//
// anonymous.cs: Support for anonymous methods and types
//
// Author:
//   Miguel de Icaza (miguel@ximain.com)
//   Marek Safar (marek.safar@gmail.com)
//
// Dual licensed under the terms of the MIT X11 or GNU GPL
// Copyright 2003-2011 Novell, Inc.
// Copyright 2011 Xamarin Inc
//

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

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

namespace Mono.CSharp {

	public abstract class CompilerGeneratedContainer : ClassOrStruct
	{
		protected CompilerGeneratedContainer (TypeContainer parent, MemberName name, Modifiers mod)
			: this (parent, name, mod, MemberKind.Class)
		{
		}

		protected CompilerGeneratedContainer (TypeContainer parent, MemberName name, Modifiers mod, MemberKind kind)
			: base (parent, name, null, kind)
		{
			Debug.Assert ((mod & Modifiers.AccessibilityMask) != 0);

			ModFlags = mod | Modifiers.COMPILER_GENERATED | Modifiers.SEALED;
			spec = new TypeSpec (Kind, null, this, null, ModFlags);
		}

		protected void CheckMembersDefined ()
		{
			if (HasMembersDefined)
				throw new InternalErrorException ("Helper class already defined!");
		}

		protected override bool DoDefineMembers ()
		{
			if (Kind == MemberKind.Class && !IsStatic && !PartialContainer.HasInstanceConstructor) {
				DefineDefaultConstructor (false);
			}

			return base.DoDefineMembers ();
		}

		protected static MemberName MakeMemberName (MemberBase host, string name, int unique_id, TypeParameters tparams, Location loc)
		{
			string host_name = host == null ? null : host is InterfaceMemberBase ? ((InterfaceMemberBase)host).GetFullName (host.MemberName) : host.MemberName.Name;
			string tname = MakeName (host_name, "c", name, unique_id);
			TypeParameters args = null;
			if (tparams != null) {
				args = new TypeParameters (tparams.Count);

				// Type parameters will be filled later when we have TypeContainer
				// instance, for now we need only correct arity to create valid name
				for (int i = 0; i < tparams.Count; ++i)
					args.Add ((TypeParameter) null);
			}

			return new MemberName (tname, args, loc);
		}

		public static string MakeName (string host, string typePrefix, string name, int id)
		{
			return "<" + host + ">" + typePrefix + "__" + name + id.ToString ("X");
		}

		protected override TypeSpec[] ResolveBaseTypes (out FullNamedExpression base_class)
		{
			base_type = Compiler.BuiltinTypes.Object;

			base_class = null;
			return null;
		}
	}

	public class HoistedStoreyClass : CompilerGeneratedContainer
	{
		public sealed class HoistedField : Field
		{
			public HoistedField (HoistedStoreyClass parent, FullNamedExpression type, Modifiers mod, string name,
				  Attributes attrs, Location loc)
				: base (parent, type, mod, new MemberName (name, loc), attrs)
			{
			}

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

				HoistedStoreyClass parent = ((HoistedStoreyClass) Parent).GetGenericStorey ();
				if (parent != null && parent.Mutator != null)
					member_type = parent.Mutator.Mutate (MemberType);

				return true;
			}
		}

		protected TypeParameterMutator mutator;

		public HoistedStoreyClass (TypeDefinition parent, MemberName name, TypeParameters tparams, Modifiers mods, MemberKind kind)
			: base (parent, name, mods | Modifiers.PRIVATE, kind)
		{

			if (tparams != null) {
				var type_params = name.TypeParameters;
				var src = new TypeParameterSpec[tparams.Count];
				var dst = new TypeParameterSpec[tparams.Count];

				for (int i = 0; i < tparams.Count; ++i) {
					type_params[i] = tparams[i].CreateHoistedCopy (spec);

					src[i] = tparams[i].Type;
					dst[i] = type_params[i].Type;
				}

				// A copy is not enough, inflate any type parameter constraints
				// using a new type parameters
				var inflator = new TypeParameterInflator (this, null, src, dst);
				for (int i = 0; i < tparams.Count; ++i) {
					src[i].InflateConstraints (inflator, dst[i]);
				}

				mutator = new TypeParameterMutator (tparams, type_params);
			}
		}

		#region Properties

		public TypeParameterMutator Mutator {
			get {
				return mutator;
			}
			set {
				mutator = value;
			}
		}

		#endregion

		public HoistedStoreyClass GetGenericStorey ()
		{
			TypeContainer storey = this;
			while (storey != null && storey.CurrentTypeParameters == null)
				storey = storey.Parent;

			return storey as HoistedStoreyClass;
		}
	}


	//
	// Anonymous method storey is created when an anonymous method uses
	// variable or parameter from outer scope. They are then hoisted to
	// anonymous method storey (captured)
	//
	public class AnonymousMethodStorey : HoistedStoreyClass
	{
		struct StoreyFieldPair
		{
			public readonly AnonymousMethodStorey Storey;
			public readonly Field Field;

			public StoreyFieldPair (AnonymousMethodStorey storey, Field field)
			{
				this.Storey = storey;
				this.Field = field;
			}
		}

