2005-09-27 Marek Safar <marek.safar@seznam.cz>

[mono.git] / mcs / mcs / 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.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.Text;

#if BOOTSTRAP_WITH_OLDLIB
using XmlElement = System.Object;
#else
using System.Xml;
#endif

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;

                                        // Skip erroneous code.
                                        if (op.OperatorMethod == null)
                                                continue;

                                        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, "The operator `{0}' requires a matching operator `false' to also be defined",
                                                        true_op.GetSignatureForError ());
                                } else if (false_op != null)
                                        Report.Error (216, false_op.Location, "The operator `{0}' requires a matching operator `true' to also be defined",
                                                false_op.GetSignatureForError ());
                                
                                //
                                // 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 `{0}' requires a matching operator `{1}' to also be defined",
                                                oe.op.GetSignatureForError (), s);
                                }

                                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;

                //
                // Points to the first non-static field added to the container.
                //
                // This is an arbitrary choice.  We are interested in looking at _some_ non-static field,
                // and the first one's as good as any.
                //
                FieldBase first_nonstatic_field = null;

                //
                // This one is computed after we can distinguish interfaces
                // from classes from the arraylist `type_bases' 
                //
                string base_class_name;
                TypeExpr base_type;
                TypeExpr[] iface_exprs;

                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";

                public TypeContainer (NamespaceEntry ns, TypeContainer parent, MemberName name,
                                      Attributes attrs, Kind kind)
                        : base (ns, parent, name, attrs)
                {
                        if (parent != null && parent != RootContext.Tree.Types && parent.NamespaceEntry != ns)
                                throw new InternalErrorException ("A nested type should be in the same NamespaceEntry as its enclosing class");

                        this.Kind = kind;

                        types = new ArrayList ();

                        base_class_name = null;
                }

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

                protected virtual bool AddToTypeContainer (DeclSpace ds)
                {
                        return AddToContainer (ds, 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 bool AddClassOrStruct (TypeContainer c)
                {
                        if (!AddToTypeContainer (c))
                                return false;

                        types.Add (c);
                        return true;
                }

                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.MemberName.Left != null)
                                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, Error111, c.GetSignatureForError ());
                                        return;
                                }

                                default_static_constructor = c;
                        } else {
                                if (c.IsDefault ()){
                                        if (default_constructor != null) {
                                                Report.SymbolRelatedToPreviousError (default_constructor);
                                                Report.Error (111, c.Location, Error111, c.Location, c.GetSignatureForError ());
                                                return;
                                        }
                                        default_constructor = c;
                                }
                                
                                if (instance_constructors == null)
                                        instance_constructors = new MemberCoreArrayList ();
                                
                                instance_constructors.Add (c);
                        }
                }

                internal static string Error111 {
                        get {
                                return "`{0}' is already defined. Rename this member or use different parameter types";
                        }
                }
                
                public bool AddInterface (TypeContainer iface)
                {
                        if (!AddToTypeContainer (iface))
                                return false;

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

                        interfaces.Add (iface);
                        return true;
                }

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

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

                        fields.Add (field);

                        if (field.HasInitializer)
                                RegisterFieldForInitialization (field);
                        
                        if ((field.ModFlags & Modifiers.STATIC) != 0)
                                return;

                        if (first_nonstatic_field == null) {
                                first_nonstatic_field = field;
                                return;
                        }

                        if (Kind == Kind.Struct &&
                            first_nonstatic_field.Parent != field.Parent &&
                            RootContext.WarningLevel >= 3) {
                                Report.SymbolRelatedToPreviousError (first_nonstatic_field.Parent);
                                Report.Warning (282, field.Location,
                                        "struct instance field `{0}' found in different declaration from instance field `{1}'",
                                        field.GetSignatureForError (), first_nonstatic_field.GetSignatureForError ());
                        }
                }

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

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

                        if (prop.MemberName.Left != null)
                                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 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;
                        }
                }

                protected override TypeAttributes TypeAttr {
                        get {
                                return Modifiers.TypeAttr (ModFlags, this) | base.TypeAttr;
                        }
                }

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

                public virtual void RegisterFieldForInitialization (FieldMember field)
                {
                        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);
                        }
                }

                bool CanElideInitializer (Type field_type, Constant c)
                {
                        if (field_type == c.Type)
                                return true;
                        if (TypeManager.IsValueType (field_type) || TypeManager.HasElementType (field_type))
                                return false;
                        // Reference type with null initializer.
                        return c.Type == TypeManager.null_type;
                }

                //
                // Emits the instance field initializers
                //
                public virtual 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 (FieldMember f in fields){
                                Expression e = f.GetInitializerExpression (ec);
                                if (e == null)
                                        return false;

                                Location l = f.Location;
                                FieldExpr fe = new FieldExpr (f.FieldBuilder, l, true);
                                fe.InstanceExpression = instance_expr;
                                ExpressionStatement a = new Assign (fe, e, l);

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

                                Constant c = e as Constant;
                                if (c != null && c.IsDefaultValue && CanElideInitializer (f.MemberType, c))
                                        continue;

                                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;

                        TypeContainer constructor_parent = this;
                        if (Parts != null)
                                constructor_parent = (TypeContainer) Parts [0];

                        c = new Constructor (constructor_parent, Basename, mods,
                                             Parameters.EmptyReadOnlyParameters,
                                             new GeneratedBaseInitializer (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 PendingImplementation GetPendingImplementations ();

                TypeExpr[] GetPartialBases (out TypeExpr base_class)
                {
                        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);
                                if (new_ifaces == null && new_base_class != null)
                                        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 (!base_loc.IsNull)
                                                Report.LocationOfPreviousError (base_loc);

                                        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);
                                }
                        }

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

                TypeExpr[] GetNormalBases (out TypeExpr base_class)
                {
                        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){
                                        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) {
                                        return null;
                                }
                                
                                ifaces [j] = resolved;
                        }

                        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)
                {
                        int i;

                        TypeExpr[] ifaces;

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

                        if (ifaces == null)
                                return null;

                        if ((base_class != null) && (Kind == Kind.Class)){

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

                                if (base_class.IsSealed){
                                        Report.SymbolRelatedToPreviousError (base_class.Type);
                                        if (base_class.Type.IsAbstract) {
                                                Report.Error (709, Location, "`{0}': Cannot derive from static class `{1}'",
                                                        GetSignatureForError (), TypeManager.CSharpName (base_class.Type));
                                        } else {
                                                Report.Error (509, Location, "`{0}': cannot derive from sealed class `{1}'",
                                                        GetSignatureForError (), TypeManager.CSharpName (base_class.Type));
                                        }
                                        return null;
                                }

                                if (!base_class.CanInheritFrom ()){
                                        Report.Error (644, Location, "`{0}' cannot derive from special class `{1}'",
                                                      GetSignatureForError (), base_class.GetSignatureForError ());
                                        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) {
                                        if (Kind != Kind.Class) {
                                                // TODO: location of symbol related ....
                                                Error_TypeInListIsNotInterface (Location, iface.FullName);
                                        }
                                        else if (base_class != null)
                                                Report.Error (1721, Location, "`{0}': Classes cannot have multiple base classes (`{1}' and `{2}')",
                                                        GetSignatureForError (), base_class.GetSignatureForError (), iface.GetSignatureForError ());
                                        else {
                                                Report.Error (1722, Location, "`{0}': Base class `{1}' must be specified as first",
                                                        GetSignatureForError (), iface.GetSignatureForError ());
                                        }
                                        return null;
                                }

                                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);
                                                return null;
                                        }
                                }

                                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);
                                        return null;
                                }
                        }
                        return ifaces;
                }

                bool error = false;
                
                protected void Error_TypeInListIsNotInterface (Location loc, string type)
                {
                        Report.Error (527, loc, "Type `{0}' in interface list is not an interface", type);
                }

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

                        if (TypeBuilder != null)
                                return TypeBuilder;
                        
