source: trunk/HeuristicLab.ExtLibs/HeuristicLab.NRefactory/5.5.0/NRefactory.CSharp-5.5.0/Parser/mcs/decl.cs @ 15888

//
// decl.cs: Declaration base class for structs, classes, enums and interfaces.
//
// Author: Miguel de Icaza (miguel@gnu.org)
//         Marek Safar (marek.safar@seznam.cz)
//
// Dual licensed under the terms of the MIT X11 or GNU GPL
//
// Copyright 2001 Ximian, Inc (http://www.ximian.com)
// Copyright 2004-2008 Novell, Inc
// Copyright 2011 Xamarin Inc
//
//

using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Text;
using Mono.CompilerServices.SymbolWriter;

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

#if STATIC
using IKVM.Reflection;
using IKVM.Reflection.Emit;
#else
using System.Reflection;
using System.Reflection.Emit;
#endif

namespace Mono.CSharp {

  //
  // Better name would be DottenName
  //
  [DebuggerDisplay ("{GetSignatureForError()}")]
  public class MemberName
  {
    public static readonly MemberName Null = new MemberName ("");

    public readonly string Name;
    public TypeParameters TypeParameters;
    public readonly FullNamedExpression ExplicitInterface;
    public readonly Location Location;

    public readonly MemberName Left;

    public MemberName (string name)
      : this (name, Location.Null)
    { }

    public MemberName (string name, Location loc)
      : this (null, name, loc)
    { }

    public MemberName (string name, TypeParameters tparams, Location loc)
    {
      this.Name = name;
      this.Location = loc;

      this.TypeParameters = tparams;
    }

    public MemberName (string name, TypeParameters tparams, FullNamedExpression explicitInterface, Location loc)
      : this (name, tparams, loc)
    {
      this.ExplicitInterface = explicitInterface;
    }

    public MemberName (MemberName left, string name, Location loc)
    {
      this.Name = name;
      this.Location = loc;
      this.Left = left;
    }

    public MemberName (MemberName left, string name, FullNamedExpression explicitInterface, Location loc)
      : this (left, name, loc)
    {
      this.ExplicitInterface = explicitInterface;
    }

    public MemberName (MemberName left, MemberName right)
    {
      this.Name = right.Name;
      this.Location = right.Location;
      this.TypeParameters = right.TypeParameters;
      this.Left = left;
    }

    public int Arity {
      get {
        return TypeParameters == null ? 0 : TypeParameters.Count;
      }
    }

    public bool IsGeneric {
      get {
        return TypeParameters != null;
      }
    }

    public string Basename {
      get {
        if (TypeParameters != null)
          return MakeName (Name, TypeParameters);
        return Name;
      }
    }

    public void CreateMetadataName (StringBuilder sb)
    {
      if (Left != null)
        Left.CreateMetadataName (sb);

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

      sb.Append (Basename);
    }

    public string GetSignatureForDocumentation ()
    {
      var s = Basename;

      if (ExplicitInterface != null)
        s = ExplicitInterface.GetSignatureForError () + "." + s;

      if (Left == null)
        return s;

      return Left.GetSignatureForDocumentation () + "." + s;
    }

    public string GetSignatureForError ()
    {
      string s = TypeParameters == null ? null : "<" + TypeParameters.GetSignatureForError () + ">";
      s = Name + s;

      if (ExplicitInterface != null)
        s = ExplicitInterface.GetSignatureForError () + "." + s;

      if (Left == null)
        return s;

      return Left.GetSignatureForError () + "." + s;
    }

    public override bool Equals (object other)
    {
      return Equals (other as MemberName);
    }

    public bool Equals (MemberName other)
    {
      if (this == other)
        return true;
      if (other == null || Name != other.Name)
        return false;

      if ((TypeParameters != null) &&
          (other.TypeParameters == null || TypeParameters.Count != other.TypeParameters.Count))
        return false;

      if ((TypeParameters == null) && (other.TypeParameters != null))
        return false;

      if (Left == null)
        return other.Left == null;

      return Left.Equals (other.Left);
    }

    public override int GetHashCode ()
    {
      int hash = Name.GetHashCode ();
      for (MemberName n = Left; n != null; n = n.Left)
        hash ^= n.Name.GetHashCode ();

      if (TypeParameters != null)
        hash ^= TypeParameters.Count << 5;

      return hash & 0x7FFFFFFF;
    }

    public static string MakeName (string name, TypeParameters args)
    {
      if (args == null)
        return name;

      return name + "`" + args.Count;
    }

    public static string MakeName (string name, int count)
    {
      return name + "`" + count;
    }
  }

  public class SimpleMemberName
  {
    public string Value;
    public Location Location;

    public SimpleMemberName (string name, Location loc)
    {
      this.Value = name;
      this.Location = loc;
    }
  }