		//
		// Needed to delay hoisted _this_ initialization. When an anonymous
		// method is used inside ctor and _this_ is hoisted, base ctor has to
		// be called first, otherwise _this_ will be initialized with 
		// uninitialized value.
		//
		sealed class ThisInitializer : Statement
		{
			readonly HoistedThis hoisted_this;
			readonly AnonymousMethodStorey parent;

			public ThisInitializer (HoistedThis hoisted_this, AnonymousMethodStorey parent)
			{
				this.hoisted_this = hoisted_this;
				this.parent = parent;
			}

			protected override void DoEmit (EmitContext ec)
			{
				Expression source;

				if (parent == null)
					source = new CompilerGeneratedThis (ec.CurrentType, loc);
				else {
					source = new FieldExpr (parent.HoistedThis.Field, Location.Null) {
						InstanceExpression = new CompilerGeneratedThis (ec.CurrentType, Location.Null)
					};
				}

				hoisted_this.EmitAssign (ec, source, false, false);
			}

			protected override bool DoFlowAnalysis (FlowAnalysisContext fc)
			{
				return false;
			}

			protected override void CloneTo (CloneContext clonectx, Statement target)
			{
				// Nothing to clone
			}
		}

		// Unique storey ID
		public readonly int ID;

		public readonly ExplicitBlock OriginalSourceBlock;

		// A list of StoreyFieldPair with local field keeping parent storey instance
		List<StoreyFieldPair> used_parent_storeys;
		List<ExplicitBlock> children_references;

		// A list of hoisted parameters
		protected List<HoistedParameter> hoisted_params;
		List<HoistedParameter> hoisted_local_params;
		protected List<HoistedVariable> hoisted_locals;

		// Hoisted this
		protected HoistedThis hoisted_this;

		// Local variable which holds this storey instance
		public Expression Instance;

		bool initialize_hoisted_this;
		AnonymousMethodStorey hoisted_this_parent;

		public AnonymousMethodStorey (ExplicitBlock block, TypeDefinition parent, MemberBase host, TypeParameters tparams, string name, MemberKind kind)
			: base (parent, MakeMemberName (host, name, parent.PartialContainer.CounterAnonymousContainers, tparams, block.StartLocation),
				tparams, 0, kind)
		{
			OriginalSourceBlock = block;
			ID = parent.PartialContainer.CounterAnonymousContainers++;
		}

		public void AddCapturedThisField (EmitContext ec, AnonymousMethodStorey parent)
		{
			TypeExpr type_expr = new TypeExpression (ec.CurrentType, Location);
			Field f = AddCompilerGeneratedField ("$this", type_expr);
			hoisted_this = new HoistedThis (this, f);

			initialize_hoisted_this = true;
			hoisted_this_parent = parent;
		}

		public Field AddCapturedVariable (string name, TypeSpec type)
		{
			CheckMembersDefined ();

			FullNamedExpression field_type = new TypeExpression (type, Location);
			if (!spec.IsGenericOrParentIsGeneric)
				return AddCompilerGeneratedField (name, field_type);

			const Modifiers mod = Modifiers.INTERNAL | Modifiers.COMPILER_GENERATED;
			Field f = new HoistedField (this, field_type, mod, name, null, Location);
			AddField (f);
			return f;
		}

		protected Field AddCompilerGeneratedField (string name, FullNamedExpression type)
		{
			return AddCompilerGeneratedField (name, type, false);
		}

		protected Field AddCompilerGeneratedField (string name, FullNamedExpression type, bool privateAccess)
		{
			Modifiers mod = Modifiers.COMPILER_GENERATED | (privateAccess ? Modifiers.PRIVATE : Modifiers.INTERNAL);
			Field f = new Field (this, type, mod, new MemberName (name, Location), null);
			AddField (f);
			return f;
		}

		//
		// Creates a link between hoisted variable block and the anonymous method storey
		//
		// An anonymous method can reference variables from any outer block, but they are
		// hoisted in their own ExplicitBlock. When more than one block is referenced we
		// need to create another link between those variable storeys
		//
		public void AddReferenceFromChildrenBlock (ExplicitBlock block)
		{
			if (children_references == null)
				children_references = new List<ExplicitBlock> ();

			if (!children_references.Contains (block))
				children_references.Add (block);
		}

		public void AddParentStoreyReference (EmitContext ec, AnonymousMethodStorey storey)
		{
			CheckMembersDefined ();

			if (used_parent_storeys == null)
				used_parent_storeys = new List<StoreyFieldPair> ();
			else if (used_parent_storeys.Exists (i => i.Storey == storey))
				return;

			TypeExpr type_expr = storey.CreateStoreyTypeExpression (ec);
			Field f = AddCompilerGeneratedField ("<>f__ref$" + storey.ID, type_expr);
			used_parent_storeys.Add (new StoreyFieldPair (storey, f));
		}

		public void CaptureLocalVariable (ResolveContext ec, LocalVariable localVariable)
		{
			if (this is StateMachine) {
				if (ec.CurrentBlock.ParametersBlock != localVariable.Block.ParametersBlock)
					ec.CurrentBlock.Explicit.HasCapturedVariable = true;
			} else {
				ec.CurrentBlock.Explicit.HasCapturedVariable = true;
			}

			var hoisted = localVariable.HoistedVariant;
			if (hoisted != null && hoisted.Storey != this && hoisted.Storey is StateMachine) {
				//
				// Variable is already hoisted but we need it in storey which can be shared
				//
				hoisted.Storey.hoisted_locals.Remove (hoisted);
				hoisted.Storey.Members.Remove (hoisted.Field);
				hoisted = null;
			}

			if (hoisted == null) {
				hoisted = new HoistedLocalVariable (this, localVariable, GetVariableMangledName (localVariable));
				localVariable.HoistedVariant = hoisted;

				if (hoisted_locals == null)
					hoisted_locals = new List<HoistedVariable> ();