                        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 = Parent.TypeBuilder;
                                        if (builder == null) {
                                                error = true;
                                                return null;
                                        }

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

                        TypeManager.AddUserType (Name, this);

                        if (Parts != null) {
                                ec = null;
                                foreach (ClassPart part in Parts) {
                                        part.TypeBuilder = TypeBuilder;
                                        part.ptype = ptype;
                                        part.ec = new EmitContext (part, Mono.CSharp.Location.Null, null, null, ModFlags);
                                        part.ec.ContainerType = TypeBuilder;
                                }
                        } else {
                                //
                                // Normally, we create the EmitContext here.
                                // The only exception is if we're an Iterator - in this case,
                                // we already have the `ec', so we don't want to create a new one.
                                //
                                if (ec == null)
                                        ec = new EmitContext (this, Mono.CSharp.Location.Null, null, null, ModFlags);
                                ec.ContainerType = TypeBuilder;
                        }

                        iface_exprs = GetClassBases (out base_type);
                        if (iface_exprs == null && base_type != null) {
                                error = true;
                                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
                                                base_type = TypeManager.system_valuetype_expr;
                                }
                        }

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

                        // Avoid attributes check when parent is not set
                        TypeResolveEmitContext.TestObsoleteMethodUsage = false;

                        if (base_type != null) {
                                // FIXME: I think this should be ...ResolveType (Parent.EmitContext).
                                //        However, if Parent == RootContext.Tree.Types, its NamespaceEntry will be null.
                                ptype = base_type.ResolveType (TypeResolveEmitContext);
                                if (ptype == null) {
                                        error = true;
                                        return null;
                                }
                        }

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

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

                        // Attribute is undefined at the begining of corlib compilation
                        if (TypeManager.obsolete_attribute_type != null) {
                                TypeResolveEmitContext.TestObsoleteMethodUsage = GetObsoleteAttribute () == null;
                                if (ptype != null && TypeResolveEmitContext.TestObsoleteMethodUsage) {
                                        CheckObsoleteType (base_type);
                                }
                        }

                        // 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.
                                TypeResolveEmitContext.ContainerType = TypeBuilder;
                                ifaces = TypeManager.ExpandInterfaces (TypeResolveEmitContext, iface_exprs);
                                if (ifaces == null) {
                                        error = true;
                                        return null;
                                }

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

                                TypeManager.RegisterBuilder (TypeBuilder, ifaces);
                        }

                        if (!(this is Iterator))
                                RootContext.RegisterOrder (this); 

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

                        return TypeBuilder;
                }

                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;
                        }

                        return true;
                }

                TypeContainer InTransit;

                protected bool CheckRecursiveDefinition (TypeContainer tc)
                {
                        if (InTransit != null) {
                                Report.SymbolRelatedToPreviousError (this);
                                if (this is Interface)
                                        Report.Error (
                                                529, tc.Location, "Inherited interface `{0}' causes a " +
                                                "cycle in the interface hierarchy of `{1}'",
                                                GetSignatureForError (), tc.GetSignatureForError ());
                                else
                                        Report.Error (
                                                146, tc.Location, "Circular base class dependency " +
                                                "involving `{0}' and `{1}'",
                                                tc.GetSignatureForError (), GetSignatureForError ());
                                return false;
                        }

                        InTransit = tc;

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

                        if (iface_exprs != null) {
                                foreach (TypeExpr iface in iface_exprs) {
                                        Type itype = iface.Type;

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

                        InTransit = null;
                        return true;
                }

                public static void Error_KeywordNotAllowed (Location loc)
                {
                        Report.Error (1530, loc, "Keyword `new' is not allowed on namespace elements");
                }

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

                        if (!base.DefineMembers (container))
                                return false;

                        members_defined_ok = DoDefineMembers ();
                        members_defined = true;

                        return members_defined_ok;
                }

                protected virtual bool DoDefineMembers ()
                {
                        if (!IsTopLevel) {
                                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, "`{0}' hides inherited member `{1}'. Use the new keyword if hiding was intended",
                                                        GetSignatureForError (), TypeManager.GetFullNameSignature (conflict_symbol));
                                        }
                                }
                        }

                        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 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 ()
                {
                        foreach (Field f in initialized_fields){
                                Report.Error (573, Location,
                                        "`{0}': Structs cannot have instance field initializers",
                                        f.GetSignatureForError ());
                        }
                }

                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;
                                }
                        }

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

                public override Type FindNestedType (string name)
                {
                        ArrayList [] lists = { types, enums, delegates, interfaces };

                        for (int j = 0; j < lists.Length; ++j) {
                                ArrayList list = lists [j];
                                if (list == null)
                                        continue;
                                
                                int len = list.Count;
                                for (int i = 0; i < len; ++i) {
                                        DeclSpace ds = (DeclSpace) list [i];
                                        if (ds.Basename == name) {
                                                ds.DefineType ();
                                                return ds.TypeBuilder;
                                        }
                                }
                        }

                        return null;
                }

                private void FindMembers_NestedTypes (int modflags,
                                                      BindingFlags bf, MemberFilter filter, object criteria,
                                                      ref ArrayList members)
                {
                        ArrayList [] lists = { types, enums, delegates, interfaces };

                        for (int j = 0; j < lists.Length; ++j) {
                                ArrayList list = lists [j];
                                if (list == null)
                                        continue;
                        
                                int len = list.Count;
                                for (int i = 0; i < len; i++) {
                                        DeclSpace ds = (DeclSpace) list [i];
                                        
                                        if ((ds.ModFlags & modflags) == 0)
                                                continue;
                                        
                                        TypeBuilder tb = ds.TypeBuilder;
                                        if (tb == null) {
                                                if (!(criteria is string) || ds.Basename.Equals (criteria))
                                                        tb = ds.DefineType ();
                                        }
                                        
                                        if (tb != null && (filter (tb, criteria) == true)) {
                                                if (members == null)
                                                        members = new ArrayList ();
                                                
                                                members.Add (tb);
                                        }
                                }
                        }
                }
                
                /// <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)
                                FindMembers_NestedTypes (modflags, bf, filter, criteria, ref members);

                        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);
                                        }
                                }
                                if (ifaces != null) {
                                        foreach (Type base_type in ifaces) {
                                                MemberList list = TypeContainer.FindMembers (base_type, 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;
                }

                void CheckMemberUsage (MemberCoreArrayList al, string member_type)
                {
                        if (al == null)
                                return;

                        foreach (MemberCore mc in al) {
                                if ((mc.ModFlags & Modifiers.Accessibility) != Modifiers.PRIVATE)
                                        continue;

                                if (!mc.IsUsed) {
                                        Report.Warning (169, mc.Location, "The private {0} `{1}' is never used", member_type, mc.GetSignatureForError ());
                                }
                        }
                }

                public virtual void VerifyMembers ()
                {
                        //
                        // Check for internal or private fields that were never assigned
                        //
                        if (RootContext.WarningLevel >= 3) {
                                CheckMemberUsage (properties, "property");
                                CheckMemberUsage (methods, "method");
                                CheckMemberUsage (constants, "constant");

                                if (fields != null){
                                        foreach (FieldMember f in fields) {
                                                if ((f.ModFlags & Modifiers.Accessibility) != Modifiers.PRIVATE)
                                                        continue;
                                                
                                                if (!f.IsUsed){
                                                        if ((f.caching_flags & Flags.IsAssigned) == 0)
                                                                Report.Warning (169, 3, f.Location, "The private field `{0}' is never used", f.GetSignatureForError ());
                                                        else {
#if NET_2_0
                                                                const int error_code = 414;
#else
                                                                const int error_code = 169;
#endif
                                                                Report.Warning (error_code, 3, f.Location, "The private field `{0}' is assigned but its value is never used",
                                                                        f.GetSignatureForError ());
                                                        }
                                                        continue;
                                                }
                                                
                                                //
                                                // Only report 649 on level 4
                                                //
                                                if (RootContext.WarningLevel < 4)
                                                        continue;
                                                
