementing = null;

                        string prefix;
                        if (member.IsExplicitImpl)
                                prefix = member.InterfaceType.FullName + ".";
                        else
                                prefix = "";

                        string name = method.MethodName.Basename;
                        string method_name = prefix + name;

                        Type[] ParameterTypes = method.ParameterTypes;

                        if (container.Pending != null){
                                if (member is Indexer)
                                        implementing = container.Pending.IsInterfaceIndexer (
                                                member.InterfaceType, method.ReturnType, ParameterTypes);
                                else
                                        implementing = container.Pending.IsInterfaceMethod (
                                                member.InterfaceType, name, method.ReturnType, ParameterTypes);

                                if (member.InterfaceType != null){
                                        if (implementing == null){
                                                Report.Error (539, method.Location,
                                                              "'{0}' in explicit interface declaration is not a member of interface", member.GetSignatureForError () );
                                                return false;
                                        }
                                }
                        }

                        //
                        // For implicit implementations, make sure we are public, for
                        // explicit implementations, make sure we are private.
                        //
                        if (implementing != null){
                                //
                                // Setting null inside this block will trigger a more
                                // verbose error reporting for missing interface implementations
                                //
                                // The "candidate" function has been flagged already
                                // but it wont get cleared
                                //
                                if (member.IsExplicitImpl){
                                        if ((modifiers & (Modifiers.PUBLIC | Modifiers.ABSTRACT | Modifiers.VIRTUAL)) != 0){
                                                Modifiers.Error_InvalidModifier (method.Location, "public, virtual or abstract");
                                                implementing = null;
                                        }
                                } else if ((flags & MethodAttributes.MemberAccessMask) != MethodAttributes.Public){
                                        if (TypeManager.IsInterfaceType (implementing.DeclaringType)){
                                                //
                                                // If this is an interface method implementation,
                                                // check for public accessibility
                                                //
                                                implementing = null;
                                        } else if ((flags & MethodAttributes.MemberAccessMask) == MethodAttributes.Private){
                                                // We may never be private.
                                                implementing = null;
                                        } else if ((modifiers & Modifiers.OVERRIDE) == 0){
                                                //
                                                // We may be protected if we're overriding something.
                                                //
                                                implementing = null;
                                        }
                                } 
                                        
                                //
                                // Static is not allowed
                                //
                                if ((modifiers & Modifiers.STATIC) != 0){
                                        implementing = null;
                                        Modifiers.Error_InvalidModifier (method.Location, "static");
                                }
                        }
                        
                        //
                        // If implementing is still valid, set flags
                        //
                        if (implementing != null){
                                //
                                // When implementing interface methods, set NewSlot
                                // unless, we are overwriting a method.
                                //
                                if (implementing.DeclaringType.IsInterface){
                                        if ((modifiers & Modifiers.OVERRIDE) == 0)
                                                flags |= MethodAttributes.NewSlot;
                                }
                                flags |=
                                        MethodAttributes.Virtual |
                                        MethodAttributes.HideBySig;

                                // Set Final unless we're virtual, abstract or already overriding a method.
                                if ((modifiers & (Modifiers.VIRTUAL | Modifiers.ABSTRACT | Modifiers.OVERRIDE)) == 0)
                                        flags |= MethodAttributes.Final;

                                IsImplementing = true;
                        }

                        EmitContext ec = method.CreateEmitContext (container, null);

                        DefineMethodBuilder (ec, container, method_name, ParameterTypes);

                        if (builder == null)
                                return false;

                        if (container.CurrentType != null)
                                declaring_type = container.CurrentType;
                        else
                                declaring_type = container.TypeBuilder;

                        if ((modifiers & Modifiers.UNSAFE) != 0)
                                builder.InitLocals = false;

                        if (IsImplementing){
                                //
                                // clear the pending implemntation flag
                                //
                                if (member is Indexer) {
                                        container.Pending.ImplementIndexer (
                                                member.InterfaceType, builder, method.ReturnType,
                                                ParameterTypes, member.IsExplicitImpl);
                                } else
                                        container.Pending.ImplementMethod (
                                                member.InterfaceType, name, method.ReturnType,
                                                ParameterTypes, member.IsExplicitImpl);

                                if (member.IsExplicitImpl)
                                        container.TypeBuilder.DefineMethodOverride (
                                                builder, implementing);

                        }

                        TypeManager.RegisterMethod (builder, ParameterInfo, ParameterTypes);
                        TypeManager.AddMethod (builder, method);

                        if (GenericMethod != null) {
                                bool is_override = member.IsExplicitImpl |
                                        ((modifiers & Modifiers.OVERRIDE) != 0);

                                if (implementing != null)
                                        parent_method = implementing;

                                if (!GenericMethod.DefineType (ec, builder, parent_method, is_override))
                                        return false;
                        }

                        return true;
                }

                /// <summary>
                /// Create the MethodBuilder for the method 
                /// </summary>
                void DefineMethodBuilder (EmitContext ec, TypeContainer container, string method_name, Type[] ParameterTypes)
                {
                        const int extern_static = Modifiers.EXTERN | Modifiers.STATIC;

                        if ((modifiers & extern_static) == extern_static) {

                                if (method.OptAttributes != null) {
                                        Attribute dllimport_attribute = method.OptAttributes.Search (TypeManager.dllimport_type, ec);
                                        if (dllimport_attribute != null) {
                                                flags |= MethodAttributes.PinvokeImpl;
                                                builder = dllimport_attribute.DefinePInvokeMethod (
                                                        ec, container.TypeBuilder, method_name, flags,
                                                        method.ReturnType, ParameterTypes);

                                                return;
                                        }
                                }

                                // for extern static method must be specified either DllImport attribute or MethodImplAttribute.
                                // We are more strict than Microsoft and report CS0626 like error
                                if (method.OptAttributes == null ||
                                        !method.OptAttributes.Contains (TypeManager.methodimpl_attr_type, ec)) {
                                        Report.Error (626, method.Location, "Method, operator, or accessor '{0}' is marked external and has no attributes on it. Consider adding a DllImport attribute to specify the external implementation", method.GetSignatureForError (container));
                                        return;
                                }
                        }

                        if (builder == null)
                                builder = container.TypeBuilder.DefineMethod (
                                        method_name, flags, method.CallingConventions,
                                        method.ReturnType, ParameterTypes);
                        else
                                builder.SetGenericMethodSignature (
                                        flags, method.CallingConventions,
                                        method.ReturnType, ParameterTypes);
                }

                //
                // Emits the code
                // 
                public void Emit (TypeContainer container, Attributable kind)
                {
                        EmitContext ec;
                        if ((flags & MethodAttributes.PinvokeImpl) == 0)
                                ec = method.CreateEmitContext (container, builder.GetILGenerator ());
                        else
                                ec = method.CreateEmitContext (container, null);

                        if (method.GetObsoleteAttribute () != null || container.GetObsoleteAttribute (container.Parent) != null)
                                ec.TestObsoleteMethodUsage = false;

                        Location loc = method.Location;
                        Attributes OptAttributes = method.OptAttributes;

                        if (OptAttributes != null)
                                OptAttributes.Emit (ec, kind);

                        if (member is MethodCore)
                                ((MethodCore) member).Parameters.LabelParameters (ec, MethodBuilder, loc);
                        
                        ToplevelBlock block = method.Block;
                        
                        //
                        // abstract or extern methods have no bodies
                        //
                        if ((modifiers & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0){
                                if (block == null)
                                        return;

                                //
                                // abstract or extern methods have no bodies.
                                //
                                if ((modifiers & Modifiers.ABSTRACT) != 0)
                                        Report.Error (
                                                500, method.Location, "Abstract method `" +
                                                TypeManager.CSharpSignature (builder) +
                                                "' can not have a body");

                                if ((modifiers & Modifiers.EXTERN) != 0)
                                        Report.Error (
                                                179, method.Location, "External method `" +
                                                TypeManager.CSharpSignature (builder) +
                                                "' can not have a body");

                                return;
                        }

                        //
                        // Methods must have a body unless they're extern or abstract
                        //
                        if (block == null) {
                                Report.Error (
                                        501, method.Location, "Method `" +
                                        TypeManager.CSharpSignature (builder) +
                                        "' must declare a body since it is not marked " +
                                        "abstract or extern");
                                return;
                        }

                        SourceMethod source = SourceMethod.Create (
                                container, MethodBuilder, method.Block);

                        //
                        // Handle destructors specially
                        //
                        // FIXME: This code generates buggy code
                        //
                        if (member is Destructor)
                                EmitDestructor (ec, block);
                        else
                                ec.EmitTopBlock (block, ParameterInfo, loc);

                        if (source != null)
                                source.CloseMethod ();
                }

                void EmitDestructor (EmitContext ec, ToplevelBlock block)
                {
                        ILGenerator ig = ec.ig;
                        
                        Label finish = ig.DefineLabel ();

                        block.SetDestructor ();
                        
                        ig.BeginExceptionBlock ();
                        ec.ReturnLabel = finish;
                        ec.HasReturnLabel = true;
                        ec.EmitTopBlock (block, null, method.Location);
                        
                        // ig.MarkLabel (finish);
                        ig.BeginFinallyBlock ();
                        
                        if (ec.ContainerType.BaseType != null) {
                                Expression member_lookup = Expression.MemberLookup (
                                        ec, ec.ContainerType.BaseType, null, ec.ContainerType.BaseType,
                                        "Finalize", MemberTypes.Method, Expression.AllBindingFlags, method.Location);

                                if (member_lookup != null){
                                        MethodGroupExpr base_destructor = ((MethodGroupExpr) member_lookup);
                                
                                        ig.Emit (OpCodes.Ldarg_0);
                                        ig.Emit (OpCodes.Call, (MethodInfo) base_destructor.Methods [0]);
                                }
                        }
                        
                        ig.EndExceptionBlock ();
                        //ig.MarkLabel (ec.ReturnLabel);
                        ig.Emit (OpCodes.Ret);
                }
        }

        public class Destructor : Method {

                public Destructor (TypeContainer ds, Expression return_type, int mod, string name,
                                   Parameters parameters, Attributes attrs, Location l)
                        : base (ds, null, return_type, mod, false, new MemberName (name),
                                parameters, attrs, l)
                { }

                public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
                {
                        if (a.Type == TypeManager.conditional_attribute_type) {
                                Report.Error (577, Location, "Conditional not valid on '{0}' because it is a destructor, operator, or explicit interface implementation", GetSignatureForError ());
                                return;
                        }

                        base.ApplyAttributeBuilder (a, cb);
                }
        }
        
        abstract public class MemberBase : MemberCore {
                public Expression Type;

                public MethodAttributes flags;

                protected readonly int explicit_mod_flags;

                //
                // The "short" name of this property / indexer / event.  This is the
                // name without the explicit interface.
                //
                public string ShortName;

                //
                // The type of this property / indexer / event
                //
                public Type MemberType;

                //
                // If true, this is an explicit interface implementation
                //
                public bool IsExplicitImpl = false;

                //
                // The name of the interface we are explicitly implementing
                //
                public MemberName ExplicitInterfaceName = null;

                //
                // Whether this is an interface member.
                //
                public bool IsInterface;

                //
                // If true, the interface type we are explicitly implementing
                //
                public Type InterfaceType = null;

                //
                // The constructor is only exposed to our children
                //
                protected MemberBase (TypeContainer parent, Expression type, int mod,
                                      int allowed_mod, int def_mod, MemberName name,
                                      Attributes attrs, Location loc)
                        : base (parent, name, attrs, loc)
                {
                        explicit_mod_flags = mod;
                        Type = type;
                        ModFlags = Modifiers.Check (allowed_mod, mod, def_mod, loc);

                        // Check for explicit interface implementation
                        if (MemberName.Left != null) {
                                ExplicitInterfaceName = MemberName.Left;
                                ShortName = MemberName.Name;
                                IsExplicitImpl = true;
                        } else
                                ShortName = Name;
                }

                protected virtual bool CheckBase ()
                {
                        if ((ModFlags & Modifiers.PROTECTED) != 0 && Parent.Kind == Kind.Struct) {
                                Report.Error (666, Location, "Protected member in struct declaration");
                                return false;
                        }