  /// <summary>
  ///   Base representation for members.  This is used to keep track
  ///   of Name, Location and Modifier flags, and handling Attributes.
  /// </summary>
  [System.Diagnostics.DebuggerDisplay ("{GetSignatureForError()}")]
  public abstract class MemberCore : Attributable, IMemberContext, IMemberDefinition
  {
    string IMemberDefinition.Name {
      get {
        return member_name.Name;
      }
    }

                // Is not readonly because of IndexerName attribute
    private MemberName member_name;
    public MemberName MemberName {
      get { return member_name; }
    }

    /// <summary>
    ///   Modifier flags that the user specified in the source code
    /// </summary>
    private Modifiers mod_flags;
    public Modifiers ModFlags {
      set {
        mod_flags = value;
        if ((value & Modifiers.COMPILER_GENERATED) != 0)
          caching_flags = Flags.IsUsed | Flags.IsAssigned;
      }
      get {
        return mod_flags;
      }
    }

    public virtual ModuleContainer Module {
      get {
        return Parent.Module;
      }
    }

    public /*readonly*/ TypeContainer Parent;

    /// <summary>
    ///   Location where this declaration happens
    /// </summary>
    public Location Location {
      get { return member_name.Location; }
    }

    /// <summary>
    ///   XML documentation comment
    /// </summary>
    protected string comment;

    /// <summary>
    ///   Represents header string for documentation comment 
    ///   for each member types.
    /// </summary>
    public abstract string DocCommentHeader { get; }

    [Flags]
    public enum Flags {
      Obsolete_Undetected = 1,    // Obsolete attribute has not been detected yet
      Obsolete = 1 << 1,      // Type has obsolete attribute
      ClsCompliance_Undetected = 1 << 2,  // CLS Compliance has not been detected yet
      ClsCompliant = 1 << 3,      // Type is CLS Compliant
      CloseTypeCreated = 1 << 4,    // Tracks whether we have Closed the type
      HasCompliantAttribute_Undetected = 1 << 5,  // Presence of CLSCompliantAttribute has not been detected
      HasClsCompliantAttribute = 1 << 6,      // Type has CLSCompliantAttribute
      ClsCompliantAttributeFalse = 1 << 7,      // Member has CLSCompliant(false)
      Excluded_Undetected = 1 << 8,   // Conditional attribute has not been detected yet
      Excluded = 1 << 9,          // Method is conditional
      MethodOverloadsExist = 1 << 10,   // Test for duplication must be performed
      IsUsed = 1 << 11,
      IsAssigned = 1 << 12,       // Field is assigned
      HasExplicitLayout = 1 << 13,
      PartialDefinitionExists = 1 << 14,  // Set when corresponding partial method definition exists
      HasStructLayout = 1 << 15,      // Has StructLayoutAttribute
      HasInstanceConstructor = 1 << 16,
      HasUserOperators = 1 << 17,
      CanBeReused = 1 << 18,
      InterfacesExpanded = 1 << 19
    }

    /// <summary>
    ///   MemberCore flags at first detected then cached
    /// </summary>
    internal Flags caching_flags;

    protected MemberCore (TypeContainer parent, MemberName name, Attributes attrs)
    {
      this.Parent = parent;
      member_name = name;
      caching_flags = Flags.Obsolete_Undetected | Flags.ClsCompliance_Undetected | Flags.HasCompliantAttribute_Undetected | Flags.Excluded_Undetected;
      AddAttributes (attrs, this);
    }

    protected virtual void SetMemberName (MemberName new_name)
    {
      member_name = new_name;
    }

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

    protected bool CheckAbstractAndExtern (bool has_block)
    {
      if (Parent.PartialContainer.Kind == MemberKind.Interface)
        return true;

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

        if ((ModFlags & Modifiers.ABSTRACT) != 0) {
          Report.Error (500, Location, "`{0}' cannot declare a body because it is marked abstract",
            GetSignatureForError ());
          return false;
        }
      } else {
        if ((ModFlags & (Modifiers.ABSTRACT | Modifiers.EXTERN | Modifiers.PARTIAL)) == 0 && !(Parent is Delegate)) {
          if (Compiler.Settings.Version >= LanguageVersion.V_3) {
            Property.PropertyMethod pm = this as Property.PropertyMethod;
            if (pm is Indexer.GetIndexerMethod || pm is Indexer.SetIndexerMethod)
              pm = null;

            if (pm != null && pm.Property.AccessorSecond == null) {
              Report.Error (840, Location,
                "`{0}' must have a body because it is not marked abstract or extern. The property can be automatically implemented when you define both accessors",
                GetSignatureForError ());
              return false;
            }
          }