                                                if ((f.caching_flags & Flags.IsAssigned) != 0)
                                                        continue;
                                                
                                                Report.Warning (649, f.Location, "Field `{0}' is never assigned to, and will always have its default value `{1}'",
                                                        f.GetSignatureForError (), f.Type.Type.IsValueType ? Activator.CreateInstance (f.Type.Type).ToString() : "null");
                                        }
                                }
                        }
                }

                /// <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);
                                
                        //
                        // 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 && first_nonstatic_field == null){
                                FieldBuilder fb = TypeBuilder.DefineField ("$PRIVATE$", TypeManager.byte_type,
                                                                           FieldAttributes.Private);

                                if (HasExplicitLayout){
                                        object [] ctor_args = new object [1];
                                        ctor_args [0] = 0;
                                
                                        CustomAttributeBuilder cba = new CustomAttributeBuilder (
                                                TypeManager.field_offset_attribute_ctor, ctor_args);
                                        fb.SetCustomAttribute (cba);
                                }
                        }

                        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 ();
                                }
                        }

                        // Can not continue if constants are broken
                        EmitConstants ();
                        if (Report.Errors > 0)
                                return;

                        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;

                        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;
                }

                //
                // 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, "A static member `{0}' cannot be marked as override, virtual or abstract",
                                                mc.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, "A member `{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}' cannot be both extern and abstract", 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, "The abstract method `{0}' cannot be marked virtual", mc.GetSignatureForError ());
                                        ok = false;
                                }

                                if ((ModFlags & Modifiers.ABSTRACT) == 0){
                                        Report.Error (513, mc.Location, "`{0}' is abstract but it is contained in nonabstract class", mc.GetSignatureForError ());
                                        ok = false;
                                }
                        }

                        if ((flags & Modifiers.PRIVATE) != 0){
                                if ((flags & vao) != 0){
                                        Report.Error (621, mc.Location, "`{0}': virtual or abstract members cannot 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 ();

                        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 (mc.Parent))
                                        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 (MemberBase mb)
                {
                        if (ifaces != null) {
                                foreach (Type t in ifaces){
                                        if (t == mb.InterfaceType)
                                                return true;
                                }
                        }
                        
                        Report.Error (540, mb.Location, "`{0}': containing type does not implement interface `{1}'",
                                mb.GetSignatureForError (), TypeManager.CSharpName (mb.InterfaceType));
                        return false;
                }


                //
                // 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)
                {
                        return FindMembers (mt, bf | BindingFlags.DeclaredOnly, 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)
                {

                        if (!CheckModFlags (0, mod_flags, member_name))
                                return null;

                        PartialContainer pc = RootContext.Tree.GetDecl (member_name) as PartialContainer;
                        if (pc != null) {
                                if (pc.Kind != kind) {
                                        Report.Error (
                                                261, member_name.Location, "Partial declarations of `{0}' " +
                                                "must be all classes, all structs or " +
                                                "all interfaces", member_name.GetPartialName ());
                                        return null;
                                }

                                if (!CheckModFlags (pc.OriginalModFlags, mod_flags, member_name))
                                        return null;
                                pc.ModFlags |= (mod_flags & pc.AllowedModifiers);

                                return pc;
                        }

                        if (parent is ClassPart)
                                parent = ((ClassPart) parent).PartialContainer;

                        pc = new PartialContainer (ns.NS, parent, member_name, mod_flags, kind);

                        if (kind == Kind.Interface) {
                                if (!parent.AddInterface (pc))
                                        return null;
                        } else if (kind == Kind.Class || kind == Kind.Struct) {
                                if (!parent.AddClassOrStruct (pc))
                                        return null;
                        } else {
                                throw new InvalidOperationException ();
                        }
                        RootContext.Tree.RecordDecl (ns.NS, member_name, pc);
                        return pc;
                }

                static bool CheckModFlags (int flags_org, int flags, MemberName member_name)
                {
                        // Check (abstract|static|sealed) sanity.
                        int tmp = (flags_org | flags) & (Modifiers.ABSTRACT | Modifiers.SEALED | Modifiers.STATIC);
                        if ((tmp & Modifiers.ABSTRACT) != 0) {
                                if ((tmp & (Modifiers.STATIC | Modifiers.SEALED)) != 0) {
                                        Report.Error (
                                                418, member_name.Location, 
                                                "`{0}': an abstract class cannot be sealed or static", member_name.ToString ());
                                        return false;
                                }
                        } else if (tmp == (Modifiers.SEALED | Modifiers.STATIC)) {
                                Report.Error (441, member_name.Location, "`{0}': a class cannot be both static and sealed", member_name.ToString ());
                                return false;
                        }

                        if (flags_org == 0)
                                return true;

                        // Check conflicts.
                        if (0 != ((flags_org ^ flags) & (0xFFFFFFFF ^ (Modifiers.SEALED | Modifiers.ABSTRACT)))) {
                                Report.Error (
                                        262, member_name.Location, "Partial declarations of `{0}' " +
                                        "have conflicting accessibility modifiers",
                                        member_name.GetPartialName ());
                                return false;
                        }
                        return true;
                }

                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);
                        if (pc == null) {
                                // An error occured; create a dummy container, but don't
                                // register it.
                                pc = new PartialContainer (ns.NS, parent, name, mod, kind);
                        }

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

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

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

                public override bool MarkForDuplicationCheck ()
                {
                        return true;
                }

                protected 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 pc, TypeContainer parent,
                                  int mod, Attributes attrs, Kind kind)
                        : base (ns, parent, pc.MemberName, attrs, kind)
                {
                        this.PartialContainer = pc;
                        this.IsPartial = true;

                        int accmods;
                        if (parent == null || parent == RootContext.Tree.Types)
                                accmods = Modifiers.INTERNAL;
                        else
                                accmods = Modifiers.PRIVATE;

                        this.ModFlags = Modifiers.Check (pc.AllowedModifiers, mod, accmods, pc.MemberName.Location);
                }

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

                public override bool VerifyImplements (MemberBase mb)
                {
                        return PartialContainer.VerifyImplements (mb);
                }


                public override void RegisterFieldForInitialization (FieldMember field)
                {
                        PartialContainer.RegisterFieldForInitialization (field);
                }

                public override bool EmitFieldInitializers (EmitContext ec)
                {
                        return PartialContainer.EmitFieldInitializers (ec);
                }

                public override Type FindNestedType (string name)
                {
                        return PartialContainer.FindNestedType (name);
                }

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

                public override TypeBuilder DefineType ()
                {
                        throw new InternalErrorException ("Should not get here");
                }

        }

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

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

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

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

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

                        if ((events != null) && (RootContext.WarningLevel >= 3)) {
                                foreach (Event e in events){
                                        if ((e.caching_flags & Flags.IsAssigned) == 0)
                                                Report.Warning (67, 3, 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 && a.GetLayoutKindValue () == LayoutKind.Explicit)
                                has_explicit_layout = 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);
                                }
                        }
                }
        }

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

                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 ());
                                        continue;
                                }

                                if (m is Destructor) {
                                        Report.Error (711, m.Location, "`{0}': Static classes cannot contain destructor", GetSignatureForError ());
                                        continue;
                                }

                                if ((m.ModFlags & Modifiers.PROTECTED) != 0) {
                                        Report.Error (1057, m.Location, "`{0}': Static classes cannot contain protected members", m.GetSignatureForError ());
                                        continue;
                                }

                                if (m is Indexer) {
                                        Report.Error (720, m.Location, "`{0}': cannot declare indexers in a static class", m.GetSignatureForError ());
                                        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;
                                }

                                Report.Error (708, m.Location, "`{0}': cannot declare instance members in a static class", m.GetSignatureForError ());
                        }

                        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 != TypeManager.object_type) {
                                Report.Error (713, Location, "Static class `{0}' cannot derive from type `{1}'. Static classes must derive from object", GetSignatureForError (), TypeManager.CSharpName (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;
                }

                protected 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;

                public Class (NamespaceEntry ns, TypeContainer parent, MemberName name, int mod,
                              Attributes attrs)
                        : base (ns, parent, name, attrs, Kind.Class)
                {
                        this.ModFlags = mod;
                }