                        if ((RootContext.WarningLevel >= 4) &&
                            ((Parent.ModFlags & Modifiers.SEALED) != 0) &&
                            ((ModFlags & Modifiers.PROTECTED) != 0) &&
                            ((ModFlags & Modifiers.OVERRIDE) == 0) && (Name != "Finalize")) {
                                Report.Warning (628, Location, "'{0}': new protected member declared in sealed class", GetSignatureForError (Parent));
                        }

                        return true;
                }

                protected abstract bool CheckGenericOverride (MethodInfo method, string name);

                protected virtual bool CheckParameters (DeclSpace ds, Type [] parameters)
                {
                        bool error = false;

                        foreach (Type partype in parameters){
                                if (partype == TypeManager.void_type) {
                                        Report.Error (
                                                1547, Location, "Keyword 'void' cannot " +
                                                "be used in this context");
                                        return false;
                                }

                                if (partype.IsPointer){
                                        if (!UnsafeOK (ds))
                                                error = true;
                                        if (!TypeManager.VerifyUnManaged (TypeManager.GetElementType (partype), Location))
                                                error = true;
                                }

                                if (ds.AsAccessible (partype, ModFlags))
                                        continue;

                                if (this is Indexer)
                                        Report.Error (55, Location,
                                                      "Inconsistent accessibility: parameter type `" +
                                                      TypeManager.CSharpName (partype) + "' is less " +
                                                      "accessible than indexer `" + Name + "'");
                                else if ((this is Method) && ((Method) this).IsOperator)
                                        Report.Error (57, Location,
                                                      "Inconsistent accessibility: parameter type `" +
                                                      TypeManager.CSharpName (partype) + "' is less " +
                                                      "accessible than operator `" + Name + "'");
                                else
                                        Report.Error (51, Location,
                                                      "Inconsistent accessibility: parameter type `" +
                                                      TypeManager.CSharpName (partype) + "' is less " +
                                                      "accessible than method `" + Name + "'");
                                error = true;
                        }

                        return !error;
                }

                protected virtual bool DoDefineBase ()
                {
                        EmitContext ec = Parent.EmitContext;
                        if (ec == null)
                                throw new InternalErrorException ("MemberBase.DoDefine called too early");

                        if (Name == null)
                                throw new InternalErrorException ();

                        if (IsInterface) {
                                ModFlags = Modifiers.PUBLIC |
                                        Modifiers.ABSTRACT |
                                        Modifiers.VIRTUAL | (ModFlags & Modifiers.UNSAFE) | (ModFlags & Modifiers.NEW);

                                flags = MethodAttributes.Public |
                                        MethodAttributes.Abstract |
                                        MethodAttributes.HideBySig |
                                        MethodAttributes.NewSlot |
                                        MethodAttributes.Virtual;
                        } else {
                                if (!Parent.MethodModifiersValid (this))
                                        return false;

                                flags = Modifiers.MethodAttr (ModFlags);
                        }

                        return true;
                }

                protected virtual bool DoDefine (DeclSpace decl)
                {
                        EmitContext ec = decl.EmitContext;
                        if (ec == null)
                                throw new InternalErrorException ("MemberBase.DoDefine called too early");

                        ec.InUnsafe = InUnsafe;

                        // Lookup Type, verify validity
                        bool old_unsafe = ec.InUnsafe;
                        ec.InUnsafe = InUnsafe;
                        TypeExpr texpr = Type.ResolveAsTypeTerminal (ec);
                        ec.InUnsafe = old_unsafe;

                        if (texpr == null)
                                return false;

                        MemberType = texpr.Type;

                        if ((Parent.ModFlags & Modifiers.SEALED) != 0){
                                if ((ModFlags & (Modifiers.VIRTUAL|Modifiers.ABSTRACT)) != 0){
                                        Report.Error (549, Location, "Virtual method can not be contained in sealed class");
                                        return false;
                                }
                        }
                        
                        // verify accessibility
                        if (!Parent.AsAccessible (MemberType, ModFlags)) {
                                Report.SymbolRelatedToPreviousError (MemberType);
                                if (this is Property)
                                        Report.Error (53, Location,
                                                      "Inconsistent accessibility: property type `" +
                                                      TypeManager.CSharpName (MemberType) + "' is less " +
                                                      "accessible than property `" + GetSignatureForError () + "'");
                                else if (this is Indexer)
                                        Report.Error (54, Location,
                                                      "Inconsistent accessibility: indexer return type `" +
                                                      TypeManager.CSharpName (MemberType) + "' is less " +
                                                      "accessible than indexer `" + Name + "'");
                                else if (this is MethodCore) {
                                        if (this is Operator)
                                                Report.Error (56, Location,
                                                              "Inconsistent accessibility: return type `" +
                                                              TypeManager.CSharpName (MemberType) + "' is less " +
                                                              "accessible than operator `" + Name + "'");
                                        else
                                                Report.Error (50, Location,
                                                              "Inconsistent accessibility: return type `" +
                                                              TypeManager.CSharpName (MemberType) + "' is less " +
                                                              "accessible than method `" + Name + "'");
                                } else {
                                        Report.Error (52, Location,
                                                      "Inconsistent accessibility: field type `" +
                                                      TypeManager.CSharpName (MemberType) + "' is less " +
                                                      "accessible than field `" + Name + "'");
                                }
                                return false;
                        }

                        if (MemberType.IsPointer && !UnsafeOK (Parent))
                                return false;

                        if (IsExplicitImpl) {
                                Expression expr = ExplicitInterfaceName.GetTypeExpression (Location);
                                TypeExpr iface_texpr = expr.ResolveAsTypeTerminal (ec);
                                if (iface_texpr == null)
                                        return false;

                                InterfaceType = iface_texpr.Type;

                                if (!InterfaceType.IsInterface) {
                                        Report.Error (538, Location, "'{0}' in explicit interface declaration is not an interface", TypeManager.CSharpName (InterfaceType));
                                        return false;
                                }

                                if (!Parent.VerifyImplements (InterfaceType, ShortName, Name, Location))
                                        return false;
                                
                                Modifiers.Check (Modifiers.AllowedExplicitImplFlags, explicit_mod_flags, 0, Location);
                        }

                        return true;
                }

                /// <summary>
                /// The name of the member can be changed during definition (see IndexerName attribute)
                /// </summary>
                protected virtual void UpdateMemberName ()
                {
                        MemberName.Name = ShortName;
                }

                public override string GetSignatureForError (TypeContainer tc)
                {
                        return String.Concat (tc.Name, '.', base.GetSignatureForError (tc));
                }

                protected bool IsTypePermitted ()
                {
                        if (MemberType == TypeManager.arg_iterator_type || MemberType == TypeManager.typed_reference_type) {
                                Report.Error (610, Location, "Field or property cannot be of type '{0}'", TypeManager.CSharpName (MemberType));
                                return false;
                        }
                        return true;
                }

                protected override bool VerifyClsCompliance(DeclSpace ds)
                {
                        if (base.VerifyClsCompliance (ds)) {
                                return true;
                        }

                        if (IsInterface && HasClsCompliantAttribute && ds.IsClsCompliaceRequired (ds)) {
                                Report.Error (3010, Location, "'{0}': CLS-compliant interfaces must have only CLS-compliant members", GetSignatureForError ());
                        }
                        return false;
                }

                protected override void VerifyObsoleteAttribute()
                {
                        CheckUsageOfObsoleteAttribute (MemberType);
                }
        }

        //
        // Fields and Events both generate FieldBuilders, we use this to share 
        // their common bits.  This is also used to flag usage of the field
        //
        abstract public class FieldBase : MemberBase {
                public FieldBuilder  FieldBuilder;
                public Status status;

                [Flags]
                public enum Status : byte {
                        ASSIGNED = 1,
                        USED = 2,
                        HAS_OFFSET = 4          // Used by FieldMember.
                }

                static string[] attribute_targets = new string [] { "field" };

                /// <summary>
                ///  Symbol with same name in base class/struct
                /// </summary>
                public MemberInfo conflict_symbol;

                //
                // The constructor is only exposed to our children
                //
                protected FieldBase (TypeContainer parent, Expression type, int mod,
                                     int allowed_mod, MemberName name, object init,
                                     Attributes attrs, Location loc)
                        : base (parent, type, mod, allowed_mod, Modifiers.PRIVATE,
                                name, attrs, loc)
                {
                        this.init = init;
                }

                public override AttributeTargets AttributeTargets {
                        get {
                                return AttributeTargets.Field;
                        }
                }

                public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
                {
                        if (a.Type == TypeManager.marshal_as_attr_type) {
                                UnmanagedMarshal marshal = a.GetMarshal (this);
                                if (marshal != null) {
                                        FieldBuilder.SetMarshal (marshal);
                                }
                                        return;
                                }

                        if (a.Type.IsSubclassOf (TypeManager.security_attr_type)) {
                                a.Error_InvalidSecurityParent ();
                                return;
                        }

                        FieldBuilder.SetCustomAttribute (cb);
                }

                //
                // Whether this field has an initializer.
                //
                public bool HasInitializer {
                        get {
                                return init != null;
                        }
                }

                protected readonly Object init;
                // Private.
                Expression init_expr;
                bool init_expr_initialized = false;

                protected override bool CheckGenericOverride (MethodInfo method, string name)
                {
                        return true;
                }

                //
                // Resolves and returns the field initializer.
                //
                public Expression GetInitializerExpression (EmitContext ec)
                {
                        if (init_expr_initialized)
                                return init_expr;

                        Expression e;
                        if (init is Expression)
                                e = (Expression) init;
                        else
                                e = new ArrayCreation (Type, "", (ArrayList)init, Location);

                        ec.IsFieldInitializer = true;
                        e = e.DoResolve (ec);
                        ec.IsFieldInitializer = false;

                        init_expr = e;
                        init_expr_initialized = true;

                        return init_expr;
                }

                protected override bool CheckBase ()
                {
                        if (!base.CheckBase ())
                                return false;

                        // TODO: Implement
                        if (IsInterface)
                                return true;

                        conflict_symbol = Parent.FindBaseMemberWithSameName (Name, false);
                        if (conflict_symbol == null) {
                                if ((RootContext.WarningLevel >= 4) && ((ModFlags & Modifiers.NEW) != 0)) {
                                        Report.Warning (109, Location, "The member '{0}' does not hide an inherited member. The new keyword is not required", GetSignatureForError (Parent));
                                }
                                return true;
                        }

                        if ((ModFlags & (Modifiers.NEW | Modifiers.OVERRIDE)) == 0) {
                                Report.SymbolRelatedToPreviousError (conflict_symbol);
                                Report.Warning (108, Location, "The keyword new is required on '{0}' because it hides inherited member", GetSignatureForError (Parent));
                        }

                        return true;
                }

                protected override bool DoDefine (DeclSpace ds)
                {
                        if (!base.DoDefine (ds))
                                return false;

                        if (MemberType == TypeManager.void_type) {
                                Report.Error (1547, Location,
                                              "Keyword 'void' cannot be used in this context");
                                return false;
                        }
                        return true;
                }

                public override string GetSignatureForError ()
                {
                        if (FieldBuilder == null) {
                                return base.GetSignatureForError (Parent);
                        }
                        return TypeManager.GetFullNameSignature (FieldBuilder);
                }

                protected virtual bool IsFieldClsCompliant {
                        get {
                                if (FieldBuilder == null)
                                        return true;

                                return AttributeTester.IsClsCompliant (FieldBuilder.FieldType);
                        }
                }

                public override string[] ValidAttributeTargets {
                        get {
                                return attribute_targets;
                        }
                }

                protected override bool VerifyClsCompliance (DeclSpace ds)
                {
                        if (!base.VerifyClsCompliance (ds))
                                return false;