          Report.Error (501, Location, "`{0}' must have a body because it is not marked abstract, extern, or partial",
                        GetSignatureForError ());
          return false;
        }
      }

      return true;
    }

    protected void CheckProtectedModifier ()
    {
      if ((ModFlags & Modifiers.PROTECTED) == 0)
        return;

      if (Parent.PartialContainer.Kind == MemberKind.Struct) {
        Report.Error (666, Location, "`{0}': Structs cannot contain protected members",
          GetSignatureForError ());
        return;
      }

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

      if ((Parent.ModFlags & Modifiers.SEALED) != 0 && (ModFlags & Modifiers.OVERRIDE) == 0 &&
        !(this is Destructor)) {
        Report.Warning (628, 4, Location, "`{0}': new protected member declared in sealed class",
          GetSignatureForError ());
        return;
      }
    }

    public abstract bool Define ();

    public virtual string DocComment {
      get {
        return comment;
      }
      set {
        comment = value;
      }
    }

    // 
    // Returns full member name for error message
    //
    public virtual string GetSignatureForError ()
    {
      var parent = Parent.GetSignatureForError ();
      if (parent == null)
        return member_name.GetSignatureForError ();

      return parent + "." + member_name.GetSignatureForError ();
    }

    /// <summary>
    /// Base Emit method. This is also entry point for CLS-Compliant verification.
    /// </summary>
    public virtual void Emit ()
    {
      if (!Compiler.Settings.VerifyClsCompliance)
        return;

      VerifyClsCompliance ();
    }

    public bool IsAvailableForReuse {
      get {
        return (caching_flags & Flags.CanBeReused) != 0;
      }
      set {
        caching_flags = value ? (caching_flags | Flags.CanBeReused) : (caching_flags & ~Flags.CanBeReused);
      }
    }

    public bool IsCompilerGenerated {
      get {
        if ((mod_flags & Modifiers.COMPILER_GENERATED) != 0)
          return true;

        return Parent != null && Parent.IsCompilerGenerated;
      }
    }

    public bool IsImported {
      get {
        return false;
      }
    }

    public virtual bool IsUsed {
      get {
        return (caching_flags & Flags.IsUsed) != 0;
      }
    }

    protected Report Report {
      get {
        return Compiler.Report;
      }
    }

    public void SetIsUsed ()
    {
      caching_flags |= Flags.IsUsed;
    }

    public void SetIsAssigned ()
    {
      caching_flags |= Flags.IsAssigned;
    }

    public virtual void SetConstraints (List<Constraints> constraints_list)
    {
      var tparams = member_name.TypeParameters;
      if (tparams == null) {
        Report.Error (80, Location, "Constraints are not allowed on non-generic declarations");
        return;
      }

      foreach (var c in constraints_list) {
        var tp = tparams.Find (c.TypeParameter.Value);
        if (tp == null) {
          Report.Error (699, c.Location, "`{0}': A constraint references nonexistent type parameter `{1}'",
            GetSignatureForError (), c.TypeParameter.Value);
          continue;
        }

        tp.Constraints = c;
      }
    }

    /// <summary>
    /// Returns instance of ObsoleteAttribute for this MemberCore
    /// </summary>
    public virtual ObsoleteAttribute GetAttributeObsolete ()
    {
      if ((caching_flags & (Flags.Obsolete_Undetected | Flags.Obsolete)) == 0)
        return null;

      caching_flags &= ~Flags.Obsolete_Undetected;

      if (OptAttributes == null)
        return null;

      Attribute obsolete_attr = OptAttributes.Search (Module.PredefinedAttributes.Obsolete);
      if (obsolete_attr == null)
        return null;

      caching_flags |= Flags.Obsolete;

      ObsoleteAttribute obsolete = obsolete_attr.GetObsoleteAttribute ();
      if (obsolete == null)
        return null;

      return obsolete;
    }

    /// <summary>
    /// Checks for ObsoleteAttribute presence. It's used for testing of all non-types elements
    /// </summary>
    public virtual void CheckObsoleteness (Location loc)
    {
      ObsoleteAttribute oa = GetAttributeObsolete ();
      if (oa != null)
        AttributeTester.Report_ObsoleteMessage (oa, GetSignatureForError (), loc, Report);
    }