				hoisted_locals.Add (hoisted);
			}

			if (ec.CurrentBlock.Explicit != localVariable.Block.Explicit && !(hoisted.Storey is StateMachine))
				hoisted.Storey.AddReferenceFromChildrenBlock (ec.CurrentBlock.Explicit);
		}

		public void CaptureParameter (ResolveContext ec, ParametersBlock.ParameterInfo parameterInfo, ParameterReference parameterReference)
		{
			if (!(this is StateMachine)) {
				ec.CurrentBlock.Explicit.HasCapturedVariable = true;
			}

			var hoisted = parameterInfo.Parameter.HoistedVariant;

			if (parameterInfo.Block.StateMachine != null) {
				//
				// Another storey in same block exists but state machine does not
				// have parameter captured. We need to add it there as well to
				// proxy parameter value correctly.
				//
				if (hoisted == null && parameterInfo.Block.StateMachine != this) {
					var storey = parameterInfo.Block.StateMachine;

					hoisted = new HoistedParameter (storey, parameterReference);
					parameterInfo.Parameter.HoistedVariant = hoisted;

					if (storey.hoisted_params == null)
						storey.hoisted_params = new List<HoistedParameter> ();

					storey.hoisted_params.Add (hoisted);
				}

				//
				// Lift captured parameter from value type storey to reference type one. Otherwise
				// any side effects would be done on a copy
				//
				if (hoisted != null && hoisted.Storey != this && hoisted.Storey is StateMachine) {
					if (hoisted_local_params == null)
						hoisted_local_params = new List<HoistedParameter> ();

					hoisted_local_params.Add (hoisted);
					hoisted = null;
				}
			}

			if (hoisted == null) {
				hoisted = new HoistedParameter (this, parameterReference);
				parameterInfo.Parameter.HoistedVariant = hoisted;

				if (hoisted_params == null)
					hoisted_params = new List<HoistedParameter> ();

				hoisted_params.Add (hoisted);
			}

			//
			// Register link between current block and parameter storey. It will
			// be used when setting up storey definition to deploy storey reference
			// when parameters are used from multiple blocks
			//
			if (ec.CurrentBlock.Explicit != parameterInfo.Block) {
				hoisted.Storey.AddReferenceFromChildrenBlock (ec.CurrentBlock.Explicit);
			}
		}

		TypeExpr CreateStoreyTypeExpression (EmitContext ec)
		{
			//
			// Create an instance of storey type
			//
			TypeExpr storey_type_expr;
			if (CurrentTypeParameters != null) {
				//
				// Use current method type parameter (MVAR) for top level storey only. All
				// nested storeys use class type parameter (VAR)
				//
				var tparams = ec.CurrentAnonymousMethod != null && ec.CurrentAnonymousMethod.Storey != null ?
					ec.CurrentAnonymousMethod.Storey.CurrentTypeParameters :
					ec.CurrentTypeParameters;

				TypeArguments targs = new TypeArguments ();

				//
				// Use type parameter name instead of resolved type parameter
				// specification to resolve to correctly nested type parameters
				//
				for (int i = 0; i < tparams.Count; ++i)
					targs.Add (new SimpleName (tparams [i].Name, Location)); //  new TypeParameterExpr (tparams[i], Location));

				storey_type_expr = new GenericTypeExpr (Definition, targs, Location);
			} else {
				storey_type_expr = new TypeExpression (CurrentType, Location);
			}

			return storey_type_expr;
		}

		public void SetNestedStoryParent (AnonymousMethodStorey parentStorey)
		{
			Parent = parentStorey;
			spec.IsGeneric = false;
			spec.DeclaringType = parentStorey.CurrentType;
			MemberName.TypeParameters = null;
		}

		protected override bool DoResolveTypeParameters ()
		{
			// Although any storey can have type parameters they are all clones of method type
			// parameters therefore have to mutate MVAR references in any of cloned constraints
			if (CurrentTypeParameters != null) {
				for (int i = 0; i < CurrentTypeParameters.Count; ++i) {
					var spec = CurrentTypeParameters[i].Type;
					spec.BaseType = mutator.Mutate (spec.BaseType);
					if (spec.InterfacesDefined != null) {
						var mutated = new TypeSpec[spec.InterfacesDefined.Length];
						for (int ii = 0; ii < mutated.Length; ++ii) {
							mutated[ii] = mutator.Mutate (spec.InterfacesDefined[ii]);
						}

						spec.InterfacesDefined = mutated;
					}

					if (spec.TypeArguments != null) {
						spec.TypeArguments = mutator.Mutate (spec.TypeArguments);
					}
				}
			}

			//
			// Update parent cache as we most likely passed the point
			// where the cache was constructed
			//
			Parent.CurrentType.MemberCache.AddMember (this.spec);

			return true;
		}

		//
		// Initializes all hoisted variables
		//
		public void EmitStoreyInstantiation (EmitContext ec, ExplicitBlock block)
		{
			// There can be only one instance variable for each storey type
			if (Instance != null)
				throw new InternalErrorException ();

			//
			// Create an instance of this storey
			//
			ResolveContext rc = new ResolveContext (ec.MemberContext);
			rc.CurrentBlock = block;

			var storey_type_expr = CreateStoreyTypeExpression (ec);
			var source = new New (storey_type_expr, null, Location).Resolve (rc);

