//
// method.cs: Method based declarations
//
// 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 2004-2008 Novell, Inc
// Copyright 2011 Xamarin Inc.
//

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

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

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

namespace Mono.CSharp {

	public abstract class MethodCore : InterfaceMemberBase, IParametersMember
	{
		protected ParametersCompiled parameters;
		protected ToplevelBlock block;
		protected MethodSpec spec;

		protected MethodCore (TypeDefinition parent, FullNamedExpression type, Modifiers mod, Modifiers allowed_mod,
			MemberName name, Attributes attrs, ParametersCompiled parameters)
			: base (parent, type, mod, allowed_mod, name, attrs)
		{
			this.parameters = parameters;
		}

		public override Variance ExpectedMemberTypeVariance {
			get {
				return Variance.Covariant;
			}
		}

		//
		//  Returns the System.Type array for the parameters of this method
		//
		public TypeSpec [] ParameterTypes {
			get {
				return parameters.Types;
			}
		}

		public ParametersCompiled ParameterInfo {
			get {
				return parameters;
			}
		}

		AParametersCollection IParametersMember.Parameters {
			get { return parameters; }
		}
		
		public ToplevelBlock Block {
			get {
				return block;
			}

			set {
				block = value;
			}
		}

		public CallingConventions CallingConventions {
			get {
				CallingConventions cc = parameters.CallingConvention;
				if (!IsInterface)
					if ((ModFlags & Modifiers.STATIC) == 0)
						cc |= CallingConventions.HasThis;

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

		protected override bool CheckOverrideAgainstBase (MemberSpec base_member)
		{
			bool res = base.CheckOverrideAgainstBase (base_member);

			//
			// Check that the permissions are not being changed
			//
			if (!CheckAccessModifiers (this, base_member)) {
				Error_CannotChangeAccessModifiers (this, base_member);
				res = false;
			}

			return res;
		}

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

			return base.CheckBase ();
		}

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

		public override void Emit ()
		{
			if ((ModFlags & Modifiers.COMPILER_GENERATED) == 0) {
				parameters.CheckConstraints (this);
			}

			base.Emit ();
		}

		public override bool EnableOverloadChecks (MemberCore overload)
		{
			if (overload is MethodCore) {
				caching_flags |= Flags.MethodOverloadsExist;
				return true;
			}

			if (overload is AbstractPropertyEventMethod)
				return true;

			return base.EnableOverloadChecks (overload);
		}

		public override string GetSignatureForDocumentation ()
		{
			string s = base.GetSignatureForDocumentation ();
			if (MemberName.Arity > 0)
				s += "``" + MemberName.Arity.ToString ();

			return s + parameters.GetSignatureForDocumentation ();
		}

		public MethodSpec Spec {
			get { return spec; }
		}

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

			if (parameters.HasArglist) {
				Report.Warning (3000, 1, Location, "Methods with variable arguments are not CLS-compliant");
			}

			if (member_type != null && !member_type.IsCLSCompliant ()) {
				Report.Warning (3002, 1, Location, "Return type of `{0}' is not CLS-compliant",
					GetSignatureForError ());
			}

			parameters.VerifyClsCompliance (this);
			return true;
		}
	}

	public interface IGenericMethodDefinition : IMethodDefinition
	{
		TypeParameterSpec[] TypeParameters { get; }
		int TypeParametersCount { get; }

//		MethodInfo MakeGenericMethod (TypeSpec[] targs);
	}

	public sealed class MethodSpec : MemberSpec, IParametersMember
	{
		MethodBase inflatedMetaInfo;
		AParametersCollection parameters;
		TypeSpec returnType;

		TypeSpec[] targs;
		TypeParameterSpec[] constraints;

		public static readonly MethodSpec Excluded = new MethodSpec (MemberKind.Method, InternalType.FakeInternalType, null, null, ParametersCompiled.EmptyReadOnlyParameters, 0);

		public MethodSpec (MemberKind kind, TypeSpec declaringType, IMethodDefinition details, TypeSpec returnType,
			AParametersCollection parameters, Modifiers modifiers)
			: base (kind, declaringType, details, modifiers)
		{
			this.parameters = parameters;
			this.returnType = returnType;
		}

		#region Properties

		public override int Arity {
			get {
				return IsGeneric ? GenericDefinition.TypeParametersCount : 0;
			}
		}

		public TypeParameterSpec[] Constraints {
			get {
				if (constraints == null && IsGeneric)
					constraints = GenericDefinition.TypeParameters;

				return constraints;
			}
		}

		public bool IsConstructor {
			get {
				return Kind == MemberKind.Constructor;
			}
		}

		public new IMethodDefinition MemberDefinition {
			get {
				return (IMethodDefinition) definition;
			}
		}

		public IGenericMethodDefinition GenericDefinition {
			get {
				return (IGenericMethodDefinition) definition;
			}
		}

		public bool IsAsync {
			get {
				return (Modifiers & Modifiers.ASYNC) != 0;
			}
		}

		public bool IsExtensionMethod {
			get {
				return IsStatic && parameters.HasExtensionMethodType;
			}
		}

		public bool IsSealed {
			get {
				return (Modifiers & Modifiers.SEALED) != 0;
			}
		}

		// When is virtual or abstract
		public bool IsVirtual {
			get {
				return (Modifiers & (Modifiers.VIRTUAL | Modifiers.ABSTRACT | Modifiers.OVERRIDE)) != 0;
			}
		}

		public bool IsReservedMethod {
			get {
				return Kind == MemberKind.Operator || IsAccessor;
			}
		}