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

                public override void ApplyAttributeBuilder(Attribute a, CustomAttributeBuilder cb)
                {
                        if (a.Type == TypeManager.attribute_usage_type) {
                                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.GetSignatureForError ());
                                }
                        }

                        if (a.Type == TypeManager.conditional_attribute_type &&
                                !(ptype == TypeManager.attribute_type || ptype.IsSubclassOf (TypeManager.attribute_type))) {
                                Report.Error (1689, a.Location, "Attribute 'System.Diagnostics.ConditionalAttribute' is only valid on methods or attribute classes");
                                return;
                        }

                        if (AttributeTester.IsAttributeExcluded (a.Type))
                                return;

                        base.ApplyAttributeBuilder (a, cb);
                }

                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 ();
                }

                /// Search for at least one defined condition in ConditionalAttribute of attribute class
                /// Valid only for attribute classes.
                public bool IsExcluded ()
                {
                        if ((caching_flags & Flags.Excluded_Undetected) == 0)
                                return (caching_flags & Flags.Excluded) != 0;

                        caching_flags &= ~Flags.Excluded_Undetected;

                        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;
                }

                //
                // FIXME: How do we deal with the user specifying a different
                // layout?
                //
                protected 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)
                        : base (ns, parent, name, attrs, Kind.Struct)
                {
                        int accmods;
                        
                        if (parent.Parent == null)
                                accmods = Modifiers.INTERNAL;
                        else
                                accmods = Modifiers.PRIVATE;
                        
                        this.ModFlags = Modifiers.Check (AllowedModifiers, mod, accmods, Location);

                        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
                //
                protected 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)
                        : base (ns, parent, name, attrs, Kind.Interface)
                {
                        int accmods;

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

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

                public override PendingImplementation GetPendingImplementations ()
                {
                        return null;
                }

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

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

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

                        if (ifaces != null) {
                                foreach (Type t in ifaces) {
                                        if (AttributeTester.IsClsCompliant (t))
                                                continue;

                                        Report.SymbolRelatedToPreviousError (t);
                                        Report.Warning (3027, 1, Location, "`{0}' is not CLS-compliant because base interface `{1}' is not CLS-compliant",
                                                GetSignatureForError (), TypeManager.CSharpName (t));
                                }
                        }

                        return true;
                }
        }

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

                // Whether this is an operator method.
                public Operator 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, Expression type, int mod,
                                   int allowed_mod, bool is_interface, MemberName name,
                                   Attributes attrs, Parameters parameters)
                        : base (parent, type, mod, allowed_mod, Modifiers.PRIVATE, name,
                                attrs)
                {
                        Parameters = parameters;
                        IsInterface = is_interface;
                }
                
                //
                //  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;
                        }
                }

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

                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 ());
                                }
                                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);
                                                if (this is PropertyBase) {
                                                        Report.Error (1715, Location, "`{0}': type must be `{1}' to match overridden member `{2}'", 
                                                                GetSignatureForError (), TypeManager.CSharpName (base_ret_type), TypeManager.CSharpSignature (base_method));
                                                }
                                                else {
                                                        Report.Error (508, Location, "`{0}': return type must be `{1}' to match overridden member `{2}'",
                                                                GetSignatureForError (), TypeManager.CSharpName (base_ret_type), TypeManager.CSharpSignature (base_method));
                                                }
                                                return false;
                                        }
                                } else {
                                        if (base_method.IsAbstract && !IsInterface) {
                                                Report.SymbolRelatedToPreviousError (base_method);
                                                Report.Error (533, Location, "`{0}' hides inherited abstract member `{1}'",
                                                        GetSignatureForError (), TypeManager.CSharpSignature (base_method));
                                                return false;
                                        }
                                }

                                if (base_method.IsSpecialName && !(this is PropertyBase)) {
                                        Report.Error (115, Location, "`{0}': no suitable method found to override", GetSignatureForError ());
                                        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 `{1}'. Add the Obsolete attribute to `{0}'",
                                                                GetSignatureForError (), TypeManager.CSharpSignature (base_method) );
                                                }
                                        }
                                }
                                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 (), TypeManager.GetFullNameSignature (conflict_symbol));
                                        else
                                                Report.Error (505, Location, "`{0}': cannot override because `{1}' is not a method", GetSignatureForError (), TypeManager.GetFullNameSignature (conflict_symbol));
                                } else
                                        Report.Error (115, Location, "`{0}': no suitable method found to override", GetSignatureForError ());
                                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 ());
                                }
                                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, "`{0}' hides inherited member `{1}'. Use the new keyword if hiding was intended",
                                        GetSignatureForError (), TypeManager.GetFullNameSignature (conflict_symbol));
                        }

                        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;

                        if ((ModFlags & Modifiers.OVERRIDE) != 0){
                                if (!(base_method.IsAbstract || base_method.IsVirtual)){
                                        Report.Error (506, Location,
                                                "`{0}': cannot override inherited member `{1}' because it is not marked virtual, abstract or override",
                                                 GetSignatureForError (), TypeManager.CSharpSignature (base_method));
                                        ok = false;
                                }
                                
                                // Now we check that the overriden method is not final
                                
                                if (base_method.IsFinal) {
                                        Report.SymbolRelatedToPreviousError (base_method);
                                        Report.Error (239, Location, "`{0}': cannot override inherited member `{1}' because it is sealed",
                                                              GetSignatureForError (), TypeManager.CSharpSignature (base_method));
                                        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 (base_method, base_classp, null);
                                        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 (), TypeManager.CSharpSignature (base_method));
                                } else {
                                        Report.Warning (108, Location, "`{0}' hides inherited member `{1}'. Use the new keyword if hiding was intended",
                                                GetSignatureForError (), TypeManager.CSharpSignature (base_method));
                                }
                        }

                        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);
                        }
                }

                public bool CheckAbstractAndExtern (bool has_block)
                {
                        if (Parent.Kind == Kind.Interface)
                                return true;

                        if (has_block) {
                                if ((ModFlags & Modifiers.EXTERN) != 0) {
                                        Report.Error (179, Location, "`{0}' cannot declare a body because it is marked extern",
                                                GetSignatureForError ());
                                        return false;
                                }

                                if ((ModFlags & Modifiers.ABSTRACT) != 0) {
                                        Report.Error (500, Location, "`{0}' cannot declare a body because it is marked abstract",
                                                GetSignatureForError ());
                                        return false;
                                }
                        } else {
                                if ((ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) == 0) {
                                        Report.Error (501, Location, "`{0}' must declare a body because it is not marked abstract or extern",
                                                GetSignatureForError ());
                                        return false;
                                }
                        }

                        return true;
                }

                protected void Error_CannotChangeAccessModifiers (MemberInfo base_method, MethodAttributes ma, string suffix)
                {
                        Report.SymbolRelatedToPreviousError (base_method);
                        string base_name = TypeManager.GetFullNameSignature (base_method);
                        string this_name = GetSignatureForError ();
                        if (suffix != null) {
                                base_name += suffix;
                                this_name += suffix;
                        }

                        Report.Error (507, Location, "`{0}': cannot change access modifiers when overriding `{1}' inherited member `{2}'",
                                this_name, Modifiers.GetDescription (ma), base_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 = Parent.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 (Parent, parameter_types))
                                return false;

                        parameter_info = new InternalParameters (parameter_types, Parameters);

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

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

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

                        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;

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

                        //
                        // 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.SymbolRelatedToPreviousError (method);
                                        Report.Error (663, Location, "`{0}': Methods cannot differ only on their use of ref and out on a parameters",
                                                GetSignatureForError ());
                                        return false;
                                }
                        }