			//
			// When the current context is async (or iterator) lift local storey
			// instantiation to the currect storey
			//
			if (ec.CurrentAnonymousMethod is StateMachineInitializer && (block.HasYield || block.HasAwait)) {
				//
				// Unfortunately, normal capture mechanism could not be used because we are
				// too late in the pipeline and standart assign cannot be used either due to
				// recursive nature of GetStoreyInstanceExpression
				//
				var field = ec.CurrentAnonymousMethod.Storey.AddCompilerGeneratedField (
					LocalVariable.GetCompilerGeneratedName (block), storey_type_expr, true);

				field.Define ();
				field.Emit ();

				var fexpr = new FieldExpr (field, Location);
				fexpr.InstanceExpression = new CompilerGeneratedThis (ec.CurrentType, Location);
				fexpr.EmitAssign (ec, source, false, false);
				Instance = fexpr;
			} else {
				var local = TemporaryVariableReference.Create (source.Type, block, Location);
				if (source.Type.IsStruct) {
					local.LocalInfo.CreateBuilder (ec);
				} else {
					local.EmitAssign (ec, source);
				}

				Instance = local;
			}

			EmitHoistedFieldsInitialization (rc, ec);

			// TODO: Implement properly
			//SymbolWriter.DefineScopeVariable (ID, Instance.Builder);
		}

		void EmitHoistedFieldsInitialization (ResolveContext rc, EmitContext ec)
		{
			//
			// Initialize all storey reference fields by using local or hoisted variables
			//
			if (used_parent_storeys != null) {
				foreach (StoreyFieldPair sf in used_parent_storeys) {
					//
					// Get instance expression of storey field
					//
					Expression instace_expr = GetStoreyInstanceExpression (ec);
					var fs = sf.Field.Spec;
					if (TypeManager.IsGenericType (instace_expr.Type))
						fs = MemberCache.GetMember (instace_expr.Type, fs);

					FieldExpr f_set_expr = new FieldExpr (fs, Location);
					f_set_expr.InstanceExpression = instace_expr;

					// TODO: CompilerAssign expression
					SimpleAssign a = new SimpleAssign (f_set_expr, sf.Storey.GetStoreyInstanceExpression (ec));
					if (a.Resolve (rc) != null)
						a.EmitStatement (ec);
				}
			}

			//
			// Initialize hoisted `this' only once, everywhere else will be
			// referenced indirectly
			//
			if (initialize_hoisted_this) {
				rc.CurrentBlock.AddScopeStatement (new ThisInitializer (hoisted_this, hoisted_this_parent));
			}

			//
			// Setting currect anonymous method to null blocks any further variable hoisting
			//
			AnonymousExpression ae = ec.CurrentAnonymousMethod;
			ec.CurrentAnonymousMethod = null;

			if (hoisted_params != null) {
				EmitHoistedParameters (ec, hoisted_params);
			}

			ec.CurrentAnonymousMethod = ae;
		}

		protected virtual void EmitHoistedParameters (EmitContext ec, List<HoistedParameter> hoisted)
		{
			foreach (HoistedParameter hp in hoisted) {
				if (hp == null)
					continue;

				//
				// Parameters could be proxied via local fields for value type storey
				//
				if (hoisted_local_params != null) {
					var local_param = hoisted_local_params.Find (l => l.Parameter.Parameter == hp.Parameter.Parameter);
					var source = new FieldExpr (local_param.Field, Location);
					source.InstanceExpression = new CompilerGeneratedThis (CurrentType, Location);
					hp.EmitAssign (ec, source, false, false);
					continue;
				}

				hp.EmitHoistingAssignment (ec);
			}
		}

		//
		// Returns a field which holds referenced storey instance
		//
		Field GetReferencedStoreyField (AnonymousMethodStorey storey)
		{
			if (used_parent_storeys == null)
				return null;

			foreach (StoreyFieldPair sf in used_parent_storeys) {
				if (sf.Storey == storey)
					return sf.Field;
			}

			return null;
		}

		//
		// Creates storey instance expression regardless of currect IP
		//
		public Expression GetStoreyInstanceExpression (EmitContext ec)
		{
			AnonymousExpression am = ec.CurrentAnonymousMethod;

			//
			// Access from original block -> storey
			//
			if (am == null)
				return Instance;

			//
			// Access from anonymous method implemented as a static -> storey
			//
			if (am.Storey == null)
				return Instance;

			Field f = am.Storey.GetReferencedStoreyField (this);
			if (f == null) {
				if (am.Storey == this) {
					//
					// Access from inside of same storey (S -> S)
					//
					return new CompilerGeneratedThis (CurrentType, Location);
				}

				//
				// External field access
				//
				return Instance;
			}

			//
			// Storey was cached to local field
			//
			FieldExpr f_ind = new FieldExpr (f, Location);
			f_ind.InstanceExpression = new CompilerGeneratedThis (CurrentType, Location);
			return f_ind;
		}

		protected virtual string GetVariableMangledName (LocalVariable local_info)
		{
			//
			// No need to mangle anonymous method hoisted variables cause they
			// are hoisted in their own scopes
			//
			return local_info.Name;
		}

		public HoistedThis HoistedThis {
			get {
				return hoisted_this;
			}
			set {
				hoisted_this = value;
			}
		}

		public IList<ExplicitBlock> ReferencesFromChildrenBlock {
			get { return children_references; }
		}
	}

	public abstract class HoistedVariable
	{
		//
		// Hoisted version of variable references used in expression
		// tree has to be delayed until we know its location. The variable
		// doesn't know its location until all stories are calculated
		//
		class ExpressionTreeVariableReference : Expression
		{
			readonly HoistedVariable hv;

			public ExpressionTreeVariableReference (HoistedVariable hv)
			{
				this.hv = hv;
			}

			public override bool ContainsEmitWithAwait ()
			{
				return false;
			}

			public override Expression CreateExpressionTree (ResolveContext ec)
			{
				return hv.CreateExpressionTree ();
			}

