source: branches/CodeEditor/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory.CSharp-5.5.0/Parser/mcs/class.cs @ 11700

//
// class.cs: Class and Struct handlers
//
// Authors: Miguel de Icaza (miguel@gnu.org)
//          Martin Baulig (martin@ximian.com)
//          Marek Safar (marek.safar@gmail.com)
//
// Dual licensed under the terms of the MIT X11 or GNU GPL
//
// Copyright 2001, 2002, 2003 Ximian, Inc (http://www.ximian.com)
// Copyright 2004-2011 Novell, Inc
// Copyright 2011 Xamarin, Inc (http://www.xamarin.com)
//

using System;
using System.Linq;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Security;
using System.Security.Permissions;
using System.Text;
using System.Diagnostics;
using Mono.CompilerServices.SymbolWriter;

#if NET_2_1
using XmlElement = System.Object;
#endif

#if STATIC
using SecurityType = System.Collections.Generic.List<IKVM.Reflection.Emit.CustomAttributeBuilder>;
using IKVM.Reflection;
using IKVM.Reflection.Emit;
#else
using SecurityType = System.Collections.Generic.Dictionary<System.Security.Permissions.SecurityAction, System.Security.PermissionSet>;
using System.Reflection;
using System.Reflection.Emit;
#endif

namespace Mono.CSharp
{
  //
  // General types container, used as a base class for all constructs which can hold types
  //
  public abstract class TypeContainer : MemberCore
  {
    public readonly MemberKind Kind;
    public readonly string Basename;

    protected List<TypeContainer> containers;

    TypeDefinition main_container;

    protected Dictionary<string, MemberCore> defined_names;

    protected bool is_defined;

    public int CounterAnonymousMethods { get; set; }
    public int CounterAnonymousContainers { get; set; }
    public int CounterSwitchTypes { get; set; }

    protected TypeContainer (TypeContainer parent, MemberName name, Attributes attrs, MemberKind kind)
      : base (parent, name, attrs)
    {
      this.Kind = kind;
      if (name != null)
        this.Basename = name.Basename;

      defined_names = new Dictionary<string, MemberCore> ();
    }

    public override TypeSpec CurrentType {
      get {
        return null;
      }
    }

    public Dictionary<string, MemberCore> DefinedNames {
      get {
        return defined_names;
      }
    }

    public TypeDefinition PartialContainer {
      get {
        return main_container;
      }
      protected set {
        main_container = value;
      }
    }

    public IList<TypeContainer> Containers {
      get {
        return containers;
      }
    }

    //
    // Any unattached attributes during parsing get added here. User
    // by FULL_AST mode
    //
    public Attributes UnattachedAttributes {
      get; set;
    }

    public void AddCompilerGeneratedClass (CompilerGeneratedContainer c)
    {
      AddTypeContainerMember (c);
    }

    public virtual void AddPartial (TypeDefinition next_part)
    {
      MemberCore mc;
      (PartialContainer ?? this).defined_names.TryGetValue (next_part.Basename, out mc);

      AddPartial (next_part, mc as TypeDefinition);
    }

    protected void AddPartial (TypeDefinition next_part, TypeDefinition existing)
    {
      next_part.ModFlags |= Modifiers.PARTIAL;

      if (existing == null) {
        AddTypeContainer (next_part);
        return;
      }

      if ((existing.ModFlags & Modifiers.PARTIAL) == 0) {
        if (existing.Kind != next_part.Kind) {
          AddTypeContainer (next_part);
        } else {
          Report.SymbolRelatedToPreviousError (next_part);
          Error_MissingPartialModifier (existing);
        }

        return;
      }

      if (existing.Kind != next_part.Kind) {
        Report.SymbolRelatedToPreviousError (existing);
        Report.Error (261, next_part.Location,
          "Partial declarations of `{0}' must be all classes, all structs or all interfaces",
          next_part.GetSignatureForError ());
      }

      if ((existing.ModFlags & Modifiers.AccessibilityMask) != (next_part.ModFlags & Modifiers.AccessibilityMask) &&
        ((existing.ModFlags & Modifiers.DEFAULT_ACCESS_MODIFIER) == 0 &&
         (next_part.ModFlags & Modifiers.DEFAULT_ACCESS_MODIFIER) == 0)) {
           Report.SymbolRelatedToPreviousError (existing);
        Report.Error (262, next_part.Location,
          "Partial declarations of `{0}' have conflicting accessibility modifiers",
          next_part.GetSignatureForError ());
      }

      var tc_names = existing.CurrentTypeParameters;
      if (tc_names != null) {
        for (int i = 0; i < tc_names.Count; ++i) {
          var tp = next_part.MemberName.TypeParameters[i];
          if (tc_names[i].MemberName.Name != tp.MemberName.Name) {
            Report.SymbolRelatedToPreviousError (existing.Location, "");
            Report.Error (264, next_part.Location, "Partial declarations of `{0}' must have the same type parameter names in the same order",
              next_part.GetSignatureForError ());
            break;
          }

          if (tc_names[i].Variance != tp.Variance) {
            Report.SymbolRelatedToPreviousError (existing.Location, "");
            Report.Error (1067, next_part.Location, "Partial declarations of `{0}' must have the same type parameter variance modifiers",
              next_part.GetSignatureForError ());
            break;
          }
        }
      }

      if ((next_part.ModFlags & Modifiers.DEFAULT_ACCESS_MODIFIER) != 0) {
        existing.ModFlags |= next_part.ModFlags & ~(Modifiers.DEFAULT_ACCESS_MODIFIER | Modifiers.AccessibilityMask);
      } else if ((existing.ModFlags & Modifiers.DEFAULT_ACCESS_MODIFIER) != 0) {
        existing.ModFlags &= ~(Modifiers.DEFAULT_ACCESS_MODIFIER | Modifiers.AccessibilityMask);
        existing.ModFlags |= next_part.ModFlags;
      } else {
        existing.ModFlags |= next_part.ModFlags;
      }

      existing.Definition.Modifiers = existing.ModFlags;

      if (next_part.attributes != null) {
        if (existing.attributes == null)
          existing.attributes = next_part.attributes;
        else
          existing.attributes.AddAttributes (next_part.attributes.Attrs);
      }

      next_part.PartialContainer = existing;

      existing.AddPartialPart (next_part);

      AddTypeContainerMember (next_part);
    }

    public virtual void AddTypeContainer (TypeContainer tc)
    {
      AddTypeContainerMember (tc);

      var tparams = tc.MemberName.TypeParameters;
      if (tparams != null && tc.PartialContainer != null) {
        var td = (TypeDefinition) tc;
        for (int i = 0; i < tparams.Count; ++i) {
          var tp = tparams[i];
          if (tp.MemberName == null)
            continue;

          td.AddNameToContainer (tp, tp.Name);
        }
      }
    }

    protected virtual void AddTypeContainerMember (TypeContainer tc)
    {
      containers.Add (tc);
    }

    public virtual void CloseContainer ()
    {
      if (containers != null) {
        foreach (TypeContainer tc in containers) {
          tc.CloseContainer ();
        }
      }
    }

    public virtual void CreateMetadataName (StringBuilder sb)
    {
      if (Parent != null && Parent.MemberName != null)
        Parent.CreateMetadataName (sb);

      MemberName.CreateMetadataName (sb);
    }

    public virtual bool CreateContainer ()
    {
      if (containers != null) {
        foreach (TypeContainer tc in containers) {
          tc.CreateContainer ();
        }
      }

      return true;
    }

    public override bool Define ()
    {
      if (containers != null) {
        foreach (TypeContainer tc in containers) {
          tc.Define ();
        }
      }

      // Release cache used by parser only
      if (Module.Evaluator == null) {
        defined_names = null;
      } else {
        defined_names.Clear ();
      }

      return true;
    }

    public virtual void PrepareEmit ()
    {
      if (containers != null) {
        foreach (var t in containers) {
          try {
            t.PrepareEmit ();
          } catch (Exception e) {
            if (MemberName == MemberName.Null)
              throw;

            throw new InternalErrorException (t, e);
          }
        }
      }
    }

    public virtual bool DefineContainer ()
    {
      if (is_defined)
        return true;

      is_defined = true;

      DoDefineContainer ();

      if (containers != null) {
        foreach (TypeContainer tc in containers) {
          try {
            tc.DefineContainer ();
          } catch (Exception e) {
            if (MemberName == MemberName.Null)
              throw;

            throw new InternalErrorException (tc, e);
          }
        }
      }

      return true;
    }

    public virtual void ExpandBaseInterfaces ()
    {
      if (containers != null) {
        foreach (TypeContainer tc in containers) {
          tc.ExpandBaseInterfaces ();
        }
      }
    }

    protected virtual void DefineNamespace ()
    {
      if (containers != null) {
        foreach (var tc in containers) {
          try {
            tc.DefineNamespace ();
          } catch (Exception e) {
            throw new InternalErrorException (tc, e);
          }
        }
      }
    }

    protected virtual void DoDefineContainer ()
    {
    }

    public virtual void EmitContainer ()
    {
      if (containers != null) {
        for (int i = 0; i < containers.Count; ++i)
          containers[i].EmitContainer ();
      }
    }

    protected void Error_MissingPartialModifier (MemberCore type)
    {
      Report.Error (260, type.Location,
        "Missing partial modifier on declaration of type `{0}'. Another partial declaration of this type exists",
        type.GetSignatureForError ());
    }

    public override string GetSignatureForDocumentation ()
    {
      if (Parent != null && Parent.MemberName != null)
        return Parent.GetSignatureForDocumentation () + "." + MemberName.GetSignatureForDocumentation ();

      return MemberName.GetSignatureForDocumentation ();
    }

    public override string GetSignatureForError ()
    {
      if (Parent != null && Parent.MemberName != null) 
        return Parent.GetSignatureForError () + "." + MemberName.GetSignatureForError ();

      return MemberName.GetSignatureForError ();
    }

    public string GetSignatureForMetadata ()
    {
      if (Parent is TypeDefinition) {
        return Parent.GetSignatureForMetadata () + "+" + TypeNameParser.Escape (MemberName.Basename);
      }

      var sb = new StringBuilder ();
      CreateMetadataName (sb);
      return sb.ToString ();
    }

    public virtual void RemoveContainer (TypeContainer cont)
    {
      if (containers != null)
        containers.Remove (cont);

      var tc = Parent == Module ? Module : this;
      tc.defined_names.Remove (cont.Basename);
    }

    public virtual void VerifyMembers ()
    {
      if (containers != null) {
        foreach (TypeContainer tc in containers)
          tc.VerifyMembers ();
      }
    }

    public override void WriteDebugSymbol (MonoSymbolFile file)
    {
      if (containers != null) {
        foreach (TypeContainer tc in containers) {
          tc.WriteDebugSymbol (file);
        }
      }
    }
  }

  public abstract class TypeDefinition : TypeContainer, ITypeDefinition
  {
    //
    // Different context is needed when resolving type container base
    // types. Type names come from the parent scope but type parameter
    // names from the container scope.
    //
    public struct BaseContext : IMemberContext
    {
      TypeContainer tc;

      public BaseContext (TypeContainer tc)
      {
        this.tc = tc;
      }

      #region IMemberContext Members

      public CompilerContext Compiler {
        get { return tc.Compiler; }
      }

      public TypeSpec CurrentType {
        get { return tc.PartialContainer.CurrentType; }
      }

      public TypeParameters CurrentTypeParameters {
        get { return tc.PartialContainer.CurrentTypeParameters; }
      }

      public MemberCore CurrentMemberDefinition {
        get { return tc; }
      }

      public bool IsObsolete {
        get { return tc.IsObsolete; }
      }

      public bool IsUnsafe {
        get { return tc.IsUnsafe; }
      }

      public bool IsStatic {
        get { return tc.IsStatic; }
      }

      public ModuleContainer Module {
        get { return tc.Module; }
      }

      public string GetSignatureForError ()
      {
        return tc.GetSignatureForError ();
      }

      public ExtensionMethodCandidates LookupExtensionMethod (TypeSpec extensionType, string name, int arity)
      {
        return null;
      }

      public FullNamedExpression LookupNamespaceAlias (string name)
      {
        return tc.Parent.LookupNamespaceAlias (name);
      }

      public FullNamedExpression LookupNamespaceOrType (string name, int arity, LookupMode mode, Location loc)
      {
        if (arity == 0) {
          var tp = CurrentTypeParameters;
          if (tp != null) {
            TypeParameter t = tp.Find (name);
            if (t != null)
              return new TypeParameterExpr (t, loc);
          }
        }

        return tc.Parent.LookupNamespaceOrType (name, arity, mode, loc);
      }

      #endregion
    }

    [Flags]
    enum CachedMethods
    {
      Equals        = 1,
      GetHashCode     = 1 << 1,
      HasStaticFieldInitializer = 1 << 2
    }

    readonly List<MemberCore> members;

    // Holds a list of fields that have initializers
    protected List<FieldInitializer> initialized_fields;

    // Holds a list of static fields that have initializers
    protected List<FieldInitializer> initialized_static_fields;

    Dictionary<MethodSpec, Method> hoisted_base_call_proxies;

    Dictionary<string, FullNamedExpression> Cache = new Dictionary<string, FullNamedExpression> ();

    //
    // 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.
    //
    protected FieldBase first_nonstatic_field;