                        Report.SymbolRelatedToPreviousError (method);
                        if (this is Operator && method is Operator)
                                Report.Error (557, Location, "Duplicate user-defined conversion in type `{0}'", Parent.Name);
                        else
                                Report.Error (111, Location, TypeContainer.Error111, GetSignatureForError ());
                        return true;
                }

                public override bool IsUsed {
                        get { return IsExplicitImpl || base.IsUsed; }
                }

                //
                // 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:"; }
                }

        }

        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, start.Column, end.Row, start.Column);
                }

                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 (start_loc.IsNull)
                                return null;

                        Location end_loc = block.EndLocation;
                        if (end_loc.IsNull)
                                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 ds, Expression return_type, int mod, bool is_iface,
                               MemberName name, Parameters parameters, Attributes attrs)
                        : base (ds, return_type, mod,
                                is_iface ? AllowedInterfaceModifiers : AllowedModifiers,
                                is_iface, name, attrs, parameters)
                {
                }

                public override AttributeTargets AttributeTargets {
                        get {
                                return AttributeTargets.Method;
                        }
                }
                
                public override string GetSignatureForError()
                {
                        if (IsOperator != null)
                                return IsOperator.GetSignatureForError ();

                        return base.GetSignatureForError () + Parameters.GetSignatureForError ();
                }

                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.GetMethodImplOptions () & MethodImplOptions.InternalCall) != 0) {
                                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 != null || IsExplicitImpl) {
                                        Report.Error (577, Location, "Conditional not valid on `{0}' because it is a constructor, 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 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.implementing != null) {
                                        Report.Error (629, Location, "Conditional member `{0}' cannot implement interface member `{1}'",
                                                GetSignatureForError (), TypeManager.CSharpSignature (MethodData.implementing));
                                        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 (!DoDefine ())
                                return false;

                        if (!CheckAbstractAndExtern (block != null))
                                return false;

                        if (RootContext.StdLib && (ReturnType == TypeManager.arg_iterator_type || ReturnType == TypeManager.typed_reference_type)) {
                                Error1599 (Location, ReturnType);
                                return false;
                        }

                        if (!CheckBase ())
                                return false;

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

                        MethodData = new MethodData (this, ParameterInfo, ModFlags, flags, this);

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

                        if (ReturnType == TypeManager.void_type && ParameterTypes.Length == 0 && 
                                Name == "Finalize" && !(this is Destructor)) {
                                Report.Warning (465, 1, Location, "Introducing a 'Finalize' method can interfere with destructor invocation. Did you intend to declare a destructor?");
                        }

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

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

                        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)) {
                                        IMethodData md = TypeManager.GetMethod (MethodBuilder);
                                        md.SetMemberIsUsed ();

                                        if (RootContext.EntryPoint == null) {
                                                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;
                }

                public static void Error1599 (Location loc, Type t)
                {
                        Report.Error (1599, loc, "Method or delegate cannot return type `{0}'", TypeManager.CSharpName (t));
                }

                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;
                }

                #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;
                        }
                }

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

                        // TODO: Destructor should derive from MethodCore
                        if (base_method != null && (ModFlags & Modifiers.OVERRIDE) != 0 && Name == "Finalize" &&
                                base_method.DeclaringType == TypeManager.object_type && !(this is Destructor)) {
                                Report.Error (249, Location, "Do not override object.Finalize. Instead, provide a destructor");
                                return false;
                        }

                        return true;
                }

                public EmitContext CreateEmitContext (TypeContainer tc, ILGenerator ig)
                {
                        EmitContext ec = new EmitContext (
                                tc, Parent, Location, ig, ReturnType, ModFlags, false);

                        ec.CurrentIterator = tc as Iterator;
                        if (ec.CurrentIterator != null)
                                ec.CurrentAnonymousMethod = ec.CurrentIterator.Host;

                        return ec;
                }

                /// <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;
                }

                #endregion
        }

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

                public ArrayList Arguments {
                        get {
                                return argument_list;
                        }
                }

                public bool Resolve (ConstructorBuilder caller_builder, Block block, EmitContext ec)
                {
                        Expression base_constructor_group;
                        Type t;
                        bool error = false;

                        ec.CurrentBlock = block;

                        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,
                                                "`{0}': Struct constructors cannot call base constructors", TypeManager.CSharpSignature (caller_builder));
                                        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){
                                error = true;
                                base_constructor_group = Expression.MemberLookup (
                                        ec, t, null, t, ".ctor", MemberTypes.Constructor,
                                        BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.DeclaredOnly,
                                        loc);
                        }

                        int errors = Report.Errors;
                        if (base_constructor_group != null)
                                base_constructor = (ConstructorInfo) Invocation.OverloadResolve (
                                        ec, (MethodGroupExpr) base_constructor_group, argument_list,
                                        false, loc);
                        
                        if (base_constructor == null) {
                                if (errors == Report.Errors)
                                        Invocation.Error_WrongNumArguments (loc, TypeManager.CSharpSignature (caller_builder),
                                                argument_list.Count);
                                return false;
                        }

                        if (error) {
                                Expression.ErrorIsInaccesible (loc, TypeManager.CSharpSignature (base_constructor));
                                base_constructor = null;
                                return false;
                        }

                        if (base_constructor == caller_builder){
                                Report.Error (516, loc, "Constructor `{0}' cannot call itself", TypeManager.CSharpSignature (caller_builder));
                                return false;
                        }
                        
                        return true;
                }

                public virtual 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);
                        }
                }
        }

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

        class GeneratedBaseInitializer: ConstructorBaseInitializer {
                public GeneratedBaseInitializer (Location loc):
                        base (null, loc)
                {
                }

                public override void Emit(EmitContext ec)
                {
                        bool old = ec.TestObsoleteMethodUsage;
                        ec.TestObsoleteMethodUsage = false;
                        base.Emit (ec);
                        ec.TestObsoleteMethodUsage = old;
                }
        }

        public class ConstructorThisInitializer : ConstructorInitializer {
                public ConstructorThisInitializer (ArrayList argument_list, Location l) :
                        base (argument_list, 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 loc)
                        : base (ds, null, mod, AllowedModifiers, false, new MemberName (name, loc),
                                null, args)
                {
                        Initializer = init;
                }

                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 cannot contain explicit parameterless constructors");
                                        return false;
                                }

                                if ((ModFlags & Modifiers.PROTECTED) != 0) {
                                        Report.Error (666, Location, "`{0}': new protected member declared in struct", GetSignatureForError ());
                                        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 ());
                        }
                        
                        return true;
                }
                
                //
                // Creates the ConstructorBuilder
                //
                public override bool Define ()
                {
                        if (ConstructorBuilder != null)
                                return true;

                        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;
                        }

                        if (!CheckAbstractAndExtern (block != null))
                                return false;
                        
                        // 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);

                        // 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);

                        if (block != null) {
                                if (!block.ResolveMeta (ec, ParameterInfo))
                                        block = null;
                        }

                        if ((ModFlags & Modifiers.STATIC) == 0){
                                if (Parent.Kind == Kind.Class && Initializer == null)
                                        Initializer = new GeneratedBaseInitializer (Location);


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

                        Parameters.LabelParameters (ec, ConstructorBuilder);
                        
                        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 () != null || Parent.GetObsoleteAttribute () != null)
                                        ec.TestObsoleteMethodUsage = false;

                                Initializer.Emit (ec);
                        }
                        
                        if ((ModFlags & Modifiers.STATIC) != 0)
                                Parent.EmitFieldInitializers (ec);

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

                        ec.EmitTopBlock (this, block, ParameterInfo);

                        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;
                }

                public override string GetSignatureForError()
                {
                        return base.GetSignatureForError () + Parameters.GetSignatureForError ();
                }

                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 bool IsExcluded(EmitContext ec)
                {
                        return false;
                }

                #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; }

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

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

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

                readonly IMethodData method;

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

                //
                // Are we implementing an interface ?
                //
                public MethodInfo implementing;

                //
                // Protected data.
                //
                protected MemberBase member;
                protected int modifiers;
                protected MethodAttributes flags;