                        if (!IsFieldClsCompliant) {
                                Report.Error (3003, Location, "Type of '{0}' is not CLS-compliant", GetSignatureForError ());
                        }
                        return true;
                }


                public void SetAssigned ()
                {
                        status |= Status.ASSIGNED;
                }
        }

        public abstract class FieldMember: FieldBase
        {
                

                protected FieldMember (TypeContainer parent, Expression type, int mod,
                        int allowed_mod, MemberName name, object init, Attributes attrs, Location loc)
                        : base (parent, type, mod, allowed_mod, name, init, attrs, loc)
                {
                }

                public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
                {
                        if (a.Type == TypeManager.field_offset_attribute_type)
                        {
                                status |= Status.HAS_OFFSET;

                                if (!Parent.HasExplicitLayout) {
                                        Report.Error (636, Location, "The FieldOffset attribute can only be placed on members of types marked with the StructLayout(LayoutKind.Explicit)");
                                        return;
                                }

                                if ((ModFlags & Modifiers.STATIC) != 0 || this is Const) {
                                        Report.Error (637, Location, "The FieldOffset attribute is not allowed on static or const fields");
                                        return;
                                }
                        }
                        base.ApplyAttributeBuilder (a, cb);
                }


                public override bool Define()
                {
                        EmitContext ec = Parent.EmitContext;
                        if (ec == null)
                                throw new InternalErrorException ("FieldMember.Define called too early");

                        bool old_unsafe = ec.InUnsafe;
                        ec.InUnsafe = InUnsafe;
                        TypeExpr texpr = Type.ResolveAsTypeTerminal (ec);
                        ec.InUnsafe = old_unsafe;
                        if (texpr == null)
                                return false;
                        
                        MemberType = texpr.Type;

                        ec.InUnsafe = old_unsafe;

                        if (MemberType == TypeManager.void_type) {
                                Report.Error (1547, Location, "Keyword 'void' cannot be used in this context");
                                return false;
                        }

                        if (!CheckBase ())
                                return false;
                        
                        if (!Parent.AsAccessible (MemberType, ModFlags)) {
                                Report.Error (52, Location,
                                        "Inconsistent accessibility: field type `" +
                                        TypeManager.CSharpName (MemberType) + "' is less " +
                                        "accessible than field `" + Name + "'");
                                return false;
                        }

                        if (!IsTypePermitted ())
                                return false;

                        if (MemberType.IsPointer && !UnsafeOK (Parent))
                                return false;

                        return true;
                }

                public override void Emit ()
                {
                        if (OptAttributes != null) {
                                EmitContext ec = new EmitContext (Parent, Location, null, FieldBuilder.FieldType, ModFlags);
                                OptAttributes.Emit (ec, this);
                        }

                        if (Parent.HasExplicitLayout && ((status & Status.HAS_OFFSET) == 0) && (ModFlags & Modifiers.STATIC) == 0) {
                                Report.Error (625, Location, "'{0}': Instance field types marked with StructLayout(LayoutKind.Explicit) must have a FieldOffset attribute.", GetSignatureForError ());
                        }

                        base.Emit ();
                }

                //
                //   Represents header string for documentation comment.
                //
                public override string DocCommentHeader {
                        get { return "F:"; }
                }
        }

        interface IFixedBuffer
        {
                FieldInfo Element { get; }
                Type ElementType { get; }
        }

        public class FixedFieldExternal: IFixedBuffer
        {
                FieldInfo element_field;

                public FixedFieldExternal (FieldInfo fi)
                {
                        element_field = fi.FieldType.GetField (FixedField.FixedElementName);
                }

                #region IFixedField Members

                public FieldInfo Element {
                        get {
                                return element_field;
                        }
                }

                public Type ElementType {
                        get {
                                return element_field.FieldType;
                        }
                }

                #endregion
        }

        /// <summary>
        /// Fixed buffer implementation
        /// </summary>
        public class FixedField: FieldMember, IFixedBuffer
        {
                public const string FixedElementName = "FixedElementField";
                static int GlobalCounter = 0;
                static object[] ctor_args = new object[] { (short)LayoutKind.Sequential };
                static FieldInfo[] fi;

                TypeBuilder fixed_buffer_type;
                FieldBuilder element;
                Expression size_expr;
                int buffer_size;

                const int AllowedModifiers =
                        Modifiers.NEW |
                        Modifiers.PUBLIC |
                        Modifiers.PROTECTED |
                        Modifiers.INTERNAL |
                        Modifiers.PRIVATE;

                public FixedField (TypeContainer parent, Expression type, int mod, string name,
                        Expression size_expr, Attributes attrs, Location loc):
                        base (parent, type, mod, AllowedModifiers, new MemberName (name), null, attrs, loc)
                {
                        if (RootContext.Version == LanguageVersion.ISO_1)
                                Report.FeatureIsNotStandardized (loc, "fixed sized buffers");

                        this.size_expr = size_expr;
                }

                public override bool Define()
                {
#if !NET_2_0
                        if ((ModFlags & (Modifiers.PUBLIC | Modifiers.PROTECTED)) != 0)
                                Report.Warning (-23, Location, "Only not private or internal fixed sized buffers are supported by .NET 1.x");
#endif

                        if (Parent.Kind != Kind.Struct) {
                                Report.Error (1642, Location, "Fixed buffer fields may only be members of structs");
                                return false;
                        }

                        if (!base.Define ())
                                return false;

                        if (!MemberType.IsPrimitive) {
                                Report.Error (1663, Location, "Fixed sized buffer type must be one of the following: bool, byte, short, int, long, char, sbyte, ushort, uint, ulong, float or double");
                                return false;
                        }

                        Expression e = size_expr.Resolve (Parent.EmitContext);
                        if (e == null)
                                return false;

                        Constant c = e as Constant;
                        if (c == null) {
                                Report.Error (133, Location, "The expression being assigned to '{0}' must be constant", GetSignatureForError ());
                                return false;
                        }

                        buffer_size = (int)c.GetValue ();
                        if (buffer_size <= 0) {
                                Report.Error (1665, Location, "Fixed sized buffer '{0}' must have a length greater than zero", GetSignatureForError ());
                                return false;
                        }
                        buffer_size *= Expression.GetTypeSize (MemberType);

                        // Define nested
                        string name = String.Format ("<{0}>__FixedBuffer{1}", Name, GlobalCounter++);

                        fixed_buffer_type = Parent.TypeBuilder.DefineNestedType (name,
                                TypeAttributes.NestedPublic | TypeAttributes.Sealed | TypeAttributes.BeforeFieldInit, TypeManager.value_type);
                        element = fixed_buffer_type.DefineField (FixedElementName, MemberType, FieldAttributes.Public);
                        RootContext.RegisterCompilerGeneratedType (fixed_buffer_type);

                        FieldBuilder = Parent.TypeBuilder.DefineField (Name, fixed_buffer_type, Modifiers.FieldAttr (ModFlags));
                        TypeManager.RegisterFieldBase (FieldBuilder, this);

                        return true;
                }

                public override void Emit()
                {
                        if (fi == null)
                                fi = new FieldInfo [] { TypeManager.struct_layout_attribute_type.GetField ("Size") };

                        object[] fi_val = new object[1];
                        fi_val [0] = buffer_size;

                        CustomAttributeBuilder cab = new CustomAttributeBuilder (TypeManager.struct_layout_attribute_ctor, 
                                ctor_args, fi, fi_val);
                        fixed_buffer_type.SetCustomAttribute (cab);

#if NET_2_0
                        cab = new CustomAttributeBuilder (TypeManager.fixed_buffer_attr_ctor, new object[] { MemberType, buffer_size } );
                        FieldBuilder.SetCustomAttribute (cab);
#endif
                        base.Emit ();
                }

                protected override bool IsFieldClsCompliant {
                        get {
                                return false;
                        }
                }

                #region IFixedField Members

                public FieldInfo Element {
                        get {
                                return element;
                        }
                }

                public Type ElementType {
                        get {
                                return MemberType;
                        }
                }

                #endregion
        }

        //
        // The Field class is used to represents class/struct fields during parsing.
        //
        public class Field : FieldMember {
                // <summary>
                //   Modifiers allowed in a class declaration
                // </summary>
                const int AllowedModifiers =
                        Modifiers.NEW |
                        Modifiers.PUBLIC |
                        Modifiers.PROTECTED |
                        Modifiers.INTERNAL |
                        Modifiers.PRIVATE |
                        Modifiers.STATIC |
                        Modifiers.VOLATILE |
                        Modifiers.UNSAFE |
                        Modifiers.READONLY;

                public Field (TypeContainer parent, Expression type, int mod, string name,
                              Object expr_or_array_init, Attributes attrs, Location loc)
                        : base (parent, type, mod, AllowedModifiers, new MemberName (name),
                                expr_or_array_init, attrs, loc)
                {
                }

                public override bool Define ()
                {
                        if (!base.Define ())
                                return false;

                        if (RootContext.WarningLevel > 1){
                                Type ptype = Parent.TypeBuilder.BaseType;

                                // ptype is only null for System.Object while compiling corlib.
                                if (ptype != null){
                                        TypeContainer.FindMembers (
                                                ptype, MemberTypes.Method,
                                                BindingFlags.Public |
                                                BindingFlags.Static | BindingFlags.Instance,
                                                System.Type.FilterName, Name);
                                }
                        }

                        if ((ModFlags & Modifiers.VOLATILE) != 0){
                                if (!MemberType.IsClass){
                                        Type vt = MemberType;
                                        
                                        if (TypeManager.IsEnumType (vt))
                                                vt = TypeManager.EnumToUnderlying (MemberType);

                                        if (!((vt == TypeManager.bool_type) ||
                                              (vt == TypeManager.sbyte_type) ||
                                              (vt == TypeManager.byte_type) ||
                                              (vt == TypeManager.short_type) ||
                                              (vt == TypeManager.ushort_type) ||
                                              (vt == TypeManager.int32_type) ||
                                              (vt == TypeManager.uint32_type) ||    
                                              (vt == TypeManager.char_type) ||
                                              (vt == TypeManager.float_type) ||
                                              (!vt.IsValueType))){
                                                Report.Error (
                                                        677, Location, Parent.MakeName (Name) +
                                                        " A volatile field can not be of type `" +
                                                        TypeManager.CSharpName (vt) + "'");
                                                return false;
                                        }
                                }

                                if ((ModFlags & Modifiers.READONLY) != 0){
                                        Report.Error (
                                                      678, Location,
                                                      "A field can not be both volatile and readonly");
                                        return false;
                                }
                        }

                        FieldAttributes fa = Modifiers.FieldAttr (ModFlags);

                        if (Parent.Kind == Kind.Struct && 
                            ((fa & FieldAttributes.Static) == 0) &&
                            MemberType == Parent.TypeBuilder &&
                            !TypeManager.IsBuiltinType (MemberType)){
                                Report.Error (523, Location, "Struct member `" + Parent.Name + "." + Name + 
                                              "' causes a cycle in the structure layout");
                                return false;
                        }

                        try {
                                FieldBuilder = Parent.TypeBuilder.DefineField (
                                        Name, MemberType, Modifiers.FieldAttr (ModFlags));

                        TypeManager.RegisterFieldBase (FieldBuilder, this);
                        }
                        catch (ArgumentException) {
                                Report.Warning (-24, Location, "The Microsoft runtime is unable to use [void|void*] as a field type, try using the Mono runtime.");
                                return false;
                        }

                        return true;
                }
        }

        //
        // `set' and `get' accessors are represented with an Accessor.
        // 
        public class Accessor {
                //
                // Null if the accessor is empty, or a Block if not
                //
                public const int AllowedModifiers = 
                        Modifiers.PUBLIC |
                        Modifiers.PROTECTED |
                        Modifiers.INTERNAL |
                        Modifiers.PRIVATE;
                
                public ToplevelBlock Block;
                public Attributes Attributes;
                public Location Location;
                public int ModFlags;
                
                public Accessor (ToplevelBlock b, int mod, Attributes attrs, Location loc)
                {
                        Block = b;
                        Attributes = attrs;
                        Location = loc;
                        ModFlags = Modifiers.Check (AllowedModifiers, mod, 0, loc);
                }
        }