    //
    // Checks whether the type P is as accessible as this member
    //
    public bool IsAccessibleAs (TypeSpec p)
    {
      //
      // if M is private, its accessibility is the same as this declspace.
      // we already know that P is accessible to T before this method, so we
      // may return true.
      //
      if ((mod_flags & Modifiers.PRIVATE) != 0)
        return true;

      while (TypeManager.HasElementType (p))
        p = TypeManager.GetElementType (p);

      if (p.IsGenericParameter)
        return true;

      for (TypeSpec p_parent; p != null; p = p_parent) {
        p_parent = p.DeclaringType;

        if (p.IsGeneric) {
          foreach (TypeSpec t in p.TypeArguments) {
            if (!IsAccessibleAs (t))
              return false;
          }
        }

        var pAccess = p.Modifiers & Modifiers.AccessibilityMask;
        if (pAccess == Modifiers.PUBLIC)
          continue;

        bool same_access_restrictions = false;
        for (MemberCore mc = this; !same_access_restrictions && mc != null && mc.Parent != null; mc = mc.Parent) {
          var al = mc.ModFlags & Modifiers.AccessibilityMask;
          switch (pAccess) {
          case Modifiers.INTERNAL:
            if (al == Modifiers.PRIVATE || al == Modifiers.INTERNAL)
              same_access_restrictions = p.MemberDefinition.IsInternalAsPublic (mc.Module.DeclaringAssembly);
            
            break;

          case Modifiers.PROTECTED:
            if (al == Modifiers.PROTECTED) {
              same_access_restrictions = mc.Parent.PartialContainer.IsBaseTypeDefinition (p_parent);
              break;
            }

            if (al == Modifiers.PRIVATE) {
              //
              // When type is private and any of its parents derives from
              // protected type then the type is accessible
              //
              while (mc.Parent != null && mc.Parent.PartialContainer != null) {
                if (mc.Parent.PartialContainer.IsBaseTypeDefinition (p_parent))
                  same_access_restrictions = true;
                mc = mc.Parent; 
              }
            }
            
            break;

          case Modifiers.PROTECTED | Modifiers.INTERNAL:
            if (al == Modifiers.INTERNAL)
              same_access_restrictions = p.MemberDefinition.IsInternalAsPublic (mc.Module.DeclaringAssembly);
            else if (al == (Modifiers.PROTECTED | Modifiers.INTERNAL))
              same_access_restrictions = mc.Parent.PartialContainer.IsBaseTypeDefinition (p_parent) && p.MemberDefinition.IsInternalAsPublic (mc.Module.DeclaringAssembly);
            else
              goto case Modifiers.PROTECTED;

            break;

          case Modifiers.PRIVATE:
            //
            // Both are private and share same parent
            //
            if (al == Modifiers.PRIVATE) {
              var decl = mc.Parent;
              do {
                same_access_restrictions = decl.CurrentType.MemberDefinition == p_parent.MemberDefinition;
              } while (!same_access_restrictions && !decl.PartialContainer.IsTopLevel && (decl = decl.Parent) != null);
            }
            
            break;
            
          default:
            throw new InternalErrorException (al.ToString ());
          }
        }
        
        if (!same_access_restrictions)
          return false;
      }

      return true;
    }

    /// <summary>
    /// Analyze whether CLS-Compliant verification must be execute for this MemberCore.
    /// </summary>
    public override bool IsClsComplianceRequired ()
    {
      if ((caching_flags & Flags.ClsCompliance_Undetected) == 0)
        return (caching_flags & Flags.ClsCompliant) != 0;

      caching_flags &= ~Flags.ClsCompliance_Undetected;

      if (HasClsCompliantAttribute) {
        if ((caching_flags & Flags.ClsCompliantAttributeFalse) != 0)
          return false;

        caching_flags |= Flags.ClsCompliant;
        return true;
      }

      if (Parent.IsClsComplianceRequired ()) {
        caching_flags |= Flags.ClsCompliant;
        return true;
      }

      return false;
    }

    public virtual string[] ConditionalConditions ()
    {
      return null;
    }

    /// <summary>
    /// Returns true when MemberCore is exposed from assembly.
    /// </summary>
    public bool IsExposedFromAssembly ()
    {
      if ((ModFlags & (Modifiers.PUBLIC | Modifiers.PROTECTED)) == 0)
        return this is NamespaceContainer;
      