    //
    // This one is computed after we can distinguish interfaces
    // from classes from the arraylist `type_bases' 
    //
    protected TypeSpec base_type;
    FullNamedExpression base_type_expr; // TODO: It's temporary variable
    protected TypeSpec[] iface_exprs;

    protected List<FullNamedExpression> type_bases;

    // Partial parts for classes only
    List<TypeDefinition> class_partial_parts;

    TypeDefinition InTransit;

    public TypeBuilder TypeBuilder;
    GenericTypeParameterBuilder[] all_tp_builders;
    //
    // All recursive type parameters put together sharing same
    // TypeParameter instances
    //
    TypeParameters all_type_parameters;

    public const string DefaultIndexerName = "Item";

    bool has_normal_indexers;
    string indexer_name;
    protected bool requires_delayed_unmanagedtype_check;
    bool error;
    bool members_defined;
    bool members_defined_ok;
    protected bool has_static_constructor;

    private CachedMethods cached_method;

    protected TypeSpec spec;
    TypeSpec current_type;

    public int DynamicSitesCounter;
    public int AnonymousMethodsCounter;
    public int MethodGroupsCounter;

    static readonly string[] attribute_targets = new [] { "type" };
    static readonly string[] attribute_targets_primary = new [] { "type", "method" };

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

    protected TypeDefinition (TypeContainer parent, MemberName name, Attributes attrs, MemberKind kind)
      : base (parent, name, attrs, kind)
    {
      PartialContainer = this;
      members = new List<MemberCore> ();
    }

    #region Properties

    public List<FullNamedExpression> BaseTypeExpressions {
      get {
        return type_bases;
      }
    }

    public override TypeSpec CurrentType {
      get {
        if (current_type == null) {
          if (IsGenericOrParentIsGeneric) {
            //
            // Switch to inflated version as it's used by all expressions
            //
            var targs = CurrentTypeParameters == null ? TypeSpec.EmptyTypes : CurrentTypeParameters.Types;
            current_type = spec.MakeGenericType (this, targs);
          } else {
            current_type = spec;
          }
        }

        return current_type;
      }
    }

    public override TypeParameters CurrentTypeParameters {
      get {
        return PartialContainer.MemberName.TypeParameters;
      }
    }

    int CurrentTypeParametersStartIndex {
      get {
        int total = all_tp_builders.Length;
        if (CurrentTypeParameters != null) {
          return total - CurrentTypeParameters.Count;
        }
        return total;
      }
    }

    public virtual AssemblyDefinition DeclaringAssembly {
      get {
        return Module.DeclaringAssembly;
      }
    }

    IAssemblyDefinition ITypeDefinition.DeclaringAssembly {
      get {
        return Module.DeclaringAssembly;
      }
    }

    public TypeSpec Definition {
      get {
        return spec;
      }
    }

    public bool HasMembersDefined {
      get {
        return members_defined;
      }
    }
    
    public List<FullNamedExpression> TypeBaseExpressions {
      get {
        return type_bases;
      }
    }

    public bool HasInstanceConstructor {
      get {
        return (caching_flags & Flags.HasInstanceConstructor) != 0;
      }
      set {
        caching_flags |= Flags.HasInstanceConstructor;
      }
    }

    // Indicated whether container has StructLayout attribute set Explicit
    public bool HasExplicitLayout {
      get { return (caching_flags & Flags.HasExplicitLayout) != 0; }
      set { caching_flags |= Flags.HasExplicitLayout; }
    }

    public bool HasOperators {
      get {
        return (caching_flags & Flags.HasUserOperators) != 0;
      }
      set {
        caching_flags |= Flags.HasUserOperators;
      }
    }

    public bool HasStructLayout {
      get { return (caching_flags & Flags.HasStructLayout) != 0; }
      set { caching_flags |= Flags.HasStructLayout; }
    }

    public TypeSpec[] Interfaces {
      get {
        return iface_exprs;
      }
    }

    public bool IsGenericOrParentIsGeneric {
      get {
        return all_type_parameters != null;
      }
    }

    public bool IsTopLevel {
      get {
        return !(Parent is TypeDefinition);
      }
    }

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

    bool ITypeDefinition.IsTypeForwarder {
      get {
        return false;
      }
    }

    bool ITypeDefinition.IsCyclicTypeForwarder {
      get {
        return false;
      }
    }

    //
    // Returns true for secondary partial containers
    //
    bool IsPartialPart {
      get {
        return PartialContainer != this;
      }
    }

    public MemberCache MemberCache {
      get {
        return spec.MemberCache;
      }
    }

    public List<MemberCore> Members {
      get {
        return members;
      }
    }

    string ITypeDefinition.Namespace {
      get {
        var p = Parent;
        while (p.Kind != MemberKind.Namespace)
          p = p.Parent;

        return p.MemberName == null ? null : p.GetSignatureForError ();
      }
    }

    public ParametersCompiled PrimaryConstructorParameters { get; set; }

    public Arguments PrimaryConstructorBaseArguments { get; set; }

    public Location PrimaryConstructorBaseArgumentsStart { get; set; }

    public TypeParameters TypeParametersAll {
      get {
        return all_type_parameters;
      }
    }

    public override string[] ValidAttributeTargets {
      get {
        return PrimaryConstructorParameters != null ? attribute_targets_primary : attribute_targets;
      }
    }

#if FULL_AST
    public bool HasOptionalSemicolon {
      get;
      private set;
    }
    Location optionalSemicolon;
    public Location OptionalSemicolon {
      get {
        return optionalSemicolon;
      }
      set {
        optionalSemicolon = value;
        HasOptionalSemicolon = true;
      }
    }
#endif

    #endregion

    public override void Accept (StructuralVisitor visitor)
    {
      visitor.Visit (this);
    }

    public void AddMember (MemberCore symbol)
    {
      if (symbol.MemberName.ExplicitInterface != null) {
        if (!(Kind == MemberKind.Class || Kind == MemberKind.Struct)) {
          Report.Error (541, symbol.Location,
            "`{0}': explicit interface declaration can only be declared in a class or struct",
            symbol.GetSignatureForError ());
        }
      }

      AddNameToContainer (symbol, symbol.MemberName.Name);
      members.Add (symbol);
    }

    public override void AddTypeContainer (TypeContainer tc)
    {
      AddNameToContainer (tc, tc.Basename);

      base.AddTypeContainer (tc);
    }

    protected override void AddTypeContainerMember (TypeContainer tc)
    {
      members.Add (tc);

      if (containers == null)
        containers = new List<TypeContainer> ();

      base.AddTypeContainerMember (tc);
    }

    //
    // Adds the member to defined_names table. It tests for duplications and enclosing name conflicts
    //
    public virtual void AddNameToContainer (MemberCore symbol, string name)
    {
      if (((ModFlags | symbol.ModFlags) & Modifiers.COMPILER_GENERATED) != 0)
        return;

      MemberCore mc;
      if (!PartialContainer.defined_names.TryGetValue (name, out mc)) {
        PartialContainer.defined_names.Add (name, symbol);
        return;
      }

      if (symbol.EnableOverloadChecks (mc))
        return;

      InterfaceMemberBase im = mc as InterfaceMemberBase;
      if (im != null && im.IsExplicitImpl)
        return;

      Report.SymbolRelatedToPreviousError (mc);
      if ((mc.ModFlags & Modifiers.PARTIAL) != 0 && (symbol is ClassOrStruct || symbol is Interface)) {
        Error_MissingPartialModifier (symbol);
        return;
      }

      if (symbol is TypeParameter) {
        Report.Error (692, symbol.Location,
          "Duplicate type parameter `{0}'", symbol.GetSignatureForError ());
      } else {
        Report.Error (102, symbol.Location,
          "The type `{0}' already contains a definition for `{1}'",
          GetSignatureForError (), name);
      }

      return;
    }

    public void AddConstructor (Constructor c)
    {
      AddConstructor (c, false);
    }

    public void AddConstructor (Constructor c, bool isDefault)
    {
      bool is_static = (c.ModFlags & Modifiers.STATIC) != 0;
      if (!isDefault)
        AddNameToContainer (c, is_static ? Constructor.TypeConstructorName : Constructor.ConstructorName);

      if (is_static && c.ParameterInfo.IsEmpty) {
        PartialContainer.has_static_constructor = true;
      } else {
        PartialContainer.HasInstanceConstructor = true;
      }

      members.Add (c);
    }

    public bool AddField (FieldBase field)
    {
      AddMember (field);

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

      var first_field = PartialContainer.first_nonstatic_field;
      if (first_field == null) {
        PartialContainer.first_nonstatic_field = field;
        return true;
      }

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

    /// <summary>
    /// Indexer has special handling in constrast to other AddXXX because the name can be driven by IndexerNameAttribute
    /// </summary>
    public void AddIndexer (Indexer i)
    {
      members.Add (i);
    }

    public void AddOperator (Operator op)
    {
      PartialContainer.HasOperators = true;
      AddMember (op);
    }

    public void AddPartialPart (TypeDefinition part)
    {
      if (Kind != MemberKind.Class)
        return;

      if (class_partial_parts == null)
        class_partial_parts = new List<TypeDefinition> ();

      class_partial_parts.Add (part);
    }

    public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
    {
      if (a.Target == AttributeTargets.Method) {
        foreach (var m in members) {
          var c = m as Constructor;
          if (c == null)
            continue;

          if (c.IsPrimaryConstructor) {
            c.ApplyAttributeBuilder (a, ctor, cdata, pa);
            return;
          }
        }

        throw new InternalErrorException ();
      }

      if (has_normal_indexers && a.Type == pa.DefaultMember) {
        Report.Error (646, a.Location, "Cannot specify the `DefaultMember' attribute on type containing an indexer");
        return;
      }

      if (a.Type == pa.Required) {
        Report.Error (1608, a.Location, "The RequiredAttribute attribute is not permitted on C# types");
        return;
      }

      TypeBuilder.SetCustomAttribute ((ConstructorInfo) ctor.GetMetaInfo (), cdata);
    } 

    public override AttributeTargets AttributeTargets {
      get {
        throw new NotSupportedException ();
      }
    }

    public TypeSpec BaseType {
      get {
        return spec.BaseType;
      }
    }

    protected virtual TypeAttributes TypeAttr {
      get {
        return ModifiersExtensions.TypeAttr (ModFlags, IsTopLevel);
      }
    }

    public int TypeParametersCount {
      get {
        return MemberName.Arity;
      }
    }

    TypeParameterSpec[] ITypeDefinition.TypeParameters {
      get {
        return PartialContainer.CurrentTypeParameters.Types;
      }
    }

    public string GetAttributeDefaultMember ()
    {
      return indexer_name ?? DefaultIndexerName;
    }

    public bool IsComImport {
      get {
        if (OptAttributes == null)
          return false;

        return OptAttributes.Contains (Module.PredefinedAttributes.ComImport);
      }
    }

    public virtual void RegisterFieldForInitialization (MemberCore field, FieldInitializer expression)
    {
      if (IsPartialPart)
        PartialContainer.RegisterFieldForInitialization (field, expression);

      if ((field.ModFlags & Modifiers.STATIC) != 0){
        if (initialized_static_fields == null) {
          HasStaticFieldInitializer = true;
          initialized_static_fields = new List<FieldInitializer> (4);
        }

        initialized_static_fields.Add (expression);
      } else {
        if (initialized_fields == null)
          initialized_fields = new List<FieldInitializer> (4);

        initialized_fields.Add (expression);
      }
    }

    public void ResolveFieldInitializers (BlockContext ec)
    {
      Debug.Assert (!IsPartialPart);

      if (ec.IsStatic) {
        if (initialized_static_fields == null)
          return;

        bool has_complex_initializer = !ec.Module.Compiler.Settings.Optimize;
        int i;
        ExpressionStatement [] init = new ExpressionStatement [initialized_static_fields.Count];
        for (i = 0; i < initialized_static_fields.Count; ++i) {
          FieldInitializer fi = initialized_static_fields [i];
          ExpressionStatement s = fi.ResolveStatement (ec);
          if (s == null) {
            s = EmptyExpressionStatement.Instance;
          } else if (!fi.IsSideEffectFree) {
            has_complex_initializer = true;
          }

          init [i] = s;
        }

        for (i = 0; i < initialized_static_fields.Count; ++i) {
          FieldInitializer fi = initialized_static_fields [i];
          //
          // Need special check to not optimize code like this
          // static int a = b = 5;
          // static int b = 0;
          //
          if (!has_complex_initializer && fi.IsDefaultInitializer)
            continue;

          ec.AssignmentInfoOffset += fi.AssignmentOffset;
          ec.CurrentBlock.AddScopeStatement (new StatementExpression (init [i]));
        }

        return;
      }

      if (initialized_fields == null)
        return;

      for (int i = 0; i < initialized_fields.Count; ++i) {
        FieldInitializer fi = initialized_fields [i];

        //
        // Clone before resolving otherwise when field initializer is needed
        // in more than 1 constructor any resolve after the initial one would
        // only took the resolved expression which is problem for expressions
        // that generate extra expressions or code during Resolve phase
        //
        var cloned = fi.Clone (new CloneContext ());

        ExpressionStatement s = fi.ResolveStatement (ec);
        if (s == null) {
          initialized_fields [i] = new FieldInitializer (fi.Field, ErrorExpression.Instance, Location.Null);
          continue;
        }

