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

//
// parameter.cs: Parameter definition.
//
// 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 2001-2003 Ximian, Inc (http://www.ximian.com)
// Copyright 2003-2008 Novell, Inc. 
// Copyright 2011 Xamarin Inc
//
//
using System;
using System.Text;

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

namespace Mono.CSharp {

  /// <summary>
  ///   Abstract Base class for parameters of a method.
  /// </summary>
  public abstract class ParameterBase : Attributable
  {
    protected ParameterBuilder builder;

    public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
    {
#if false
      if (a.Type == pa.MarshalAs) {
        UnmanagedMarshal marshal = a.GetMarshal (this);
        if (marshal != null) {
          builder.SetMarshal (marshal);
        }
        return;
      }
#endif
      if (a.HasSecurityAttribute) {
        a.Error_InvalidSecurityParent ();
        return;
      }

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

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

    public ParameterBuilder Builder {
      get {
        return builder;
      }
    }

    public override bool IsClsComplianceRequired()
    {
      return false;
    }
  }

  /// <summary>
  /// Class for applying custom attributes on the return type
  /// </summary>
  public class ReturnParameter : ParameterBase
  {
    MemberCore method;

    // TODO: merge method and mb
    public ReturnParameter (MemberCore method, MethodBuilder mb, Location location)
    {
      this.method = method;
      try {
        builder = mb.DefineParameter (0, ParameterAttributes.None, "");     
      }
      catch (ArgumentOutOfRangeException) {
        method.Compiler.Report.RuntimeMissingSupport (location, "custom attributes on the return type");
      }
    }

    public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
    {
      if (a.Type == pa.CLSCompliant) {
        method.Compiler.Report.Warning (3023, 1, a.Location,
          "CLSCompliant attribute has no meaning when applied to return types. Try putting it on the method instead");
      }

      // This occurs after Warning -28
      if (builder == null)
        return;

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

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

    /// <summary>
    /// Is never called
    /// </summary>
    public override string[] ValidAttributeTargets {
      get {
        return null;
      }
    }
  }

  public class ImplicitLambdaParameter : Parameter
  {
    public ImplicitLambdaParameter (string name, Location loc)
      : base (null, name, Modifier.NONE, null, loc)
    {
    }

    public override TypeSpec Resolve (IMemberContext ec, int index)
    {
      if (parameter_type == null)
        throw new InternalErrorException ("A type of implicit lambda parameter `{0}' is not set",
          Name);

      base.idx = index;
      return parameter_type;
    }

    public void SetParameterType (TypeSpec type)
    {
      parameter_type = type;
    }
  }

  public class ParamsParameter : Parameter {
    public ParamsParameter (FullNamedExpression type, string name, Attributes attrs, Location loc):
      base (type, name, Parameter.Modifier.PARAMS, attrs, loc)
    {
    }

    public override TypeSpec Resolve (IMemberContext ec, int index)
    {
      if (base.Resolve (ec, index) == null)
        return null;

      var ac = parameter_type as ArrayContainer;
      if (ac == null || ac.Rank != 1) {
        ec.Module.Compiler.Report.Error (225, Location, "The params parameter must be a single dimensional array");
        return null;
      }

      return parameter_type;
    }

    public override void ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index, PredefinedAttributes pa)
    {
      base.ApplyAttributes (mb, cb, index, pa);
      pa.ParamArray.EmitAttribute (builder);
    }
  }

  public class ArglistParameter : Parameter {
    // Doesn't have proper type because it's never chosen for better conversion
    public ArglistParameter (Location loc) :
      base (null, String.Empty, Parameter.Modifier.NONE, null, loc)
    {
      parameter_type = InternalType.Arglist;
    }

    public override void  ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index, PredefinedAttributes pa)
    {
      // Nothing to do
    }

    public override bool CheckAccessibility (InterfaceMemberBase member)
    {
      return true;
    }

    public override TypeSpec Resolve (IMemberContext ec, int index)
    {
      return parameter_type;
    }
  }

  public interface IParameterData
  {
    Expression DefaultValue { get; }
    bool HasExtensionMethodModifier { get; }
    bool HasDefaultValue { get; }
    Parameter.Modifier ModFlags { get; }
    string Name { get; }
  }

  //
  // Parameter information created by parser
  //
  public class Parameter : ParameterBase, IParameterData, ILocalVariable // TODO: INamedBlockVariable
  {
    [Flags]
    public enum Modifier : byte {
      NONE    = 0,
      PARAMS  = 1 << 0,
      REF = 1 << 1,
      OUT = 1 << 2,
      This = 1 << 3,
      CallerMemberName = 1 << 4,
      CallerLineNumber = 1 << 5,
      CallerFilePath = 1 << 6,

      RefOutMask = REF | OUT,
      ModifierMask = PARAMS | REF | OUT | This,
      CallerMask = CallerMemberName | CallerLineNumber | CallerFilePath
    }

    static readonly string[] attribute_targets = new [] { "param" };

    FullNamedExpression texpr;
    Modifier modFlags;
    string name;
    Expression default_expr;
    protected TypeSpec parameter_type;
    readonly Location loc;
    protected int idx;
    public bool HasAddressTaken;

    TemporaryVariableReference expr_tree_variable;