      var parentContainer = Parent.PartialContainer;
      while (parentContainer != null) {
        if ((parentContainer.ModFlags & (Modifiers.PUBLIC | Modifiers.PROTECTED)) == 0)
          return false;

        parentContainer = parentContainer.Parent.PartialContainer;
      }

      return true;
    }

    //
    // Does extension methods look up to find a method which matches name and extensionType.
    // Search starts from this namespace and continues hierarchically up to top level.
    //
    public ExtensionMethodCandidates LookupExtensionMethod (TypeSpec extensionType, string name, int arity)
    {
      var m = Parent;
      do {
        var ns = m as NamespaceContainer;
        if (ns != null)
          return ns.LookupExtensionMethod (this, extensionType, name, arity, 0);

        m = m.Parent;
      } while (m != null);

      return null;
    }

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

    public virtual FullNamedExpression LookupNamespaceOrType (string name, int arity, LookupMode mode, Location loc)
    {
      return Parent.LookupNamespaceOrType (name, arity, mode, loc);
    }

    /// <summary>
    /// Goes through class hierarchy and gets value of first found CLSCompliantAttribute.
    /// If no is attribute exists then assembly CLSCompliantAttribute is returned.
    /// </summary>
    public bool? CLSAttributeValue {
      get {
        if ((caching_flags & Flags.HasCompliantAttribute_Undetected) == 0) {
          if ((caching_flags & Flags.HasClsCompliantAttribute) == 0)
            return null;

          return (caching_flags & Flags.ClsCompliantAttributeFalse) == 0;
        }

        caching_flags &= ~Flags.HasCompliantAttribute_Undetected;

        if (OptAttributes != null) {
          Attribute cls_attribute = OptAttributes.Search (Module.PredefinedAttributes.CLSCompliant);
          if (cls_attribute != null) {
            caching_flags |= Flags.HasClsCompliantAttribute;
            if (cls_attribute.GetClsCompliantAttributeValue ())
              return true;

            caching_flags |= Flags.ClsCompliantAttributeFalse;
            return false;
          }
        }

        return null;
      }
    }

    /// <summary>
    /// Returns true if MemberCore is explicitly marked with CLSCompliantAttribute
    /// </summary>
    protected bool HasClsCompliantAttribute {
      get {
        return CLSAttributeValue.HasValue;
      }
    }

    /// <summary>
    /// Returns true when a member supports multiple overloads (methods, indexers, etc)
    /// </summary>
    public virtual bool EnableOverloadChecks (MemberCore overload)
    {
      return false;
    }

    /// <summary>
    /// The main virtual method for CLS-Compliant verifications.
    /// The method returns true if member is CLS-Compliant and false if member is not
    /// CLS-Compliant which means that CLS-Compliant tests are not necessary. A descendants override it
    /// and add their extra verifications.
    /// </summary>
    protected virtual bool VerifyClsCompliance ()
    {
      if (HasClsCompliantAttribute) {
        if (!Module.DeclaringAssembly.HasCLSCompliantAttribute) {
          Attribute a = OptAttributes.Search (Module.PredefinedAttributes.CLSCompliant);
          if ((caching_flags & Flags.ClsCompliantAttributeFalse) != 0) {
            Report.Warning (3021, 2, a.Location,
              "`{0}' does not need a CLSCompliant attribute because the assembly is not marked as CLS-compliant",
              GetSignatureForError ());
          } else {
            Report.Warning (3014, 1, a.Location,
              "`{0}' cannot be marked as CLS-compliant because the assembly is not marked as CLS-compliant",
              GetSignatureForError ());
          }
          return false;
        }

        if (!IsExposedFromAssembly ()) {
          Attribute a = OptAttributes.Search (Module.PredefinedAttributes.CLSCompliant);
          Report.Warning (3019, 2, a.Location, "CLS compliance checking will not be performed on `{0}' because it is not visible from outside this assembly", GetSignatureForError ());
          return false;
        }

        if ((caching_flags & Flags.ClsCompliantAttributeFalse) != 0) {
          if (Parent is Interface && Parent.IsClsComplianceRequired ()) {
            Report.Warning (3010, 1, Location, "`{0}': CLS-compliant interfaces must have only CLS-compliant members", GetSignatureForError ());
          } else if (Parent.Kind == MemberKind.Class && (ModFlags & Modifiers.ABSTRACT) != 0 && Parent.IsClsComplianceRequired ()) {
            Report.Warning (3011, 1, Location, "`{0}': only CLS-compliant members can be abstract", GetSignatureForError ());
          }