        //
        // Field is re-initialized to its default value => removed
        //
        if (fi.IsDefaultInitializer && ec.Module.Compiler.Settings.Optimize)
          continue;

        ec.AssignmentInfoOffset += fi.AssignmentOffset;
        ec.CurrentBlock.AddScopeStatement (new StatementExpression (s));
        initialized_fields [i] = (FieldInitializer) cloned;
      }
    }

    public override string DocComment {
      get {
        return comment;
      }
      set {
        if (value == null)
          return;

        comment += value;
      }
    }

    public PendingImplementation PendingImplementations {
      get { return pending; }
    }

    internal override void GenerateDocComment (DocumentationBuilder builder)
    {
      if (IsPartialPart)
        return;

      base.GenerateDocComment (builder);

      foreach (var member in members)
        member.GenerateDocComment (builder);
    }

    public TypeSpec GetAttributeCoClass ()
    {
      if (OptAttributes == null)
        return null;

      Attribute a = OptAttributes.Search (Module.PredefinedAttributes.CoClass);
      if (a == null)
        return null;

      return a.GetCoClassAttributeValue ();
    }

    public AttributeUsageAttribute GetAttributeUsage (PredefinedAttribute pa)
    {
      Attribute a = null;
      if (OptAttributes != null) {
        a = OptAttributes.Search (pa);
      }

      if (a == null)
        return null;

      return a.GetAttributeUsageAttribute ();
    }

    public virtual CompilationSourceFile GetCompilationSourceFile ()
    {
      TypeContainer ns = Parent;
      while (true) {
        var sf = ns as CompilationSourceFile;
        if (sf != null)
          return sf;

        ns = ns.Parent;
      }
    }

    public virtual void SetBaseTypes (List<FullNamedExpression> baseTypes)
    {
      type_bases = baseTypes;
    }

    /// <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>
    protected virtual TypeSpec[] ResolveBaseTypes (out FullNamedExpression base_class)
    {
      base_class = null;
      if (type_bases == null)
        return null;

      int count = type_bases.Count;
      TypeSpec[] ifaces = null;
      var base_context = new BaseContext (this);
      for (int i = 0, j = 0; i < count; i++){
        FullNamedExpression fne = type_bases [i];

        var fne_resolved = fne.ResolveAsType (base_context);
        if (fne_resolved == null)
          continue;

        if (i == 0 && Kind == MemberKind.Class && !fne_resolved.IsInterface) {
          if (fne_resolved.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
            Report.Error (1965, Location, "Class `{0}' cannot derive from the dynamic type",
              GetSignatureForError ());

            continue;
          }
          
          base_type = fne_resolved;
          base_class = fne;
          continue;
        }

        if (ifaces == null)
          ifaces = new TypeSpec [count - i];

        if (fne_resolved.IsInterface) {
          for (int ii = 0; ii < j; ++ii) {
            if (fne_resolved == ifaces [ii]) {
              Report.Error (528, Location, "`{0}' is already listed in interface list",
                fne_resolved.GetSignatureForError ());
              break;
            }
          }

          if (Kind == MemberKind.Interface && !IsAccessibleAs (fne_resolved)) {
            Report.Error (61, fne.Location,
              "Inconsistent accessibility: base interface `{0}' is less accessible than interface `{1}'",
              fne_resolved.GetSignatureForError (), GetSignatureForError ());
          }
        } else {
          Report.SymbolRelatedToPreviousError (fne_resolved);
          if (Kind != MemberKind.Class) {
            Report.Error (527, fne.Location, "Type `{0}' in interface list is not an interface", fne_resolved.GetSignatureForError ());
          } else if (base_class != null)
            Report.Error (1721, fne.Location, "`{0}': Classes cannot have multiple base classes (`{1}' and `{2}')",
              GetSignatureForError (), base_class.GetSignatureForError (), fne_resolved.GetSignatureForError ());
          else {
            Report.Error (1722, fne.Location, "`{0}': Base class `{1}' must be specified as first",
              GetSignatureForError (), fne_resolved.GetSignatureForError ());
          }
        }

        ifaces [j++] = fne_resolved;
      }

      return ifaces;
    }

    //
    // 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 ()
    {
      bool has_equality_or_inequality = false;
      List<Operator.OpType> found_matched = new List<Operator.OpType> ();

      for (int i = 0; i < members.Count; ++i) {
        var o_a = members[i] as Operator;
        if (o_a == null)
          continue;

        var o_type = o_a.OperatorType;
        if (o_type == Operator.OpType.Equality || o_type == Operator.OpType.Inequality)
          has_equality_or_inequality = true;

        if (found_matched.Contains (o_type))
          continue;

        var matching_type = o_a.GetMatchingOperator ();
        if (matching_type == Operator.OpType.TOP) {
          continue;
        }

        bool pair_found = false;
        for (int ii = 0; ii < members.Count; ++ii) {
          var o_b = members[ii] as Operator;
          if (o_b == null || o_b.OperatorType != matching_type)
            continue;

          if (!TypeSpecComparer.IsEqual (o_a.ReturnType, o_b.ReturnType))
            continue;

          if (!TypeSpecComparer.Equals (o_a.ParameterTypes, o_b.ParameterTypes))
            continue;

          found_matched.Add (matching_type);
          pair_found = true;
          break;
        }

        if (!pair_found) {
          Report.Error (216, o_a.Location,
            "The operator `{0}' requires a matching operator `{1}' to also be defined",
            o_a.GetSignatureForError (), Operator.GetName (matching_type));
        }
      }

      if (has_equality_or_inequality) {
        if (!HasEquals)
          Report.Warning (660, 2, Location, "`{0}' defines operator == or operator != but does not override Object.Equals(object o)",
            GetSignatureForError ());

        if (!HasGetHashCode)
          Report.Warning (661, 2, Location, "`{0}' defines operator == or operator != but does not override Object.GetHashCode()",
            GetSignatureForError ());
      }
    }

    public override void CreateMetadataName (StringBuilder sb)
    {
      if (Parent.MemberName != null) {
        Parent.CreateMetadataName (sb);

        if (sb.Length != 0) {
          sb.Append (".");
        }
      }

      sb.Append (MemberName.Basename);
    }
  
    bool CreateTypeBuilder ()
    {
      //
      // Sets .size to 1 for structs with no instance fields
      //
      int type_size = Kind == MemberKind.Struct && first_nonstatic_field == null && !(this is StateMachine) ? 1 : 0;

      var parent_def = Parent as TypeDefinition;
      if (parent_def == null) {
        var sb = new StringBuilder ();
        CreateMetadataName (sb);
        TypeBuilder = Module.CreateBuilder (sb.ToString (), TypeAttr, type_size);
      } else {
        TypeBuilder = parent_def.TypeBuilder.DefineNestedType (Basename, TypeAttr, null, type_size);
      }

      if (DeclaringAssembly.Importer != null)
        DeclaringAssembly.Importer.AddCompiledType (TypeBuilder, spec);

      spec.SetMetaInfo (TypeBuilder);
      spec.MemberCache = new MemberCache (this);

      TypeParameters parentAllTypeParameters = null;
      if (parent_def != null) {
        spec.DeclaringType = Parent.CurrentType;
        parent_def.MemberCache.AddMember (spec);
        parentAllTypeParameters = parent_def.all_type_parameters;
      }

      if (MemberName.TypeParameters != null || parentAllTypeParameters != null) {
        var tparam_names = CreateTypeParameters (parentAllTypeParameters);

        all_tp_builders = TypeBuilder.DefineGenericParameters (tparam_names);

        if (CurrentTypeParameters != null) {
          CurrentTypeParameters.Create (spec, CurrentTypeParametersStartIndex, this);
          CurrentTypeParameters.Define (all_tp_builders);
        }
      }

      return true;
    }

    string[] CreateTypeParameters (TypeParameters parentAllTypeParameters)
    {
      string[] names;
      int parent_offset = 0;
      if (parentAllTypeParameters != null) {
        if (CurrentTypeParameters == null) {
          all_type_parameters = parentAllTypeParameters;
          return parentAllTypeParameters.GetAllNames ();
        }

        names = new string[parentAllTypeParameters.Count + CurrentTypeParameters.Count];
        all_type_parameters = new TypeParameters (names.Length);
        all_type_parameters.Add (parentAllTypeParameters);

        parent_offset = all_type_parameters.Count;
        for (int i = 0; i < parent_offset; ++i)
          names[i] = all_type_parameters[i].MemberName.Name;

      } else {
        names = new string[CurrentTypeParameters.Count];
      }

      for (int i = 0; i < CurrentTypeParameters.Count; ++i) {
        if (all_type_parameters != null)
          all_type_parameters.Add (MemberName.TypeParameters[i]);

        var name = CurrentTypeParameters[i].MemberName.Name;
        names[parent_offset + i] = name;
        for (int ii = 0; ii < parent_offset + i; ++ii) {
          if (names[ii] != name)
            continue;

          var tp = CurrentTypeParameters[i];
          var conflict = all_type_parameters[ii];

          tp.WarningParentNameConflict (conflict);
        }
      }

      if (all_type_parameters == null)
        all_type_parameters = CurrentTypeParameters;

      return names;
    }


    public SourceMethodBuilder CreateMethodSymbolEntry ()
    {
      if (Module.DeclaringAssembly.SymbolWriter == null || (ModFlags & Modifiers.DEBUGGER_HIDDEN) != 0)
        return null;

      var source_file = GetCompilationSourceFile ();
      if (source_file == null)
        return null;

      return new SourceMethodBuilder (source_file.SymbolUnitEntry);
    }

    //
    // Creates a proxy base method call inside this container for hoisted base member calls
    //
    public MethodSpec CreateHoistedBaseCallProxy (ResolveContext rc, MethodSpec method)
    {
      Method proxy_method;

      //
      // One proxy per base method is enough
      //
      if (hoisted_base_call_proxies == null) {
        hoisted_base_call_proxies = new Dictionary<MethodSpec, Method> ();
        proxy_method = null;
      } else {
        hoisted_base_call_proxies.TryGetValue (method, out proxy_method);
      }

      if (proxy_method == null) {
        string name = CompilerGeneratedContainer.MakeName (method.Name, null, "BaseCallProxy", hoisted_base_call_proxies.Count);

        MemberName member_name;
        TypeArguments targs = null;
        TypeSpec return_type = method.ReturnType;
        var local_param_types = method.Parameters.Types;

        if (method.IsGeneric) {
          //
          // Copy all base generic method type parameters info
          //
          var hoisted_tparams = method.GenericDefinition.TypeParameters;
          var tparams = new TypeParameters ();

          targs = new TypeArguments ();
          targs.Arguments = new TypeSpec[hoisted_tparams.Length];
          for (int i = 0; i < hoisted_tparams.Length; ++i) {
            var tp = hoisted_tparams[i];
            var local_tp = new TypeParameter (tp, null, new MemberName (tp.Name, Location), null);
            tparams.Add (local_tp);

            targs.Add (new SimpleName (tp.Name, Location));
            targs.Arguments[i] = local_tp.Type;
          }

          member_name = new MemberName (name, tparams, Location);

          //
          // Mutate any method type parameters from original
          // to newly created hoisted version
          //
          var mutator = new TypeParameterMutator (hoisted_tparams, tparams);
          return_type = mutator.Mutate (return_type);
          local_param_types = mutator.Mutate (local_param_types);
        } else {
          member_name = new MemberName (name);
        }

        var base_parameters = new Parameter[method.Parameters.Count];
        for (int i = 0; i < base_parameters.Length; ++i) {
          var base_param = method.Parameters.FixedParameters[i];
          base_parameters[i] = new Parameter (new TypeExpression (local_param_types [i], Location),
            base_param.Name, base_param.ModFlags, null, Location);
          base_parameters[i].Resolve (this, i);
        }

        var cloned_params = ParametersCompiled.CreateFullyResolved (base_parameters, method.Parameters.Types);
        if (method.Parameters.HasArglist) {
          cloned_params.FixedParameters[0] = new Parameter (null, "__arglist", Parameter.Modifier.NONE, null, Location);
          cloned_params.Types[0] = Module.PredefinedTypes.RuntimeArgumentHandle.Resolve ();
        }

        // Compiler generated proxy
        proxy_method = new Method (this, new TypeExpression (return_type, Location),
          Modifiers.PRIVATE | Modifiers.COMPILER_GENERATED | Modifiers.DEBUGGER_HIDDEN,
          member_name, cloned_params, null);

        var block = new ToplevelBlock (Compiler, proxy_method.ParameterInfo, Location) {
          IsCompilerGenerated = true
        };

        var mg = MethodGroupExpr.CreatePredefined (method, method.DeclaringType, Location);
        mg.InstanceExpression = new BaseThis (method.DeclaringType, Location);
        if (targs != null)
          mg.SetTypeArguments (rc, targs);