    HoistedParameter hoisted_variant;

    public Parameter (FullNamedExpression type, string name, Modifier mod, Attributes attrs, Location loc)
    {
      this.name = name;
      modFlags = mod;
      this.loc = loc;
      texpr = type;

      // Only assign, attributes will be attached during resolve
      base.attributes = attrs;
    }

    #region Properties

    public Expression DefaultExpression {
      get {
        return default_expr;
      }
    }

    public DefaultParameterValueExpression DefaultValue {
      get {
        return default_expr as DefaultParameterValueExpression;
      }
      set {
        default_expr = value;
      }
    }

    Expression IParameterData.DefaultValue {
      get {
        var expr = default_expr as DefaultParameterValueExpression;
        return expr == null ? default_expr : expr.Child;
      }
    }

    bool HasOptionalExpression {
      get {
        return default_expr is DefaultParameterValueExpression;
      }
    }

    public Location Location {
      get {
        return loc;
      }
    }

    public Modifier ParameterModifier {
      get {
        return modFlags;
      }
    }

    public TypeSpec Type {
      get {
        return parameter_type;
      }
      set {
        parameter_type = value;
      }
    }

    public FullNamedExpression TypeExpression  {
      get {
        return texpr;
      }
    }

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

    #endregion

    public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
    {
      if (a.Type == pa.In && ModFlags == Modifier.OUT) {
        a.Report.Error (36, a.Location, "An out parameter cannot have the `In' attribute");
        return;
      }

      if (a.Type == pa.ParamArray) {
        a.Report.Error (674, a.Location, "Do not use `System.ParamArrayAttribute'. Use the `params' keyword instead");
        return;
      }

      if (a.Type == pa.Out && (ModFlags & Modifier.REF) != 0 &&
          !OptAttributes.Contains (pa.In)) {
        a.Report.Error (662, a.Location,
          "Cannot specify only `Out' attribute on a ref parameter. Use both `In' and `Out' attributes or neither");
        return;
      }

      if (a.Type == pa.CLSCompliant) {
        a.Report.Warning (3022, 1, a.Location, "CLSCompliant attribute has no meaning when applied to parameters. Try putting it on the method instead");
      } else if (a.Type == pa.DefaultParameterValue || a.Type == pa.OptionalParameter) {
        if (HasOptionalExpression) {
          a.Report.Error (1745, a.Location,
            "Cannot specify `{0}' attribute on optional parameter `{1}'",
            a.Type.GetSignatureForError ().Replace ("Attribute", ""), Name);
        }

        if (a.Type == pa.DefaultParameterValue)
          return;
      } else if (a.Type == pa.CallerMemberNameAttribute) {
        if ((modFlags & Modifier.CallerMemberName) == 0) {
          a.Report.Error (4022, a.Location,
            "The CallerMemberName attribute can only be applied to parameters with default value");
        }
      } else if (a.Type == pa.CallerLineNumberAttribute) {
        if ((modFlags & Modifier.CallerLineNumber) == 0) {
          a.Report.Error (4020, a.Location,
            "The CallerLineNumber attribute can only be applied to parameters with default value");
        }
      } else if (a.Type == pa.CallerFilePathAttribute) {
        if ((modFlags & Modifier.CallerFilePath) == 0) {
          a.Report.Error (4021, a.Location,
            "The CallerFilePath attribute can only be applied to parameters with default value");
        }
      }

      base.ApplyAttributeBuilder (a, ctor, cdata, pa);
    }
    
    public virtual bool CheckAccessibility (InterfaceMemberBase member)
    {
      if (parameter_type == null)
        return true;

      return member.IsAccessibleAs (parameter_type);
    }

    bool IsValidCallerContext (MemberCore memberContext)
    {
      var m = memberContext as Method;
      if (m != null)
        return !m.IsPartialImplementation;

      return true;
    }

    // <summary>
    //   Resolve is used in method definitions
    // </summary>
    public virtual TypeSpec Resolve (IMemberContext rc, int index)
    {
      if (parameter_type != null)
        return parameter_type;

      if (attributes != null)
        attributes.AttachTo (this, rc);

      parameter_type = texpr.ResolveAsType (rc);
      if (parameter_type == null)
        return null;

      this.idx = index;

      if ((modFlags & Parameter.Modifier.RefOutMask) != 0 && parameter_type.IsSpecialRuntimeType) {
        rc.Module.Compiler.Report.Error (1601, Location, "Method or delegate parameter cannot be of type `{0}'",
          GetSignatureForError ());
        return null;
      }