        // Ooouh Martin, templates are missing here.
        // When it will be possible move here a lot of child code and template method type.
        public abstract class AbstractPropertyEventMethod: MemberCore, IMethodData {
                protected MethodData method_data;
                protected ToplevelBlock block;
                protected ListDictionary declarative_security;

                // The accessor are created event if they are not wanted.
                // But we need them because their names are reserved.
                // Field says whether accessor will be emited or not
                public readonly bool IsDummy;

                protected readonly string prefix;

                ReturnParameter return_attributes;

                public AbstractPropertyEventMethod (MemberBase member, string prefix)
                        : base (null, SetupName (prefix, member), null, member.Location)
                {
                        this.prefix = prefix;
                        IsDummy = true;
                }

                public AbstractPropertyEventMethod (MemberBase member, Accessor accessor,
                                                    string prefix)
                        : base (null, SetupName (prefix, member),
                                accessor.Attributes, accessor.Location)
                {
                        this.prefix = prefix;
                        this.block = accessor.Block;
                }

                static MemberName SetupName (string prefix, MemberBase member)
                {
                        MemberName name = member.MemberName.Clone ();
                        name.Name = prefix + member.ShortName;
                        return name;
                }

                public void UpdateName (MemberBase member)
                {
                        MemberName.Name = prefix + member.ShortName;
                }

                #region IMethodData Members

                public ToplevelBlock Block {
                        get {
                                return block;
                        }

                        set {
                                block = value;
                        }
                }

                public CallingConventions CallingConventions {
                        get {
                                return CallingConventions.Standard;
                        }
                }

                public bool IsExcluded (EmitContext ec)
                {
                        return false;
                }

                GenericMethod IMethodData.GenericMethod {
                        get {
                                return null;
                        }
                }

                public MemberName MethodName {
                        get {
                                return MemberName;
                        }
                }

                public abstract ObsoleteAttribute GetObsoleteAttribute ();
                public abstract Type[] ParameterTypes { get; }
                public abstract Type ReturnType { get; }
                public abstract EmitContext CreateEmitContext(TypeContainer tc, ILGenerator ig);

                #endregion

                public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
                {
                        if (a.Type == TypeManager.cls_compliant_attribute_type || a.Type == TypeManager.obsolete_attribute_type ||
                                        a.Type == TypeManager.conditional_attribute_type) {
                                Report.Error (1667, a.Location, "'{0}' is not valid on property or event accessors. It is valid on {1} declarations only", TypeManager.CSharpName (a.Type), a.GetValidTargets ());
                                return;
                        }

                        if (a.Type.IsSubclassOf (TypeManager.security_attr_type) && a.CheckSecurityActionValidity (false)) {
                                if (declarative_security == null)
                                        declarative_security = new ListDictionary ();
                                a.ExtractSecurityPermissionSet (declarative_security);
                                return;
                        }

                        if (a.Target == AttributeTargets.Method) {
                                method_data.MethodBuilder.SetCustomAttribute (cb);
                                return;
                        }

                        if (a.Target == AttributeTargets.ReturnValue) {
                                if (return_attributes == null)
                                        return_attributes = new ReturnParameter (method_data.MethodBuilder, Location);

                                return_attributes.ApplyAttributeBuilder (a, cb);
                                return;
                        }

                        ApplyToExtraTarget (a, cb);
                }

                virtual protected void ApplyToExtraTarget (Attribute a, CustomAttributeBuilder cb)
                {
                        System.Diagnostics.Debug.Fail ("You forgot to define special attribute target handling");
                }

                public override bool Define()
                {
                        throw new NotSupportedException ();
                }

                public virtual void Emit (TypeContainer container)
                {
                        method_data.Emit (container, this);

                        if (declarative_security != null) {
                                foreach (DictionaryEntry de in declarative_security) {
                                        method_data.MethodBuilder.AddDeclarativeSecurity ((SecurityAction)de.Key, (PermissionSet)de.Value);
                                }
                        }

                        block = null;
                }

                public override bool IsClsCompliaceRequired(DeclSpace ds)
                {
                        return false;
                }

                public bool IsDuplicateImplementation (MethodCore method)
                {
                        if (Name != method.Name)
                                return false;

                        Type[] param_types = method.ParameterTypes;

                        if (param_types.Length != ParameterTypes.Length)
                                return false;

                        for (int i = 0; i < param_types.Length; i++)
                                if (param_types [i] != ParameterTypes [i])
                                        return false;

                        Report.SymbolRelatedToPreviousError (method);
                        Report.Error (111, Location, "Type '{0}' already defines a member called '{1}' with " +
                                      "the same parameter types", Parent.Name, Name);
                        return true;
                }

                public new Location Location { 
                        get {
                                return base.Location;
                        }
                }

                //
                //   Represents header string for documentation comment.
                //
                public override string DocCommentHeader {
                        get { throw new InvalidOperationException ("Unexpected attempt to get doc comment from " + this.GetType () + "."); }
                }

                protected override void VerifyObsoleteAttribute()
                {
                }

        }

        //
        // Properties and Indexers both generate PropertyBuilders, we use this to share 
        // their common bits.
        //
        abstract public class PropertyBase : MethodCore {

                public class GetMethod: PropertyMethod
                {
                        static string[] attribute_targets = new string [] { "method", "return" };

                        public GetMethod (MethodCore method):
                                base (method, "get_")
                        {
                        }

                        public GetMethod (MethodCore method, Accessor accessor):
                                base (method, accessor, "get_")
                        {
                        }

                        public override MethodBuilder Define(TypeContainer container)
                        {
                                base.Define (container);
                                
                                method_data = new MethodData (method, method.ParameterInfo, ModFlags, flags, this);

                                if (!method_data.Define (container))
                                        return null;

                                return method_data.MethodBuilder;
                        }

                        public override string GetSignatureForError (TypeContainer tc)
                        {
                                return String.Concat (base.GetSignatureForError (tc), ".get");
                        }

                        public override Type ReturnType {
                                get {
                                        return method.MemberType;
                                }
                        }

                        public override string[] ValidAttributeTargets {
                                get {
                                        return attribute_targets;
                                }
                        }
                }

                public class SetMethod: PropertyMethod {

                        static string[] attribute_targets = new string [] { "method", "param", "return" };
                       ImplicitParameter param_attr;

                        public SetMethod (MethodCore method):
                                base (method, "set_")
                        {
                        }

                        public SetMethod (MethodCore method, Accessor accessor):
                                base (method, accessor, "set_")
                        {
                        }

                        protected override void ApplyToExtraTarget(Attribute a, CustomAttributeBuilder cb)
                        {
                                if (a.Target == AttributeTargets.Parameter) {
                                        if (param_attr == null)
                                               param_attr = new ImplicitParameter (method_data.MethodBuilder);

                                        param_attr.ApplyAttributeBuilder (a, cb);
                                        return;
                                }

                                base.ApplyAttributeBuilder (a, cb);
                        }

                        protected virtual InternalParameters GetParameterInfo (EmitContext ec)
                        {
                                Parameter [] parms = new Parameter [1];
                                parms [0] = new Parameter (method.Type, "value", Parameter.Modifier.NONE, null);
                                Parameters parameters = new Parameters (parms, null, method.Location);

                                bool old_unsafe = ec.InUnsafe;
                                ec.InUnsafe = InUnsafe;
                                Type [] types = parameters.GetParameterInfo (ec);
                                ec.InUnsafe = old_unsafe;

                                return new InternalParameters (types, parameters);
                        }

                        public override MethodBuilder Define (TypeContainer container)
                        {
                                if (container.EmitContext == null)
                                        throw new InternalErrorException ("SetMethod.Define called too early");
                                        
                                base.Define (container);
                                
                                method_data = new MethodData (method, GetParameterInfo (container.EmitContext), ModFlags, flags, this);

                                if (!method_data.Define (container))
                                        return null;

                                return method_data.MethodBuilder;
                        }

                        public override string GetSignatureForError (TypeContainer tc)
                        {
                                return String.Concat (base.GetSignatureForError (tc), ".set");
                        }

                        public override Type[] ParameterTypes {
                                get {
                                        return new Type[] { method.MemberType };
                                }
                        }

                        public override Type ReturnType {
                                get {
                                        return TypeManager.void_type;
                                }
                        }

                        public override string[] ValidAttributeTargets {
                                get {
                                        return attribute_targets;
                                }
                        }
                }

                static string[] attribute_targets = new string [] { "property" };

                public abstract class PropertyMethod: AbstractPropertyEventMethod {
                        protected readonly MethodCore method;
                        protected MethodAttributes flags;

                        public PropertyMethod (MethodCore method, string prefix)
                                : base (method, prefix)
                        {
                                this.method = method;
                                Parent = method.Parent;
                        }

                        public PropertyMethod (MethodCore method, Accessor accessor, string prefix)
                                : base (method, accessor, prefix)
                        {
                                this.method = method;
                                Parent = method.Parent;
                                this.ModFlags = accessor.ModFlags;

                                if (accessor.ModFlags != 0 && RootContext.Version == LanguageVersion.ISO_1) {
                                        Report.FeatureIsNotStandardized (Location, "accessor modifiers");
                                        Environment.Exit (1);
                                }
                        }

                        public override AttributeTargets AttributeTargets {
                                get {
                                        return AttributeTargets.Method;
                                }
                        }

                        public override bool IsClsCompliaceRequired(DeclSpace ds)
                        {
                                return method.IsClsCompliaceRequired (ds);
                        }

                        public InternalParameters ParameterInfo 
                        {
                                get {
                                        return method_data.ParameterInfo;
                                }
                        }

                        public virtual MethodBuilder Define (TypeContainer container)
                        {
                                //
                                // Check for custom access modifier
                                //
                                if (ModFlags == 0) {
                                        ModFlags = method.ModFlags;
                                        flags = method.flags;
                                } else {
                                        CheckModifiers (container, ModFlags);
                                        ModFlags |= (method.ModFlags & (~Modifiers.Accessibility));
                                        flags = Modifiers.MethodAttr (ModFlags);
                                        flags |= (method.flags & (~MethodAttributes.MemberAccessMask));
                                }

                                return null;

                        }

                        public override Type[] ParameterTypes {
                                get {
                                        return TypeManager.NoTypes;
                                }
                        }

                        public override EmitContext CreateEmitContext (TypeContainer tc,
                                                                       ILGenerator ig)
                        {
                                return new EmitContext (
                                        tc, method.ds, method.Location, ig, ReturnType,
                                        method.ModFlags, false);
                        }

                        public override ObsoleteAttribute GetObsoleteAttribute ()
                        {
                                return method.GetObsoleteAttribute (method.ds);
                        }

                        public override string GetSignatureForError (TypeContainer tc)
                        {
                                return String.Concat (tc.Name, '.', method.Name);
                        }

                        void CheckModifiers (TypeContainer container, int modflags)
                        {
                                int flags = 0;
                                int mflags = method.ModFlags & Modifiers.Accessibility;

                                if ((mflags & Modifiers.PUBLIC) != 0) {
                                        flags |= Modifiers.PROTECTED | Modifiers.INTERNAL | Modifiers.PRIVATE;
                                }
                                else if ((mflags & Modifiers.PROTECTED) != 0) {
                                        if ((mflags & Modifiers.INTERNAL) != 0)
                                                flags |= Modifiers.PROTECTED | Modifiers.INTERNAL;

                                        flags |= Modifiers.PRIVATE;
                                }
                                else if ((mflags & Modifiers.INTERNAL) != 0)
                                        flags |= Modifiers.PRIVATE;

                                if ((mflags == modflags) || (modflags & (~flags)) != 0)
                                        Report.Error (273, Location, "{0}: accessibility modifier must be more restrictive than the property or indexer",
                                                GetSignatureForError (container));
                        }