		TypeSpec IInterfaceMemberSpec.MemberType {
			get {
				return returnType;
			}
		}

		public AParametersCollection Parameters {
			get { 
				return parameters;
			}
		}

		public TypeSpec ReturnType {
			get {
				return returnType;
			}
		}

		public TypeSpec[] TypeArguments {
			get {
				return targs;
			}
		}

		#endregion

		public MethodSpec GetGenericMethodDefinition ()
		{
			if (!IsGeneric && !DeclaringType.IsGeneric)
				return this;

			return MemberCache.GetMember (declaringType, this);
		}

		public MethodBase GetMetaInfo ()
		{
			//
			// inflatedMetaInfo is extra field needed for cases where we
			// inflate method but another nested type can later inflate
			// again (the cache would be build with inflated metaInfo) and
			// TypeBuilder can work with method definitions only
			//
			if (inflatedMetaInfo == null) {
				if ((state & StateFlags.PendingMetaInflate) != 0) {
					var dt_meta = DeclaringType.GetMetaInfo ();

					if (DeclaringType.IsTypeBuilder) {
						if (IsConstructor)
							inflatedMetaInfo = TypeBuilder.GetConstructor (dt_meta, (ConstructorInfo) MemberDefinition.Metadata);
						else
							inflatedMetaInfo = TypeBuilder.GetMethod (dt_meta, (MethodInfo) MemberDefinition.Metadata);
					} else {
#if STATIC
						// it should not be reached
						throw new NotImplementedException ();
#else
						inflatedMetaInfo = MethodInfo.GetMethodFromHandle (MemberDefinition.Metadata.MethodHandle, dt_meta.TypeHandle);
#endif
					}

					state &= ~StateFlags.PendingMetaInflate;
				} else {
					inflatedMetaInfo = MemberDefinition.Metadata;
				}
			}

			if ((state & StateFlags.PendingMakeMethod) != 0) {
				var sre_targs = new MetaType[targs.Length];
				for (int i = 0; i < sre_targs.Length; ++i)
					sre_targs[i] = targs[i].GetMetaInfo ();

				inflatedMetaInfo = ((MethodInfo) inflatedMetaInfo).MakeGenericMethod (sre_targs);
				state &= ~StateFlags.PendingMakeMethod;
			}

			return inflatedMetaInfo;
		}

		public override string GetSignatureForDocumentation ()
		{
			string name;
			switch (Kind) {
			case MemberKind.Constructor:
				name = "#ctor";
				break;
			case MemberKind.Method:
				if (Arity > 0)
					name = Name + "``" + Arity.ToString ();
				else
					name = Name;

				break;
			default:
				name = Name;
				break;
			}

			name = DeclaringType.GetSignatureForDocumentation () + "." + name + parameters.GetSignatureForDocumentation ();
			if (Kind == MemberKind.Operator) {
				var op = Operator.GetType (Name).Value;
				if (op == Operator.OpType.Explicit || op == Operator.OpType.Implicit) {
					name += "~" + ReturnType.GetSignatureForDocumentation ();
				}
			}

			return name;
		}

		public override string GetSignatureForError ()
		{
			string name;
			if (IsConstructor) {
				name = DeclaringType.GetSignatureForError () + "." + DeclaringType.Name;
			} else if (Kind == MemberKind.Operator) {
				var op = Operator.GetType (Name).Value;
				if (op == Operator.OpType.Implicit || op == Operator.OpType.Explicit) {
					name = DeclaringType.GetSignatureForError () + "." + Operator.GetName (op) + " operator " + returnType.GetSignatureForError ();
				} else {
					name = DeclaringType.GetSignatureForError () + ".operator " + Operator.GetName (op);
				}
			} else if (IsAccessor) {
				int split = Name.IndexOf ('_');
				name = Name.Substring (split + 1);
				var postfix = Name.Substring (0, split);
				if (split == 3) {
					var pc = parameters.Count;
					if (pc > 0 && postfix == "get") {
						name = "this" + parameters.GetSignatureForError ("[", "]", pc);
					} else if (pc > 1 && postfix == "set") {
						name = "this" + parameters.GetSignatureForError ("[", "]", pc - 1);
					}
				}

				return DeclaringType.GetSignatureForError () + "." + name + "." + postfix;
			} else {
				name = base.GetSignatureForError ();
				if (targs != null)
					name += "<" + TypeManager.CSharpName (targs) + ">";
				else if (IsGeneric)
					name += "<" + TypeManager.CSharpName (GenericDefinition.TypeParameters) + ">";
			}

			return name + parameters.GetSignatureForError ();
		}

		public override MemberSpec InflateMember (TypeParameterInflator inflator)
		{
			var ms = (MethodSpec) base.InflateMember (inflator);
			ms.inflatedMetaInfo = null;
			ms.returnType = inflator.Inflate (returnType);
			ms.parameters = parameters.Inflate (inflator);
			if (IsGeneric)
				ms.constraints = TypeParameterSpec.InflateConstraints (inflator, Constraints);

			return ms;
		}

		public MethodSpec MakeGenericMethod (IMemberContext context, params TypeSpec[] targs)
		{
			if (targs == null)
				throw new ArgumentNullException ();
// TODO MemberCache
//			if (generic_intances != null && generic_intances.TryGetValue (targs, out ginstance))
//				return ginstance;

			//if (generic_intances == null)
			//    generic_intances = new Dictionary<TypeSpec[], Method> (TypeSpecArrayComparer.Default);

			var inflator = new TypeParameterInflator (context, DeclaringType, GenericDefinition.TypeParameters, targs);

			var inflated = (MethodSpec) MemberwiseClone ();
			inflated.declaringType = inflator.TypeInstance;
			inflated.returnType = inflator.Inflate (returnType);
			inflated.parameters = parameters.Inflate (inflator);
			inflated.targs = targs;
			inflated.constraints = TypeParameterSpec.InflateConstraints (inflator, constraints ?? GenericDefinition.TypeParameters);
			inflated.state |= StateFlags.PendingMakeMethod;

			//			if (inflated.parent == null)
			//				inflated.parent = parent;