      VarianceDecl.CheckTypeVariance (parameter_type,
        (modFlags & Parameter.Modifier.RefOutMask) != 0 ? Variance.None : Variance.Contravariant,
        rc);

      if (parameter_type.IsStatic) {
        rc.Module.Compiler.Report.Error (721, Location, "`{0}': static types cannot be used as parameters",
          texpr.GetSignatureForError ());
        return parameter_type;
      }

      if ((modFlags & Modifier.This) != 0 && (parameter_type.IsPointer || parameter_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic)) {
        rc.Module.Compiler.Report.Error (1103, Location, "The extension method cannot be of type `{0}'",
          parameter_type.GetSignatureForError ());
      }

      return parameter_type;
    }

    void ResolveCallerAttributes (ResolveContext rc)
    {
      var pa = rc.Module.PredefinedAttributes;
      TypeSpec caller_type;
      Attribute callerMemberName = null, callerFilePath = null;

      foreach (var attr in attributes.Attrs) {
        var atype = attr.ResolveTypeForComparison ();
        if (atype == null)
          continue;

        if (atype == pa.CallerMemberNameAttribute) {
          caller_type = rc.BuiltinTypes.String;
          if (caller_type != parameter_type && !Convert.ImplicitReferenceConversionExists (caller_type, parameter_type)) {
            rc.Report.Error (4019, attr.Location,
              "The CallerMemberName attribute cannot be applied because there is no standard conversion from `{0}' to `{1}'",
              caller_type.GetSignatureForError (), parameter_type.GetSignatureForError ());
          }

          if (!IsValidCallerContext (rc.CurrentMemberDefinition)) {
            rc.Report.Warning (4026, 1, attr.Location,
              "The CallerMemberName applied to parameter `{0}' will have no effect because it applies to a member that is used in context that do not allow optional arguments",
              name);
          }

          modFlags |= Modifier.CallerMemberName;
          callerMemberName = attr;
          continue;
        }

        if (atype == pa.CallerLineNumberAttribute) {
          caller_type = rc.BuiltinTypes.Int;
          if (caller_type != parameter_type && !Convert.ImplicitStandardConversionExists (new IntConstant (caller_type, int.MaxValue, Location.Null), parameter_type)) {
            rc.Report.Error (4017, attr.Location,
              "The CallerLineNumberAttribute attribute cannot be applied because there is no standard conversion from `{0}' to `{1}'",
              caller_type.GetSignatureForError (), parameter_type.GetSignatureForError ());
          }

          if (!IsValidCallerContext (rc.CurrentMemberDefinition)) {
            rc.Report.Warning (4024, 1, attr.Location,
              "The CallerLineNumberAttribute applied to parameter `{0}' will have no effect because it applies to a member that is used in context that do not allow optional arguments",
              name);
          }

          modFlags |= Modifier.CallerLineNumber;
          continue;
        }

        if (atype == pa.CallerFilePathAttribute) {
          caller_type = rc.BuiltinTypes.String;
          if (caller_type != parameter_type && !Convert.ImplicitReferenceConversionExists (caller_type, parameter_type)) {
            rc.Report.Error (4018, attr.Location,
              "The CallerFilePath attribute cannot be applied because there is no standard conversion from `{0}' to `{1}'",
              caller_type.GetSignatureForError (), parameter_type.GetSignatureForError ());
          }

          if (!IsValidCallerContext (rc.CurrentMemberDefinition)) {
            rc.Report.Warning (4025, 1, attr.Location,
              "The CallerFilePath applied to parameter `{0}' will have no effect because it applies to a member that is used in context that do not allow optional arguments",
              name);
          }

          modFlags |= Modifier.CallerFilePath;
          callerFilePath = attr;
          continue;
        }
      }

      if ((modFlags & Modifier.CallerLineNumber) != 0) {
        if (callerMemberName != null) {
          rc.Report.Warning (7081, 1, callerMemberName.Location,
            "The CallerMemberNameAttribute applied to parameter `{0}' will have no effect. It is overridden by the CallerLineNumberAttribute",
            Name);
        }

        if (callerFilePath != null) {
          rc.Report.Warning (7082, 1, callerFilePath.Location,
            "The CallerFilePathAttribute applied to parameter `{0}' will have no effect. It is overridden by the CallerLineNumberAttribute",
            name);
        }
      }

      if ((modFlags & Modifier.CallerMemberName) != 0) {
        if (callerFilePath != null) {
          rc.Report.Warning (7080, 1, callerFilePath.Location,
            "The CallerMemberNameAttribute applied to parameter `{0}' will have no effect. It is overridden by the CallerFilePathAttribute",
            name);
        }

      }
    }

    public void ResolveDefaultValue (ResolveContext rc)
    {
      //
      // Default value was specified using an expression
      //
      if (default_expr != null) {
        ((DefaultParameterValueExpression)default_expr).Resolve (rc, this);
        if (attributes != null)
          ResolveCallerAttributes (rc);

        return;
      }

      if (attributes == null)
        return;

      var pa = rc.Module.PredefinedAttributes;
      var def_attr = attributes.Search (pa.DefaultParameterValue);
      if (def_attr != null) {
        if (def_attr.Resolve () == null)
          return;

        var default_expr_attr = def_attr.GetParameterDefaultValue ();
        if (default_expr_attr == null)
          return;

        var dpa_rc = def_attr.CreateResolveContext ();
        default_expr = default_expr_attr.Resolve (dpa_rc);

        if (default_expr is BoxedCast)
          default_expr = ((BoxedCast) default_expr).Child;