        // Get all the method parameters and pass them as arguments
        var real_base_call = new Invocation (mg, block.GetAllParametersArguments ());
        Statement statement;
        if (method.ReturnType.Kind == MemberKind.Void)
          statement = new StatementExpression (real_base_call);
        else
          statement = new Return (real_base_call, Location);

        block.AddStatement (statement);
        proxy_method.Block = block;

        members.Add (proxy_method);
        proxy_method.Define ();
        proxy_method.PrepareEmit ();

        hoisted_base_call_proxies.Add (method, proxy_method);
      }

      return proxy_method.Spec;
    }

    protected bool DefineBaseTypes ()
    {
      if (IsPartialPart && Kind == MemberKind.Class)
        return true;

      return DoDefineBaseType ();
    }

    bool DoDefineBaseType ()
    {
      iface_exprs = ResolveBaseTypes (out base_type_expr);
      bool set_base_type;

      if (IsPartialPart) {
        set_base_type = false;

        if (base_type_expr != null) {
          if (PartialContainer.base_type_expr != null && PartialContainer.base_type != base_type) {
            Report.SymbolRelatedToPreviousError (base_type_expr.Location, "");
            Report.Error (263, Location,
              "Partial declarations of `{0}' must not specify different base classes",
              GetSignatureForError ());
          } else {
            PartialContainer.base_type_expr = base_type_expr;
            PartialContainer.base_type = base_type;
            set_base_type = true;
          }
        }

        if (iface_exprs != null) {
          if (PartialContainer.iface_exprs == null)
            PartialContainer.iface_exprs = iface_exprs;
          else {
            var ifaces = new List<TypeSpec> (PartialContainer.iface_exprs);
            foreach (var iface_partial in iface_exprs) {
              if (ifaces.Contains (iface_partial))
                continue;

              ifaces.Add (iface_partial);
            }

            PartialContainer.iface_exprs = ifaces.ToArray ();
          }
        }

        PartialContainer.members.AddRange (members);
        if (containers != null) {
          if (PartialContainer.containers == null)
            PartialContainer.containers = new List<TypeContainer> ();

          PartialContainer.containers.AddRange (containers);
        }

        if (PrimaryConstructorParameters != null) {
          if (PartialContainer.PrimaryConstructorParameters != null) {
            Report.Error (8036, Location, "Only one part of a partial type can declare primary constructor parameters");
          } else {
            PartialContainer.PrimaryConstructorParameters = PrimaryConstructorParameters;
          }
        }

        members_defined = members_defined_ok = true;
        caching_flags |= Flags.CloseTypeCreated;
      } else {
        set_base_type = true;
      }

      var cycle = CheckRecursiveDefinition (this);
      if (cycle != null) {
        Report.SymbolRelatedToPreviousError (cycle);
        if (this is Interface) {
          Report.Error (529, Location,
            "Inherited interface `{0}' causes a cycle in the interface hierarchy of `{1}'",
              GetSignatureForError (), cycle.GetSignatureForError ());

          iface_exprs = null;
          PartialContainer.iface_exprs = null;
        } else {
          Report.Error (146, Location,
            "Circular base class dependency involving `{0}' and `{1}'",
            GetSignatureForError (), cycle.GetSignatureForError ());

          base_type = null;
          PartialContainer.base_type = null;
        }
      }

      if (iface_exprs != null) {
        if (!PrimaryConstructorBaseArgumentsStart.IsNull) {
          Report.Error (8049, PrimaryConstructorBaseArgumentsStart, "Implemented interfaces cannot have arguments");
        }

        foreach (var iface_type in iface_exprs) {
          // Prevents a crash, the interface might not have been resolved: 442144
          if (iface_type == null)
            continue;
          
          if (!spec.AddInterfaceDefined (iface_type))
            continue;

          TypeBuilder.AddInterfaceImplementation (iface_type.GetMetaInfo ());
        }
      }

      if (Kind == MemberKind.Interface) {
        spec.BaseType = Compiler.BuiltinTypes.Object;
        return true;
      }

      if (set_base_type) {
        SetBaseType ();
      }

      //
      // Base type of partial container has to be resolved before we
      // resolve any nested types of the container. We need to know
      // partial parts because the base type can be specified in file
      // defined after current container
      //
      if (class_partial_parts != null) {
        foreach (var pp in class_partial_parts) {
          if (pp.PrimaryConstructorBaseArguments != null)
            PrimaryConstructorBaseArguments = pp.PrimaryConstructorBaseArguments;

          pp.DoDefineBaseType ();
        }

      }

      return true;
    }

    void SetBaseType ()
    {
      if (base_type == null) {
        TypeBuilder.SetParent (null);
        return;
      }

      if (spec.BaseType == base_type)
        return;

      spec.BaseType = base_type;

      if (IsPartialPart)
        spec.UpdateInflatedInstancesBaseType ();

      // Set base type after type creation
      TypeBuilder.SetParent (base_type.GetMetaInfo ());
    }

    public override void ExpandBaseInterfaces ()
    {
      if (!IsPartialPart)
        DoExpandBaseInterfaces ();

      base.ExpandBaseInterfaces ();
    }

    public void DoExpandBaseInterfaces ()
    {
      if ((caching_flags & Flags.InterfacesExpanded) != 0)
        return;

      caching_flags |= Flags.InterfacesExpanded;

      //
      // Expand base interfaces. It cannot be done earlier because all partial
      // interface parts need to be defined before the type they are used from
      //
      if (iface_exprs != null) {
        foreach (var iface in iface_exprs) {
          if (iface == null)
            continue;

          var td = iface.MemberDefinition as TypeDefinition;
          if (td != null)
            td.DoExpandBaseInterfaces ();

          if (iface.Interfaces == null)
            continue;

          foreach (var biface in iface.Interfaces) {
            if (spec.AddInterfaceDefined (biface)) {
              TypeBuilder.AddInterfaceImplementation (biface.GetMetaInfo ());
            }
          }
        }
      }

      //
      // Include all base type interfaces too, see ImportTypeBase for details
      //
      if (base_type != null) {
        var td = base_type.MemberDefinition as TypeDefinition;
        if (td != null)
          td.DoExpandBaseInterfaces ();

        //
        // Simply use base interfaces only, they are all expanded which makes
        // it easy to handle generic type argument propagation with single
        // inflator only.
        //
        // interface IA<T> : IB<T>
        // interface IB<U> : IC<U>
        // interface IC<V>
        //
        if (base_type.Interfaces != null) {
          foreach (var iface in base_type.Interfaces) {
            spec.AddInterfaceDefined (iface);
          }
        }
      }
    }

    public override void PrepareEmit ()
    {
      if ((caching_flags & Flags.CloseTypeCreated) != 0)
        return;

      foreach (var member in members) {
        var pbm = member as PropertyBasedMember;
        if (pbm != null)
          pbm.PrepareEmit ();

        var pm = member as IParametersMember;
        if (pm != null) {
          var mc = member as MethodOrOperator;
          if (mc != null) {
            mc.PrepareEmit ();
          }

          var p = pm.Parameters;
          if (p.IsEmpty)
            continue;

          ((ParametersCompiled) p).ResolveDefaultValues (member);
          continue;
        }

        var c = member as Const;
        if (c != null)
          c.DefineValue ();
      }

      base.PrepareEmit ();
    }

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

      if (error)
        return false;

      if (IsPartialPart) {
        spec = PartialContainer.spec;
        TypeBuilder = PartialContainer.TypeBuilder;
        all_tp_builders = PartialContainer.all_tp_builders;
        all_type_parameters = PartialContainer.all_type_parameters;
      } else {
        if (!CreateTypeBuilder ()) {
          error = true;
          return false;
        }
      }

      return base.CreateContainer ();
    }

    protected override void DoDefineContainer ()
    {
      DefineBaseTypes ();

      DoResolveTypeParameters ();
    }

    //
    // Replaces normal spec with predefined one when compiling corlib
    // and this type container defines predefined type
    //
    public void SetPredefinedSpec (BuiltinTypeSpec spec)
    {
      // When compiling build-in types we start with two
      // version of same type. One is of BuiltinTypeSpec and
      // second one is ordinary TypeSpec. The unification
      // happens at later stage when we know which type
      // really matches the builtin type signature. However
      // that means TypeSpec create during CreateType of this
      // type has to be replaced with builtin one
      // 
      spec.SetMetaInfo (TypeBuilder);
      spec.MemberCache = this.spec.MemberCache;
      spec.DeclaringType = this.spec.DeclaringType;

      this.spec = spec;
      current_type = null;
    }

    public override void RemoveContainer (TypeContainer cont)
    {
      base.RemoveContainer (cont);
      Members.Remove (cont);
      Cache.Remove (cont.Basename);
    }

    protected virtual bool DoResolveTypeParameters ()
    {
      var tparams = MemberName.TypeParameters;
      if (tparams == null)
        return true;

      var base_context = new BaseContext (this);
      for (int i = 0; i < tparams.Count; ++i) {
        var tp = tparams[i];

        if (!tp.ResolveConstraints (base_context)) {
          error = true;
          return false;
        }

        if (IsPartialPart) {
          var pc_tp = PartialContainer.CurrentTypeParameters [i];

          tp.Create (spec, this);
          tp.Define (pc_tp);

          if (tp.OptAttributes != null) {
            if (pc_tp.OptAttributes == null)
              pc_tp.OptAttributes = tp.OptAttributes;
            else
              pc_tp.OptAttributes.Attrs.AddRange (tp.OptAttributes.Attrs);
          }
        }
      }

      if (IsPartialPart) {
        PartialContainer.CurrentTypeParameters.UpdateConstraints (this);
      }

      return true;
    }

    TypeSpec CheckRecursiveDefinition (TypeDefinition tc)
    {
      if (InTransit != null)
        return spec;

      InTransit = tc;

      if (base_type != null) {
        var ptc = base_type.MemberDefinition as TypeDefinition;
        if (ptc != null && ptc.CheckRecursiveDefinition (this) != null)
          return base_type;
      }

      if (iface_exprs != null) {
        foreach (var iface in iface_exprs) {
          // the interface might not have been resolved, prevents a crash, see #442144
          if (iface == null)
            continue;
          var ptc = iface.MemberDefinition as Interface;
          if (ptc != null && ptc.CheckRecursiveDefinition (this) != null)
            return iface;
        }
      }

      if (!IsTopLevel && Parent.PartialContainer.CheckRecursiveDefinition (this) != null)
        return spec;

      InTransit = null;
      return null;
    }

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

      members_defined_ok = DoDefineMembers ();
      members_defined = true;

      base.Define ();

      return members_defined_ok;
    }

    protected virtual bool DoDefineMembers ()
    {
      Debug.Assert (!IsPartialPart);

      if (iface_exprs != null) {
        foreach (var iface_type in iface_exprs) {
          if (iface_type == null)
            continue;

          // Ensure the base is always setup
          var compiled_iface = iface_type.MemberDefinition as Interface;
          if (compiled_iface != null)
            compiled_iface.Define ();

          ObsoleteAttribute oa = iface_type.GetAttributeObsolete ();
          if (oa != null && !IsObsolete)
            AttributeTester.Report_ObsoleteMessage (oa, iface_type.GetSignatureForError (), Location, Report);

          if (iface_type.Arity > 0) {
            // TODO: passing `this' is wrong, should be base type iface instead
            VarianceDecl.CheckTypeVariance (iface_type, Variance.Covariant, this);

            if (((InflatedTypeSpec) iface_type).HasDynamicArgument () && !IsCompilerGenerated) {
              Report.Error (1966, Location,
                "`{0}': cannot implement a dynamic interface `{1}'",
                GetSignatureForError (), iface_type.GetSignatureForError ());
              return false;
            }
          }

          if (iface_type.IsGenericOrParentIsGeneric) {
            foreach (var prev_iface in iface_exprs) {
              if (prev_iface == iface_type || prev_iface == null)
                break;

              if (!TypeSpecComparer.Unify.IsEqual (iface_type, prev_iface))
                continue;

              Report.Error (695, Location,
                "`{0}' cannot implement both `{1}' and `{2}' because they may unify for some type parameter substitutions",
                GetSignatureForError (), prev_iface.GetSignatureForError (), iface_type.GetSignatureForError ());
            }
          }
        }

        if (Kind == MemberKind.Interface) {
          foreach (var iface in spec.Interfaces) {
            MemberCache.AddInterface (iface);
          }
        }
      }

      if (base_type != null) {
        //
        // Run checks skipped during DefineType (e.g FullNamedExpression::ResolveAsType)
        //
        if (base_type_expr != null) {
          ObsoleteAttribute obsolete_attr = base_type.GetAttributeObsolete ();
          if (obsolete_attr != null && !IsObsolete)
            AttributeTester.Report_ObsoleteMessage (obsolete_attr, base_type.GetSignatureForError (), base_type_expr.Location, Report);

          if (IsGenericOrParentIsGeneric && base_type.IsAttribute) {
            Report.Error (698, base_type_expr.Location,
              "A generic type cannot derive from `{0}' because it is an attribute class",
              base_type.GetSignatureForError ());
          }
        }

        var baseContainer = base_type.MemberDefinition as ClassOrStruct;
        if (baseContainer != null) {
          baseContainer.Define ();

          //
          // It can trigger define of this type (for generic types only)
          //
          if (HasMembersDefined)
            return true;
        }
      }

      if (Kind == MemberKind.Struct || Kind == MemberKind.Class) {
        pending = PendingImplementation.GetPendingImplementations (this);
      }

      var count = members.Count;    
      for (int i = 0; i < count; ++i) {
        var mc = members[i] as InterfaceMemberBase;
        if (mc == null || !mc.IsExplicitImpl)
          continue;

        try {
          mc.Define ();
        } catch (Exception e) {
          throw new InternalErrorException (mc, e);
        }
      }

      for (int i = 0; i < count; ++i) {
        var mc = members[i] as InterfaceMemberBase;
        if (mc != null && mc.IsExplicitImpl)
          continue;

        if (members[i] is TypeContainer)
          continue;

        try {
          members[i].Define ();
        } catch (Exception e) {
          throw new InternalErrorException (members[i], e);
        }
      }

      if (HasOperators) {
        CheckPairedOperators ();
      }

      if (requires_delayed_unmanagedtype_check) {
        requires_delayed_unmanagedtype_check = false;
        foreach (var member in members) {
          var f = member as Field;
          if (f != null && f.MemberType != null && f.MemberType.IsPointer)
            TypeManager.VerifyUnmanaged (Module, f.MemberType, f.Location);
        }
      }