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

                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 bool Define (TypeContainer container)
                {
                        string name = method.MethodName.Name;
                        string method_name = name;

                        Type[] ParameterTypes = method.ParameterTypes;

                        if (container.Pending != null){
                                if (member is Indexer) // TODO: test it, but it should work without this IF
                                        implementing = container.Pending.IsInterfaceIndexer (
                                                member.InterfaceType, method.ReturnType, ParameterInfo);
                                else
                                        implementing = container.Pending.IsInterfaceMethod (
                                                member.InterfaceType, name, method.ReturnType, ParameterInfo);

                                if (member.InterfaceType != null){
                                        if (implementing == null){
                                                if (member is PropertyBase) {
                                                        Report.Error (550, method.Location, "`{0}' is an accessor not found in interface member `{1}{2}'",
                                                                method.GetSignatureForError (), TypeManager.CSharpName (member.InterfaceType),
                                                                member.GetSignatureForError ().Substring (member.GetSignatureForError ().LastIndexOf ('.')));

                                                } else {
                                                        Report.Error (539, method.Location,
                                                                "`{0}.{1}' in explicit interface declaration is not a member of interface",
                                                                TypeManager.CSharpName (member.InterfaceType), member.ShortName);
                                                }
                                                return false;
                                        }
                                        if (implementing.IsSpecialName && !(method is AbstractPropertyEventMethod)) {
                                                Report.SymbolRelatedToPreviousError (implementing);
                                                Report.Error (683, method.Location, "`{0}' explicit method implementation cannot implement `{1}' because it is an accessor",
                                                        member.GetSignatureForError (), TypeManager.CSharpSignature (implementing));
                                                return false;
                                        }
                                        method_name = member.InterfaceType.FullName + "." + name;
                                } else {
                                        if (implementing != null) {
                                                AbstractPropertyEventMethod prop_method = method as AbstractPropertyEventMethod;
                                                if (prop_method != null) {
                                                        if (!implementing.IsSpecialName) {
                                                                Report.SymbolRelatedToPreviousError (implementing);
                                                                Report.Error (686, method.Location, "Accessor `{0}' cannot implement interface member `{1}' for type `{2}'. Use an explicit interface implementation",
                                                                        method.GetSignatureForError (), TypeManager.CSharpSignature (implementing), container.GetSignatureForError ());
                                                                return false;
                                                        }
                                                        PropertyBase.PropertyMethod pm = prop_method as PropertyBase.PropertyMethod;
                                                        if (pm != null && pm.HasCustomAccessModifier && (pm.ModFlags & Modifiers.PUBLIC) == 0) {
                                                                Report.SymbolRelatedToPreviousError (implementing);
                                                                Report.Error (277, method.Location, "Accessor `{0}' must be declared public to implement interface member `{1}'",
                                                                        method.GetSignatureForError (), TypeManager.CSharpSignature (implementing, true));
                                                                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;
                                }
                        }
                        
                        //
                        // 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;
                        }

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

                        DefineMethodBuilder (ec, container, method_name, ParameterTypes);

                        if (builder == null)
                                return false;

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

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

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

                        }

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

                        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 ());
                                        return;
                                }
                        }

                        builder = container.TypeBuilder.DefineMethod (
                                method_name, 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 () != null)
                                ec.TestObsoleteMethodUsage = false;

                        Attributes OptAttributes = method.OptAttributes;

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

                        if (member is MethodCore)
                                ((MethodCore) member).Parameters.LabelParameters (ec, MethodBuilder);

                        ToplevelBlock block = method.Block;
                        
                        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 (method, block, ParameterInfo);

                        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 (method, block, null);
                        
                        // 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);
                }
        }

        // TODO: Should derive from MethodCore
        public class Destructor : Method {

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

                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 constructor, destructor, operator or explicit interface implementation",
                                        GetSignatureForError ());
                                return;
                        }

                        base.ApplyAttributeBuilder (a, cb);
                }

                public override string GetSignatureForError ()
                {
                        return Parent.GetSignatureForError () + ".~" + Parent.MemberName.Name + "()";
                }

        }
        
        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 {
                        get { return MemberName.Name; }
                        set {
                                SetMemberName (new MemberName (MemberName.Left, value, Location));
                        }
                }

                //
                // The type of this property / indexer / event
                //
                Type member_type;
                public Type MemberType {
                        get {
                                if (member_type == null && Type != null) {
                                        EmitContext ec = Parent.EmitContext;
                                        bool old_unsafe = ec.InUnsafe;
                                        ec.InUnsafe = InUnsafe;
                                        Type = Type.ResolveAsTypeTerminal (ec, false);
                                        ec.InUnsafe = old_unsafe;
                                        if (Type != null) {
                                                member_type = Type.Type;
                                        }
                                }
                                return member_type;
                        }
                }

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

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

                //
                // 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)
                        : base (parent, name, attrs)
                {
                        explicit_mod_flags = mod;
                        Type = type;
                        ModFlags = Modifiers.Check (allowed_mod, mod, def_mod, Location);
                        IsExplicitImpl = (MemberName.Left != null);
                }

                protected virtual bool CheckBase ()
                {
                        if ((ModFlags & Modifiers.PROTECTED) != 0 && Parent.Kind == Kind.Struct) {
                                Report.Error (666, Location, "`{0}': new protected member declared in struct", GetSignatureForError ());
                                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 ());
                        }
                        return true;
                }

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

                        return !error;
                }

                protected virtual bool DoDefine ()
                {
                        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);
                        }

                        if (MemberType == null)
                                return false;

                        CheckObsoleteType (Type);

                        if ((Parent.ModFlags & Modifiers.SEALED) != 0 && 
                                (ModFlags & (Modifiers.VIRTUAL|Modifiers.ABSTRACT)) != 0) {
                                        Report.Error (549, Location, "New virtual member `{0}' is declared in a sealed class `{1}'",
                                                GetSignatureForError (), Parent.GetSignatureForError ());
                                        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 `" + GetSignatureForError () + "'");
                                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 `" + GetSignatureForError () + "'");
                                        else
                                                Report.Error (50, Location,
                                                              "Inconsistent accessibility: return type `" +
                                                              TypeManager.CSharpName (MemberType) + "' is less " +
                                                              "accessible than method `" + GetSignatureForError () + "'");
                                } else {
                                        Report.Error (52, Location,
                                                      "Inconsistent accessibility: field type `" +
                                                      TypeManager.CSharpName (MemberType) + "' is less " +
                                                      "accessible than field `" + GetSignatureForError () + "'");
                                }
                                return false;
                        }

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

                        if (IsExplicitImpl) {
                                Expression expr = MemberName.Left.GetTypeExpression ();
                                TypeExpr texpr = expr.ResolveAsTypeTerminal (ec, false);
                                if (texpr == null)
                                        return false;

                                InterfaceType = texpr.ResolveType (ec);

                                if (!InterfaceType.IsInterface) {
                                        Report.Error (538, Location, "`{0}' in explicit interface declaration is not an interface", TypeManager.CSharpName (InterfaceType));
                                        return false;
                                }
                                
                                if (!Parent.VerifyImplements (this))
                                        return false;
                                
                                Modifiers.Check (Modifiers.AllowedExplicitImplFlags, explicit_mod_flags, 0, Location);
                                
                        }
                        return true;
                }

                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;
                }

        }

        //
        // 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 {
                        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)
                        : base (parent, type, mod, allowed_mod, Modifiers.PRIVATE,
                                name, attrs)
                {
                        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;

                //
                // 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);

                        // TODO: Any reason why we are using parent EC ?
                        EmitContext parent_ec = Parent.EmitContext;

                        bool old_is_static = parent_ec.IsStatic;
                        bool old_is_ctor = parent_ec.IsConstructor;
                        parent_ec.IsStatic = ec.IsStatic;
                        parent_ec.IsConstructor = ec.IsConstructor;
                        parent_ec.IsFieldInitializer = true;
                        e = e.DoResolve (parent_ec);
                        parent_ec.IsFieldInitializer = false;
                        parent_ec.IsStatic = old_is_static;
                        parent_ec.IsConstructor = old_is_ctor;