        Constant c = default_expr as Constant;
        if (c == null) {
          if (parameter_type.BuiltinType == BuiltinTypeSpec.Type.Object) {
            rc.Report.Error (1910, default_expr.Location,
              "Argument of type `{0}' is not applicable for the DefaultParameterValue attribute",
              default_expr.Type.GetSignatureForError ());
          } else {
            rc.Report.Error (1909, default_expr.Location,
              "The DefaultParameterValue attribute is not applicable on parameters of type `{0}'",
              default_expr.Type.GetSignatureForError ());
          }

          default_expr = null;
          return;
        }

        if (TypeSpecComparer.IsEqual (default_expr.Type, parameter_type) ||
          (default_expr is NullConstant && TypeSpec.IsReferenceType (parameter_type) && !parameter_type.IsGenericParameter) ||
          parameter_type.BuiltinType == BuiltinTypeSpec.Type.Object) {
          return;
        }

        //
        // LAMESPEC: Some really weird csc behaviour which we have to mimic
        // User operators returning same type as parameter type are considered
        // valid for this attribute only
        //
        // struct S { public static implicit operator S (int i) {} }
        //
        // void M ([DefaultParameterValue (3)]S s)
        //
        var expr = Convert.ImplicitUserConversion (dpa_rc, default_expr, parameter_type, loc);
        if (expr != null && TypeSpecComparer.IsEqual (expr.Type, parameter_type)) {
          return;
        }
        
        rc.Report.Error (1908, default_expr.Location, "The type of the default value should match the type of the parameter");
        return;
      }

      var opt_attr = attributes.Search (pa.OptionalParameter);
      if (opt_attr != null) {
        default_expr = EmptyExpression.MissingValue;
      }
    }

    public bool HasDefaultValue {
      get { return default_expr != null; }
    }

    public bool HasExtensionMethodModifier {
      get { return (modFlags & Modifier.This) != 0; }
    }

    //
    // Hoisted parameter variant
    //
    public HoistedParameter HoistedVariant {
      get {
        return hoisted_variant;
      }
      set {
        hoisted_variant = value;
      }
    }

    public Modifier ModFlags {
      get { return modFlags & ~Modifier.This; }
    }

    public string Name {
      get { return name; }
      set { name = value; }
    }

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

    public void Error_DuplicateName (Report r)
    {
      r.Error (100, Location, "The parameter name `{0}' is a duplicate", Name);
    }

    public virtual string GetSignatureForError ()
    {
      string type_name;
      if (parameter_type != null)
        type_name = parameter_type.GetSignatureForError ();
      else
        type_name = texpr.GetSignatureForError ();

      string mod = GetModifierSignature (modFlags);
      if (mod.Length > 0)
        return String.Concat (mod, " ", type_name);

      return type_name;
    }

    public static string GetModifierSignature (Modifier mod)
    {
      switch (mod) {
      case Modifier.OUT:
        return "out";
      case Modifier.PARAMS:
        return "params";
      case Modifier.REF:
        return "ref";
      case Modifier.This:
        return "this";
      default:
        return "";
      }
    }

    public void IsClsCompliant (IMemberContext ctx)
    {
      if (parameter_type.IsCLSCompliant ())
        return;

      ctx.Module.Compiler.Report.Warning (3001, 1, Location,
        "Argument type `{0}' is not CLS-compliant", parameter_type.GetSignatureForError ());
    }

    public virtual void ApplyAttributes (MethodBuilder mb, ConstructorBuilder cb, int index, PredefinedAttributes pa)
    {
      if (builder != null)
        throw new InternalErrorException ("builder already exists");

      var pattrs = ParametersCompiled.GetParameterAttribute (modFlags);
      if (HasOptionalExpression)
        pattrs |= ParameterAttributes.Optional;

      if (mb == null)
        builder = cb.DefineParameter (index, pattrs, Name);
      else
        builder = mb.DefineParameter (index, pattrs, Name);

      if (OptAttributes != null)
        OptAttributes.Emit ();

      if (HasDefaultValue && default_expr.Type != null) {
        //
        // Emit constant values for true constants only, the other
        // constant-like expressions will rely on default value expression
        //
        var def_value = DefaultValue;
        Constant c = def_value != null ? def_value.Child as Constant : default_expr as Constant;
        if (c != null) {
          if (c.Type.BuiltinType == BuiltinTypeSpec.Type.Decimal) {
            pa.DecimalConstant.EmitAttribute (builder, (decimal) c.GetValue (), c.Location);
          } else {
            builder.SetConstant (c.GetValue ());
          }
        } else if (default_expr.Type.IsStruct || default_expr.Type.IsGenericParameter) {
          //
          // Handles special case where default expression is used with value-type or type parameter
          //
          // void Foo (S s = default (S)) {}
          //
          builder.SetConstant (null);
        }
      }

      if (parameter_type != null) {
        if (parameter_type.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
          pa.Dynamic.EmitAttribute (builder);
        } else if (parameter_type.HasDynamicElement) {
          pa.Dynamic.EmitAttribute (builder, parameter_type, Location);
        }
      }
    }

    public Parameter Clone ()
    {
      Parameter p = (Parameter) MemberwiseClone ();
      if (attributes != null)
        p.attributes = attributes.Clone ();

      return p;
    }

    public ExpressionStatement CreateExpressionTreeVariable (BlockContext ec)
    {
      if ((modFlags & Modifier.RefOutMask) != 0)
        ec.Report.Error (1951, Location, "An expression tree parameter cannot use `ref' or `out' modifier");

      expr_tree_variable = TemporaryVariableReference.Create (ResolveParameterExpressionType (ec, Location).Type, ec.CurrentBlock.ParametersBlock, Location);
      expr_tree_variable = (TemporaryVariableReference) expr_tree_variable.Resolve (ec);