			//generic_intances.Add (targs, inflated);
			return inflated;
		}

		public MethodSpec Mutate (TypeParameterMutator mutator)
		{
			var targs = TypeArguments;
			if (targs != null)
				targs = mutator.Mutate (targs);

			var decl = DeclaringType;
			if (DeclaringType.IsGenericOrParentIsGeneric) {
				decl = mutator.Mutate (decl);
			}

			if (targs == TypeArguments && decl == DeclaringType)
				return this;

			var ms = (MethodSpec) MemberwiseClone ();
			if (decl != DeclaringType) {
				ms.inflatedMetaInfo = null;
				ms.declaringType = decl;
				ms.state |= StateFlags.PendingMetaInflate;
			}

			if (targs != null) {
				ms.targs = targs;
				ms.state |= StateFlags.PendingMakeMethod;
			}

			return ms;
		}

		public override List<MissingTypeSpecReference> ResolveMissingDependencies (MemberSpec caller)
		{
			var missing = returnType.ResolveMissingDependencies (this);
			foreach (var pt in parameters.Types) {
				var m = pt.GetMissingDependencies (this);
				if (m == null)
					continue;

				if (missing == null)
					missing = new List<MissingTypeSpecReference> ();

				missing.AddRange (m);
			}

			if (Arity > 0) {
				foreach (var tp in GenericDefinition.TypeParameters) {
					var m = tp.GetMissingDependencies (this);

					if (m == null)
						continue;

					if (missing == null)
						missing = new List<MissingTypeSpecReference> ();

					missing.AddRange (m);
				}
			}

			return missing;			
		}
	}

	public abstract class MethodOrOperator : MethodCore, IMethodData, IMethodDefinition
	{
		ReturnParameter return_attributes;
		SecurityType declarative_security;
		protected MethodData MethodData;

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

		protected MethodOrOperator (TypeDefinition parent, FullNamedExpression type, Modifiers mod, Modifiers allowed_mod, MemberName name,
				Attributes attrs, ParametersCompiled parameters)
			: base (parent, type, mod, allowed_mod, name, attrs, parameters)
		{
		}

		public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
		{
			if (a.Target == AttributeTargets.ReturnValue) {
				if (return_attributes == null)
					return_attributes = new ReturnParameter (this, MethodBuilder, Location);

				return_attributes.ApplyAttributeBuilder (a, ctor, cdata, pa);
				return;
			}

			if (a.Type == pa.MethodImpl) {
				if ((ModFlags & Modifiers.ASYNC) != 0 && (a.GetMethodImplOptions () & MethodImplOptions.Synchronized) != 0) {
					Report.Error (4015, a.Location, "`{0}': Async methods cannot use `MethodImplOptions.Synchronized'",
						GetSignatureForError ());
				}

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

				if (MemberName.IsGeneric || Parent.IsGenericOrParentIsGeneric) {
					Report.Error (7042, a.Location, 
						"The DllImport attribute cannot be applied to a method that is generic or contained in a generic type");
				}

				is_external_implementation = true;
			}

			if (a.IsValidSecurityAttribute ()) {
				a.ExtractSecurityPermissionSet (ctor, ref declarative_security);
				return;
			}

			if (MethodBuilder != null)
				MethodBuilder.SetCustomAttribute ((ConstructorInfo) ctor.GetMetaInfo (), cdata);
		}

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

		MethodBase IMethodDefinition.Metadata {
			get {
				return MethodData.MethodBuilder;
			}
		}

		// TODO: Remove and use MethodData abstraction
		public MethodBuilder MethodBuilder {
			get {
				return MethodData.MethodBuilder;
			}
		}

		protected override bool CheckForDuplications ()
		{
			return Parent.MemberCache.CheckExistingMembersOverloads (this, parameters);
		}

		public virtual EmitContext CreateEmitContext (ILGenerator ig, SourceMethodBuilder sourceMethod)
		{
			return new EmitContext (this, ig, MemberType, sourceMethod);
		}

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

			if (!CheckBase ())
				return false;

			MemberKind kind;
			if (this is Operator)
				kind = MemberKind.Operator;
			else if (this is Destructor)
				kind = MemberKind.Destructor;
			else
				kind = MemberKind.Method;

			string explicit_name;

			if (IsPartialDefinition) {
				caching_flags &= ~Flags.Excluded_Undetected;
				caching_flags |= Flags.Excluded;

				// Add to member cache only when a partial method implementation has not been found yet
				if ((caching_flags & Flags.PartialDefinitionExists) != 0)
					return true;

				if (IsExplicitImpl)
					return true;

				explicit_name = null;
			} else {
				MethodData = new MethodData (this, ModFlags, flags, this, base_method);

				if (!MethodData.Define (Parent.PartialContainer, GetFullName (MemberName)))
					return false;

				explicit_name = MethodData.MetadataName;
			}

			spec = new MethodSpec (kind, Parent.Definition, this, ReturnType, parameters, ModFlags);
			if (MemberName.Arity > 0)
				spec.IsGeneric = true;

			Parent.MemberCache.AddMember (this, explicit_name, spec);

			return true;
		}

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

			CheckAbstractAndExtern (block != null);

			if ((ModFlags & Modifiers.PARTIAL) != 0) {
				for (int i = 0; i < parameters.Count; ++i) {
					IParameterData p = parameters.FixedParameters [i];
					if ((p.ModFlags & Parameter.Modifier.OUT) != 0) {
						Report.Error (752, Location, "`{0}': A partial method parameters cannot use `out' modifier",
							GetSignatureForError ());
					}

					if (p.HasDefaultValue && IsPartialImplementation)
						((Parameter) p).Warning_UselessOptionalParameter (Report);
				}
			}
		}