      ComputeIndexerName();

      if (HasEquals && !HasGetHashCode) {
        Report.Warning (659, 3, Location,
          "`{0}' overrides Object.Equals(object) but does not override Object.GetHashCode()", GetSignatureForError ());
      }

      if (Kind == MemberKind.Interface && iface_exprs != null) {
        MemberCache.RemoveHiddenMembers (spec);
      }

      return true;
    }

    void ComputeIndexerName ()
    {
      var indexers = MemberCache.FindMembers (spec, MemberCache.IndexerNameAlias, true);
      if (indexers == null)
        return;

      string class_indexer_name = null;

      //
      // Check normal indexers for consistent name, explicit interface implementation
      // indexers are ignored
      //
      foreach (var indexer in indexers) {
        //
        // FindMembers can return unfiltered full hierarchy names
        //
        if (indexer.DeclaringType != spec)
          continue;

        has_normal_indexers = true;

        if (class_indexer_name == null) {
          indexer_name = class_indexer_name = indexer.Name;
          continue;
        }

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

    void EmitIndexerName ()
    {
      if (!has_normal_indexers)
        return;

      var ctor = Module.PredefinedMembers.DefaultMemberAttributeCtor.Get ();
      if (ctor == null)
        return;

      var encoder = new AttributeEncoder ();
      encoder.Encode (GetAttributeDefaultMember ());
      encoder.EncodeEmptyNamedArguments ();

      TypeBuilder.SetCustomAttribute ((ConstructorInfo) ctor.GetMetaInfo (), encoder.ToArray ());
    }

    public override void VerifyMembers ()
    {
      //
      // Check for internal or private fields that were never assigned
      //
      if (!IsCompilerGenerated && Compiler.Settings.WarningLevel >= 3 && this == PartialContainer) {
        bool is_type_exposed = Kind == MemberKind.Struct || IsExposedFromAssembly ();
        foreach (var member in members) {
          if (member is Event) {
            //
            // An event can be assigned from same class only, report
            // this warning for all accessibility modes
            //
            if (!member.IsUsed && !PartialContainer.HasStructLayout)
              Report.Warning (67, 3, member.Location, "The event `{0}' is never used", member.GetSignatureForError ());

            continue;
          }

          if ((member.ModFlags & Modifiers.AccessibilityMask) != Modifiers.PRIVATE) {
            if (is_type_exposed)
              continue;

            member.SetIsUsed ();
          }

          var f = member as Field;
          if (f == null)
            continue;

          if (!member.IsUsed) {
            if (!PartialContainer.HasStructLayout) {
              if ((member.caching_flags & Flags.IsAssigned) == 0) {
                Report.Warning (169, 3, member.Location, "The private field `{0}' is never used", member.GetSignatureForError ());
              } else {
                Report.Warning (414, 3, member.Location, "The private field `{0}' is assigned but its value is never used",
                  member.GetSignatureForError ());
              }
            }

            continue;
          }

          if ((f.caching_flags & Flags.IsAssigned) != 0)
            continue;

          //
          // Only report 649 on level 4
          //
          if (Compiler.Settings.WarningLevel < 4)
            continue;

          //
          // Don't be pedantic when type requires specific layout
          //
          if (f.OptAttributes != null || PartialContainer.HasStructLayout)
            continue;

          Constant c = New.Constantify (f.MemberType, f.Location);
          string value;
          if (c != null) {
            value = c.GetValueAsLiteral ();
          } else if (TypeSpec.IsReferenceType (f.MemberType)) {
            value = "null";
          } else {
            value = null;
          }

          if (value != null)
            value = " `" + value + "'";

          Report.Warning (649, 4, f.Location, "Field `{0}' is never assigned to, and will always have its default value{1}",
            f.GetSignatureForError (), value);
        }
      }

      base.VerifyMembers ();
    }

    public override void Emit ()
    {
      if (OptAttributes != null)
        OptAttributes.Emit ();

      if (!IsCompilerGenerated) {
        if (!IsTopLevel) {
          MemberSpec candidate;
          bool overrides = false;
          var conflict_symbol = MemberCache.FindBaseMember (this, out candidate, ref overrides);
          if (conflict_symbol == null && candidate == null) {
            if ((ModFlags & Modifiers.NEW) != 0)
              Report.Warning (109, 4, Location, "The member `{0}' does not hide an inherited member. The new keyword is not required",
                GetSignatureForError ());
          } else {
            if ((ModFlags & Modifiers.NEW) == 0) {
              if (candidate == null)
                candidate = conflict_symbol;

              Report.SymbolRelatedToPreviousError (candidate);
              Report.Warning (108, 2, Location, "`{0}' hides inherited member `{1}'. Use the new keyword if hiding was intended",
                GetSignatureForError (), candidate.GetSignatureForError ());
            }
          }
        }

        // Run constraints check on all possible generic types
        if (base_type != null && base_type_expr != null) {
          ConstraintChecker.Check (this, base_type, base_type_expr.Location);
        }

        if (iface_exprs != null) {
          foreach (var iface_type in iface_exprs) {
            if (iface_type == null)
              continue;

            ConstraintChecker.Check (this, iface_type, Location); // TODO: Location is wrong
          }
        }
      }

      if (all_tp_builders != null) {
        int current_starts_index = CurrentTypeParametersStartIndex;
        for (int i = 0; i < all_tp_builders.Length; i++) {
          if (i < current_starts_index) {
            all_type_parameters[i].EmitConstraints (all_tp_builders [i]);
          } else {
            var tp = CurrentTypeParameters [i - current_starts_index];
            tp.CheckGenericConstraints (!IsObsolete);
            tp.Emit ();
          }
        }
      }

      if ((ModFlags & Modifiers.COMPILER_GENERATED) != 0 && !Parent.IsCompilerGenerated)
        Module.PredefinedAttributes.CompilerGenerated.EmitAttribute (TypeBuilder);

#if STATIC
      if ((TypeBuilder.Attributes & TypeAttributes.StringFormatMask) == 0 && Module.HasDefaultCharSet)
        TypeBuilder.__SetAttributes (TypeBuilder.Attributes | Module.DefaultCharSetType);
#endif

      base.Emit ();

      for (int i = 0; i < members.Count; i++) {
        var m = members[i];
        if ((m.caching_flags & Flags.CloseTypeCreated) != 0)
          continue;

        m.Emit ();
      }

      EmitIndexerName ();
      CheckAttributeClsCompliance ();

      if (pending != null)
        pending.VerifyPendingMethods ();
    }


    void CheckAttributeClsCompliance ()
    {
      if (!spec.IsAttribute || !IsExposedFromAssembly () || !Compiler.Settings.VerifyClsCompliance || !IsClsComplianceRequired ())
        return;

      foreach (var m in members) {
        var c = m as Constructor;
        if (c == null)
          continue;

        if (c.HasCompliantArgs)
          return;
      }

      Report.Warning (3015, 1, Location, "`{0}' has no accessible constructors which use only CLS-compliant types", GetSignatureForError ());
    }

    public sealed override void EmitContainer ()
    {
      if ((caching_flags & Flags.CloseTypeCreated) != 0)
        return;

      Emit ();
    }

    public override void CloseContainer ()
    {
      if ((caching_flags & Flags.CloseTypeCreated) != 0)
        return;

      // Close base type container first to avoid TypeLoadException
      if (spec.BaseType != null) {
        var btype = spec.BaseType.MemberDefinition as TypeContainer;
        if (btype != null) {
          btype.CloseContainer ();

          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
        //
      } catch (Exception e) {
        throw new InternalErrorException (this, e);
      }

      base.CloseContainer ();
      
      containers = null;
      initialized_fields = null;
      initialized_static_fields = null;
      type_bases = null;
      OptAttributes = null;
    }

    //
    // Performs the validation on a Method's modifiers (properties have
    // the same properties).
    //
    // TODO: Why is it not done at parse stage, move to Modifiers::Check
    //
    public bool MethodModifiersValid (MemberCore mc)
    {
      const Modifiers vao = (Modifiers.VIRTUAL | Modifiers.ABSTRACT | Modifiers.OVERRIDE);
      const Modifiers nv = (Modifiers.NEW | Modifiers.VIRTUAL);
      bool ok = true;
      var 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 ((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.SymbolRelatedToPreviousError (this);
          Report.Error (513, mc.Location, "`{0}' is abstract but it is declared in the non-abstract class `{1}'",
            mc.GetSignatureForError (), 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;
    }

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

      // Check all container names for user classes
      if (Kind != MemberKind.Delegate)
        MemberCache.VerifyClsCompliance (Definition, Report);

      if (BaseType != null && !BaseType.IsCLSCompliant ()) {
        Report.Warning (3009, 1, Location, "`{0}': base type `{1}' is not CLS-compliant",
          GetSignatureForError (), BaseType.GetSignatureForError ());
      }
      return true;
    }

    /// <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 bool VerifyImplements (InterfaceMemberBase mb)
    {
      var ifaces = PartialContainer.Interfaces;
      if (ifaces != null) {
        foreach (TypeSpec t in ifaces){
          if (t == mb.InterfaceType)
            return true;

          var expanded_base = t.Interfaces;
          if (expanded_base == null)
            continue;

          foreach (var bt in expanded_base) {
            if (bt == mb.InterfaceType)
              return true;
          }
        }
      }
      
      Report.SymbolRelatedToPreviousError (mb.InterfaceType);
      Report.Error (540, mb.Location, "`{0}': containing type does not implement interface `{1}'",
        mb.GetSignatureForError (), mb.InterfaceType.GetSignatureForError ());
      return false;
    }

    //
    // Used for visiblity checks to tests whether this definition shares
    // base type baseType, it does member-definition search
    //
    public bool IsBaseTypeDefinition (TypeSpec baseType)
    {
      // RootContext check
      if (TypeBuilder == null)
        return false;

      var type = spec;
      do {
        if (type.MemberDefinition == baseType.MemberDefinition)
          return true;

        type = type.BaseType;
      } while (type != null);

      return false;
    }

    public override bool IsClsComplianceRequired ()
    {
      if (IsPartialPart)
        return PartialContainer.IsClsComplianceRequired ();

      return base.IsClsComplianceRequired ();
    }

    bool ITypeDefinition.IsInternalAsPublic (IAssemblyDefinition assembly)
    {
      return Module.DeclaringAssembly == assembly;
    }

    public virtual bool IsUnmanagedType ()
    {
      return false;
    }

    public void LoadMembers (TypeSpec declaringType, bool onlyTypes, ref MemberCache cache)
    {
      throw new NotSupportedException ("Not supported for compiled definition " + GetSignatureForError ());
    }

    //
    // Public function used to locate types.
    //
    // Returns: Type or null if they type can not be found.
    //
    public override FullNamedExpression LookupNamespaceOrType (string name, int arity, LookupMode mode, Location loc)
    {
      FullNamedExpression e;
      if (arity == 0 && Cache.TryGetValue (name, out e) && mode != LookupMode.IgnoreAccessibility)
        return e;

      e = null;

      if (arity == 0) {
        var tp = CurrentTypeParameters;
        if (tp != null) {
          TypeParameter tparam = tp.Find (name);
          if (tparam != null)
            e = new TypeParameterExpr (tparam, Location.Null);
        }
      }

      if (e == null) {
        TypeSpec t = LookupNestedTypeInHierarchy (name, arity);

        if (t != null && (t.IsAccessible (this) || mode == LookupMode.IgnoreAccessibility))
          e = new TypeExpression (t, Location.Null);
        else {
          var errors = Compiler.Report.Errors;
          e = Parent.LookupNamespaceOrType (name, arity, mode, loc);

          // TODO: LookupNamespaceOrType does more than just lookup. The result
          // cannot be cached or the error reporting won't happen
          if (errors != Compiler.Report.Errors)
            return e;
        }
      }

      // TODO MemberCache: How to cache arity stuff ?
      if (arity == 0 && mode == LookupMode.Normal)
        Cache[name] = e;

      return e;
    }

    TypeSpec LookupNestedTypeInHierarchy (string name, int arity)
    {
      // Has any nested type
      // Does not work, because base type can have
      //if (PartialContainer.Types == null)
      //  return null;

      var container = PartialContainer.CurrentType;
      return MemberCache.FindNestedType (container, name, arity);
    }

    public void Mark_HasEquals ()
    {
      cached_method |= CachedMethods.Equals;
    }

    public void Mark_HasGetHashCode ()
    {
      cached_method |= CachedMethods.GetHashCode;
    }

    public override void WriteDebugSymbol (MonoSymbolFile file)
    {
      if (IsPartialPart)
        return;

      foreach (var m in members) {
        m.WriteDebugSymbol (file);
      }
    }

    /// <summary>
    /// Method container contains Equals method
    /// </summary>
    public bool HasEquals {
      get {
        return (cached_method & CachedMethods.Equals) != 0;
      }
    }
 