                        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 ());
                                }
                                return true;
                        }
 
                        if ((ModFlags & (Modifiers.NEW | Modifiers.OVERRIDE)) == 0) {
                                Report.SymbolRelatedToPreviousError (conflict_symbol);
                                Report.Warning (108, Location, "`{0}' hides inherited member `{1}'. Use the new keyword if hiding was intended",
                                        GetSignatureForError (), TypeManager.GetFullNameSignature (conflict_symbol));
                        }
 
                        return true;
                }

                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 ()
                {
                        caching_flags |= Flags.IsAssigned;
                }
        }

        public abstract class FieldMember: FieldBase
        {
                protected FieldMember (TypeContainer parent, Expression type, int mod,
                        int allowed_mod, MemberName name, object init, Attributes attrs)
                        : base (parent, type, mod, allowed_mod | Modifiers.ABSTRACT, name, init, attrs)
                {
                        if ((mod & Modifiers.ABSTRACT) != 0)
                                Report.Error (681, Location, "The modifier 'abstract' is not valid on fields. Try using a property instead");
                }

                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;
                                }
                        }

#if NET_2_0
                        if (a.Type == TypeManager.fixed_buffer_attr_type) {
                                Report.Error (1716, Location, "Do not use 'System.Runtime.CompilerServices.FixedBuffer' attribute. Use the 'fixed' field modifier instead");
                                return;
                        }
#endif

                        base.ApplyAttributeBuilder (a, cb);
                }


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

                        if (MemberType == null || Type == null)
                                return false;

                        CheckObsoleteType (Type);

                        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 `" + GetSignatureForError () + "'");
                                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, loc), null, attrs)
                {
                        if (RootContext.Version == LanguageVersion.ISO_1)
                                Report.FeatureIsNotStandardized (loc, "fixed size 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 private or internal fixed sized buffers are supported by .NET 1.x");
#endif

                        if (Parent.Kind != Kind.Struct) {
                                Report.Error (1642, Location, "`{0}': Fixed size buffer fields may only be members of structs",
                                        GetSignatureForError ());
                                return false;
                        }

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

                        if (!TypeManager.IsPrimitiveType (MemberType)) {
                                Report.Error (1663, Location, "`{0}': Fixed size buffers type must be one of the following: bool, byte, short, int, long, char, sbyte, ushort, uint, ulong, float or double",
                                        GetSignatureForError ());
                                return false;
                        }

                        Constant c = size_expr.ResolveAsConstant (Parent.EmitContext, this);
                        if (c == null)
                                return false;

                        IntConstant buffer_size_const = c.ToInt (Location);
                        if (buffer_size_const == null)
                                return false;

                        buffer_size = buffer_size_const.Value;

                        if (buffer_size <= 0) {
                                Report.Error (1665, Location, "`{0}': Fixed size buffers must have a length greater than zero", GetSignatureForError ());
                                return false;
                        }

                        int type_size = Expression.GetTypeSize (MemberType);

                        if (buffer_size > int.MaxValue / type_size) {
                                Report.Error (1664, Location, "Fixed size buffer `{0}' of length `{1}' and type `{2}' exceeded 2^31 limit",
                                        GetSignatureForError (), buffer_size.ToString (), TypeManager.CSharpName (MemberType));
                                return false;
                        }

                        buffer_size *= type_size;

                        // 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, loc),
                                expr_or_array_init, attrs)
                {
                }

                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, "`{0}': A volatile field cannot be of the type `{1}'",
                                                        GetSignatureForError (), TypeManager.CSharpName (vt));
                                                return false;
                                        }
                                }

                                if ((ModFlags & Modifiers.READONLY) != 0){
                                        Report.Error (678, Location, "`{0}': A field cannot be both volatile and readonly",
                                                GetSignatureForError ());
                                        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;
                }

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

                        if ((ModFlags & Modifiers.VOLATILE) != 0) {
                                Report.Warning (3026, 1, Location, "CLS-compliant field `{0}' cannot be volatile", GetSignatureForError ());
                        }

                        return true;
                }
        }

        //
        // `set' and `get' accessors are represented with an Accessor.
        // 
        public class Accessor : IIteratorContainer {
                //
                // 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 bool Yields;
                
                public Accessor (ToplevelBlock b, int mod, Attributes attrs, Location loc)
                {
                        Block = b;
                        Attributes = attrs;
                        Location = loc;
                        ModFlags = Modifiers.Check (AllowedModifiers, mod, 0, loc);
                }

                public void SetYields ()
                {
                        Yields = true;
                }
        }

        // 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 (member.Parent, SetupName (prefix, member, member.Location), null)
                {
                        this.prefix = prefix;
                        IsDummy = true;
                }

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

                static MemberName SetupName (string prefix, MemberBase member, Location loc)
                {
                        return new MemberName (member.MemberName.Left, prefix + member.ShortName, loc);
                }

                public void UpdateName (MemberBase member)
                {
                        SetMemberName (SetupName (prefix, member, Location));
                }

                #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;
                }

                public MemberName MethodName {
                        get {
                                return MemberName;
                        }
                }

                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,
                                        "Attribute `{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)
                {
                        EmitMethod (container);

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

                        block = null;
                }

                protected virtual void EmitMethod (TypeContainer container)
                {
                        method_data.Emit (container, this);
                }

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

                public bool IsDuplicateImplementation (MethodCore method)
                {
                        if (!MemberName.Equals (method.MemberName))
                                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, TypeContainer.Error111, method.GetSignatureForError ());
                        return true;
                }

                public override bool IsUsed
                {
                        get {
                                if (IsDummy)
                                        return false;

                                return base.IsUsed;
                        }
                }

                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 () + "."); }
                }

        }

        //
        // 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 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, method.Location);

                                        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, method.Location);
                                Parameters parameters = new Parameters (parms, null);

                                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 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;
                        bool yields;

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

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

                                if (accessor.ModFlags != 0 && RootContext.Version == LanguageVersion.ISO_1) {
                                        Report.FeatureIsNotStandardized (Location, "access modifiers on properties");
                                }
                        }

                        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)
                        {
                                if (!method.CheckAbstractAndExtern (block != null))
                                        return null;

                                //
                                // Check for custom access modifier
                                //
                                if (ModFlags == 0) {
                                        ModFlags = method.ModFlags;
                                        flags = method.flags;
                                } else {
                                        if (container.Kind == Kind.Interface)
                                                Report.Error (275, Location, "`{0}': accessibility modifiers may not be used on accessors in an interface",
                                                        GetSignatureForError ());

                                        if ((method.ModFlags & Modifiers.ABSTRACT) != 0 && (ModFlags & Modifiers.PRIVATE) != 0) {
                                                Report.Error (442, Location, "`{0}': abstract properties cannot have private accessors", GetSignatureForError ());
                                        }

                                        CheckModifiers (container, ModFlags);
                                        ModFlags |= (method.ModFlags & (~Modifiers.Accessibility));
                                        ModFlags |= Modifiers.PROPERTY_CUSTOM;
                                        flags = Modifiers.MethodAttr (ModFlags);
                                        flags |= (method.flags & (~MethodAttributes.MemberAccessMask));
                                }

                                //
                                // Setup iterator if we are one
                                //
                                if (yields) {
                                        Iterator iterator = new Iterator (this,
                                                Parent, method.ParameterInfo, ModFlags);
                                        
                                        if (!iterator.DefineIterator ())
                                                return null;
                                }

                                return null;
                        }

                        public bool HasCustomAccessModifier
                        {
                                get {
                                        return (ModFlags & Modifiers.PROPERTY_CUSTOM) != 0;
                                }
                        }

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

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

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

                        public override string GetSignatureForError()
                        {
                                return method.GetSignatureForError () + '.' + prefix.Substring (0, 3);
                        }
                        