                        public override bool MarkForDuplicationCheck ()
                        {
                                caching_flags |= Flags.TestMethodDuplication;
                                return true;
                        }
                }

                public PropertyMethod Get, Set;
                public PropertyBuilder PropertyBuilder;
                public MethodBuilder GetBuilder, SetBuilder;

                protected EmitContext ec;

                public PropertyBase (TypeContainer parent, Expression type, int mod_flags,
                                     int allowed_mod, bool is_iface, MemberName name,
                                     Parameters parameters, Attributes attrs,
                                     Location loc)
                        : base (parent, null, type, mod_flags, allowed_mod, is_iface, name,
                                attrs, parameters, loc)
                {
                }

                public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
                {
                        if (a.Type.IsSubclassOf (TypeManager.security_attr_type)) {
                                a.Error_InvalidSecurityParent ();
                                return;
                        }

                        PropertyBuilder.SetCustomAttribute (cb);
                }

                public override AttributeTargets AttributeTargets {
                        get {
                                return AttributeTargets.Property;
                        }
                }

                public override bool Define ()
                {
                        if (!DoDefine (Parent))
                                return false;

                        if (!IsTypePermitted ())
                                return false;

                        return true;
                }

                protected override bool DoDefine (DeclSpace ds)
                {
                        if (!base.DoDefine (ds))
                                return false;

                        //
                        // Accessors modifiers check
                        //
                        if (Get.ModFlags != 0 && Set.ModFlags != 0) {
                                Report.Error (274, Location, "'{0}': cannot specify accessibility modifiers for both accessors of the property or indexer.",
                                                GetSignatureForError ());
                                return false;
                        }

                        if ((Get.IsDummy || Set.IsDummy)
                                        && (Get.ModFlags != 0 || Set.ModFlags != 0) && (ModFlags & Modifiers.OVERRIDE) == 0) {
                                Report.Error (276, Location, 
                                        "'{0}': accessibility modifiers on accessors may only be used if the property or indexer has both a get and a set accessor.",
                                        GetSignatureForError ());
                                return false;
                        }

                        if (MemberType.IsAbstract && MemberType.IsSealed) {
                                Report.Error (722, Location, Error722, TypeManager.CSharpName (MemberType));
                                return false;
                        }

                        ec = new EmitContext (Parent, Location, null, MemberType, ModFlags);
                        return true;
                }

                public override string GetSignatureForError()
                {
                        if (PropertyBuilder == null)
                                return GetSignatureForError (Parent);

                        return TypeManager.CSharpSignature (PropertyBuilder, false);
                }

                protected override bool CheckForDuplications ()
                {
                        ArrayList ar = Parent.Indexers;
                        if (ar != null) {
                                int arLen = ar.Count;
                                        
                                for (int i = 0; i < arLen; i++) {
                                        Indexer m = (Indexer) ar [i];
                                        if (IsDuplicateImplementation (m))
                                                return false;
                                }
                        }

                        ar = Parent.Properties;
                        if (ar != null) {
                                int arLen = ar.Count;
                                        
                                for (int i = 0; i < arLen; i++) {
                                        Property m = (Property) ar [i];
                                        if (IsDuplicateImplementation (m))
                                                return false;
                                }
                        }

                        return true;
                }

                // TODO: rename to Resolve......
                protected override MethodInfo FindOutBaseMethod (TypeContainer container, ref Type base_ret_type)
                {
                        PropertyInfo base_property = container.BaseCache.FindMemberToOverride (
                                container.TypeBuilder, Name, ParameterTypes, true) as PropertyInfo;

                        if (base_property == null)
                                return null;

                        base_ret_type = base_property.PropertyType;
                        MethodInfo get_accessor = base_property.GetGetMethod (true);
                        MethodInfo set_accessor = base_property.GetSetMethod (true);
                        MethodAttributes get_accessor_access, set_accessor_access;

                        if ((ModFlags & Modifiers.OVERRIDE) != 0) {
                                if (Get != null && !Get.IsDummy && get_accessor == null) {
                                        Report.SymbolRelatedToPreviousError (base_property);
                                        Report.Error (545, Location, "'{0}': cannot override because '{1}' does not have an overridable get accessor", GetSignatureForError (), TypeManager.GetFullNameSignature (base_property));
                                }

                                if (Set != null && !Set.IsDummy && set_accessor == null) {
                                        Report.SymbolRelatedToPreviousError (base_property);
                                        Report.Error (546, Location, "'{0}': cannot override because '{1}' does not have an overridable set accessor", GetSignatureForError (), TypeManager.GetFullNameSignature (base_property));
                                }
                        }
                        
                        //
                        // Check base class accessors access
                        //
                        get_accessor_access = set_accessor_access = 0;
                        if ((ModFlags & Modifiers.NEW) == 0) {
                                if (get_accessor != null) {
                                        MethodAttributes get_flags = Modifiers.MethodAttr (Get.ModFlags != 0 ? Get.ModFlags : ModFlags);
                                        get_accessor_access = (get_accessor.Attributes & MethodAttributes.MemberAccessMask);

                                        if (!Get.IsDummy && !CheckAccessModifiers (get_flags & MethodAttributes.MemberAccessMask, get_accessor_access, get_accessor))
                                                Report.Error (507, Location, "'{0}' can't change the access modifiers when overriding inherited member '{1}'",
                                                                GetSignatureForError (), TypeManager.GetFullNameSignature (base_property));
                                }

                                if (set_accessor != null)  {
                                        MethodAttributes set_flags = Modifiers.MethodAttr (Set.ModFlags != 0 ? Set.ModFlags : ModFlags);
                                        set_accessor_access = (set_accessor.Attributes & MethodAttributes.MemberAccessMask);

                                        if (!Set.IsDummy && !CheckAccessModifiers (set_flags & MethodAttributes.MemberAccessMask, set_accessor_access, set_accessor))
                                                Report.Error (507, Location, "'{0}' can't change the access modifiers when overriding inherited member '{1}'",
                                                                GetSignatureForError (container), TypeManager.GetFullNameSignature (base_property));
                                }
                        }

                        //
                        // Get the less restrictive access
                        //
                        return get_accessor_access > set_accessor_access ? get_accessor : set_accessor;
                }

                public override void Emit ()
                {
                        //
                        // The PropertyBuilder can be null for explicit implementations, in that
                        // case, we do not actually emit the ".property", so there is nowhere to
                        // put the attribute
                        //
                        if (PropertyBuilder != null && OptAttributes != null)
                                OptAttributes.Emit (ec, this);

                        if (!Get.IsDummy)
                                Get.Emit (Parent);

                        if (!Set.IsDummy)
                                Set.Emit (Parent);

                        base.Emit ();
                }

                /// <summary>
                /// Tests whether accessors are not in collision with some method (CS0111)
                /// </summary>
                public bool AreAccessorsDuplicateImplementation (MethodCore mc)
                {
                        return Get.IsDuplicateImplementation (mc) || Set.IsDuplicateImplementation (mc);
                }

                protected override void UpdateMemberName ()
                {
                        base.UpdateMemberName ();

                        Get.UpdateName (this);
                        Set.UpdateName (this);
                }

                protected override bool VerifyClsCompliance (DeclSpace ds)
                {
                        if (!base.VerifyClsCompliance (ds))
                                return false;

                        if ((Get.ModFlags != ModFlags && !Get.IsDummy) || (Set.ModFlags != ModFlags && !Set.IsDummy)) {
                                Report.Error (3025, Get.ModFlags != ModFlags ? Get.Location : Set.Location,
                                        "CLS-compliant accessors must have the same accessibility as their property");
                        }
                        return true;
                }

                public override string[] ValidAttributeTargets {
                        get {
                                return attribute_targets;
                        }
                }

                //
                //   Represents header string for documentation comment.
                //
                public override string DocCommentHeader {
                        get { return "P:"; }
                }
        }
                        
        public class Property : PropertyBase, IIteratorContainer {
                const int AllowedModifiers =
                        Modifiers.NEW |
                        Modifiers.PUBLIC |
                        Modifiers.PROTECTED |
                        Modifiers.INTERNAL |
                        Modifiers.PRIVATE |
                        Modifiers.STATIC |
                        Modifiers.SEALED |
                        Modifiers.OVERRIDE |
                        Modifiers.ABSTRACT |
                        Modifiers.UNSAFE |
                        Modifiers.EXTERN |
                        Modifiers.METHOD_YIELDS |
                        Modifiers.VIRTUAL;

                const int AllowedInterfaceModifiers =
                        Modifiers.NEW;

                public Property (TypeContainer parent, Expression type, int mod_flags,
                                 bool is_iface, MemberName name, Attributes attrs,
                                 Accessor get_block, Accessor set_block, Location loc)
                        : base (parent, type, mod_flags,
                                is_iface ? AllowedInterfaceModifiers : AllowedModifiers,
                                is_iface, name, Parameters.EmptyReadOnlyParameters, attrs,
                                loc)
                {
                        if (get_block == null)
                                Get = new GetMethod (this);
                        else
                                Get = new GetMethod (this, get_block);

                        if (set_block == null)
                                Set = new SetMethod (this);
                        else
                                Set = new SetMethod (this, set_block);
                }

                public override bool Define ()
                {
                        if (!DoDefineBase ())
                                return false;

                        if (!base.Define ())
                                return false;

                        if (!CheckBase ())
                                return false;

                        flags |= MethodAttributes.HideBySig | MethodAttributes.SpecialName;

                        if (!Get.IsDummy) {

                                GetBuilder = Get.Define (Parent);
                                if (GetBuilder == null)
                                        return false;

                                //
                                // Setup iterator if we are one
                                //
                                if ((ModFlags & Modifiers.METHOD_YIELDS) != 0){
                                        Iterator iterator = new Iterator (
                                                Parent, "get", MemberType,
                                                TypeManager.NoTypes, Get.ParameterInfo,
                                                ModFlags, Get.Block, Location);
                                        
                                        if (!iterator.DefineIterator ())
                                                return false;
                                        Get.Block = iterator.Block;
                                }
                        }

                        if (!Set.IsDummy) {
                                SetBuilder = Set.Define (Parent);
                                if (SetBuilder == null)
                                        return false;

                                SetBuilder.DefineParameter (1, ParameterAttributes.None, "value"); 
                        }

                        // FIXME - PropertyAttributes.HasDefault ?
                        
                        PropertyAttributes prop_attr = PropertyAttributes.None;
                        if (!IsInterface)
                                prop_attr |= PropertyAttributes.RTSpecialName |
                        PropertyAttributes.SpecialName;

                                PropertyBuilder = Parent.TypeBuilder.DefineProperty (
                                        Name, prop_attr, MemberType, null);
                                
                                if (!Get.IsDummy)
                                        PropertyBuilder.SetGetMethod (GetBuilder);
                                
                                if (!Set.IsDummy)
                                        PropertyBuilder.SetSetMethod (SetBuilder);

                                TypeManager.RegisterProperty (PropertyBuilder, GetBuilder, SetBuilder);
                        return true;
                }

                public void SetYields ()
                {
                        ModFlags |= Modifiers.METHOD_YIELDS;
                }
        }

        /// </summary>
        ///  Gigantic workaround  for lameness in SRE follows :
        ///  This class derives from EventInfo and attempts to basically
        ///  wrap around the EventBuilder so that FindMembers can quickly
        ///  return this in it search for members
        /// </summary>
        public class MyEventBuilder : EventInfo {
                
                //
                // We use this to "point" to our Builder which is
                // not really a MemberInfo
                //
                EventBuilder MyBuilder;
                
                //
                // We "catch" and wrap these methods
                //
                MethodInfo raise, remove, add;

                EventAttributes attributes;
                Type declaring_type, reflected_type, event_type;
                string name;

                Event my_event;

                public MyEventBuilder (Event ev, TypeBuilder type_builder, string name, EventAttributes event_attr, Type event_type)
                {
                        MyBuilder = type_builder.DefineEvent (name, event_attr, event_type);

                        // And now store the values in our own fields.
                        