			protected override Expression DoResolve (ResolveContext ec)
			{
				eclass = ExprClass.Value;
				type = ec.Module.PredefinedTypes.Expression.Resolve ();
				return this;
			}

			public override void Emit (EmitContext ec)
			{
				ResolveContext rc = new ResolveContext (ec.MemberContext);
				Expression e = hv.GetFieldExpression (ec).CreateExpressionTree (rc, false);
				// This should never fail
				e = e.Resolve (rc);
				if (e != null)
					e.Emit (ec);
			}
		}
	
		protected readonly AnonymousMethodStorey storey;
		protected Field field;
		Dictionary<AnonymousExpression, FieldExpr> cached_inner_access; // TODO: Hashtable is too heavyweight
		FieldExpr cached_outer_access;

		protected HoistedVariable (AnonymousMethodStorey storey, string name, TypeSpec type)
			: this (storey, storey.AddCapturedVariable (name, type))
		{
		}

		protected HoistedVariable (AnonymousMethodStorey storey, Field field)
		{
			this.storey = storey;
			this.field = field;
		}

		public Field Field {
			get {
				return field;
			}
		}

		public AnonymousMethodStorey Storey {
			get {
				return storey;
			}
		}

		public void AddressOf (EmitContext ec, AddressOp mode)
		{
			GetFieldExpression (ec).AddressOf (ec, mode);
		}

		public Expression CreateExpressionTree ()
		{
			return new ExpressionTreeVariableReference (this);
		}

		public void Emit (EmitContext ec)
		{
			GetFieldExpression (ec).Emit (ec);
		}

		public Expression EmitToField (EmitContext ec)
		{
			return GetFieldExpression (ec);
		}

		//
		// Creates field access expression for hoisted variable
		//
		protected virtual FieldExpr GetFieldExpression (EmitContext ec)
		{
			if (ec.CurrentAnonymousMethod == null || ec.CurrentAnonymousMethod.Storey == null) {
				if (cached_outer_access != null)
					return cached_outer_access;

				//
				// When setting top-level hoisted variable in generic storey
				// change storey generic types to method generic types (VAR -> MVAR)
				//
				if (storey.Instance.Type.IsGenericOrParentIsGeneric) {
					var fs = MemberCache.GetMember (storey.Instance.Type, field.Spec);
					cached_outer_access = new FieldExpr (fs, field.Location);
				} else {
					cached_outer_access = new FieldExpr (field, field.Location);
				}

				cached_outer_access.InstanceExpression = storey.GetStoreyInstanceExpression (ec);
				return cached_outer_access;
			}

			FieldExpr inner_access;
			if (cached_inner_access != null) {
				if (!cached_inner_access.TryGetValue (ec.CurrentAnonymousMethod, out inner_access))
					inner_access = null;
			} else {
				inner_access = null;
				cached_inner_access = new Dictionary<AnonymousExpression, FieldExpr> (4);
			}

			if (inner_access == null) {
				if (field.Parent.IsGenericOrParentIsGeneric) {
					var fs = MemberCache.GetMember (field.Parent.CurrentType, field.Spec);
					inner_access = new FieldExpr (fs, field.Location);
				} else {
					inner_access = new FieldExpr (field, field.Location);
				}

				inner_access.InstanceExpression = storey.GetStoreyInstanceExpression (ec);
				cached_inner_access.Add (ec.CurrentAnonymousMethod, inner_access);
			}

			return inner_access;
		}

		public void Emit (EmitContext ec, bool leave_copy)
		{
			GetFieldExpression (ec).Emit (ec, leave_copy);
		}

		public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool isCompound)
		{
			GetFieldExpression (ec).EmitAssign (ec, source, leave_copy, false);
		}
	}

	public class HoistedParameter : HoistedVariable
	{
		sealed class HoistedFieldAssign : CompilerAssign
		{
			public HoistedFieldAssign (Expression target, Expression source)
				: base (target, source, target.Location)
			{
			}

			protected override Expression ResolveConversions (ResolveContext ec)
			{
				//
				// Implicit conversion check fails for hoisted type arguments
				// as they are of different types (!!0 x !0)
				//
				return this;
			}
		}

		readonly ParameterReference parameter;

		public HoistedParameter (AnonymousMethodStorey scope, ParameterReference par)
			: base (scope, par.Name, par.Type)
		{
			this.parameter = par;
		}

		public HoistedParameter (HoistedParameter hp, string name)
			: base (hp.storey, name, hp.parameter.Type)
		{
			this.parameter = hp.parameter;
		}

		#region Properties

		public bool IsAssigned { get; set; }

		public ParameterReference Parameter {
			get {
				return parameter;
			}
		}

		#endregion

		public void EmitHoistingAssignment (EmitContext ec)
		{
			//
			// Remove hoisted redirection to emit assignment from original parameter
			//
			var temp = parameter.Parameter.HoistedVariant;
			parameter.Parameter.HoistedVariant = null;

			var a = new HoistedFieldAssign (GetFieldExpression (ec), parameter);
			a.EmitStatement (ec);

			parameter.Parameter.HoistedVariant = temp;
		}
	}

	class HoistedLocalVariable : HoistedVariable
	{
		public HoistedLocalVariable (AnonymousMethodStorey storey, LocalVariable local, string name)
			: base (storey, name, local.Type)
		{
		}
	}

	public class HoistedThis : HoistedVariable
	{
		public HoistedThis (AnonymousMethodStorey storey, Field field)
			: base (storey, field)
		{
		}
	}