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

			if (MemberType.IsStatic) {
				Error_StaticReturnType ();
			}
		}

		public override void Emit ()
		{
			if ((ModFlags & Modifiers.COMPILER_GENERATED) != 0 && !Parent.IsCompilerGenerated)
				Module.PredefinedAttributes.CompilerGenerated.EmitAttribute (MethodBuilder);
			if ((ModFlags & Modifiers.DEBUGGER_HIDDEN) != 0)
				Module.PredefinedAttributes.DebuggerHidden.EmitAttribute (MethodBuilder);
			if ((ModFlags & Modifiers.DEBUGGER_STEP_THROUGH) != 0)
				Module.PredefinedAttributes.DebuggerStepThrough.EmitAttribute (MethodBuilder);

			if (ReturnType.BuiltinType == BuiltinTypeSpec.Type.Dynamic) {
				return_attributes = new ReturnParameter (this, MethodBuilder, Location);
				Module.PredefinedAttributes.Dynamic.EmitAttribute (return_attributes.Builder);
			} else if (ReturnType.HasDynamicElement) {
				return_attributes = new ReturnParameter (this, MethodBuilder, Location);
				Module.PredefinedAttributes.Dynamic.EmitAttribute (return_attributes.Builder, ReturnType, Location);
			}

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

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

			if (type_expr != null)
				ConstraintChecker.Check (this, member_type, type_expr.Location);

			base.Emit ();

			if (MethodData != null)
				MethodData.Emit (Parent);

			if (block != null && block.StateMachine is AsyncTaskStorey) {
				var psm = Module.PredefinedAttributes.AsyncStateMachine;
				psm.EmitAttribute (MethodBuilder, block.StateMachine);
			}

			if ((ModFlags & Modifiers.PARTIAL) == 0)
				Block = null;
		}

		protected void Error_ConditionalAttributeIsNotValid ()
		{
			Report.Error (577, Location,
				"Conditional not valid on `{0}' because it is a constructor, destructor, operator or explicit interface implementation",
				GetSignatureForError ());
		}

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

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

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

		#region IMethodData Members

		bool IMethodData.IsAccessor {
			get {
				return false;
			}
		}

		public TypeSpec ReturnType {
			get {
				return MemberType;
			}
		}

		public MemberName MethodName {
			get {
				return MemberName;
			}
		}

		/// <summary>
		/// Returns true if method has conditional attribute and the conditions is not defined (method is excluded).
		/// </summary>
		public override string[] ConditionalConditions ()
		{
			if ((caching_flags & (Flags.Excluded_Undetected | Flags.Excluded)) == 0)
				return null;

			if ((ModFlags & Modifiers.PARTIAL) != 0 && (caching_flags & Flags.Excluded) != 0)
				return new string [0];

			caching_flags &= ~Flags.Excluded_Undetected;
			string[] conditions;

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

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

				conditions = new string[attrs.Length];
				for (int i = 0; i < conditions.Length; ++i)
					conditions[i] = attrs[i].GetConditionalAttributeValue ();
			} else {
				conditions = base_method.MemberDefinition.ConditionalConditions();
			}

			if (conditions != null)
				caching_flags |= Flags.Excluded;

			return conditions;
		}

		#endregion

		public virtual void PrepareEmit ()
		{
			var mb = MethodData.DefineMethodBuilder (Parent);

			if (CurrentTypeParameters != null) {
				string[] gnames = new string[CurrentTypeParameters.Count];
				for (int i = 0; i < gnames.Length; ++i) {
					gnames[i] = CurrentTypeParameters[i].Name;
				}

				var gen_params = MethodBuilder.DefineGenericParameters (gnames);

				for (int i = 0; i < CurrentTypeParameters.Count; ++i) {
					var tp = CurrentTypeParameters[i];

					tp.Define (gen_params[i]);
				}
			}

			//
			// Generic method has been already defined to resolve method parameters
			// correctly when they use type parameters
			//
			mb.SetParameters (parameters.GetMetaInfo ());
			mb.SetReturnType (ReturnType.GetMetaInfo ());
		}

		public override void WriteDebugSymbol (MonoSymbolFile file)
		{
			if (MethodData != null && !IsPartialDefinition)
				MethodData.WriteDebugSymbol (file);
		}
	}

	public class Method : MethodOrOperator, IGenericMethodDefinition
	{
		Method partialMethodImplementation;

		public Method (TypeDefinition parent, FullNamedExpression return_type, Modifiers mod, MemberName name, ParametersCompiled parameters, Attributes attrs)
			: base (parent, return_type, mod,
				parent.PartialContainer.Kind == MemberKind.Interface ? AllowedModifiersInterface :
				parent.PartialContainer.Kind == MemberKind.Struct ? AllowedModifiersStruct | Modifiers.ASYNC :
				AllowedModifiersClass | Modifiers.ASYNC,
				name, attrs, parameters)
		{
		}

		protected Method (TypeDefinition parent, FullNamedExpression return_type, Modifiers mod, Modifiers amod,
					MemberName name, ParametersCompiled parameters, Attributes attrs)
			: base (parent, return_type, mod, amod, name, attrs, parameters)
		{
		}

		#region Properties

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

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

		public int TypeParametersCount {
			get {
				return CurrentTypeParameters == null ? 0 : CurrentTypeParameters.Count;
			}
		}

		#endregion

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

		public static Method Create (TypeDefinition parent, FullNamedExpression returnType, Modifiers mod,
				   MemberName name, ParametersCompiled parameters, Attributes attrs)
		{
			var m = new Method (parent, returnType, mod, name, parameters, attrs);

			if ((mod & Modifiers.PARTIAL) != 0) {
				const Modifiers invalid_partial_mod = Modifiers.AccessibilityMask | Modifiers.ABSTRACT | Modifiers.EXTERN |
					Modifiers.NEW | Modifiers.OVERRIDE | Modifiers.SEALED | Modifiers.VIRTUAL;

				if ((mod & invalid_partial_mod) != 0) {
					m.Report.Error (750, m.Location,
						"A partial method cannot define access modifier or any of abstract, extern, new, override, sealed, or virtual modifiers");
					mod &= ~invalid_partial_mod;
				}

				if ((parent.ModFlags & Modifiers.PARTIAL) == 0) {
					m.Report.Error (751, m.Location, 
						"A partial method must be declared within a partial class or partial struct");
				}
			}