    /// <summary>
    /// Method container contains GetHashCode method
    /// </summary>
    public bool HasGetHashCode {
      get {
        return (cached_method & CachedMethods.GetHashCode) != 0;
      }
    }

    public bool HasStaticFieldInitializer {
      get {
        return (cached_method & CachedMethods.HasStaticFieldInitializer) != 0;
      }
      set {
        if (value)
          cached_method |= CachedMethods.HasStaticFieldInitializer;
        else
          cached_method &= ~CachedMethods.HasStaticFieldInitializer;
      }
    }

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

  public abstract class ClassOrStruct : TypeDefinition
  {
    public const TypeAttributes StaticClassAttribute = TypeAttributes.Abstract | TypeAttributes.Sealed;

    SecurityType declarative_security;
    protected Constructor generated_primary_constructor;

    protected ClassOrStruct (TypeContainer parent, MemberName name, Attributes attrs, MemberKind kind)
      : base (parent, name, attrs, kind)
    {
    }

    public ToplevelBlock PrimaryConstructorBlock { get; set; }

    protected override TypeAttributes TypeAttr {
      get {
        TypeAttributes ta = base.TypeAttr;
        if (!has_static_constructor)
          ta |= TypeAttributes.BeforeFieldInit;

        if (Kind == MemberKind.Class) {
          ta |= TypeAttributes.AutoLayout | TypeAttributes.Class;
          if (IsStatic)
            ta |= StaticClassAttribute;
        } else {
          ta |= TypeAttributes.SequentialLayout;
        }

        return ta;
      }
    }

    public override void AddNameToContainer (MemberCore symbol, string name)
    {
      if (!(symbol is Constructor) && symbol.MemberName.Name == MemberName.Name) {
        if (symbol is TypeParameter) {
          Report.Error (694, symbol.Location,
            "Type parameter `{0}' has same name as containing type, or method",
            symbol.GetSignatureForError ());
          return;
        }

        InterfaceMemberBase imb = symbol as InterfaceMemberBase;
        if (imb == null || !imb.IsExplicitImpl) {
          Report.SymbolRelatedToPreviousError (this);
          Report.Error (542, symbol.Location, "`{0}': member names cannot be the same as their enclosing type",
            symbol.GetSignatureForError ());
          return;
        }
      }

      base.AddNameToContainer (symbol, name);
    }

    public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
    {
      if (a.IsValidSecurityAttribute ()) {
        a.ExtractSecurityPermissionSet (ctor, ref declarative_security);
        return;
      }

      if (a.Type == pa.StructLayout) {
        PartialContainer.HasStructLayout = true;
        if (a.IsExplicitLayoutKind ())
          PartialContainer.HasExplicitLayout = true;
      }

      if (a.Type == pa.Dynamic) {
        a.Error_MisusedDynamicAttribute ();
        return;
      }

      base.ApplyAttributeBuilder (a, ctor, cdata, pa);
    }

    /// <summary>
    /// Defines the default constructors 
    /// </summary>
    protected virtual Constructor DefineDefaultConstructor (bool is_static)
    {
      // The default instance constructor is public
      // If the class is abstract, the default constructor is protected
      // The default static constructor is private

      Modifiers mods;
      ParametersCompiled parameters = null;
      if (is_static) {
        mods = Modifiers.STATIC | Modifiers.PRIVATE;
        parameters = ParametersCompiled.EmptyReadOnlyParameters;
      } else {
        mods = ((ModFlags & Modifiers.ABSTRACT) != 0) ? Modifiers.PROTECTED : Modifiers.PUBLIC;
        parameters = PrimaryConstructorParameters ?? ParametersCompiled.EmptyReadOnlyParameters;
      }

      var c = new Constructor (this, MemberName.Name, mods, null, parameters, Location);
      if (Kind == MemberKind.Class)
        c.Initializer = new GeneratedBaseInitializer (Location, PrimaryConstructorBaseArguments);

      if (PrimaryConstructorParameters != null && !is_static)
        c.IsPrimaryConstructor = true;
      
      AddConstructor (c, true);
      if (PrimaryConstructorBlock == null) {
        c.Block = new ToplevelBlock (Compiler, parameters, Location) {
          IsCompilerGenerated = true
        };
      } else {
        c.Block = PrimaryConstructorBlock;
      }

      return c;
    }

    protected override bool DoDefineMembers ()
    {
      CheckProtectedModifier ();

      if (PrimaryConstructorParameters != null) {
        foreach (Parameter p in PrimaryConstructorParameters.FixedParameters) {
          if (p.Name == MemberName.Name) {
            Report.Error (8039, p.Location, "Primary constructor of type `{0}' has parameter of same name as containing type",
              GetSignatureForError ());
          }

          if (CurrentTypeParameters != null) {
            for (int i = 0; i < CurrentTypeParameters.Count; ++i) {
              var tp = CurrentTypeParameters [i];
              if (p.Name == tp.Name) {
                Report.Error (8038, p.Location, "Primary constructor of type `{0}' has parameter of same name as type parameter `{1}'",
                  GetSignatureForError (), p.GetSignatureForError ());
              }
            }
          }
        }
      }

      base.DoDefineMembers ();

      return true;
    }

    public override void Emit ()
    {
      if (!has_static_constructor && HasStaticFieldInitializer) {
        var c = DefineDefaultConstructor (true);
        c.Define ();
      }

      base.Emit ();

      if (declarative_security != null) {
        foreach (var de in declarative_security) {
#if STATIC
          TypeBuilder.__AddDeclarativeSecurity (de);
#else
          TypeBuilder.AddDeclarativeSecurity (de.Key, de.Value);
#endif
        }
      }
    }
  }


  public sealed class Class : ClassOrStruct
  {
    const Modifiers AllowedModifiers =
      Modifiers.NEW |
      Modifiers.PUBLIC |
      Modifiers.PROTECTED |
      Modifiers.INTERNAL |
      Modifiers.PRIVATE |
      Modifiers.ABSTRACT |
      Modifiers.SEALED |
      Modifiers.STATIC |
      Modifiers.UNSAFE;
      
    public Class (TypeContainer parent, MemberName name, Modifiers mod, Attributes attrs)
      : base (parent, name, attrs, MemberKind.Class)
    {
      var accmods = IsTopLevel ? Modifiers.INTERNAL : Modifiers.PRIVATE;
      this.ModFlags = ModifiersExtensions.Check (AllowedModifiers, mod, accmods, Location, Report);
      spec = new TypeSpec (Kind, null, this, null, ModFlags);
    }

    public override void Accept (StructuralVisitor visitor)
    {
      visitor.Visit (this);
    }

    public override void SetBaseTypes (List<FullNamedExpression> baseTypes)
    {
      var pmn = MemberName;
      if (pmn.Name == "Object" && !pmn.IsGeneric && Parent.MemberName.Name == "System" && Parent.MemberName.Left == null)
        Report.Error (537, Location,
          "The class System.Object cannot have a base class or implement an interface.");

      base.SetBaseTypes (baseTypes);
    }

    public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
    {
      if (a.Type == pa.AttributeUsage) {
        if (!BaseType.IsAttribute && spec.BuiltinType != BuiltinTypeSpec.Type.Attribute) {
          Report.Error (641, a.Location, "Attribute `{0}' is only valid on classes derived from System.Attribute", a.GetSignatureForError ());
        }
      }

      if (a.Type == pa.Conditional && !BaseType.IsAttribute) {
        Report.Error (1689, a.Location, "Attribute `System.Diagnostics.ConditionalAttribute' is only valid on methods or attribute classes");
        return;
      }

      if (a.Type == pa.ComImport && !attributes.Contains (pa.Guid)) {
        a.Error_MissingGuidAttribute ();
        return;
      }

      if (a.Type == pa.Extension) {
        a.Error_MisusedExtensionAttribute ();
        return;
      }

      if (a.Type.IsConditionallyExcluded (this))
        return;

      base.ApplyAttributeBuilder (a, ctor, cdata, pa);
    }

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

    protected override bool DoDefineMembers ()
    {
      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 ());
      }

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

      if (IsStatic) {
        if (PrimaryConstructorParameters != null) {
          Report.Error (-800, Location, "`{0}': Static classes cannot have primary constructor", GetSignatureForError ());
          PrimaryConstructorParameters = null;
        }

        foreach (var m in Members) {
          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 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 TypeContainer)
            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 ());
        }
      } else {
        if (!PartialContainer.HasInstanceConstructor || PrimaryConstructorParameters != null)
          generated_primary_constructor = DefineDefaultConstructor (false);
      }

      return base.DoDefineMembers ();
    }

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

      if ((ModFlags & Modifiers.METHOD_EXTENSION) != 0)
        Module.PredefinedAttributes.Extension.EmitAttribute (TypeBuilder);

      if (base_type != null && base_type.HasDynamicElement) {
        Module.PredefinedAttributes.Dynamic.EmitAttribute (TypeBuilder, base_type, Location);
      }
    }

    public override void GetCompletionStartingWith (string prefix, List<string> results)
    {
      base.GetCompletionStartingWith (prefix, results);

      var bt = base_type;
      while (bt != null) {
        results.AddRange (MemberCache.GetCompletitionMembers (this, bt, prefix).Where (l => l.IsStatic).Select (l => l.Name));
        bt = bt.BaseType;
      }
    }

    protected override TypeSpec[] ResolveBaseTypes (out FullNamedExpression base_class)
    {
      var ifaces = base.ResolveBaseTypes (out base_class);

      if (base_class == null) {
        if (spec.BuiltinType != BuiltinTypeSpec.Type.Object)
          base_type = Compiler.BuiltinTypes.Object;
      } else {
        if (base_type.IsGenericParameter){
          Report.Error (689, base_class.Location, "`{0}': Cannot derive from type parameter `{1}'",
            GetSignatureForError (), base_type.GetSignatureForError ());
        } else if (base_type.IsStatic) {
          Report.SymbolRelatedToPreviousError (base_type);
          Report.Error (709, Location, "`{0}': Cannot derive from static class `{1}'",
            GetSignatureForError (), base_type.GetSignatureForError ());
        } else if (base_type.IsSealed) {
          Report.SymbolRelatedToPreviousError (base_type);
          Report.Error (509, Location, "`{0}': cannot derive from sealed type `{1}'",
            GetSignatureForError (), base_type.GetSignatureForError ());
        } else if (PartialContainer.IsStatic && base_type.BuiltinType != BuiltinTypeSpec.Type.Object) {
          Report.Error (713, Location, "Static class `{0}' cannot derive from type `{1}'. Static classes must derive from object",
            GetSignatureForError (), base_type.GetSignatureForError ());
        }

        switch (base_type.BuiltinType) {
        case BuiltinTypeSpec.Type.Enum:
        case BuiltinTypeSpec.Type.ValueType:
        case BuiltinTypeSpec.Type.MulticastDelegate:
        case BuiltinTypeSpec.Type.Delegate:
        case BuiltinTypeSpec.Type.Array:
          if (!(spec is BuiltinTypeSpec)) {
            Report.Error (644, Location, "`{0}' cannot derive from special class `{1}'",
              GetSignatureForError (), base_type.GetSignatureForError ());

            base_type = Compiler.BuiltinTypes.Object;
          }
          break;
        }

        if (!IsAccessibleAs (base_type)) {
          Report.SymbolRelatedToPreviousError (base_type);
          Report.Error (60, Location, "Inconsistent accessibility: base class `{0}' is less accessible than class `{1}'",
            base_type.GetSignatureForError (), GetSignatureForError ());
        }
      }

      if (PartialContainer.IsStatic && ifaces != null) {
        foreach (var t in ifaces)
          Report.SymbolRelatedToPreviousError (t);
        Report.Error (714, Location, "Static class `{0}' cannot implement interfaces", GetSignatureForError ());
      }

      return ifaces;
    }

    /// Search for at least one defined condition in ConditionalAttribute of attribute class
    /// Valid only for attribute classes.
    public override string[] ConditionalConditions ()
    {
      if ((caching_flags & (Flags.Excluded_Undetected | Flags.Excluded)) == 0)
        return null;

      caching_flags &= ~Flags.Excluded_Undetected;

      if (OptAttributes == null)
        return null;

      Attribute[] attrs = OptAttributes.SearchMulti (Module.PredefinedAttributes.Conditional);
      if (attrs == null)
        return null;

      string[] conditions = new string[attrs.Length];
      for (int i = 0; i < conditions.Length; ++i)
        conditions[i] = attrs[i].GetConditionalAttributeValue ();

      caching_flags |= Flags.Excluded;
      return conditions;
    }
  }

  public sealed class Struct : ClassOrStruct
  {
    bool is_unmanaged, has_unmanaged_check_done;
    bool InTransit;

    // <summary>
    //   Modifiers allowed in a struct declaration
    // </summary>
    const Modifiers AllowedModifiers =
      Modifiers.NEW       |
      Modifiers.PUBLIC    |
      Modifiers.PROTECTED |
      Modifiers.INTERNAL  |
      Modifiers.UNSAFE    |
      Modifiers.PRIVATE;

    public Struct (TypeContainer parent, MemberName name, Modifiers mod, Attributes attrs)
      : base (parent, name, attrs, MemberKind.Struct)
    {
      var accmods = IsTopLevel ? Modifiers.INTERNAL : Modifiers.PRIVATE;      
      this.ModFlags = ModifiersExtensions.Check (AllowedModifiers, mod, accmods, Location, Report) | Modifiers.SEALED ;
      spec = new TypeSpec (Kind, null, this, null, ModFlags);
    }