	//
	// Anonymous method expression as created by parser
	//
	public class AnonymousMethodExpression : Expression
	{
		//
		// Special conversion for nested expression tree lambdas
		//
		class Quote : ShimExpression
		{
			public Quote (Expression expr)
				: base (expr)
			{
			}

			public override Expression CreateExpressionTree (ResolveContext ec)
			{
				var args = new Arguments (1);
				args.Add (new Argument (expr.CreateExpressionTree (ec)));
				return CreateExpressionFactoryCall (ec, "Quote", args);
			}

			protected override Expression DoResolve (ResolveContext rc)
			{
				expr = expr.Resolve (rc);
				if (expr == null)
					return null;

				eclass = expr.eclass;
				type = expr.Type;
				return this;
			}
		}

		readonly Dictionary<TypeSpec, Expression> compatibles;

		public ParametersBlock Block;

		public AnonymousMethodExpression (Location loc)
		{
			this.loc = loc;
			this.compatibles = new Dictionary<TypeSpec, Expression> ();
		}

		#region Properties

		public override string ExprClassName {
			get {
				return "anonymous method";
			}
		}

		public virtual bool HasExplicitParameters {
			get {
				return Parameters != ParametersCompiled.Undefined;
			}
		}

		public override bool IsSideEffectFree {
			get {
				return true;
			}
		}

		public ParametersCompiled Parameters {
			get {
				return Block.Parameters;
			}
		}

		public bool IsAsync {
			get;
			internal set;
		}

		public ReportPrinter TypeInferenceReportPrinter {
			get; set;
		}

		#endregion

		//
		// Returns true if the body of lambda expression can be implicitly
		// converted to the delegate of type `delegate_type'
		//
		public bool ImplicitStandardConversionExists (ResolveContext ec, TypeSpec delegate_type)
		{
			using (ec.With (ResolveContext.Options.InferReturnType, false)) {
				using (ec.Set (ResolveContext.Options.ProbingMode)) {
					var prev = ec.Report.SetPrinter (TypeInferenceReportPrinter ?? new NullReportPrinter ());

					var res = Compatible (ec, delegate_type) != null;

					ec.Report.SetPrinter (prev);

					return res;
				}
			}
		}

		TypeSpec CompatibleChecks (ResolveContext ec, TypeSpec delegate_type)
		{
			if (delegate_type.IsDelegate)
				return delegate_type;

			if (delegate_type.IsExpressionTreeType) {
				delegate_type = delegate_type.TypeArguments [0];
				if (delegate_type.IsDelegate)
					return delegate_type;

				ec.Report.Error (835, loc, "Cannot convert `{0}' to an expression tree of non-delegate type `{1}'",
					GetSignatureForError (), delegate_type.GetSignatureForError ());
				return null;
			}

			ec.Report.Error (1660, loc, "Cannot convert `{0}' to non-delegate type `{1}'",
				      GetSignatureForError (), delegate_type.GetSignatureForError ());
			return null;
		}

		protected bool VerifyExplicitParameters (ResolveContext ec, TypeInferenceContext tic, TypeSpec delegate_type, AParametersCollection parameters)
		{
			if (VerifyParameterCompatibility (ec, tic, delegate_type, parameters, ec.IsInProbingMode))
				return true;

			if (!ec.IsInProbingMode)
				ec.Report.Error (1661, loc,
					"Cannot convert `{0}' to delegate type `{1}' since there is a parameter mismatch",
					GetSignatureForError (), delegate_type.GetSignatureForError ());

			return false;
		}

		protected bool VerifyParameterCompatibility (ResolveContext ec, TypeInferenceContext tic, TypeSpec delegate_type, AParametersCollection invoke_pd, bool ignore_errors)
		{
			if (Parameters.Count != invoke_pd.Count) {
				if (ignore_errors)
					return false;
				
				ec.Report.Error (1593, loc, "Delegate `{0}' does not take `{1}' arguments",
					      delegate_type.GetSignatureForError (), Parameters.Count.ToString ());
				return false;
			}

			bool has_implicit_parameters = !HasExplicitParameters;
			bool error = false;

			for (int i = 0; i < Parameters.Count; ++i) {
				Parameter.Modifier p_mod = invoke_pd.FixedParameters [i].ModFlags;
				if (Parameters.FixedParameters [i].ModFlags != p_mod && p_mod != Parameter.Modifier.PARAMS) {
					if (ignore_errors)
						return false;
					
					if (p_mod == Parameter.Modifier.NONE)
						ec.Report.Error (1677, Parameters[i].Location, "Parameter `{0}' should not be declared with the `{1}' keyword",
							      (i + 1).ToString (), Parameter.GetModifierSignature (Parameters [i].ModFlags));
					else
						ec.Report.Error (1676, Parameters[i].Location, "Parameter `{0}' must be declared with the `{1}' keyword",
							      (i+1).ToString (), Parameter.GetModifierSignature (p_mod));
					error = true;
				}

				if (has_implicit_parameters)
					continue;

				TypeSpec type = invoke_pd.Types [i];

				if (tic != null)
					type = tic.InflateGenericArgument (ec, type);
				
				if (!TypeSpecComparer.IsEqual (type, Parameters.Types [i])) {
					if (ignore_errors)
						return false;
					
					ec.Report.Error (1678, Parameters [i].Location, "Parameter `{0}' is declared as type `{1}' but should be `{2}'",
						      (i+1).ToString (),
						      Parameters.Types [i].GetSignatureForError (),
						      invoke_pd.Types [i].GetSignatureForError ());
					error = true;
				}
			}

			return !error;
		}

		//
		// Infers type arguments based on explicit arguments
		//
		public bool ExplicitTypeInference (TypeInferenceContext type_inference, TypeSpec delegate_type)
		{
			if (!HasExplicitParameters)
				return false;

			if (!delegate_type.IsDelegate) {
				if (!delegate_type.IsExpressionTreeType)
					return false;

				delegate_type = TypeManager.GetTypeArguments (delegate_type) [0];
				if (!delegate_type.IsDelegate)
					return false;
			}
			