			if ((mod & Modifiers.STATIC) == 0 && parameters.HasExtensionMethodType) {
				m.Report.Error (1105, m.Location, "`{0}': Extension methods must be declared static",
					m.GetSignatureForError ());
			}


			return m;
		}

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

		void Error_DuplicateEntryPoint (Method b)
		{
			Report.Error (17, b.Location,
				"Program `{0}' has more than one entry point defined: `{1}'",
				b.Module.Builder.ScopeName, b.GetSignatureForError ());
		}

		bool IsEntryPoint ()
		{
			if (ReturnType.Kind != MemberKind.Void && ReturnType.BuiltinType != BuiltinTypeSpec.Type.Int)
				return false;

			if (parameters.IsEmpty)
				return true;

			if (parameters.Count > 1)
				return false;

			var ac = parameters.Types [0] as ArrayContainer;
			return ac != null && ac.Rank == 1 && ac.Element.BuiltinType == BuiltinTypeSpec.Type.String &&
					(parameters[0].ModFlags & Parameter.Modifier.RefOutMask) == 0;
		}

		public override 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 base.LookupNamespaceOrType (name, arity, mode, loc);
		}

		public override void ApplyAttributeBuilder (Attribute a, MethodSpec ctor, byte[] cdata, PredefinedAttributes pa)
		{
			if (a.Type == pa.Conditional) {
				if (IsExplicitImpl) {
					Error_ConditionalAttributeIsNotValid ();
					return;
				}

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

				if (ReturnType.Kind != MemberKind.Void) {
					Report.Error (578, Location, "Conditional not valid on `{0}' because its return type is not void", GetSignatureForError ());
					return;
				}

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

				if (MethodData.implementing != null) {
					Report.SymbolRelatedToPreviousError (MethodData.implementing.DeclaringType);
					Report.Error (629, Location, "Conditional member `{0}' cannot implement interface member `{1}'",
						GetSignatureForError (), TypeManager.CSharpSignature (MethodData.implementing));
					return;
				}

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

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

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

		void CreateTypeParameters ()
		{
			var tparams = MemberName.TypeParameters;
			var parent_tparams = Parent.TypeParametersAll;

			for (int i = 0; i < MemberName.Arity; i++) {
				string type_argument_name = tparams[i].MemberName.Name;

				if (block == null) {
					int idx = parameters.GetParameterIndexByName (type_argument_name);
					if (idx >= 0) {
						var b = block;
						if (b == null)
							b = new ToplevelBlock (Compiler, Location);

						b.Error_AlreadyDeclaredTypeParameter (type_argument_name, parameters[i].Location);
					}
				} else {
					INamedBlockVariable variable = null;
					block.GetLocalName (type_argument_name, block, ref variable);
					if (variable != null)
						variable.Block.Error_AlreadyDeclaredTypeParameter (type_argument_name, variable.Location);
				}

				if (parent_tparams != null) {
					var tp = parent_tparams.Find (type_argument_name);
					if (tp != null) {
						tparams[i].WarningParentNameConflict (tp);
					}
				}
			}

			tparams.Create (null, 0, Parent);
		}

		protected virtual void DefineTypeParameters ()
		{
			var tparams = CurrentTypeParameters;

			TypeParameterSpec[] base_tparams = null;
			TypeParameterSpec[] base_decl_tparams = TypeParameterSpec.EmptyTypes;
			TypeSpec[] base_targs = TypeSpec.EmptyTypes;
			if (((ModFlags & Modifiers.OVERRIDE) != 0 || IsExplicitImpl)) {
				MethodSpec base_override = base_method ?? MethodData.implementing;

				if (base_override != null) {
					base_tparams = base_override.GenericDefinition.TypeParameters;

					if (base_override.DeclaringType.IsGeneric) {
						base_decl_tparams = base_override.DeclaringType.MemberDefinition.TypeParameters;

						if (base_method != null) {
							var base_type_parent = CurrentType;
							while (base_type_parent.BaseType != base_override.DeclaringType) {
								base_type_parent = base_type_parent.BaseType;
							}

							base_targs = base_type_parent.BaseType.TypeArguments;
						} else {
							foreach (var iface in Parent.CurrentType.Interfaces) {
								if (iface == base_override.DeclaringType) {
									base_targs = iface.TypeArguments;
									break;
								}
							}
						}
					}

					if (base_override.IsGeneric) {
						ObsoleteAttribute oa;
						foreach (var base_tp in base_tparams) {
							oa = base_tp.BaseType.GetAttributeObsolete ();
							if (oa != null) {
								AttributeTester.Report_ObsoleteMessage (oa, base_tp.BaseType.GetSignatureForError (), Location, Report);
							}

							if (base_tp.InterfacesDefined != null) {
								foreach (var iface in base_tp.InterfacesDefined) {
									oa = iface.GetAttributeObsolete ();
									if (oa != null) {
										AttributeTester.Report_ObsoleteMessage (oa, iface.GetSignatureForError (), Location, Report);
									}
								}
							}
						}

						if (base_decl_tparams.Length != 0) {
							base_decl_tparams = base_decl_tparams.Concat (base_tparams).ToArray ();
							base_targs = base_targs.Concat (tparams.Types).ToArray ();
						} else {
							base_decl_tparams = base_tparams;
							base_targs = tparams.Types;
						}
					}
				}
			}

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

				if (base_tparams == null) {
					tp.ResolveConstraints (this);
					continue;
				}

				//
				// Copy base constraints for override/explicit methods
				//
				var base_tparam = base_tparams [i];
				var local_tparam = tp.Type;
				local_tparam.SpecialConstraint = base_tparam.SpecialConstraint;

				var inflator = new TypeParameterInflator (this, CurrentType, base_decl_tparams, base_targs);
				base_tparam.InflateConstraints (inflator, local_tparam);