      Arguments arguments = new Arguments (2);
      arguments.Add (new Argument (new TypeOf (parameter_type, Location)));
      arguments.Add (new Argument (new StringConstant (ec.BuiltinTypes, Name, Location)));
      return new SimpleAssign (ExpressionTreeVariableReference (),
        Expression.CreateExpressionFactoryCall (ec, "Parameter", null, arguments, Location));
    }

    public void Emit (EmitContext ec)
    {
      ec.EmitArgumentLoad (idx);
    }

    public void EmitAssign (EmitContext ec)
    {
      ec.EmitArgumentStore (idx);
    }

    public void EmitAddressOf (EmitContext ec)
    {
      if ((ModFlags & Modifier.RefOutMask) != 0) {
        ec.EmitArgumentLoad (idx);
      } else {
        ec.EmitArgumentAddress (idx);
      }
    }

    public TemporaryVariableReference ExpressionTreeVariableReference ()
    {
      return expr_tree_variable;
    }

    //
    // System.Linq.Expressions.ParameterExpression type
    //
    public static TypeExpr ResolveParameterExpressionType (IMemberContext ec, Location location)
    {
      TypeSpec p_type = ec.Module.PredefinedTypes.ParameterExpression.Resolve ();
      return new TypeExpression (p_type, location);
    }

    public void SetIndex (int index)
    {
      idx = index;
    }

    public void Warning_UselessOptionalParameter (Report Report)
    {
      Report.Warning (1066, 1, Location,
        "The default value specified for optional parameter `{0}' will never be used",
        Name);
    }
  }

  //
  // Imported or resolved parameter information
  //
  public class ParameterData : IParameterData
  {
    readonly string name;
    readonly Parameter.Modifier modifiers;
    readonly Expression default_value;

    public ParameterData (string name, Parameter.Modifier modifiers)
    {
      this.name = name;
      this.modifiers = modifiers;
    }

    public ParameterData (string name, Parameter.Modifier modifiers, Expression defaultValue)
      : this (name, modifiers)
    {
      this.default_value = defaultValue;
    }

    #region IParameterData Members

    public Expression DefaultValue {
      get { return default_value; }
    }

    public bool HasExtensionMethodModifier {
      get { return (modifiers & Parameter.Modifier.This) != 0; }
    }

    public bool HasDefaultValue {
      get { return default_value != null; }
    }

    public Parameter.Modifier ModFlags {
      get { return modifiers; }
    }

    public string Name {
      get { return name; }
    }

    #endregion
  }

  public abstract class AParametersCollection
  {
    protected bool has_arglist;
    protected bool has_params;

    // Null object pattern
    protected IParameterData [] parameters;
    protected TypeSpec [] types;

    public CallingConventions CallingConvention {
      get {
        return has_arglist ?
          CallingConventions.VarArgs :
          CallingConventions.Standard;
      }
    }

    public int Count {
      get { return parameters.Length; }
    }

    public TypeSpec ExtensionMethodType {
      get {
        if (Count == 0)
          return null;

        return FixedParameters [0].HasExtensionMethodModifier ?
          types [0] : null;
      }
    }

    public IParameterData [] FixedParameters {
      get {
        return parameters;
      }
    }

    public static ParameterAttributes GetParameterAttribute (Parameter.Modifier modFlags)
    {
      return (modFlags & Parameter.Modifier.OUT) != 0 ?
        ParameterAttributes.Out : ParameterAttributes.None;
    }

    // Very expensive operation
    public MetaType[] GetMetaInfo ()
    {
      MetaType[] types;
      if (has_arglist) {
        if (Count == 1)
          return MetaType.EmptyTypes;

        types = new MetaType[Count - 1];
      } else {
        if (Count == 0)
          return MetaType.EmptyTypes;

        types = new MetaType[Count];
      }

      for (int i = 0; i < types.Length; ++i) {
        types[i] = Types[i].GetMetaInfo ();

        if ((FixedParameters[i].ModFlags & Parameter.Modifier.RefOutMask) == 0)
          continue;

        // TODO MemberCache: Should go to MetaInfo getter
        types [i] = types [i].MakeByRefType ();
      }

      return types;
    }

    //
    // Returns the parameter information based on the name
    //
    public int GetParameterIndexByName (string name)
    {
      for (int idx = 0; idx < Count; ++idx) {
        if (parameters [idx].Name == name)
          return idx;
      }

      return -1;
    }

    public string GetSignatureForDocumentation ()
    {
      if (IsEmpty)
        return string.Empty;