			AParametersCollection d_params = Delegate.GetParameters (delegate_type);
			if (d_params.Count != Parameters.Count)
				return false;

			var ptypes = Parameters.Types;
			var dtypes = d_params.Types;
			for (int i = 0; i < Parameters.Count; ++i) {
				if (type_inference.ExactInference (ptypes[i], dtypes[i]) == 0) {
					//
					// Continue when 0 (quick path) does not mean inference failure. Checking for
					// same type handles cases like int -> int
					//
					if (ptypes[i] == dtypes[i])
						continue;

					return false;
				}
			}

			return true;
		}

		public TypeSpec InferReturnType (ResolveContext ec, TypeInferenceContext tic, TypeSpec delegate_type)
		{
			Expression expr;
			AnonymousExpression am;

			if (compatibles.TryGetValue (delegate_type, out expr)) {
				am = expr as AnonymousExpression;
				return am == null ? null : am.ReturnType;
			}

			using (ec.Set (ResolveContext.Options.ProbingMode | ResolveContext.Options.InferReturnType)) {
				ReportPrinter prev;
				if (TypeInferenceReportPrinter != null) {
					prev = ec.Report.SetPrinter (TypeInferenceReportPrinter);
				} else {
					prev = null;
				}

				var body = CompatibleMethodBody (ec, tic, null, delegate_type);
				if (body != null) {
					am = body.Compatible (ec, body);
				} else {
					am = null;
				}

				if (TypeInferenceReportPrinter != null) {
					ec.Report.SetPrinter (prev);
				}
			}

			if (am == null)
				return null;

//			compatibles.Add (delegate_type, am);
			return am.ReturnType;
		}

		public override bool ContainsEmitWithAwait ()
		{
			return false;
		}

		//
		// Returns AnonymousMethod container if this anonymous method
		// expression can be implicitly converted to the delegate type `delegate_type'
		//
		public Expression Compatible (ResolveContext ec, TypeSpec type)
		{
			Expression am;
			if (compatibles.TryGetValue (type, out am))
				return am;

			TypeSpec delegate_type = CompatibleChecks (ec, type);
			if (delegate_type == null)
				return null;

			//
			// At this point its the first time we know the return type that is 
			// needed for the anonymous method.  We create the method here.
			//

			var invoke_mb = Delegate.GetInvokeMethod (delegate_type);
			TypeSpec return_type = invoke_mb.ReturnType;

			//
			// Second: the return type of the delegate must be compatible with 
			// the anonymous type.   Instead of doing a pass to examine the block
			// we satisfy the rule by setting the return type on the EmitContext
			// to be the delegate type return type.
			//

			var body = CompatibleMethodBody (ec, null, return_type, delegate_type);
			if (body == null)
				return null;

			bool etree_conversion = delegate_type != type;

			try {
				if (etree_conversion) {
					if (ec.HasSet (ResolveContext.Options.ExpressionTreeConversion)) {
						//
						// Nested expression tree lambda use same scope as parent
						// lambda, this also means no variable capturing between this
						// and parent scope
						//
						am = body.Compatible (ec, ec.CurrentAnonymousMethod);

						//
						// Quote nested expression tree
						//
						if (am != null)
							am = new Quote (am);
					} else {
						int errors = ec.Report.Errors;

						if (Block.IsAsync) {
							ec.Report.Error (1989, loc, "Async lambda expressions cannot be converted to expression trees");
						}

						using (ec.Set (ResolveContext.Options.ExpressionTreeConversion)) {
							am = body.Compatible (ec);
						}

						//
						// Rewrite expressions into expression tree when targeting Expression<T>
						//
						if (am != null && errors == ec.Report.Errors)
							am = CreateExpressionTree (ec, delegate_type);
					}
				} else {
					am = body.Compatible (ec);

					if (body.DirectMethodGroupConversion != null) {
						var errors_printer = new SessionReportPrinter ();
						var old = ec.Report.SetPrinter (errors_printer);
						var expr = new ImplicitDelegateCreation (delegate_type, body.DirectMethodGroupConversion, loc) {
							AllowSpecialMethodsInvocation = true
						}.Resolve (ec);
						ec.Report.SetPrinter (old);
						if (expr != null && errors_printer.ErrorsCount == 0)
							am = expr;
					}
				}
			} catch (CompletionResult) {
				throw;
			} catch (FatalException) {
				throw;
			} catch (Exception e) {
				throw new InternalErrorException (e, loc);
			}

			if (!ec.IsInProbingMode && !etree_conversion) {
				compatibles.Add (type, am ?? EmptyExpression.Null);
			}

			return am;
		}

		protected virtual Expression CreateExpressionTree (ResolveContext ec, TypeSpec delegate_type)
		{
			return CreateExpressionTree (ec);
		}

		public override Expression CreateExpressionTree (ResolveContext ec)
		{
			ec.Report.Error (1946, loc, "An anonymous method cannot be converted to an expression tree");
			return null;
		}

		protected virtual ParametersCompiled ResolveParameters (ResolveContext ec, TypeInferenceContext tic, TypeSpec delegate_type)
		{
			var delegate_parameters = Delegate.GetParameters (delegate_type);