				//
				// Check all type argument constraints for possible collision or unification
				// introduced by inflating inherited constraints in this context
				//
				// Conflict example:
				//
				// class A<T> { virtual void Foo<U> () where U : class, T {} }
				// class B : A<int> { override void Foo<U> {} }
				//
				var local_tparam_targs = local_tparam.TypeArguments;
				if (local_tparam_targs != null) {
					for (int ii = 0; ii < local_tparam_targs.Length; ++ii) {
						var ta = local_tparam_targs [ii];
						if (!ta.IsClass && !ta.IsStruct)
							continue;

						TypeSpec[] unique_tparams = null;
						for (int iii = ii + 1; iii < local_tparam_targs.Length; ++iii) {
							//
							// Remove any identical or unified constraint types
							//
							var tparam_checked = local_tparam_targs [iii];
							if (TypeSpecComparer.IsEqual (ta, tparam_checked) || TypeSpec.IsBaseClass (ta, tparam_checked, false)) {
								unique_tparams = new TypeSpec[local_tparam_targs.Length - 1];
								Array.Copy (local_tparam_targs, 0, unique_tparams, 0, iii);
								Array.Copy (local_tparam_targs, iii + 1, unique_tparams, iii, local_tparam_targs.Length - iii - 1);
							} else if (!TypeSpec.IsBaseClass (tparam_checked, ta, false)) {
								Constraints.Error_ConflictingConstraints (this, local_tparam, ta, tparam_checked, Location);
							}
						}

						if (unique_tparams != null) {
							local_tparam_targs = unique_tparams;
							local_tparam.TypeArguments = local_tparam_targs;
							continue;
						}

						Constraints.CheckConflictingInheritedConstraint (local_tparam, ta, this, Location);
					}
				}
			}

			if (base_tparams == null && MethodData != null && MethodData.implementing != null) {
				CheckImplementingMethodConstraints (Parent, spec, MethodData.implementing);
			}
		}

		public static bool CheckImplementingMethodConstraints (TypeContainer container, MethodSpec method, MethodSpec baseMethod)
		{
			var tparams = method.Constraints;
			var base_tparams = baseMethod.Constraints;
			for (int i = 0; i < tparams.Length; ++i) {
				if (!tparams[i].HasSameConstraintsImplementation (base_tparams[i])) {
					container.Compiler.Report.SymbolRelatedToPreviousError (method);
					container.Compiler.Report.SymbolRelatedToPreviousError (baseMethod);

					// Using container location because the interface can be implemented
					// by base class
					var tp = (tparams [i].MemberDefinition as MemberCore) ?? container;
					container.Compiler.Report.Error (425, tp.Location,
						"The constraints for type parameter `{0}' of method `{1}' must match the constraints for type parameter `{2}' of interface method `{3}'. Consider using an explicit interface implementation instead",
						tparams[i].GetSignatureForError (), method.GetSignatureForError (),
						base_tparams[i].GetSignatureForError (), baseMethod.GetSignatureForError ());
 
					return false;
				}
			}

			return true;
		}

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

			if (member_type.Kind == MemberKind.Void && parameters.IsEmpty && MemberName.Arity == 0 && MemberName.Name == Destructor.MetadataName) {
				Report.Warning (465, 1, Location,
					"Introducing `Finalize' method can interfere with destructor invocation. Did you intend to declare a destructor?");
			}

			if (Compiler.Settings.StdLib && ReturnType.IsSpecialRuntimeType) {
				Error1599 (Location, ReturnType, Report);
				return false;
			}

			if (CurrentTypeParameters == null) {
				if (base_method != null && !IsExplicitImpl) {
					if (parameters.Count == 1 && ParameterTypes[0].BuiltinType == BuiltinTypeSpec.Type.Object && MemberName.Name == "Equals")
						Parent.PartialContainer.Mark_HasEquals ();
					else if (parameters.IsEmpty && MemberName.Name == "GetHashCode")
						Parent.PartialContainer.Mark_HasGetHashCode ();
				}
					
			} else {
				DefineTypeParameters ();
			}

			if (block != null) {
				if (block.IsIterator) {
					//
					// Current method is turned into automatically generated
					// wrapper which creates an instance of iterator
					//
					Iterator.CreateIterator (this, Parent.PartialContainer, ModFlags);
					ModFlags |= Modifiers.DEBUGGER_HIDDEN;
				}

				if ((ModFlags & Modifiers.ASYNC) != 0) {
					if (ReturnType.Kind != MemberKind.Void &&
						ReturnType != Module.PredefinedTypes.Task.TypeSpec &&
						!ReturnType.IsGenericTask) {
						Report.Error (1983, Location, "The return type of an async method must be void, Task, or Task<T>");
					}

					block = (ToplevelBlock) block.ConvertToAsyncTask (this, Parent.PartialContainer, parameters, ReturnType, null, Location);
					ModFlags |= Modifiers.DEBUGGER_STEP_THROUGH;
				}

				if (Compiler.Settings.WriteMetadataOnly)
					block = null;
			}

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

			if (parameters.HasExtensionMethodType) {
				if (Parent.PartialContainer.IsStatic && !Parent.IsGenericOrParentIsGeneric) {
					if (!Parent.IsTopLevel)
						Report.Error (1109, Location, "`{0}': Extension methods cannot be defined in a nested class",
							GetSignatureForError ());

					PredefinedAttribute pa = Module.PredefinedAttributes.Extension;
					if (!pa.IsDefined) {
						Report.Error (1110, Location,
							"`{0}': Extension methods require `System.Runtime.CompilerServices.ExtensionAttribute' type to be available. Are you missing an assembly reference?",
							GetSignatureForError ());
					}

					ModFlags |= Modifiers.METHOD_EXTENSION;
					Parent.PartialContainer.ModFlags |= Modifiers.METHOD_EXTENSION;
					Spec.DeclaringType.SetExtensionMethodContainer ();
					Parent.Module.HasExtensionMethod = true;
				} else {
					Report.Error (1106, Location, "`{0}': Extension methods must be defined in a non-generic static class",
						GetSignatureForError ());
				}
			}