          return false;
        }

        if (Parent.Kind != MemberKind.Namespace && Parent.Kind != 0 && !Parent.IsClsComplianceRequired ()) {
          Attribute a = OptAttributes.Search (Module.PredefinedAttributes.CLSCompliant);
          Report.Warning (3018, 1, a.Location, "`{0}' cannot be marked as CLS-compliant because it is a member of non CLS-compliant type `{1}'",
            GetSignatureForError (), Parent.GetSignatureForError ());
          return false;
        }
      } else {
        if (!IsExposedFromAssembly ())
          return false;

        if (!Parent.IsClsComplianceRequired ())
          return false;
      }

      if (member_name.Name [0] == '_') {
        Warning_IdentifierNotCompliant ();
      }

      if (member_name.TypeParameters != null)
        member_name.TypeParameters.VerifyClsCompliance ();

      return true;
    }

    protected void Warning_IdentifierNotCompliant ()
    {
      Report.Warning (3008, 1, MemberName.Location, "Identifier `{0}' is not CLS-compliant", GetSignatureForError ());
    }

    public virtual string GetCallerMemberName ()
    {
      return MemberName.Name;
    }

    //
    // Returns a string that represents the signature for this 
    // member which should be used in XML documentation.
    //
    public abstract string GetSignatureForDocumentation ();

    public virtual void GetCompletionStartingWith (string prefix, List<string> results)
    {
      Parent.GetCompletionStartingWith (prefix, results);
    }

    //
    // Generates xml doc comments (if any), and if required,
    // handle warning report.
    //
    internal virtual void GenerateDocComment (DocumentationBuilder builder)
    {
      if (DocComment == null) {
        if (IsExposedFromAssembly ()) {
          Constructor c = this as Constructor;
          if (c == null || !c.IsDefault ())
            Report.Warning (1591, 4, Location,
              "Missing XML comment for publicly visible type or member `{0}'", GetSignatureForError ());
        }

        return;
      }

      try {
        builder.GenerateDocumentationForMember (this);
      } catch (Exception e) {
        throw new InternalErrorException (this, e);
      }
    }

    public virtual void WriteDebugSymbol (MonoSymbolFile file)
    {
    }

    #region IMemberContext Members

    public virtual CompilerContext Compiler {
      get {
        return Module.Compiler;
      }
    }

    public virtual TypeSpec CurrentType {
      get { return Parent.CurrentType; }
    }

    public MemberCore CurrentMemberDefinition {
      get { return this; }
    }

    public virtual TypeParameters CurrentTypeParameters {
      get { return null; }
    }

    public bool IsObsolete {
      get {
        if (GetAttributeObsolete () != null)
          return true;

        return Parent != null && Parent.IsObsolete;
      }
    }

    public bool IsUnsafe {
      get {
        if ((ModFlags & Modifiers.UNSAFE) != 0)
          return true;

        return Parent != null && Parent.IsUnsafe;
      }
    }

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

    #endregion
  }

  //
  // Base member specification. A member specification contains
  // member details which can alter in the context (e.g. generic instances)
  //
  public abstract class MemberSpec
  {
    [Flags]
    public enum StateFlags
    {
      Obsolete_Undetected = 1,  // Obsolete attribute has not been detected yet
      Obsolete = 1 << 1,      // Member has obsolete attribute
      CLSCompliant_Undetected = 1 << 2, // CLSCompliant attribute has not been detected yet
      CLSCompliant = 1 << 3,    // Member is CLS Compliant
      MissingDependency_Undetected = 1 << 4,
      MissingDependency = 1 << 5,
      HasDynamicElement = 1 << 6,
      ConstraintsChecked = 1 << 7,

      IsAccessor = 1 << 9,    // Method is an accessor
      IsGeneric = 1 << 10,    // Member contains type arguments

      PendingMetaInflate = 1 << 12,
      PendingMakeMethod = 1 << 13,
      PendingMemberCacheMembers = 1 << 14,
      PendingBaseTypeInflate = 1 << 15,
      InterfacesExpanded = 1 << 16,
      IsNotCSharpCompatible = 1 << 17,
      SpecialRuntimeType = 1 << 18,
      InflatedExpressionType = 1 << 19,
      InflatedNullableType = 1 << 20,
      GenericIterateInterface = 1 << 21,
      GenericTask = 1 << 22,
      InterfacesImported = 1 << 23,
    }