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

    public override void Accept (StructuralVisitor visitor)
    {
      visitor.Visit (this);
    }

    public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
    {
      base.ApplyAttributeBuilder (a, ctor, cdata, pa);

      //
      // When struct constains fixed fixed and struct layout has explicitly
      // set CharSet, its value has to be propagated to compiler generated
      // fixed types
      //
      if (a.Type == pa.StructLayout) {
        var value = a.GetNamedValue ("CharSet");
        if (value == null)
          return;

        for (int i = 0; i < Members.Count; ++i) {
          FixedField ff = Members [i] as FixedField;
          if (ff == null)
            continue;

          ff.CharSet = (CharSet) System.Enum.Parse (typeof (CharSet), value.GetValue ().ToString ());
        }
      }
    }

    bool CheckStructCycles ()
    {
      if (InTransit)
        return false;

      InTransit = true;
      foreach (var member in Members) {
        var field = member as Field;
        if (field == null)
          continue;

        TypeSpec ftype = field.Spec.MemberType;
        if (!ftype.IsStruct)
          continue;

        if (ftype is BuiltinTypeSpec)
          continue;

        foreach (var targ in ftype.TypeArguments) {
          if (!CheckFieldTypeCycle (targ)) {
            Report.Error (523, field.Location,
              "Struct member `{0}' of type `{1}' causes a cycle in the struct layout",
              field.GetSignatureForError (), ftype.GetSignatureForError ());
            break;
          }
        }

        //
        // Static fields of exactly same type are allowed
        //
        if (field.IsStatic && ftype == CurrentType)
          continue;

        if (!CheckFieldTypeCycle (ftype)) {
          Report.Error (523, field.Location,
            "Struct member `{0}' of type `{1}' causes a cycle in the struct layout",
            field.GetSignatureForError (), ftype.GetSignatureForError ());
          break;
        }
      }

      InTransit = false;
      return true;
    }

    static bool CheckFieldTypeCycle (TypeSpec ts)
    {
      var fts = ts.MemberDefinition as Struct;
      if (fts == null)
        return true;

      return fts.CheckStructCycles ();
    }

    protected override bool DoDefineMembers ()
    {
      if (PrimaryConstructorParameters != null)
        generated_primary_constructor = DefineDefaultConstructor (false);

      return base.DoDefineMembers ();
    }

    public override void Emit ()
    {
      CheckStructCycles ();

      base.Emit ();
    }

    bool HasExplicitConstructor ()
    {
      foreach (var m in Members) {
        var c = m as Constructor;
        if (c == null)
          continue;

        if (!c.ParameterInfo.IsEmpty)
          return true;
      }

      return false;
    }

    public override bool IsUnmanagedType ()
    {
      if (has_unmanaged_check_done)
        return is_unmanaged;

      if (requires_delayed_unmanagedtype_check)
        return true;

      var parent_def = Parent.PartialContainer;
      if (parent_def != null && parent_def.IsGenericOrParentIsGeneric) {
        has_unmanaged_check_done = true;
        return false;
      }

      if (first_nonstatic_field != null) {
        requires_delayed_unmanagedtype_check = true;

        foreach (var member in Members) {
          var f = member as Field;
          if (f == null)
            continue;

          if (f.IsStatic)
            continue;

          // It can happen when recursive unmanaged types are defined
          // struct S { S* s; }
          TypeSpec mt = f.MemberType;
          if (mt == null) {
            return true;
          }

          if (mt.IsUnmanaged)
            continue;

          has_unmanaged_check_done = true;
          return false;
        }

        has_unmanaged_check_done = true;
      }

      is_unmanaged = true;
      return true;
    }

    protected override TypeSpec[] ResolveBaseTypes (out FullNamedExpression base_class)
    {
      var ifaces = base.ResolveBaseTypes (out base_class);
      base_type = Compiler.BuiltinTypes.ValueType;
      return ifaces;
    }

    public override void RegisterFieldForInitialization (MemberCore field, FieldInitializer expression)
    {
      if ((field.ModFlags & Modifiers.STATIC) == 0 && !HasExplicitConstructor ()) {
        Report.Error (8054, field.Location, "`{0}': Structs without explicit constructors cannot contain members with initializers",
          field.GetSignatureForError ());

        return;
      }

      base.RegisterFieldForInitialization (field, expression);
    }
  }

  /// <summary>
  ///   Interfaces
  /// </summary>
  public sealed class Interface : TypeDefinition {

    /// <summary>
    ///   Modifiers allowed in a class declaration
    /// </summary>
    const Modifiers AllowedModifiers =
      Modifiers.NEW       |
      Modifiers.PUBLIC    |
      Modifiers.PROTECTED |
      Modifiers.INTERNAL  |
      Modifiers.UNSAFE    |
      Modifiers.PRIVATE;

    public Interface (TypeContainer parent, MemberName name, Modifiers mod, Attributes attrs)
      : base (parent, name, attrs, MemberKind.Interface)
    {
      var accmods = IsTopLevel ? Modifiers.INTERNAL : Modifiers.PRIVATE;

      this.ModFlags = ModifiersExtensions.Check (AllowedModifiers, mod, accmods, name.Location, Report);
      spec = new TypeSpec (Kind, null, this, null, ModFlags);
    }

    #region Properties

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

    protected override TypeAttributes TypeAttr {
      get {
        const TypeAttributes DefaultTypeAttributes =
          TypeAttributes.AutoLayout |
          TypeAttributes.Abstract |
          TypeAttributes.Interface;

        return base.TypeAttr | DefaultTypeAttributes;
      }
    }

    #endregion

    public override void Accept (StructuralVisitor visitor)
    {
      visitor.Visit (this);
    }

    public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
    {
      if (a.Type == pa.ComImport && !attributes.Contains (pa.Guid)) {
        a.Error_MissingGuidAttribute ();
        return;
      }

      base.ApplyAttributeBuilder (a, ctor, cdata, pa);
    }

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

      if (iface_exprs != null) {
        foreach (var iface in iface_exprs) {
          if (iface.IsCLSCompliant ())
            continue;

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

      return true;
    }
  }

  public abstract class InterfaceMemberBase : MemberBase
  {
    //
    // Common modifiers allowed in a class declaration
    //
    protected const Modifiers AllowedModifiersClass =
      Modifiers.NEW |
      Modifiers.PUBLIC |
      Modifiers.PROTECTED |
      Modifiers.INTERNAL |
      Modifiers.PRIVATE |
      Modifiers.STATIC |
      Modifiers.VIRTUAL |
      Modifiers.SEALED |
      Modifiers.OVERRIDE |
      Modifiers.ABSTRACT |
      Modifiers.UNSAFE |
      Modifiers.EXTERN;

    //
    // Common modifiers allowed in a struct declaration
    //
    protected const Modifiers AllowedModifiersStruct =
      Modifiers.NEW |
      Modifiers.PUBLIC |
      Modifiers.PROTECTED |
      Modifiers.INTERNAL |
      Modifiers.PRIVATE |
      Modifiers.STATIC |
      Modifiers.OVERRIDE |
      Modifiers.UNSAFE |
      Modifiers.EXTERN;

    //
    // Common modifiers allowed in a interface declaration
    //
    protected const Modifiers AllowedModifiersInterface =
      Modifiers.NEW |
      Modifiers.UNSAFE;

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

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

    protected bool is_external_implementation;

    //
    // The interface type we are explicitly implementing
    //
    public TypeSpec InterfaceType;

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

    readonly Modifiers explicit_mod_flags;
    public MethodAttributes flags;

    protected InterfaceMemberBase (TypeDefinition parent, FullNamedExpression type, Modifiers mod, Modifiers allowed_mod, MemberName name, Attributes attrs)
      : base (parent, type, mod, allowed_mod, Modifiers.PRIVATE, name, attrs)
    {
      IsInterface = parent.Kind == MemberKind.Interface;
      IsExplicitImpl = (MemberName.ExplicitInterface != null);
      explicit_mod_flags = mod;
    }

    public abstract Variance ExpectedMemberTypeVariance { get; }
    
    protected override bool CheckBase ()
    {
      if (!base.CheckBase ())
        return false;

      if ((caching_flags & Flags.MethodOverloadsExist) != 0)
        CheckForDuplications ();
      
      if (IsExplicitImpl)
        return true;

      // For System.Object only
      if (Parent.BaseType == null)
        return true;

      MemberSpec candidate;
      bool overrides = false;
      var base_member = FindBaseMember (out candidate, ref overrides);

      if ((ModFlags & Modifiers.OVERRIDE) != 0) {
        if (base_member == null) {
          if (candidate == null) {
            if (this is Method && ((Method)this).ParameterInfo.IsEmpty && MemberName.Name == Destructor.MetadataName && MemberName.Arity == 0) {
              Report.Error (249, Location, "Do not override `{0}'. Use destructor syntax instead",
                "object.Finalize()");
            } else {
              Report.Error (115, Location, "`{0}' is marked as an override but no suitable {1} found to override",
                GetSignatureForError (), SimpleName.GetMemberType (this));
            }
          } else {
            Report.SymbolRelatedToPreviousError (candidate);
            if (this is Event)
              Report.Error (72, Location, "`{0}': cannot override because `{1}' is not an event",
                GetSignatureForError (), TypeManager.GetFullNameSignature (candidate));
            else if (this is PropertyBase)
              Report.Error (544, Location, "`{0}': cannot override because `{1}' is not a property",
                GetSignatureForError (), TypeManager.GetFullNameSignature (candidate));
            else
              Report.Error (505, Location, "`{0}': cannot override because `{1}' is not a method",
                GetSignatureForError (), TypeManager.GetFullNameSignature (candidate));
          }

          return false;
        }

        //
        // Handles ambiguous overrides
        //
        if (candidate != null) {
          Report.SymbolRelatedToPreviousError (candidate);
          Report.SymbolRelatedToPreviousError (base_member);

          // Get member definition for error reporting
          var m1 = MemberCache.GetMember (base_member.DeclaringType.GetDefinition (), base_member);
          var m2 = MemberCache.GetMember (candidate.DeclaringType.GetDefinition (), candidate);

          Report.Error (462, Location,
            "`{0}' cannot override inherited members `{1}' and `{2}' because they have the same signature when used in type `{3}'",
            GetSignatureForError (), m1.GetSignatureForError (), m2.GetSignatureForError (), Parent.GetSignatureForError ());
        }

        if (!CheckOverrideAgainstBase (base_member))
          return false;

        ObsoleteAttribute oa = base_member.GetAttributeObsolete ();
        if (oa != null) {
          if (OptAttributes == null || !OptAttributes.Contains (Module.PredefinedAttributes.Obsolete)) {
            Report.SymbolRelatedToPreviousError (base_member);
            Report.Warning (672, 1, Location, "Member `{0}' overrides obsolete member `{1}'. Add the Obsolete attribute to `{0}'",
              GetSignatureForError (), base_member.GetSignatureForError ());
          }
        } else {
          if (OptAttributes != null && OptAttributes.Contains (Module.PredefinedAttributes.Obsolete)) {
            Report.SymbolRelatedToPreviousError (base_member);
            Report.Warning (809, 1, Location, "Obsolete member `{0}' overrides non-obsolete member `{1}'",
              GetSignatureForError (), base_member.GetSignatureForError ());
          }
        }

        base_method = base_member as MethodSpec;
        return true;
      }

      if (base_member == null && candidate != null && (!(candidate is IParametersMember) || !(this is IParametersMember)))
        base_member = candidate;

      if (base_member == null) {
        if ((ModFlags & Modifiers.NEW) != 0) {
          if (base_member == null) {
            Report.Warning (109, 4, Location, "The member `{0}' does not hide an inherited member. The new keyword is not required",
              GetSignatureForError ());
          }
        }
      } else {
        if ((ModFlags & Modifiers.NEW) == 0) {
          ModFlags |= Modifiers.NEW;
          if (!IsCompilerGenerated) {
            Report.SymbolRelatedToPreviousError (base_member);
            if (!IsInterface && (base_member.Modifiers & (Modifiers.ABSTRACT | Modifiers.VIRTUAL | Modifiers.OVERRIDE)) != 0) {
              Report.Warning (114, 2, Location, "`{0}' hides inherited member `{1}'. To make the current member override that implementation, add the override keyword. Otherwise add the new keyword",
                GetSignatureForError (), base_member.GetSignatureForError ());
            } else {
              Report.Warning (108, 2, Location, "`{0}' hides inherited member `{1}'. Use the new keyword if hiding was intended",
                GetSignatureForError (), base_member.GetSignatureForError ());
            }
          }
        }

        if (!IsInterface && base_member.IsAbstract && !overrides && !IsStatic) {
          Report.SymbolRelatedToPreviousError (base_member);
          Report.Error (533, Location, "`{0}' hides inherited abstract member `{1}'",
            GetSignatureForError (), base_member.GetSignatureForError ());
        }
      }

      return true;
    }

    protected virtual bool CheckForDuplications ()
    {
      return Parent.MemberCache.CheckExistingMembersOverloads (this, ParametersCompiled.EmptyReadOnlyParameters);
    }