			//
			// This is used to track the Entry Point,
			//
			var settings = Compiler.Settings;
			if (settings.NeedsEntryPoint && MemberName.Name == "Main" && !IsPartialDefinition && (settings.MainClass == null || settings.MainClass == Parent.TypeBuilder.FullName)) {
				if (IsEntryPoint ()) {
					if (Parent.DeclaringAssembly.EntryPoint == null) {
						if (Parent.IsGenericOrParentIsGeneric || MemberName.IsGeneric) {
							Report.Warning (402, 4, Location, "`{0}': an entry point cannot be generic or in a generic type",
								GetSignatureForError ());
						} else if ((ModFlags & Modifiers.ASYNC) != 0) {
							Report.Error (4009, Location, "`{0}': an entry point cannot be async method",
								GetSignatureForError ());
						} else {
							SetIsUsed ();
							Parent.DeclaringAssembly.EntryPoint = this;
						}
					} else {
						Error_DuplicateEntryPoint (Parent.DeclaringAssembly.EntryPoint);
						Error_DuplicateEntryPoint (this);
					}
				} else {
					Report.Warning (28, 4, Location, "`{0}' has the wrong signature to be an entry point",
						GetSignatureForError ());
				}
			}

			return true;
		}

		public override void PrepareEmit ()
		{
			if (IsPartialDefinition) {
				//
				// Use partial method implementation builder for partial method declaration attributes
				//
				if (partialMethodImplementation != null) {
					MethodData = partialMethodImplementation.MethodData;
				}

				return;
			}

			base.PrepareEmit ();
		}

		//
		// Emits the code
		// 
		public override void Emit ()
		{
			try {
				if (IsPartialDefinition) {
					if (partialMethodImplementation != null && CurrentTypeParameters != null) {
						CurrentTypeParameters.CheckPartialConstraints (partialMethodImplementation);

						var otp = partialMethodImplementation.CurrentTypeParameters;
						for (int i = 0; i < CurrentTypeParameters.Count; ++i) {
							var tp = CurrentTypeParameters [i];
							tp.Define (otp[i]);
						}
					}

					return;
				}
				
				if ((ModFlags & Modifiers.PARTIAL) != 0 && (caching_flags & Flags.PartialDefinitionExists) == 0) {
					Report.Error (759, Location, "A partial method `{0}' implementation is missing a partial method declaration",
						GetSignatureForError ());
				}

				if (CurrentTypeParameters != null) {
					for (int i = 0; i < CurrentTypeParameters.Count; ++i) {
						var tp = CurrentTypeParameters [i];

						tp.CheckGenericConstraints (false);
						tp.Emit ();
					}
				}

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

				base.Emit ();
			} catch (Exception e) {
				throw new InternalErrorException (this, e);
			}
		}

		public override bool EnableOverloadChecks (MemberCore overload)
		{
			if (overload is Indexer)
				return false;

			return base.EnableOverloadChecks (overload);
		}

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

		protected override bool ResolveMemberType ()
		{
			if (CurrentTypeParameters != null) {
				CreateTypeParameters ();
			}

			return base.ResolveMemberType ();
		}

		public void SetPartialDefinition (Method methodDefinition)
		{
			caching_flags |= Flags.PartialDefinitionExists;
			methodDefinition.partialMethodImplementation = this;

			// Ensure we are always using method declaration parameters
			for (int i = 0; i < methodDefinition.parameters.Count; ++i ) {
				var md_p = methodDefinition.parameters [i];
				var p = parameters [i];
				p.Name = md_p.Name;
				p.DefaultValue = md_p.DefaultValue;
				if (md_p.OptAttributes != null) {
					if (p.OptAttributes == null) {
						p.OptAttributes = md_p.OptAttributes;
					} else {
						p.OptAttributes.Attrs.AddRange (md_p.OptAttributes.Attrs);
					}
				}
			}

			if (methodDefinition.attributes != null) {
				if (attributes == null) {
					attributes = methodDefinition.attributes;
				} else {
					attributes.Attrs.AddRange (methodDefinition.attributes.Attrs);
				}
			}

			if (CurrentTypeParameters != null) {
				for (int i = 0; i < CurrentTypeParameters.Count; ++i) {
					var tp_other = methodDefinition.CurrentTypeParameters [i];
					if (tp_other.OptAttributes == null)
						continue;

					var tp = CurrentTypeParameters [i];
					if (tp.OptAttributes == null) {
						tp.OptAttributes = tp_other.OptAttributes;
					} else {
						tp.OptAttributes.Attrs.AddRange (tp.OptAttributes.Attrs);
					}
				}
			}
		}
	}

	public abstract class ConstructorInitializer : ExpressionStatement
	{
		Arguments argument_list;
		MethodSpec base_ctor;

		protected ConstructorInitializer (Arguments argument_list, Location loc)
		{
			this.argument_list = argument_list;
			this.loc = loc;
		}

		public Arguments Arguments {
			get {
				return argument_list;
			}
		}

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

		public override Expression CreateExpressionTree (ResolveContext ec)
		{
			throw new NotSupportedException ("ET");
		}

		protected override Expression DoResolve (ResolveContext ec)
		{
			eclass = ExprClass.Value;

			// FIXME: Hack
			var caller_builder = (Constructor) ec.MemberContext;