      StringBuilder sb = new StringBuilder ("(");
      for (int i = 0; i < Count; ++i) {
        if (i != 0)
          sb.Append (",");

        sb.Append (types [i].GetSignatureForDocumentation ());

        if ((parameters[i].ModFlags & Parameter.Modifier.RefOutMask) != 0)
          sb.Append ("@");
      }
      sb.Append (")");

      return sb.ToString ();
    }

    public string GetSignatureForError ()
    {
      return GetSignatureForError ("(", ")", Count);
    }

    public string GetSignatureForError (string start, string end, int count)
    {
      StringBuilder sb = new StringBuilder (start);
      for (int i = 0; i < count; ++i) {
        if (i != 0)
          sb.Append (", ");
        sb.Append (ParameterDesc (i));
      }
      sb.Append (end);
      return sb.ToString ();
    }

    public bool HasArglist {
      get { return has_arglist; }
    }

    public bool HasExtensionMethodType {
      get {
        if (Count == 0)
          return false;

        return FixedParameters [0].HasExtensionMethodModifier;
      }
    }

    public bool HasParams {
      get { return has_params; }
    }

    public bool IsEmpty {
      get { return parameters.Length == 0; }
    }

    public AParametersCollection Inflate (TypeParameterInflator inflator)
    {
      TypeSpec[] inflated_types = null;
      bool default_value = false;

      for (int i = 0; i < Count; ++i) {
        var inflated_param = inflator.Inflate (types[i]);
        if (inflated_types == null) {
          if (inflated_param == types[i])
            continue;

          default_value |= FixedParameters[i].HasDefaultValue;
          inflated_types = new TypeSpec[types.Length];
          Array.Copy (types, inflated_types, types.Length);
        } else {
          if (inflated_param == types[i])
            continue;

          default_value |= FixedParameters[i].HasDefaultValue;
        }

        inflated_types[i] = inflated_param;
      }

      if (inflated_types == null)
        return this;

      var clone = (AParametersCollection) MemberwiseClone ();
      clone.types = inflated_types;

      //
      // Default expression is original expression from the parameter
      // declaration context which can be of nested enum in generic class type.
      // In such case we end up with expression type of G<T>.E and e.g. parameter
      // type of G<int>.E and conversion would fail without inflate in this
      // context.
      //
      if (default_value) {
        clone.parameters = new IParameterData[Count];
        for (int i = 0; i < Count; ++i) {
          var fp = FixedParameters[i];
          clone.FixedParameters[i] = fp;

          if (!fp.HasDefaultValue)
            continue;

          var expr = fp.DefaultValue;

          if (inflated_types[i] == expr.Type)
            continue;

          var c = expr as Constant;
          if (c != null) {
            //
            // It may fail we are inflating before type validation is done
            //
            c = Constant.ExtractConstantFromValue (inflated_types[i], c.GetValue (), expr.Location);
            if (c == null)
              expr = new DefaultValueExpression (new TypeExpression (inflated_types[i], expr.Location), expr.Location);
            else
              expr = c;
          } else if (expr is DefaultValueExpression)
            expr = new DefaultValueExpression (new TypeExpression (inflated_types[i], expr.Location), expr.Location);

          clone.FixedParameters[i] = new ParameterData (fp.Name, fp.ModFlags, expr);
        }
      }

      return clone;
    }

    public string ParameterDesc (int pos)
    {
      if (types == null || types [pos] == null)
        return ((Parameter)FixedParameters [pos]).GetSignatureForError ();

      string type = types [pos].GetSignatureForError ();
      if (FixedParameters [pos].HasExtensionMethodModifier)
        return "this " + type;

      var mod = FixedParameters[pos].ModFlags & Parameter.Modifier.ModifierMask;
      if (mod == 0)
        return type;

      return Parameter.GetModifierSignature (mod) + " " + type;
    }

    public TypeSpec[] Types {
      get { return types; }
      set { types = value; }
    }
  }

  //
  // A collection of imported or resolved parameters
  //
  public class ParametersImported : AParametersCollection
  {
    public ParametersImported (IParameterData [] parameters, TypeSpec [] types, bool hasArglist, bool hasParams)
    {
      this.parameters = parameters;
      this.types = types;
      this.has_arglist = hasArglist;
      this.has_params = hasParams;
    }

    public ParametersImported (IParameterData[] param, TypeSpec[] types, bool hasParams)
    {
      this.parameters = param;
      this.types = types;
      this.has_params = hasParams;
    }
  }

  /// <summary>
  ///   Represents the methods parameters
  /// </summary>
  public class ParametersCompiled : AParametersCollection
  {
    public static readonly ParametersCompiled EmptyReadOnlyParameters = new ParametersCompiled ();
    
    // Used by C# 2.0 delegates
    public static readonly ParametersCompiled Undefined = new ParametersCompiled ();

    private ParametersCompiled ()
    {
      parameters = new Parameter [0];
      types = TypeSpec.EmptyTypes;
    }

    private ParametersCompiled (IParameterData[] parameters, TypeSpec[] types)
    {
      this.parameters = parameters;
        this.types = types;
    }
    
    public ParametersCompiled (params Parameter[] parameters)
    {
      if (parameters == null || parameters.Length == 0)
        throw new ArgumentException ("Use EmptyReadOnlyParameters");

      this.parameters = parameters;
      int count = parameters.Length;

      for (int i = 0; i < count; i++){
        has_params |= (parameters [i].ModFlags & Parameter.Modifier.PARAMS) != 0;
      }
    }

    public ParametersCompiled (Parameter [] parameters, bool has_arglist) :
      this (parameters)
    {
      this.has_arglist = has_arglist;
    }
    