                        declaring_type = type_builder;

                        reflected_type = type_builder;
                        
                        attributes = event_attr;
                        this.name = name;
                        my_event = ev;
                        this.event_type = event_type;
                }
                
                //
                // Methods that you have to override.  Note that you only need 
                // to "implement" the variants that take the argument (those are
                // the "abstract" methods, the others (GetAddMethod()) are 
                // regular.
                //
                public override MethodInfo GetAddMethod (bool nonPublic)
                {
                        return add;
                }
                
                public override MethodInfo GetRemoveMethod (bool nonPublic)
                {
                        return remove;
                }
                
                public override MethodInfo GetRaiseMethod (bool nonPublic)
                {
                        return raise;
                }
                
                //
                // These methods make "MyEventInfo" look like a Builder
                //
                public void SetRaiseMethod (MethodBuilder raiseMethod)
                {
                        raise = raiseMethod;
                        MyBuilder.SetRaiseMethod (raiseMethod);
                }

                public void SetRemoveOnMethod (MethodBuilder removeMethod)
                {
                        remove = removeMethod;
                        MyBuilder.SetRemoveOnMethod (removeMethod);
                }

                public void SetAddOnMethod (MethodBuilder addMethod)
                {
                        add = addMethod;
                        MyBuilder.SetAddOnMethod (addMethod);
                }

                public void SetCustomAttribute (CustomAttributeBuilder cb)
                {
                        MyBuilder.SetCustomAttribute (cb);
                }
                
                public override object [] GetCustomAttributes (bool inherit)
                {
                        // FIXME : There's nothing which can be seemingly done here because
                        // we have no way of getting at the custom attribute objects of the
                        // EventBuilder !
                        return null;
                }

                public override object [] GetCustomAttributes (Type t, bool inherit)
                {
                        // FIXME : Same here !
                        return null;
                }

                public override bool IsDefined (Type t, bool b)
                {
                        return true;
                }

                public override EventAttributes Attributes {
                        get {
                                return attributes;
                        }
                }

                public override string Name {
                        get {
                                return name;
                        }
                }

                public override Type DeclaringType {
                        get {
                                return declaring_type;
                        }
                }

                public override Type ReflectedType {
                        get {
                                return reflected_type;
                        }
                }

                public Type EventType {
                        get {
                                return event_type;
                        }
                }
                
                public void SetUsed ()
                {
                        if (my_event != null)
                                my_event.status = (FieldBase.Status.ASSIGNED | FieldBase.Status.USED);
                }
        }
        
        /// <summary>
        /// For case when event is declared like property (with add and remove accessors).
        /// </summary>
        public class EventProperty: Event {

                static string[] attribute_targets = new string [] { "event", "property" };

                public EventProperty (TypeContainer parent, Expression type, int mod_flags,
                                      bool is_iface, MemberName name, Object init,
                                      Attributes attrs, Accessor add, Accessor remove,
                                      Location loc)
                        : base (parent, type, mod_flags, is_iface, name, init, attrs, loc)
                {
                        Add = new AddDelegateMethod (this, add);
                        Remove = new RemoveDelegateMethod (this, remove);

                        // For this event syntax we don't report error CS0067
                        // because it is hard to do it.
                        SetAssigned ();
                }

                public override string[] ValidAttributeTargets {
                        get {
                                return attribute_targets;
                        }
                }
        }

        /// <summary>
        /// Event is declared like field.
        /// </summary>
        public class EventField: Event {

                static string[] attribute_targets = new string [] { "event", "field", "method" };
                static string[] attribute_targets_interface = new string[] { "event", "method" };

                public EventField (TypeContainer parent, Expression type, int mod_flags,
                                   bool is_iface, MemberName name, Object init,
                                   Attributes attrs, Location loc)
                        : base (parent, type, mod_flags, is_iface, name, init, attrs, loc)
                {
                        Add = new AddDelegateMethod (this);
                        Remove = new RemoveDelegateMethod (this);
                }

                public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
                {
                        if (a.Target == AttributeTargets.Field) {
                                FieldBuilder.SetCustomAttribute (cb);
                                return;
                        }

                        if (a.Target == AttributeTargets.Method) {
                                Add.ApplyAttributeBuilder (a, cb);
                                Remove.ApplyAttributeBuilder (a, cb);
                                return;
                        }

                        base.ApplyAttributeBuilder (a, cb);
                }

                public override string[] ValidAttributeTargets {
                        get {
                                return IsInterface ? attribute_targets_interface : attribute_targets;
                        }
                }
        }

        public abstract class Event : FieldBase {

                protected sealed class AddDelegateMethod: DelegateMethod
                {

                        public AddDelegateMethod (Event method):
                                base (method, "add_")
                        {
                        }

                        public AddDelegateMethod (Event method, Accessor accessor):
                                base (method, accessor, "add_")
                        {
                        }

                        protected override MethodInfo DelegateMethodInfo {
                                get {
                                        return TypeManager.delegate_combine_delegate_delegate;
                                }
                        }

                }

                protected sealed class RemoveDelegateMethod: DelegateMethod
                {
                        public RemoveDelegateMethod (Event method):
                                base (method, "remove_")
                        {
                        }

                        public RemoveDelegateMethod (Event method, Accessor accessor):
                                base (method, accessor, "remove_")
                        {
                        }

                        protected override MethodInfo DelegateMethodInfo {
                                get {
                                        return TypeManager.delegate_remove_delegate_delegate;
                                }
                        }

                }

                public abstract class DelegateMethod: AbstractPropertyEventMethod
                {
                        protected readonly Event method;
                       ImplicitParameter param_attr;

                        static string[] attribute_targets = new string [] { "method", "param", "return" };

                        public DelegateMethod (Event method, string prefix)
                                : base (method, prefix)
                        {
                                this.method = method;
                        }

                        public DelegateMethod (Event method, Accessor accessor, string prefix)
                                : base (method, accessor, prefix)
                        {
                                this.method = method;
                        }

                        protected override void ApplyToExtraTarget(Attribute a, CustomAttributeBuilder cb)
                        {
                                if (a.Target == AttributeTargets.Parameter) {
                                        if (param_attr == null)
                                               param_attr = new ImplicitParameter (method_data.MethodBuilder);

                                        param_attr.ApplyAttributeBuilder (a, cb);
                                        return;
                                }

                                base.ApplyAttributeBuilder (a, cb);
                        }

                        public override AttributeTargets AttributeTargets {
                                get {
                                        return AttributeTargets.Method;
                                }
                        }

                        public override bool IsClsCompliaceRequired(DeclSpace ds)
                        {
                                return method.IsClsCompliaceRequired (ds);
                        }

                        public MethodBuilder Define (TypeContainer container, InternalParameters ip)
                        {
                                method_data = new MethodData (method, ip, method.ModFlags,
                                        method.flags | MethodAttributes.HideBySig | MethodAttributes.SpecialName, this);

                                if (!method_data.Define (container))
                                        return null;

                                MethodBuilder mb = method_data.MethodBuilder;
                                mb.DefineParameter (1, ParameterAttributes.None, "value");
                                return mb;
                        }


                        public override void Emit (TypeContainer tc)
                        {
                                if (block != null) {
                                        base.Emit (tc);
                                        return;
                                }

                                ILGenerator ig = method_data.MethodBuilder.GetILGenerator ();
                                FieldInfo field_info = (FieldInfo)method.FieldBuilder;

                                method_data.MethodBuilder.SetImplementationFlags (MethodImplAttributes.Synchronized);
                                if ((method.ModFlags & Modifiers.STATIC) != 0) {
                                        ig.Emit (OpCodes.Ldsfld, field_info);
                                        ig.Emit (OpCodes.Ldarg_0);
                                        ig.Emit (OpCodes.Call, DelegateMethodInfo);
                                        ig.Emit (OpCodes.Castclass, method.MemberType);
                                        ig.Emit (OpCodes.Stsfld, field_info);
                                } else {
                                        ig.Emit (OpCodes.Ldarg_0);
                                        ig.Emit (OpCodes.Ldarg_0);
                                        ig.Emit (OpCodes.Ldfld, field_info);
                                        ig.Emit (OpCodes.Ldarg_1);
                                        ig.Emit (OpCodes.Call, DelegateMethodInfo);
                                        ig.Emit (OpCodes.Castclass, method.MemberType);
                                        ig.Emit (OpCodes.Stfld, field_info);
                                }
                                ig.Emit (OpCodes.Ret);
                        }

                        protected abstract MethodInfo DelegateMethodInfo { get; }

                        public override Type[] ParameterTypes {
                                get {
                                        return new Type[] { method.MemberType };
                                }
                        }

                        public override Type ReturnType {
                                get {
                                        return TypeManager.void_type;
                                }
                        }

                        public override EmitContext CreateEmitContext (TypeContainer tc,
                                                                       ILGenerator ig)
                        {
                                return new EmitContext (
                                        tc, method.Parent, Location, ig, ReturnType,
                                        method.ModFlags, false);
                        }

                        public override string GetSignatureForError (TypeContainer tc)
                        {
                                return String.Concat (tc.Name, '.', method.Name);
                        }

                        public override ObsoleteAttribute GetObsoleteAttribute ()
                        {
                                return method.GetObsoleteAttribute (method.Parent);
                        }

                        public override string[] ValidAttributeTargets {
                                get {
                                        return attribute_targets;
                                }
                        }
                }


                const int AllowedModifiers =
                        Modifiers.NEW |
                        Modifiers.PUBLIC |
                        Modifiers.PROTECTED |
                        Modifiers.INTERNAL |
                        Modifiers.PRIVATE |
                        Modifiers.STATIC |
                        Modifiers.VIRTUAL |
                        Modifiers.SEALED |
                        Modifiers.OVERRIDE |
                        Modifiers.UNSAFE |
                        Modifiers.ABSTRACT;

                const int AllowedInterfaceModifiers =
                        Modifiers.NEW;

                public DelegateMethod Add, Remove;
                public MyEventBuilder     EventBuilder;
                public MethodBuilder AddBuilder, RemoveBuilder;

                MethodData AddData, RemoveData;
                
                public Event (TypeContainer parent, Expression type, int mod_flags,
                              bool is_iface, MemberName name, Object init, Attributes attrs,
                              Location loc)
                        : base (parent, type, mod_flags,
                                is_iface ? AllowedInterfaceModifiers : AllowedModifiers,
                                name, init, attrs, loc)
                {
                        IsInterface = is_iface;
                }

                public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb)
                {
                        if (a.Type.IsSubclassOf (TypeManager.security_attr_type)) {
                                a.Error_InvalidSecurityParent ();
                                return;
                        }
                        
                        EventBuilder.SetCustomAttribute (cb);
                }

                public bool AreAccessorsDuplicateImplementation (MethodCore mc)
                {
                        return Add.IsDuplicateImplementation (mc) || Remove.IsDuplicateImplementation (mc);
                }

                public override AttributeTargets AttributeTargets {
                        get {
                                return AttributeTargets.Event;
                        }
                }
  
                public override bool Define ()
                {
                        EventAttributes e_attr;
                        e_attr = EventAttributes.None;

                        if (!DoDefineBase ())
                                return false;

                        if (!DoDefine (Parent))
                                return false;

                        if (init != null && ((ModFlags & Modifiers.ABSTRACT) != 0)){
                                Report.Error (74, Location, "'" + Parent.Name + "." + Name +
                                              "': abstract event can not have an initializer");
                                return false;
                        }

                        if (!TypeManager.IsDelegateType (MemberType)) {
                                Report.Error (66, Location, "'" + Parent.Name + "." + Name +
                                              "' : event must be of a delegate type");
                                return false;
                        }

                        EmitContext ec = Parent.EmitContext;
                        if (ec == null)
                                throw new InternalErrorException ("Event.Define called too early?");
                        bool old_unsafe = ec.InUnsafe;
                        ec.InUnsafe = InUnsafe;

                        Parameter [] parms = new Parameter [1];
                        parms [0] = new Parameter (Type, "value", Parameter.Modifier.NONE, null);
                        Parameters parameters = new Parameters (parms, null, Location);
                        Type [] types = parameters.GetParameterInfo (ec);
                        InternalParameters ip = new InternalParameters (types, parameters);

                        ec.InUnsafe = old_unsafe;

                        if (!CheckBase ())
                                return false;

                        //
                        // Now define the accessors
                        //

                        AddBuilder = Add.Define (Parent, ip);
                        if (AddBuilder == null)
                                return false;

                        RemoveBuilder = Remove.Define (Parent, ip);
                        if (RemoveBuilder == null)
                                return false;