    //
    // Some flags can be copied directly from other member
    //
    protected const StateFlags SharedStateFlags =
      StateFlags.CLSCompliant | StateFlags.CLSCompliant_Undetected |
      StateFlags.Obsolete | StateFlags.Obsolete_Undetected |
      StateFlags.MissingDependency | StateFlags.MissingDependency_Undetected |
      StateFlags.HasDynamicElement;

    protected Modifiers modifiers;
    public StateFlags state;
    protected IMemberDefinition definition;
    public readonly MemberKind Kind;
    protected TypeSpec declaringType;

#if DEBUG
    static int counter;
    public int ID = counter++;
#endif

    protected MemberSpec (MemberKind kind, TypeSpec declaringType, IMemberDefinition definition, Modifiers modifiers)
    {
      this.Kind = kind;
      this.declaringType = declaringType;
      this.definition = definition;
      this.modifiers = modifiers;

      if (kind == MemberKind.MissingType)
        state = StateFlags.MissingDependency;
      else
        state = StateFlags.Obsolete_Undetected | StateFlags.CLSCompliant_Undetected | StateFlags.MissingDependency_Undetected;
    }

    #region Properties

    public virtual int Arity {
      get {
        return 0;
      }
    }

    public TypeSpec DeclaringType {
      get {
        return declaringType;
      }
      set {
        declaringType = value;
      }
    }

    public IMemberDefinition MemberDefinition {
      get {
        return definition;
      }
    }

    public Modifiers Modifiers {
      get {
        return modifiers;
      }
      set {
        modifiers = value;
      }
    }
    
    public virtual string Name {
      get {
        return definition.Name;
      }
    }

    public bool IsAbstract {
      get { return (modifiers & Modifiers.ABSTRACT) != 0; }
    }

    public bool IsAccessor {
      get {
        return (state & StateFlags.IsAccessor) != 0;
      }
      set {
        state = value ? state | StateFlags.IsAccessor : state & ~StateFlags.IsAccessor;
      }
    }

    //
    // Return true when this member is a generic in C# terms
    // A nested non-generic type of generic type will return false
    //
    public bool IsGeneric {
      get {
        return (state & StateFlags.IsGeneric) != 0;
      }
      set {
        state = value ? state | StateFlags.IsGeneric : state & ~StateFlags.IsGeneric;
      }
    }

    //
    // Returns true for imported members which are not compatible with C# language
    //
    public bool IsNotCSharpCompatible {
      get {
        return (state & StateFlags.IsNotCSharpCompatible) != 0;
      }
      set {
        state = value ? state | StateFlags.IsNotCSharpCompatible : state & ~StateFlags.IsNotCSharpCompatible;
      }
    }

    public bool IsPrivate {
      get { return (modifiers & Modifiers.PRIVATE) != 0; }
    }

    public bool IsPublic {
      get { return (modifiers & Modifiers.PUBLIC) != 0; }
    }

    public bool IsStatic {
      get { 
        return (modifiers & Modifiers.STATIC) != 0;
      }
    }

    #endregion

    public virtual ObsoleteAttribute GetAttributeObsolete ()
    {
      if ((state & (StateFlags.Obsolete | StateFlags.Obsolete_Undetected)) == 0)
        return null;

      state &= ~StateFlags.Obsolete_Undetected;

      var oa = definition.GetAttributeObsolete ();
      if (oa != null)
        state |= StateFlags.Obsolete;

      return oa;
    }

    //
    // Returns a list of missing dependencies of this member. The list
    // will contain types only but it can have numerous values for members
    // like methods where both return type and all parameters are checked
    //
    public List<MissingTypeSpecReference> GetMissingDependencies ()
    {
      return GetMissingDependencies (this);
    }

    public List<MissingTypeSpecReference> GetMissingDependencies (MemberSpec caller)
    {
      if ((state & (StateFlags.MissingDependency | StateFlags.MissingDependency_Undetected)) == 0)
        return null;

      state &= ~StateFlags.MissingDependency_Undetected;

      var imported = definition as ImportedDefinition;
      List<MissingTypeSpecReference> missing;
      if (imported != null) {
        missing = ResolveMissingDependencies (caller);
      } else if (this is ElementTypeSpec) {
        missing = ((ElementTypeSpec) this).Element.GetMissingDependencies (caller);
      } else {
        missing = null;
      }

      if (missing != null) {
        state |= StateFlags.MissingDependency;
      }

      return missing;
    }

    public abstract List<MissingTypeSpecReference> ResolveMissingDependencies (MemberSpec caller);

    protected virtual bool IsNotCLSCompliant (out bool attrValue)
    {
      var cls = MemberDefinition.CLSAttributeValue;
      attrValue = cls ?? false;
      return cls == false;
    }