                        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,
                                                "The accessibility modifier of the `{0}' accessor must be more restrictive than the modifier of the property or indexer `{1}'",
                                                GetSignatureForError (), method.GetSignatureForError ());
                                }
                        }

                        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 ds, Expression type, int mod_flags,
                                     int allowed_mod, bool is_iface, MemberName name,
                                     Parameters parameters, Attributes attrs)
                        : base (ds, type, mod_flags, allowed_mod, is_iface, name,
                                attrs, parameters)
                {
                }

                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 ())
                                return false;

                        if (!IsTypePermitted ())
                                return false;

                        return true;
                }

                protected override bool DoDefine ()
                {
                        if (!base.DoDefine ())
                                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;
                }

                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}.get': 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}.set': cannot override because `{1}' does not have an overridable set accessor", GetSignatureForError (), TypeManager.GetFullNameSignature (base_property));
                                }
                        }
                        
                        //
                        // Check base class accessors access
                        //

                        // TODO: rewrite to reuse Get|Set.CheckAccessModifiers and share code there
                        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))
                                                Error_CannotChangeAccessModifiers (get_accessor, get_accessor_access,  ".get");
                                }

                                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))
                                                Error_CannotChangeAccessModifiers (set_accessor, set_accessor_access, ".set");
                                }
                        }

                        //
                        // 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);
                }

                public override bool IsUsed
                {
                        get {
                                if (IsExplicitImpl)
                                        return true;

                                return Get.IsUsed | Set.IsUsed;
                        }
                }

                protected override void SetMemberName (MemberName new_name)
                {
                        base.SetMemberName (new_name);

                        Get.UpdateName (this);
                        Set.UpdateName (this);
                }

                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 {
                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 ds, Expression type, int mod, bool is_iface,
                                 MemberName name, Attributes attrs, Accessor get_block,
                                 Accessor set_block)
                        : base (ds, type, mod,
                                is_iface ? AllowedInterfaceModifiers : AllowedModifiers,
                                is_iface, name, Parameters.EmptyReadOnlyParameters, attrs)
                {
                        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 (!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;
                        }

                        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);
                        
                        return true;
                }
        }

        /// </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.SetAssigned ();
                                my_event.SetMemberIsUsed ();
                        }
                }
        }
        
        /// <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" target was disabled for 2.0 version

                public EventProperty (TypeContainer parent, Expression type, int mod_flags,
                                      bool is_iface, MemberName name, Object init,
                                      Attributes attrs, Accessor add, Accessor remove)
                        : base (parent, type, mod_flags, is_iface, name, init, attrs)
                {
                        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)
                        : base (parent, type, mod_flags, is_iface, name, init, attrs)
                {
                        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, method.Location);

                                        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;
                        }


                        protected override void EmitMethod (TypeContainer tc)
                        {
                                if (block != null) {
                                        base.EmitMethod (tc);
                                        return;
                                }

                                if ((method.ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN)) != 0)
                                        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 ObsoleteAttribute GetObsoleteAttribute ()
                        {
                                return method.GetObsoleteAttribute ();
                        }

                        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;

                public Event (TypeContainer parent, Expression type, int mod_flags,
                              bool is_iface, MemberName name, Object init, Attributes attrs)
                        : base (parent, type, mod_flags,
                                is_iface ? AllowedInterfaceModifiers : AllowedModifiers,
                                name, init, attrs)
                {
                        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 (!DoDefine ())
                                return false;

                        if (init != null && ((ModFlags & Modifiers.ABSTRACT) != 0)){
                                Report.Error (74, Location, "`" + GetSignatureForError () +
                                              "': abstract event cannot have an initializer");
                                return false;
                        }
                        
                        if (!MemberType.IsSubclassOf (TypeManager.delegate_type)) {
                                Report.Error (66, Location, "`{0}': event must be of a delegate type", GetSignatureForError ());
                                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, Location);
                        Parameters parameters = new Parameters (parms, null);
                        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 ());
                                        return false;
                                }
                        }
 
                        return true;
                }

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

                        Add.Emit (Parent);
                        Remove.Emit (Parent);

                        base.Emit ();
                }

                public override string GetSignatureForError ()
                {
                        return base.GetSignatureForError ();
                }

                //
                //   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, method.Location);

                                Parameters set_formal_params = new Parameters (tmp, null);
                                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;


                public Indexer (TypeContainer ds, Expression type, MemberName name, int mod,
                                bool is_iface, Parameters parameters, Attributes attrs,
                                Accessor get_block, Accessor set_block)
                        : base (ds, type, mod,
                                is_iface ? AllowedInterfaceModifiers : AllowedModifiers,
                                is_iface, name, parameters, attrs)
                {
                        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 (!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;
                                        }
                                }
                        }

                        if (InterfaceType != null) {
                                string base_IndexerName = TypeManager.IndexerPropertyName (InterfaceType);
                                if (base_IndexerName != Name)
                                        ShortName = base_IndexerName;
                        }

                        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 ()
                {
                        StringBuilder sb = new StringBuilder (Parent.GetSignatureForError ());
                        if (MemberName.Left != null) {
                                sb.Append ('.');
                                sb.Append (MemberName.Left);
                        }

                        sb.Append (".this");
                        sb.Append (Parameters.GetSignatureForError ().Replace ('(', '[').Replace (')', ']'));
                        return sb.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,

                        // Just because of enum
                        TOP
                };

                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, ret_type, mod_flags, AllowedModifiers, false,
                                new MemberName ("op_" + type, loc), attrs, parameters)
                {
                        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 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 operator `{0}' must be declared static and public", GetSignatureForError ());
                                return false;
                        }

                        if (!DoDefine ())
                                return false;

                        if (MemberType == TypeManager.void_type) {
                                Report.Error (590, Location, "User-defined operators cannot return void");
                                return false;
                        }

                        OperatorMethod = new Method (
                                Parent, Type, ModFlags, false, MemberName,
                                Parameters, OptAttributes);

                        OperatorMethod.Block = Block;
                        OperatorMethod.IsOperator = this;                       
                        OperatorMethod.flags |= MethodAttributes.SpecialName | MethodAttributes.HideBySig;
                        OperatorMethod.Define ();

                        if (OperatorMethod.MethodBuilder == null)
                                return false;

                        OperatorMethodBuilder = OperatorMethod.MethodBuilder;

                        parameter_types = OperatorMethod.ParameterTypes;
                        Type declaring_type = OperatorMethodBuilder.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 operator 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 `{0}' cannot convert to or from an interface type",
                                                GetSignatureForError ());
                                        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, "User-defined conversion `{0}' cannot convert to or from base class",
                                                        GetSignatureForError ());
                                                return false;
                                        }
                                        Report.Error (554, Location, "User-defined conversion `{0}' cannot convert to or 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 static OpType GetOperatorType (string name)
                {
                        if (name.StartsWith ("op_")){
                                for (int i = 0; i < Unary.oper_names.Length; ++i) {
                                        if (Unary.oper_names [i] == name)
                                                return (OpType)i;
                                }

                                for (int i = 0; i < Binary.oper_names.Length; ++i) {
                                        if (Binary.oper_names [i] == name)
                                                return (OpType)i;
                                }
                        }
                        return OpType.TOP;
                }

                public override string GetSignatureForError ()
                {
                        StringBuilder sb = new StringBuilder ();
                        if (OperatorType == OpType.Implicit || OperatorType == OpType.Explicit) {
                                sb.AppendFormat ("{0}.{1} operator {2}", Parent.GetSignatureForError (), GetName (OperatorType), Type.Type == null ? Type.ToString () : TypeManager.CSharpName (Type.Type));
                        }
                        else {
                                sb.AppendFormat ("{0}.operator {1}", Parent.GetSignatureForError (), GetName (OperatorType));
                        }

                        sb.Append (Parameters.GetSignatureForError ());
                        return sb.ToString ();
                }

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

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

        //
        // 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;
                }
        }
}