    public static ParametersCompiled CreateFullyResolved (Parameter p, TypeSpec type)
    {
      return new ParametersCompiled (new Parameter [] { p }, new TypeSpec [] { type });
    }
    
    public static ParametersCompiled CreateFullyResolved (Parameter[] parameters, TypeSpec[] types)
    {
      return new ParametersCompiled (parameters, types);
    }

    public static ParametersCompiled Prefix (ParametersCompiled parameters, Parameter p, TypeSpec type)
    {
      var ptypes = new TypeSpec [parameters.Count + 1];
      ptypes [0] = type;
      Array.Copy (parameters.Types, 0, ptypes, 1, parameters.Count);

      var param = new Parameter [ptypes.Length];
      param [0] = p;
      for (int i = 0; i < parameters.Count; ++i) {
        var pi = parameters [i];
        param [i + 1] = pi;
        pi.SetIndex (i + 1);
      }

      return ParametersCompiled.CreateFullyResolved (param, ptypes);
    }

    //
    // TODO: This does not fit here, it should go to different version of AParametersCollection
    // as the underlying type is not Parameter and some methods will fail to cast
    //
    public static AParametersCollection CreateFullyResolved (params TypeSpec[] types)
    {
      var pd = new ParameterData [types.Length];
      for (int i = 0; i < pd.Length; ++i)
        pd[i] = new ParameterData (null, Parameter.Modifier.NONE, null);

      return new ParametersCompiled (pd, types);
    }

    public static ParametersCompiled CreateImplicitParameter (FullNamedExpression texpr, Location loc)
    {
      return new ParametersCompiled (
        new[] { new Parameter (texpr, "value", Parameter.Modifier.NONE, null, loc) },
        null);
    }

    public void CheckConstraints (IMemberContext mc)
    {
      foreach (Parameter p in parameters) {
        //
        // It's null for compiler generated types or special types like __arglist
        //
        if (p.TypeExpression != null)
          ConstraintChecker.Check (mc, p.Type, p.TypeExpression.Location);
      }
    }

    //
    // Returns non-zero value for equal CLS parameter signatures
    //
    public static int IsSameClsSignature (AParametersCollection a, AParametersCollection b)
    {
      int res = 0;

      for (int i = 0; i < a.Count; ++i) {
        var a_type = a.Types[i];
        var b_type = b.Types[i];
        if (TypeSpecComparer.Override.IsEqual (a_type, b_type)) {
          if ((a.FixedParameters[i].ModFlags & Parameter.Modifier.RefOutMask) != (b.FixedParameters[i].ModFlags & Parameter.Modifier.RefOutMask))
            res |= 1;

          continue;
        }

        var ac_a = a_type as ArrayContainer;
        if (ac_a == null)
          return 0;

        var ac_b = b_type as ArrayContainer;
        if (ac_b == null)
          return 0;

        if (ac_a.Element is ArrayContainer || ac_b.Element is ArrayContainer) {
          res |= 2;
          continue;
        }

        if (ac_a.Rank != ac_b.Rank && TypeSpecComparer.Override.IsEqual (ac_a.Element, ac_b.Element)) {
          res |= 1;
          continue;
        }

        return 0;
      }

      return res;
    }

    public static ParametersCompiled MergeGenerated (CompilerContext ctx, ParametersCompiled userParams, bool checkConflicts, Parameter compilerParams, TypeSpec compilerTypes)
    {
      return MergeGenerated (ctx, userParams, checkConflicts,
        new Parameter [] { compilerParams },
        new TypeSpec [] { compilerTypes });
    }

    //
    // Use this method when you merge compiler generated parameters with user parameters
    //
    public static ParametersCompiled MergeGenerated (CompilerContext ctx, ParametersCompiled userParams, bool checkConflicts, Parameter[] compilerParams, TypeSpec[] compilerTypes)
    {
      Parameter[] all_params = new Parameter [userParams.Count + compilerParams.Length];
      userParams.FixedParameters.CopyTo(all_params, 0);

      TypeSpec [] all_types;
      if (userParams.types != null) {
        all_types = new TypeSpec [all_params.Length];
        userParams.Types.CopyTo (all_types, 0);
      } else {
        all_types = null;
      }

      int last_filled = userParams.Count;
      int index = 0;
      foreach (Parameter p in compilerParams) {
        for (int i = 0; i < last_filled; ++i) {
          while (p.Name == all_params [i].Name) {
            if (checkConflicts && i < userParams.Count) {
              ctx.Report.Error (316, userParams[i].Location,
                "The parameter name `{0}' conflicts with a compiler generated name", p.Name);
            }
            p.Name = '_' + p.Name;
          }
        }
        all_params [last_filled] = p;
        if (all_types != null)
          all_types [last_filled] = compilerTypes [index++];
        ++last_filled;
      }
      
      ParametersCompiled parameters = new ParametersCompiled (all_params, all_types);
      parameters.has_params = userParams.has_params;
      return parameters;
    }