    public virtual string GetSignatureForDocumentation ()
    {
      return DeclaringType.GetSignatureForDocumentation () + "." + Name;
    }

    public virtual string GetSignatureForError ()
    {
      var bf = MemberDefinition as Property.BackingField;
      string name;
      if (bf == null) {
        name = Name;
      } else {
        name = bf.OriginalProperty.MemberName.Name;
      }

      return DeclaringType.GetSignatureForError () + "." + name;
    }

    public virtual MemberSpec InflateMember (TypeParameterInflator inflator)
    {
      var inflated = (MemberSpec) MemberwiseClone ();
      inflated.declaringType = inflator.TypeInstance;
      if (DeclaringType.IsGenericOrParentIsGeneric)
        inflated.state |= StateFlags.PendingMetaInflate;
#if DEBUG
      inflated.ID += 1000000;
#endif
      return inflated;
    }

    //
    // Is this member accessible from invocation context
    //
    public bool IsAccessible (IMemberContext ctx)
    {
      var ma = Modifiers & Modifiers.AccessibilityMask;
      if (ma == Modifiers.PUBLIC)
        return true;

      var parentType = /* this as TypeSpec ?? */ DeclaringType;
      var ctype = ctx.CurrentType;

      if (ma == Modifiers.PRIVATE) {
        if (ctype == null || parentType == null)
          return false;
        //
        // It's only accessible to the current class or children
        //
        if (parentType.MemberDefinition == ctype.MemberDefinition)
          return true;

        return TypeManager.IsNestedChildOf (ctype, parentType.MemberDefinition);
      }

      if ((ma & Modifiers.INTERNAL) != 0) {
        bool b;
        var assembly = ctype == null ? ctx.Module.DeclaringAssembly : ctype.MemberDefinition.DeclaringAssembly;

        if (parentType == null) {
          b = ((ITypeDefinition) MemberDefinition).IsInternalAsPublic (assembly);
        } else {
          b = DeclaringType.MemberDefinition.IsInternalAsPublic (assembly);
        }

        if (b || ma == Modifiers.INTERNAL)
          return b;
      }

      //
      // Checks whether `ctype' is a subclass or nested child of `parentType'.
      //
      while (ctype != null) {
        if (TypeManager.IsFamilyAccessible (ctype, parentType))
          return true;

        // Handle nested types.
        ctype = ctype.DeclaringType;  // TODO: Untested ???
      }

      return false;
    }

    //
    // Returns member CLS compliance based on full member hierarchy
    //
    public bool IsCLSCompliant ()
    {
      if ((state & StateFlags.CLSCompliant_Undetected) != 0) {
        state &= ~StateFlags.CLSCompliant_Undetected;

        bool compliant;
        if (IsNotCLSCompliant (out compliant))
          return false;

        if (!compliant) {
          if (DeclaringType != null) {
            compliant = DeclaringType.IsCLSCompliant ();
          } else {
            compliant = ((ITypeDefinition) MemberDefinition).DeclaringAssembly.IsCLSCompliant;
          }
        }

        if (compliant)
          state |= StateFlags.CLSCompliant;
      }

      return (state & StateFlags.CLSCompliant) != 0;
    }

    public bool IsConditionallyExcluded (IMemberContext ctx)
    {
      if ((Kind & (MemberKind.Class | MemberKind.Method)) == 0)
        return false;

      var conditions = MemberDefinition.ConditionalConditions ();
      if (conditions == null)
        return false;

      var m = ctx.CurrentMemberDefinition;
      CompilationSourceFile unit = null;
      while (m != null && unit == null) {
        unit = m as CompilationSourceFile;
        m = m.Parent;
      }

      if (unit != null) {
        foreach (var condition in conditions) {
          if (unit.IsConditionalDefined (condition))
            return false;
        }
      }

      return true;
    }

    public override string ToString ()
    {
      return GetSignatureForError ();
    }
  }

  //
  // Member details which are same between all member
  // specifications
  //
  public interface IMemberDefinition
  {
    bool? CLSAttributeValue { get; }
    string Name { get; }
    bool IsImported { get; }

    string[] ConditionalConditions ();
    ObsoleteAttribute GetAttributeObsolete ();
    void SetIsAssigned ();
    void SetIsUsed ();
  }

  public interface IMethodDefinition : IMemberDefinition
  {
    MethodBase Metadata { get; }
  }

  public interface IParametersMember : IInterfaceMemberSpec
  {
    AParametersCollection Parameters { get; }
  }

  public interface IInterfaceMemberSpec
  {
    TypeSpec MemberType { get; }
  }
}