    //
    // Performs various checks on the MethodInfo `mb' regarding the modifier flags
    // that have been defined.
    //
    protected virtual bool CheckOverrideAgainstBase (MemberSpec base_member)
    {
      bool ok = true;

      if ((base_member.Modifiers & (Modifiers.ABSTRACT | Modifiers.VIRTUAL | Modifiers.OVERRIDE)) == 0) {
        Report.SymbolRelatedToPreviousError (base_member);
        Report.Error (506, Location,
          "`{0}': cannot override inherited member `{1}' because it is not marked virtual, abstract or override",
           GetSignatureForError (), TypeManager.CSharpSignature (base_member));
        ok = false;
      }

      // Now we check that the overriden method is not final  
      if ((base_member.Modifiers & Modifiers.SEALED) != 0) {
        Report.SymbolRelatedToPreviousError (base_member);
        Report.Error (239, Location, "`{0}': cannot override inherited member `{1}' because it is sealed",
                GetSignatureForError (), TypeManager.CSharpSignature (base_member));
        ok = false;
      }

      var base_member_type = ((IInterfaceMemberSpec) base_member).MemberType;
      if (!TypeSpecComparer.Override.IsEqual (MemberType, base_member_type)) {
        Report.SymbolRelatedToPreviousError (base_member);
        if (this is PropertyBasedMember) {
          Report.Error (1715, Location, "`{0}': type must be `{1}' to match overridden member `{2}'",
            GetSignatureForError (), base_member_type.GetSignatureForError (), base_member.GetSignatureForError ());
        } else {
          Report.Error (508, Location, "`{0}': return type must be `{1}' to match overridden member `{2}'",
            GetSignatureForError (), base_member_type.GetSignatureForError (), base_member.GetSignatureForError ());
        }
        ok = false;
      }

      return ok;
    }

    protected static bool CheckAccessModifiers (MemberCore this_member, MemberSpec base_member)
    {
      var thisp = this_member.ModFlags & Modifiers.AccessibilityMask;
      var base_classp = base_member.Modifiers & Modifiers.AccessibilityMask;

      if ((base_classp & (Modifiers.PROTECTED | Modifiers.INTERNAL)) == (Modifiers.PROTECTED | Modifiers.INTERNAL)) {
        //
        // It must be at least "protected"
        //
        if ((thisp & Modifiers.PROTECTED) == 0) {
          return false;
        }

        //
        // when overriding protected internal, the method can be declared
        // protected internal only within the same assembly or assembly
        // which has InternalsVisibleTo
        //
        if ((thisp & Modifiers.INTERNAL) != 0) {
          return base_member.DeclaringType.MemberDefinition.IsInternalAsPublic (this_member.Module.DeclaringAssembly);
        }

        //
        // protected overriding protected internal inside same assembly
        // requires internal modifier as well
        //
        if (base_member.DeclaringType.MemberDefinition.IsInternalAsPublic (this_member.Module.DeclaringAssembly)) {
          return false;
        }

        return true;
      }

      return thisp == base_classp;
    }

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

        flags = MethodAttributes.Public |
          MethodAttributes.Abstract |
          MethodAttributes.HideBySig |
          MethodAttributes.NewSlot |
          MethodAttributes.Virtual;
      } else {
        Parent.PartialContainer.MethodModifiersValid (this);

        flags = ModifiersExtensions.MethodAttr (ModFlags);
      }

      if (IsExplicitImpl) {
        InterfaceType = MemberName.ExplicitInterface.ResolveAsType (Parent);
        if (InterfaceType == null)
          return false;

        if ((ModFlags & Modifiers.PARTIAL) != 0) {
          Report.Error (754, Location, "A partial method `{0}' cannot explicitly implement an interface",
            GetSignatureForError ());
        }

        if (!InterfaceType.IsInterface) {
          Report.SymbolRelatedToPreviousError (InterfaceType);
          Report.Error (538, Location, "The type `{0}' in explicit interface declaration is not an interface",
            InterfaceType.GetSignatureForError ());
        } else {
          Parent.PartialContainer.VerifyImplements (this);
        }

        Modifiers allowed_explicit = Modifiers.AllowedExplicitImplFlags;
        if (this is Method)
          allowed_explicit |= Modifiers.ASYNC;

        ModifiersExtensions.Check (allowed_explicit, explicit_mod_flags, 0, Location, Report);
      }

      return base.Define ();
    }

    protected bool DefineParameters (ParametersCompiled parameters)
    {
      if (!parameters.Resolve (this))
        return false;

      bool error = false;
      for (int i = 0; i < parameters.Count; ++i) {
        Parameter p = parameters [i];

        if (p.HasDefaultValue && (IsExplicitImpl || this is Operator || (this is Indexer && parameters.Count == 1)))
          p.Warning_UselessOptionalParameter (Report);

        if (p.CheckAccessibility (this))
          continue;

        TypeSpec t = parameters.Types [i];
        Report.SymbolRelatedToPreviousError (t);
        if (this is Indexer)
          Report.Error (55, Location,
                  "Inconsistent accessibility: parameter type `{0}' is less accessible than indexer `{1}'",
                  t.GetSignatureForError (), GetSignatureForError ());
        else if (this is Operator)
          Report.Error (57, Location,
                  "Inconsistent accessibility: parameter type `{0}' is less accessible than operator `{1}'",
                  t.GetSignatureForError (), GetSignatureForError ());
        else
          Report.Error (51, Location,
            "Inconsistent accessibility: parameter type `{0}' is less accessible than method `{1}'",
            t.GetSignatureForError (), GetSignatureForError ());
        error = true;
      }
      return !error;
    }

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

      VarianceDecl.CheckTypeVariance (MemberType, ExpectedMemberTypeVariance, this);
    }

    public override void Emit()
    {
      // for extern static method must be specified either DllImport attribute or MethodImplAttribute.
      // We are more strict than csc and report this as an error because SRE does not allow emit that
      if ((ModFlags & Modifiers.EXTERN) != 0 && !is_external_implementation && (OptAttributes == null || !OptAttributes.HasResolveError ())) {
        if (this is Constructor) {
          Report.Warning (824, 1, Location,
            "Constructor `{0}' is marked `external' but has no external implementation specified", GetSignatureForError ());
        } else {
          Report.Warning (626, 1, Location,
            "`{0}' is marked as an external but has no DllImport attribute. Consider adding a DllImport attribute to specify the external implementation",
            GetSignatureForError ());
        }
      }

      base.Emit ();
    }

    public override bool EnableOverloadChecks (MemberCore overload)
    {
      //
      // Two members can differ in their explicit interface
      // type parameter only
      //
      InterfaceMemberBase imb = overload as InterfaceMemberBase;
      if (imb != null && imb.IsExplicitImpl) {
        if (IsExplicitImpl) {
          caching_flags |= Flags.MethodOverloadsExist;
        }
        return true;
      }

      return IsExplicitImpl;
    }

    protected void Error_CannotChangeAccessModifiers (MemberCore member, MemberSpec base_member)
    {
      var base_modifiers = base_member.Modifiers;

      // Remove internal modifier from types which are not internally accessible
      if ((base_modifiers & Modifiers.AccessibilityMask) == (Modifiers.PROTECTED | Modifiers.INTERNAL) &&
        !base_member.DeclaringType.MemberDefinition.IsInternalAsPublic (member.Module.DeclaringAssembly))
        base_modifiers = Modifiers.PROTECTED;

      Report.SymbolRelatedToPreviousError (base_member);
      Report.Error (507, member.Location,
        "`{0}': cannot change access modifiers when overriding `{1}' inherited member `{2}'",
        member.GetSignatureForError (),
        ModifiersExtensions.AccessibilityName (base_modifiers),
        base_member.GetSignatureForError ());
    }

    protected void Error_StaticReturnType ()
    {
      Report.Error (722, Location,
        "`{0}': static types cannot be used as return types",
        MemberType.GetSignatureForError ());
    }

    /// <summary>
    /// Gets base method and its return type
    /// </summary>
    protected virtual MemberSpec FindBaseMember (out MemberSpec bestCandidate, ref bool overrides)
    {
      return MemberCache.FindBaseMember (this, out bestCandidate, ref overrides);
    }

    //
    // The "short" name of this property / indexer / event.  This is the
    // name without the explicit interface.
    //
    public string ShortName {
      get { return MemberName.Name; }
    }
    
    //
    // Returns full metadata method name
    //
    public string GetFullName (MemberName name)
    {
      return GetFullName (name.Name);
    }

    public string GetFullName (string name)
    {
      if (!IsExplicitImpl)
        return name;

      //
      // When dealing with explicit members a full interface type
      // name is added to member name to avoid possible name conflicts
      //
      // We use CSharpName which gets us full name with benefit of
      // replacing predefined names which saves some space and name
      // is still unique
      //
      return InterfaceType.GetSignatureForError () + "." + name;
    }

    public override string GetSignatureForDocumentation ()
    {
      if (IsExplicitImpl)
        return Parent.GetSignatureForDocumentation () + "." + InterfaceType.GetExplicitNameSignatureForDocumentation () + "#" + ShortName;

      return Parent.GetSignatureForDocumentation () + "." + ShortName;
    }

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

    public override void SetConstraints (List<Constraints> constraints_list)
    {
      if (((ModFlags & Modifiers.OVERRIDE) != 0 || IsExplicitImpl)) {
        Report.Error (460, Location,
          "`{0}': Cannot specify constraints for overrides and explicit interface implementation methods",
          GetSignatureForError ());
      }

      base.SetConstraints (constraints_list);
    }
  }

  public abstract class MemberBase : MemberCore
  {
    protected FullNamedExpression type_expr;
    protected TypeSpec member_type;
    public new TypeDefinition Parent;

    protected MemberBase (TypeDefinition parent, FullNamedExpression type, Modifiers mod, Modifiers allowed_mod, Modifiers def_mod, MemberName name, Attributes attrs)
      : base (parent, name, attrs)
    {
      this.Parent = parent;
      this.type_expr = type;

      if (name != MemberName.Null)
        ModFlags = ModifiersExtensions.Check (allowed_mod, mod, def_mod, Location, Report);
    }

    #region Properties

    public TypeSpec MemberType {
      get {
        return member_type;
      }
    }

    public FullNamedExpression TypeExpression {
      get {
        return type_expr;
      }
    }

    #endregion

    //
    // Main member define entry
    //
    public override bool Define ()
    {
      DoMemberTypeIndependentChecks ();

      //
      // Returns false only when type resolution failed
      //
      if (!ResolveMemberType ())
        return false;

      DoMemberTypeDependentChecks ();
      return true;
    }

    //
    // Any type_name independent checks
    //
    protected virtual void DoMemberTypeIndependentChecks ()
    {
      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 ());
      }
    }

    //
    // Any type_name dependent checks
    //
    protected virtual void DoMemberTypeDependentChecks ()
    {
      // verify accessibility
      if (!IsAccessibleAs (MemberType)) {
        Report.SymbolRelatedToPreviousError (MemberType);
        if (this is Property)
          Report.Error (53, Location,
            "Inconsistent accessibility: property type `" +
            MemberType.GetSignatureForError () + "' is less " +
            "accessible than property `" + GetSignatureForError () + "'");
        else if (this is Indexer)
          Report.Error (54, Location,
            "Inconsistent accessibility: indexer return type `" +
            MemberType.GetSignatureForError () + "' is less " +
            "accessible than indexer `" + GetSignatureForError () + "'");
        else if (this is MethodCore) {
          if (this is Operator)
            Report.Error (56, Location,
              "Inconsistent accessibility: return type `" +
              MemberType.GetSignatureForError () + "' is less " +
              "accessible than operator `" + GetSignatureForError () + "'");
          else
            Report.Error (50, Location,
              "Inconsistent accessibility: return type `" +
              MemberType.GetSignatureForError () + "' is less " +
              "accessible than method `" + GetSignatureForError () + "'");
        } else if (this is Event) {
          Report.Error (7025, Location,
            "Inconsistent accessibility: event type `{0}' is less accessible than event `{1}'",
            MemberType.GetSignatureForError (), GetSignatureForError ());
        } else {
          Report.Error (52, Location,
                  "Inconsistent accessibility: field type `" +
                  MemberType.GetSignatureForError () + "' is less " +
                  "accessible than field `" + GetSignatureForError () + "'");
        }
      }
    }

    protected void IsTypePermitted ()
    {
      if (MemberType.IsSpecialRuntimeType) {
        if (Parent is StateMachine) {
          Report.Error (4012, Location,
            "Parameters or local variables of type `{0}' cannot be declared in async methods or iterators",
            MemberType.GetSignatureForError ());
        } else if (Parent is HoistedStoreyClass) {
          Report.Error (4013, Location,
            "Local variables of type `{0}' cannot be used inside anonymous methods, lambda expressions or query expressions",
            MemberType.GetSignatureForError ());
        } else {
          Report.Error (610, Location, 
            "Field or property cannot be of type `{0}'", MemberType.GetSignatureForError ());
        }
      }
    }

    protected virtual bool CheckBase ()
    {
      CheckProtectedModifier ();

      return true;
    }

    public override string GetSignatureForDocumentation ()
    {
      return Parent.GetSignatureForDocumentation () + "." + MemberName.Basename;
    }

    protected virtual bool ResolveMemberType ()
    {
      if (member_type != null)
        throw new InternalErrorException ("Multi-resolve");

      member_type = type_expr.ResolveAsType (this);
      return member_type != null;
    }
  }
}