                        EventBuilder = new MyEventBuilder (this, Parent.TypeBuilder, Name, e_attr, MemberType);
                                        
                        if (Add.Block == null && Remove.Block == null && !IsInterface) {
                                        FieldBuilder = Parent.TypeBuilder.DefineField (
                                                Name, MemberType,
                                                FieldAttributes.Private | ((ModFlags & Modifiers.STATIC) != 0 ? FieldAttributes.Static : 0));
                                        TypeManager.RegisterPrivateFieldOfEvent (
                                                (EventInfo) EventBuilder, FieldBuilder);
                                        TypeManager.RegisterFieldBase (FieldBuilder, this);
                                }
                        
                                EventBuilder.SetAddOnMethod (AddBuilder);
                                EventBuilder.SetRemoveOnMethod (RemoveBuilder);

                                TypeManager.RegisterEvent (EventBuilder, AddBuilder, RemoveBuilder);
                        return true;
                }

                protected override bool CheckBase ()
                {
                        if (!base.CheckBase ())
                                return false;
 
                        if (conflict_symbol != null && (ModFlags & Modifiers.NEW) == 0) {
                                if (!(conflict_symbol is EventInfo)) {
                                        Report.SymbolRelatedToPreviousError (conflict_symbol);
                                        Report.Error (72, Location, "Event '{0}' can override only event", GetSignatureForError (Parent));
                                        return false;
                                }
                        }
 
                        return true;
                }

                public override void Emit ()
                {
                        if (OptAttributes != null) {
                                EmitContext ec = new EmitContext (
                                        Parent, Location, null, MemberType, ModFlags);
                                OptAttributes.Emit (ec, this);
                        }

                        if (!IsInterface) {
                                Add.Emit (Parent);
                                Remove.Emit (Parent);
                        }

                        base.Emit ();
                }

                public override string GetSignatureForError ()
                {
                        if (EventBuilder == null)
                                return base.GetSignatureForError (Parent);

                        return TypeManager.GetFullNameSignature (EventBuilder);
                }

                //
                //   Represents header string for documentation comment.
                //
                public override string DocCommentHeader {
                        get { return "E:"; }
                }
        }

 
        public class Indexer : PropertyBase {

                class GetIndexerMethod: GetMethod
                {
                        public GetIndexerMethod (MethodCore method):
                                base (method)
                        {
                        }

                        public GetIndexerMethod (MethodCore method, Accessor accessor):
                                base (method, accessor)
                        {
                        }

                        public override Type[] ParameterTypes {
                                get {
                                        return method.ParameterTypes;
                                }
                        }
                }

                class SetIndexerMethod: SetMethod
                {
                        readonly Parameters parameters;

                        public SetIndexerMethod (MethodCore method):
                                base (method)
                        {
                        }

                        public SetIndexerMethod (MethodCore method, Parameters parameters, Accessor accessor):
                                base (method, accessor)
                        {
                                this.parameters = parameters;
                        }

                        public override Type[] ParameterTypes {
                                get {
                                        int top = method.ParameterTypes.Length;
                                        Type [] set_pars = new Type [top + 1];
                                        method.ParameterTypes.CopyTo (set_pars, 0);
                                        set_pars [top] = method.MemberType;
                                        return set_pars;
                                }
                        }

                        protected override InternalParameters GetParameterInfo (EmitContext ec)
                        {
                                Parameter [] fixed_parms = parameters.FixedParameters;

                                if (fixed_parms == null){
                                        throw new Exception ("We currently do not support only array arguments in an indexer at: " + method.Location);
                                        // BUG BUG BUG BUG BUG BUG BUG BUG BUG BUG
                                        // BUG BUG BUG BUG BUG BUG BUG BUG BUG BUG
                                        //
                                        // Here is the problem: the `value' parameter has
                                        // to come *after* the array parameter in the declaration
                                        // like this:
                                        // X (object [] x, Type value)
                                        // .param [0]
                                        //
                                        // BUG BUG BUG BUG BUG BUG BUG BUG BUG BUG
                                        // BUG BUG BUG BUG BUG BUG BUG BUG BUG BUG
                                        
                                }
                                
                                Parameter [] tmp = new Parameter [fixed_parms.Length + 1];

                                fixed_parms.CopyTo (tmp, 0);
                                tmp [fixed_parms.Length] = new Parameter (
                                        method.Type, "value", Parameter.Modifier.NONE, null);

                                Parameters set_formal_params = new Parameters (tmp, null, method.Location);
                                Type [] types = set_formal_params.GetParameterInfo (ec);
                                
                                return new InternalParameters (types, set_formal_params);
                        }
                }

                const int AllowedModifiers =
                        Modifiers.NEW |
                        Modifiers.PUBLIC |
                        Modifiers.PROTECTED |
                        Modifiers.INTERNAL |
                        Modifiers.PRIVATE |
                        Modifiers.VIRTUAL |
                        Modifiers.SEALED |
                        Modifiers.OVERRIDE |
                        Modifiers.UNSAFE |
                        Modifiers.EXTERN |
                        Modifiers.ABSTRACT;

                const int AllowedInterfaceModifiers =
                        Modifiers.NEW;

                //
                // Are we implementing an interface ?
                //
                public Indexer (TypeContainer parent, Expression type, MemberName name, int mod,
                                bool is_iface, Parameters parameters, Attributes attrs,
                                Accessor get_block, Accessor set_block, Location loc)
                        : base (parent, type, mod,
                                is_iface ? AllowedInterfaceModifiers : AllowedModifiers,
                                is_iface, name, parameters, attrs, loc)
                {
                        if (get_block == null)
                                Get = new GetIndexerMethod (this);
                        else
                                Get = new GetIndexerMethod (this, get_block);

                        if (set_block == null)
                                Set = new SetIndexerMethod (this);
                        else
                                Set = new SetIndexerMethod (this, parameters, set_block);
                }

                public override bool Define ()
                {
                        PropertyAttributes prop_attr =
                                PropertyAttributes.RTSpecialName |
                                PropertyAttributes.SpecialName;
                        
                        if (!DoDefineBase ())
                                return false;

                        if (!base.Define ())
                                return false;

                        if (MemberType == TypeManager.void_type) {
                                Report.Error (620, Location, "Indexers cannot have void type");
                                return false;
                        }

                        if (OptAttributes != null) {
                                Attribute indexer_attr = OptAttributes.Search (TypeManager.indexer_name_type, ec);
                                if (indexer_attr != null) {
                                        // Remove the attribute from the list because it is not emitted
                                        OptAttributes.Attrs.Remove (indexer_attr);

                                        ShortName = indexer_attr.GetIndexerAttributeValue (ec);

                                        if (IsExplicitImpl) {
                                                Report.Error (415, indexer_attr.Location,
                                                              "The 'IndexerName' attribute is valid only on an" +
                                                              "indexer that is not an explicit interface member declaration");
                                                return false;
                                        }
                                
                                        if ((ModFlags & Modifiers.OVERRIDE) != 0) {
                                                Report.Error (609, indexer_attr.Location,
                                                              "Cannot set the 'IndexerName' attribute on an indexer marked override");
                                                return false;
                                        }

                                        if (!Tokenizer.IsValidIdentifier (ShortName)) {
                                                Report.Error (633, indexer_attr.Location,
                                                              "The argument to the 'IndexerName' attribute must be a valid identifier");
                                                return false;
                                        }

                                        UpdateMemberName ();
                                }
                        }

                        if (InterfaceType != null) {
                                string base_IndexerName = TypeManager.IndexerPropertyName (InterfaceType);
                                if (base_IndexerName != Name)
                                        ShortName = base_IndexerName;
                                UpdateMemberName ();
                        }

                        if (!Parent.AddToMemberContainer (this) ||
                                !Parent.AddToMemberContainer (Get) || !Parent.AddToMemberContainer (Set))
                                return false;

                        if (!CheckBase ())
                                return false;

                        flags |= MethodAttributes.HideBySig | MethodAttributes.SpecialName;
                        if (!Get.IsDummy){
                                GetBuilder = Get.Define (Parent);
                                if (GetBuilder == null)
                                        return false;
                        }
                        
                        if (!Set.IsDummy){
                                SetBuilder = Set.Define (Parent);
                                if (SetBuilder == null)
                                        return false;
                        }

                        //
                        // Now name the parameters
                        //
                        Parameter [] p = Parameters.FixedParameters;
                        if (p != null) {
                                if ((p [0].ModFlags & Parameter.Modifier.ISBYREF) != 0) {
                                        Report.Error (631, Location, "ref and out are not valid in this context");
                                        return false;
                                }

                                int i;
                                
                                for (i = 0; i < p.Length; ++i) {
                                        if (!Get.IsDummy)
                                                GetBuilder.DefineParameter (
                                                        i + 1, p [i].Attributes, p [i].Name);

                                        if (!Set.IsDummy)
                                                SetBuilder.DefineParameter (
                                                        i + 1, p [i].Attributes, p [i].Name);
                                }

                                if (!Set.IsDummy)
                                        SetBuilder.DefineParameter (
                                                i + 1, ParameterAttributes.None, "value");
                                        
                                if (i != ParameterTypes.Length) {
                                        Parameter array_param = Parameters.ArrayParameter;

                                        SetBuilder.DefineParameter (
                                                i + 1, array_param.Attributes, array_param.Name);
                                }
                        }

                                PropertyBuilder = Parent.TypeBuilder.DefineProperty (
                                Name, prop_attr, MemberType, ParameterTypes);

                                if (!Get.IsDummy)
                                        PropertyBuilder.SetGetMethod (GetBuilder);

                                if (!Set.IsDummy)
                                        PropertyBuilder.SetSetMethod (SetBuilder);
                                
                        TypeManager.RegisterIndexer (PropertyBuilder, GetBuilder, SetBuilder, ParameterTypes);

                        return true;
                }

                public override string GetSignatureForError ()
                {
                        if (PropertyBuilder == null)
                                return GetSignatureForError (Parent);

                        return TypeManager.CSharpSignature (PropertyBuilder, true);
                }

                public override string GetSignatureForError(TypeContainer tc)
                {
                        return String.Concat (tc.Name, ".this[", Parameters.FixedParameters [0].TypeName.ToString (), ']');
                }

                public override bool MarkForDuplicationCheck ()
                {
                        caching_flags |= Flags.TestMethodDuplication;
                        return true;
                }

        }

        public class Operator : MethodCore, IIteratorContainer {

                const int AllowedModifiers =
                        Modifiers.PUBLIC |
                        Modifiers.UNSAFE |
                        Modifiers.EXTERN |
                        Modifiers.STATIC;

                public enum OpType : byte {

                        // Unary operators
                        LogicalNot,
                        OnesComplement,
                        Increment,
                        Decrement,
                        True,
                        False,

                        // Unary and Binary operators
                        Addition,
                        Subtraction,

                        UnaryPlus,
                        UnaryNegation,
                        
                        // Binary operators
                        Multiply,
                        Division,
                        Modulus,
                        BitwiseAnd,
                        BitwiseOr,
                        ExclusiveOr,
                        LeftShift,
                        RightShift,
                        Equality,
                        Inequality,
                        GreaterThan,
                        LessThan,
                        GreaterThanOrEqual,
                        LessThanOrEqual,

                        // Implicit and Explicit
                        Implicit,
                        Explicit
                };

                public readonly OpType OperatorType;
                public MethodBuilder   OperatorMethodBuilder;
                
                public Method OperatorMethod;

                static string[] attribute_targets = new string [] { "method", "return" };

                public Operator (TypeContainer parent, OpType type, Expression ret_type,
                                 int mod_flags, Parameters parameters,
                                 ToplevelBlock block, Attributes attrs, Location loc)
                        : base (parent, null, ret_type, mod_flags, AllowedModifiers, false,
                                new MemberName ("op_" + type), attrs, parameters, loc)
                {
                        OperatorType = type;
                        Block = block;
                }

                public override void ApplyAttributeBuilder (Attribute a, CustomAttributeBuilder cb) 
                {
                        OperatorMethod.ApplyAttributeBuilder (a, cb);
                }

                public override AttributeTargets AttributeTargets {
                        get {
                                return AttributeTargets.Method; 
                        }
                }
                
                protected override bool CheckGenericOverride (MethodInfo method,  string name)
                {
                        return true;
                }

                protected override bool CheckForDuplications()
                {
                        ArrayList ar = Parent.Operators;
                        if (ar != null) {
                                int arLen = ar.Count;