    //
    // Parameters checks for members which don't have a block
    //
    public void CheckParameters (MemberCore member)
    {
      for (int i = 0; i < parameters.Length; ++i) {
        var name = parameters[i].Name;
        for (int ii = i + 1; ii < parameters.Length; ++ii) {
          if (parameters[ii].Name == name)
            this[ii].Error_DuplicateName (member.Compiler.Report);
        }
      }
    }

    public bool Resolve (IMemberContext ec)
    {
      if (types != null)
        return true;
      
      types = new TypeSpec [Count];
      
      bool ok = true;
      Parameter p;
      for (int i = 0; i < FixedParameters.Length; ++i) {
        p = this [i];
        TypeSpec t = p.Resolve (ec, i);
        if (t == null) {
          ok = false;
          continue;
        }

        types [i] = t;
      }

      return ok;
    }

    public void ResolveDefaultValues (MemberCore m)
    {
      ResolveContext rc = null;
      for (int i = 0; i < parameters.Length; ++i) {
        Parameter p = (Parameter) parameters [i];

        //
        // Try not to enter default values resolution if there are is not any default value possible
        //
        if (p.HasDefaultValue || p.OptAttributes != null) {
          if (rc == null)
            rc = new ResolveContext (m);

          p.ResolveDefaultValue (rc);
        }
      }
    }

    // Define each type attribute (in/out/ref) and
    // the argument names.
    public void ApplyAttributes (IMemberContext mc, MethodBase builder)
    {
      if (Count == 0)
        return;

      MethodBuilder mb = builder as MethodBuilder;
      ConstructorBuilder cb = builder as ConstructorBuilder;
      var pa = mc.Module.PredefinedAttributes;

      for (int i = 0; i < Count; i++) {
        this [i].ApplyAttributes (mb, cb, i + 1, pa);
      }
    }

    public void VerifyClsCompliance (IMemberContext ctx)
    {
      foreach (Parameter p in FixedParameters)
        p.IsClsCompliant (ctx);
    }

    public Parameter this [int pos] {
      get { return (Parameter) parameters [pos]; }
    }

    public Expression CreateExpressionTree (BlockContext ec, Location loc)
    {
      var initializers = new ArrayInitializer (Count, loc);
      foreach (Parameter p in FixedParameters) {
        //
        // Each parameter expression is stored to local variable
        // to save some memory when referenced later.
        //
        StatementExpression se = new StatementExpression (p.CreateExpressionTreeVariable (ec), Location.Null);
        if (se.Resolve (ec)) {
          ec.CurrentBlock.AddScopeStatement (new TemporaryVariableReference.Declarator (p.ExpressionTreeVariableReference ()));
          ec.CurrentBlock.AddScopeStatement (se);
        }
        
        initializers.Add (p.ExpressionTreeVariableReference ());
      }

      return new ArrayCreation (
        Parameter.ResolveParameterExpressionType (ec, loc),
        initializers, loc);
    }

    public ParametersCompiled Clone ()
    {
      ParametersCompiled p = (ParametersCompiled) MemberwiseClone ();

      p.parameters = new IParameterData [parameters.Length];
      for (int i = 0; i < Count; ++i)
        p.parameters [i] = this [i].Clone ();

      return p;
    }
  }

  //
  // Default parameter value expression. We need this wrapper to handle
  // default parameter values of folded constants (e.g. indexer parameters).
  // The expression is resolved only once but applied to two methods which
  // both share reference to this expression and we ensure that resolving
  // this expression always returns same instance
  //
  public class DefaultParameterValueExpression : CompositeExpression
  {
    public DefaultParameterValueExpression (Expression expr)
      : base (expr)
    {
    }

    public void Resolve (ResolveContext rc, Parameter p)
    {
      var expr = Resolve (rc);
      if (expr == null) {
        this.expr = ErrorExpression.Instance;
        return;
      }

      expr = Child;

      if (!(expr is Constant || expr is DefaultValueExpression || (expr is New && ((New) expr).IsDefaultStruct))) {
        if (!(expr is ErrorExpression)) {
          rc.Report.Error (1736, Location,
            "The expression being assigned to optional parameter `{0}' must be a constant or default value",
            p.Name);
        }

        return;
      }

      var parameter_type = p.Type;
      if (type == parameter_type)
        return;

      var res = Convert.ImplicitConversionStandard (rc, expr, parameter_type, Location);
      if (res != null) {
        if (parameter_type.IsNullableType && res is Nullable.Wrap) {
          Nullable.Wrap wrap = (Nullable.Wrap) res;
          res = wrap.Child;
          if (!(res is Constant)) {
            rc.Report.Error (1770, Location,
              "The expression being assigned to nullable optional parameter `{0}' must be default value",
              p.Name);
            return;
          }
        }

        if (!expr.IsNull && TypeSpec.IsReferenceType (parameter_type) && parameter_type.BuiltinType != BuiltinTypeSpec.Type.String) {
          rc.Report.Error (1763, Location,
            "Optional parameter `{0}' of type `{1}' can only be initialized with `null'",
            p.Name, parameter_type.GetSignatureForError ());

          return;
        }

        this.expr = res;
        return;
      }

      rc.Report.Error (1750, Location,
        "Optional parameter expression of type `{0}' cannot be converted to parameter type `{1}'",
        type.GetSignatureForError (), parameter_type.GetSignatureForError ());

      this.expr = ErrorExpression.Instance;
    }
    
    public override object Accept (StructuralVisitor visitor)
    {
      return visitor.Visit (this);
    }
  }
}