			//
			// Spec mandates that constructor initializer will not have `this' access
			//
			using (ec.Set (ResolveContext.Options.BaseInitializer)) {
				if (argument_list != null) {
					bool dynamic;
					argument_list.Resolve (ec, out dynamic);

					if (dynamic) {
						ec.Report.Error (1975, loc,
							"The constructor call cannot be dynamically dispatched within constructor initializer");

						return null;
					}
				}

				type = ec.CurrentType;
				if (this is ConstructorBaseInitializer) {
					if (ec.CurrentType.BaseType == null)
						return this;

					type = ec.CurrentType.BaseType;
					if (ec.CurrentType.IsStruct) {
						ec.Report.Error (522, loc,
							"`{0}': Struct constructors cannot call base constructors", caller_builder.GetSignatureForError ());
						return this;
					}
				} else {
					//
					// It is legal to have "this" initializers that take no arguments
					// in structs
					//
					// struct D { public D (int a) : this () {}
					//
					if (ec.CurrentType.IsStruct && argument_list == null)
						return this;
				}

				base_ctor = ConstructorLookup (ec, type, ref argument_list, loc);
			}
	
			if (base_ctor != null && base_ctor.MemberDefinition == caller_builder.Spec.MemberDefinition) {
				ec.Report.Error (516, loc, "Constructor `{0}' cannot call itself",
					caller_builder.GetSignatureForError ());
			}

			return this;
		}

		public override void Emit (EmitContext ec)
		{
			//
			// It can be null for struct initializers or System.Object
			//
			if (base_ctor == null) {
				if (type == ec.BuiltinTypes.Object)
					return;

				ec.Emit (OpCodes.Ldarg_0);
				ec.Emit (OpCodes.Initobj, type);
				return;
			}
			
			var call = new CallEmitter ();
			call.InstanceExpression = new CompilerGeneratedThis (type, loc); 
			call.EmitPredefined (ec, base_ctor, argument_list, false);
		}

		public override void EmitStatement (EmitContext ec)
		{
			Emit (ec);
		}

		public override void FlowAnalysis (FlowAnalysisContext fc)
		{
			if (argument_list != null)
				argument_list.FlowAnalysis (fc);
		}
	}

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

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

	public class ConstructorThisInitializer : ConstructorInitializer {
		public ConstructorThisInitializer (Arguments argument_list, Location l) :
			base (argument_list, l)
		{
		}
	}
	
	public class Constructor : MethodCore, IMethodData, IMethodDefinition
	{
		public ConstructorBuilder ConstructorBuilder;
		public ConstructorInitializer Initializer;
		SecurityType declarative_security;
		bool has_compliant_args;
		SourceMethodBuilder debug_builder;

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

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

		public static readonly string ConstructorName = ".ctor";
		public static readonly string TypeConstructorName = ".cctor";

		public Constructor (TypeDefinition parent, string name, Modifiers mod, Attributes attrs, ParametersCompiled args, Location loc)
			: base (parent, null, mod, AllowedModifiers, new MemberName (name, loc), attrs, args)
		{
		}

		public bool HasCompliantArgs {
			get {
				return has_compliant_args;
			}
		}

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

		bool IMethodData.IsAccessor {
		    get {
		        return false;
		    }
		}

		public bool IsPrimaryConstructor { get; set; }
		
		MethodBase IMethodDefinition.Metadata {
			get {
				return ConstructorBuilder;
			}
		}

		//
		// Returns true if this is a default constructor
		//
		public bool IsDefault ()
		{
			if ((ModFlags & Modifiers.STATIC) != 0)
				return parameters.IsEmpty;

			return parameters.IsEmpty &&
					(Initializer is ConstructorBaseInitializer) &&
					(Initializer.Arguments == null);
		}

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

		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.MethodImpl) {
				is_external_implementation = a.IsInternalCall ();
			}

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

		protected override bool CheckBase ()
		{
			if ((ModFlags & Modifiers.STATIC) != 0) {
				if (!parameters.IsEmpty) {
					Report.Error (132, Location, "`{0}': The static constructor must be parameterless",
						GetSignatureForError ());
					return false;
				}

				if ((caching_flags & Flags.MethodOverloadsExist) != 0)
					Parent.MemberCache.CheckExistingMembersOverloads (this, parameters);

				// the rest can be ignored
				return true;
			}

			// Check whether arguments were correct.
			if (!DefineParameters (parameters))
				return false;

			if ((caching_flags & Flags.MethodOverloadsExist) != 0)
				Parent.MemberCache.CheckExistingMembersOverloads (this, parameters);

			if (Parent.PartialContainer.Kind == MemberKind.Struct && parameters.IsEmpty) {
				Report.Error (568, Location, 
					"Structs cannot contain explicit parameterless constructors");
				return false;
			}

			CheckProtectedModifier ();
			
			return true;
		}
		
		//
		// Creates the ConstructorBuilder
		//
		public override bool Define ()
		{
			if (ConstructorBuilder != null)
				return true;

			if (!CheckAbstractAndExtern (block != null))
				return false;
			
			// Check if arguments were correct.
			if (!CheckBase ())
				return false;

			if (Parent.PrimaryConstructorParameters != null && !IsPrimaryConstructor && !IsStatic) {
				if (Parent.Kind == MemberKind.Struct && Initializer is ConstructorThisInitializer && Initializer.Arguments == null) {
					Report.Error (8043, Location, "`{0}': Structs with primary constructor cannot specify default constructor initializer",
						GetSignatureForError ());
				} else if (Initializer == null || Initializer is ConstructorBaseInitializer) {
					Report.Error (8037, Location, "`{0}': Instance constructor of type with primary constructor must specify `this' constructor initializer",
						GetSignatureForError ());
				}
			}

			var ca = ModifiersExtensions.MethodAttr (ModFlags) | MethodAttributes.RTSpecialName | MethodAttributes.SpecialName;

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

			spec = new MethodSpec (MemberKind.Constructor, Parent.Definition, this, Compiler.BuiltinTypes.Void, parameters, ModFlags);
			
			Parent.MemberCache.AddMember (spec);
			
			if (block != null) {
				// It's here only to report an error
				if (block.IsIterator) {
					member_type = Compiler.BuiltinTypes.Void;
					Iterator.CreateIterator (this, Parent.PartialContainer, ModFlags);
				}

				if (Compiler.Settings.WriteMetadataOnly)
					block = null;
			}

			return true;
		}

		//
		// Emits the code
		//
		public o…