                                for (int i = 0; i < arLen; i++) {
                                        Operator o = (Operator) ar [i];
                                        if (IsDuplicateImplementation (o))
                                                return false;
                                }
                        }

                        ar = Parent.Methods;
                        if (ar != null) {
                                int arLen = ar.Count;

                                for (int i = 0; i < arLen; i++) {
                                        Method m = (Method) ar [i];
                                        if (IsDuplicateImplementation (m))
                                                return false;
                                }
                        }

                        return true;
                }

                public override bool Define ()
                {
                        const int RequiredModifiers = Modifiers.PUBLIC | Modifiers.STATIC;
                        if ((ModFlags & RequiredModifiers) != RequiredModifiers){
                                Report.Error (558, Location, "User defined operators '{0}' must be declared static and public", GetSignatureForError (Parent));
                                return false;
                        }

                        if (!DoDefine (ds))
                                return false;

                        if (MemberType == TypeManager.void_type) {
                                Report.Error (590, Location, "User-defined operators cannot return void");
                                return false;
                        }

                        OperatorMethod = new Method (
                                Parent, null, Type, ModFlags, false, MemberName,
                                Parameters, OptAttributes, Location);

                        OperatorMethod.Block = Block;
                        OperatorMethod.IsOperator = true;                       
                        OperatorMethod.flags |= MethodAttributes.SpecialName | MethodAttributes.HideBySig;
                        OperatorMethod.Define ();

                        if (OperatorMethod.MethodBuilder == null)
                                return false;
                        
                        OperatorMethodBuilder = OperatorMethod.MethodBuilder;

                        parameter_types = OperatorMethod.ParameterTypes;
                        Type declaring_type = OperatorMethod.MethodData.DeclaringType;
                        Type return_type = OperatorMethod.ReturnType;
                        Type first_arg_type = parameter_types [0];

                        if (!CheckBase ())
                                return false;

                        // Rules for conversion operators
                        
                        if (OperatorType == OpType.Implicit || OperatorType == OpType.Explicit) {
                                if (first_arg_type == return_type && first_arg_type == declaring_type){
                                        Report.Error (
                                                555, Location,
                                                "User-defined conversion cannot take an object of the " +
                                                "enclosing type and convert to an object of the enclosing" +
                                                " type");
                                        return false;
                                }
                                
                                if (first_arg_type != declaring_type && return_type != declaring_type){
                                        Report.Error (
                                                556, Location, 
                                                "User-defined conversion must convert to or from the " +
                                                "enclosing type");
                                        return false;
                                }
                                
                                if (first_arg_type == TypeManager.object_type ||
                                    return_type == TypeManager.object_type){
                                        Report.Error (
                                                -8, Location,
                                                "User-defined conversion cannot convert to or from " +
                                                "object type");
                                        return false;
                                }

                                if (first_arg_type.IsInterface || return_type.IsInterface){
                                        Report.Error (
                                                552, Location,
                                                "User-defined conversion cannot convert to or from an " +
                                                "interface type");
                                        return false;
                                }
                                
                                if (first_arg_type.IsSubclassOf (return_type)
                                        || return_type.IsSubclassOf (first_arg_type)){
                                        if (declaring_type.IsSubclassOf (return_type)) {
                                                Report.Error (553, Location, "'{0}' : user defined conversion to/from base class", GetSignatureForError ());
                                                return false;
                                        }
                                        Report.Error (554, Location, "'{0}' : user defined conversion to/from derived class", GetSignatureForError ());
                                        return false;
                                }
                        } else if (OperatorType == OpType.LeftShift || OperatorType == OpType.RightShift) {
                                if (first_arg_type != declaring_type || parameter_types [1] != TypeManager.int32_type) {
                                        Report.Error (564, Location, "Overloaded shift operator must have the type of the first operand be the containing type, and the type of the second operand must be int");
                                        return false;
                                }
                        } else if (Parameters.FixedParameters.Length == 1) {
                                // Checks for Unary operators
                                
                                if (OperatorType == OpType.Increment || OperatorType == OpType.Decrement) {
                                        if (return_type != declaring_type && !return_type.IsSubclassOf (declaring_type)) {
                                                Report.Error (448, Location,
                                                        "The return type for ++ or -- operator must be the containing type or derived from the containing type");
                                                return false;
                                        }
                                if (first_arg_type != declaring_type){
                                        Report.Error (
                                                        559, Location, "The parameter type for ++ or -- operator must be the containing type");
                                        return false;
                                }
                                }
                                
                                if (first_arg_type != declaring_type){
                                                Report.Error (
                                                562, Location,
                                                "The parameter of a unary operator must be the " +
                                                "containing type");
                                                return false;
                                }
                                
                                if (OperatorType == OpType.True || OperatorType == OpType.False) {
                                        if (return_type != TypeManager.bool_type){
                                                Report.Error (
                                                        215, Location,
                                                        "The return type of operator True or False " +
                                                        "must be bool");
                                                return false;
                                        }
                                }
                                
                        } else {
                                // Checks for Binary operators
                                
                                if (first_arg_type != declaring_type &&
                                    parameter_types [1] != declaring_type){
                                        Report.Error (
                                                563, Location,
                                                "One of the parameters of a binary operator must " +
                                                "be the containing type");
                                        return false;
                                }
                        }

                        return true;
                }
                
                public override void Emit ()
                {
                        //
                        // abstract or extern methods have no bodies
                        //
                        if ((ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0)
                                return;
                        
                        OperatorMethod.Emit ();
                        Block = null;
                }

                // Operator cannot be override
                protected override MethodInfo FindOutBaseMethod (TypeContainer container, ref Type base_ret_type)
                {
                        return null;
                }

                public static string GetName (OpType ot)
                {
                        switch (ot){
                        case OpType.LogicalNot:
                                return "!";
                        case OpType.OnesComplement:
                                return "~";
                        case OpType.Increment:
                                return "++";
                        case OpType.Decrement:
                                return "--";
                        case OpType.True:
                                return "true";
                        case OpType.False:
                                return "false";
                        case OpType.Addition:
                                return "+";
                        case OpType.Subtraction:
                                return "-";
                        case OpType.UnaryPlus:
                                return "+";
                        case OpType.UnaryNegation:
                                return "-";
                        case OpType.Multiply:
                                return "*";
                        case OpType.Division:
                                return "/";
                        case OpType.Modulus:
                                return "%";
                        case OpType.BitwiseAnd:
                                return "&";
                        case OpType.BitwiseOr:
                                return "|";
                        case OpType.ExclusiveOr:
                                return "^";
                        case OpType.LeftShift:
                                return "<<";
                        case OpType.RightShift:
                                return ">>";
                        case OpType.Equality:
                                return "==";
                        case OpType.Inequality:
                                return "!=";
                        case OpType.GreaterThan:
                                return ">";
                        case OpType.LessThan:
                                return "<";
                        case OpType.GreaterThanOrEqual:
                                return ">=";
                        case OpType.LessThanOrEqual:
                                return "<=";
                        case OpType.Implicit:
                                return "implicit";
                        case OpType.Explicit:
                                return "explicit";
                        default: return "";
                        }
                }

                public override string GetSignatureForError (TypeContainer tc)
                {
                        StringBuilder sb = new StringBuilder ();
                        sb.AppendFormat ("{0}.operator {1} {2}({3}", tc.Name, GetName (OperatorType), Type.Type == null ? Type.ToString () : TypeManager.CSharpName (Type.Type),
                                Parameters.FixedParameters [0].GetSignatureForError ());
                        
                        if (Parameters.FixedParameters.Length > 1) {
                                sb.Append (",");
                                sb.Append (Parameters.FixedParameters [1].GetSignatureForError ());
                        }
                        sb.Append (")");
                        return sb.ToString ();
                }

                public override string GetSignatureForError ()
                {
                        return ToString ();
                }
                
                public override bool MarkForDuplicationCheck ()
                {
                        caching_flags |= Flags.TestMethodDuplication;
                        return true;
                }

                public override string ToString ()
                {
                        if (OperatorMethod == null)
                                return Name;

                        Type return_type = OperatorMethod.ReturnType;
                        Type [] param_types = OperatorMethod.ParameterTypes;
                        
                        if (Parameters.FixedParameters.Length == 1)
                                return String.Format (
                                        "{0} operator {1}({2})",
                                        TypeManager.CSharpName (return_type),
                                        GetName (OperatorType),
                                        param_types [0]);
                        else
                                return String.Format (
                                        "{0} operator {1}({2}, {3})",
                                        TypeManager.CSharpName (return_type),
                                        GetName (OperatorType),
                                        param_types [0], param_types [1]);
                }

                public override string[] ValidAttributeTargets {
                        get {
                                return attribute_targets;
                        }
                }

                public void SetYields ()
                {
                        ModFlags |= Modifiers.METHOD_YIELDS;
                }
        }

        //
        // This is used to compare method signatures
        //
        struct MethodSignature {
                public string Name;
                public Type RetType;
                public Type [] Parameters;
                
                /// <summary>
                ///    This delegate is used to extract methods which have the
                ///    same signature as the argument
                /// </summary>
                public static MemberFilter method_signature_filter = new MemberFilter (MemberSignatureCompare);
                
                public MethodSignature (string name, Type ret_type, Type [] parameters)
                {
                        Name = name;
                        RetType = ret_type;

                        if (parameters == null)
                                Parameters = TypeManager.NoTypes;
                        else
                                Parameters = parameters;
                }

                public override string ToString ()
                {
                        string pars = "";
                        if (Parameters.Length != 0){
                                System.Text.StringBuilder sb = new System.Text.StringBuilder ();
                                for (int i = 0; i < Parameters.Length; i++){
                                        sb.Append (Parameters [i]);
                                        if (i+1 < Parameters.Length)
                                                sb.Append (", ");
                                }
                                pars = sb.ToString ();
                        }

                        return String.Format ("{0} {1} ({2})", RetType, Name, pars);
                }
                
                public override int GetHashCode ()
                {
                        return Name.GetHashCode ();
                }

                public override bool Equals (Object o)
                {
                        MethodSignature other = (MethodSignature) o;

                        if (other.Name != Name)
                                return false;

                        if (other.RetType != RetType)
                                return false;
                        
                        if (Parameters == null){
                                if (other.Parameters == null)
                                        return true;
                                return false;
                        }

                        if (other.Parameters == null)
                                return false;
                        
                        int c = Parameters.Length;
                        if (other.Parameters.Length != c)
                                return false;

                        for (int i = 0; i < c; i++)
                                if (other.Parameters [i] != Parameters [i])
                                        return false;

                        return true;
                }

                static bool MemberSignatureCompare (MemberInfo m, object filter_criteria)
                {
                        MethodSignature sig = (MethodSignature) filter_criteria;

                        if (m.Name != sig.Name)
                                return false;

                        Type ReturnType;
                        MethodInfo mi = m as MethodInfo;
                        PropertyInfo pi = m as PropertyInfo;

                        if (mi != null)
                                ReturnType = mi.ReturnType;
                        else if (pi != null)
                                ReturnType = pi.PropertyType;
                        else
                                return false;
                        
                        //
                        // we use sig.RetType == null to mean `do not check the
                        // method return value.  
                        //
                        if (sig.RetType != null)
                                if (ReturnType != sig.RetType)
                                        return false;

                        Type [] args;
                        if (mi != null)
                                args = TypeManager.GetArgumentTypes (mi);
                        else
                                args = TypeManager.GetArgumentTypes (pi);
                        Type [] sigp = sig.Parameters;

                        if (args.Length != sigp.Length)
                                return false;

                        for (int i = args.Length; i > 0; ){
                                i--;
                                if (args [i] != sigp [i])
                                        return false;
                        }
                        return true;
                }
        }
}