			if (Parameters == ParametersCompiled.Undefined) {
				//
				// We provide a set of inaccessible parameters
				//
				Parameter[] fixedpars = new Parameter[delegate_parameters.Count];

				for (int i = 0; i < delegate_parameters.Count; i++) {
					Parameter.Modifier i_mod = delegate_parameters.FixedParameters [i].ModFlags;
					if ((i_mod & Parameter.Modifier.OUT) != 0) {
						if (!ec.IsInProbingMode) {
							ec.Report.Error (1688, loc,
								"Cannot convert anonymous method block without a parameter list to delegate type `{0}' because it has one or more `out' parameters",
								delegate_type.GetSignatureForError ());
						}

						return null;
					}
					fixedpars[i] = new Parameter (
						new TypeExpression (delegate_parameters.Types [i], loc), null,
						delegate_parameters.FixedParameters [i].ModFlags, null, loc);
				}

				return ParametersCompiled.CreateFullyResolved (fixedpars, delegate_parameters.Types);
			}

			if (!VerifyExplicitParameters (ec, tic, delegate_type, delegate_parameters)) {
				return null;
			}

			return Parameters;
		}

		protected override Expression DoResolve (ResolveContext rc)
		{
			if (rc.HasSet (ResolveContext.Options.ConstantScope)) {
				rc.Report.Error (1706, loc, "Anonymous methods and lambda expressions cannot be used in the current context");
				return null;
			}

			//
			// Update top-level block generated duting parsing with actual top-level block
			//
			if (rc.HasAny (ResolveContext.Options.FieldInitializerScope | ResolveContext.Options.BaseInitializer) && rc.CurrentMemberDefinition.Parent.PartialContainer.PrimaryConstructorParameters != null) {
				var tb = rc.ConstructorBlock.ParametersBlock.TopBlock;
				if (Block.TopBlock != tb) {
					Block b = Block;
					while (b.Parent != Block.TopBlock && b != Block.TopBlock)
						b = b.Parent;

					b.Parent = tb;
					tb.IncludeBlock (Block, Block.TopBlock);
					b.ParametersBlock.TopBlock = tb;
				}
			}

			eclass = ExprClass.Value;

			//
			// This hack means `The type is not accessible
			// anywhere', we depend on special conversion
			// rules.
			// 
			type = InternalType.AnonymousMethod;

			if (!DoResolveParameters (rc))
				return null;

			return this;
		}

		protected virtual bool DoResolveParameters (ResolveContext rc)
		{
			return Parameters.Resolve (rc);
		}

		public override void Emit (EmitContext ec)
		{
			// nothing, as we only exist to not do anything.
		}

		public static void Error_AddressOfCapturedVar (ResolveContext rc, IVariableReference var, Location loc)
		{
			if (rc.CurrentAnonymousMethod is AsyncInitializer)
				return;

			rc.Report.Error (1686, loc,
				"Local variable or parameter `{0}' cannot have their address taken and be used inside an anonymous method, lambda expression or query expression",
				var.Name);
		}

		public override string GetSignatureForError ()
		{
			return ExprClassName;
		}

		AnonymousMethodBody CompatibleMethodBody (ResolveContext ec, TypeInferenceContext tic, TypeSpec return_type, TypeSpec delegate_type)
		{
			ParametersCompiled p = ResolveParameters (ec, tic, delegate_type);
			if (p == null)
				return null;

			ParametersBlock b = ec.IsInProbingMode ? (ParametersBlock) Block.PerformClone () : Block;

			if (b.IsAsync) {
				var rt = return_type;
				if (rt != null && rt.Kind != MemberKind.Void && rt != ec.Module.PredefinedTypes.Task.TypeSpec && !rt.IsGenericTask) {
					ec.Report.Error (4010, loc, "Cannot convert async {0} to delegate type `{1}'",
						GetSignatureForError (), delegate_type.GetSignatureForError ());

					return null;
				}

				b = b.ConvertToAsyncTask (ec, ec.CurrentMemberDefinition.Parent.PartialContainer, p, return_type, delegate_type, loc);
			}

			return CompatibleMethodFactory (return_type ?? InternalType.ErrorType, delegate_type, p, b);
		}

		protected virtual AnonymousMethodBody CompatibleMethodFactory (TypeSpec return_type, TypeSpec delegate_type, ParametersCompiled p, ParametersBlock b)
		{
			return new AnonymousMethodBody (p, b, return_type, delegate_type, loc);
		}

		protected override void CloneTo (CloneContext clonectx, Expression t)
		{
			AnonymousMethodExpression target = (AnonymousMethodExpression) t;

			target.Block = (ParametersBlock) clonectx.LookupBlock (Block);
		}
		
		public override object Accept (StructuralVisitor visitor)
		{
			return visitor.Visit (this);
		}
	}

	//
	// Abstract expression for any block which requires variables hoisting
	//
	public abstract class AnonymousExpression : ExpressionStatement
	{
		protected class AnonymousMethodMethod : Method
		{
			public readonly AnonymousExpression AnonymousMethod;
			public readonly AnonymousMethodStorey Storey;

			public AnonymousMethodMethod (TypeDefinition parent, AnonymousExpression am, AnonymousMethodStorey storey,
							  TypeExpr return_type,
							  Modifiers mod, MemberName name,
							  ParametersCompiled parameters)
				: base (parent, return_type, mod | Modifiers.COMPILER_GENERATED,
						name, parameters, null)
			{
				this.AnonymousMethod = am;
				this.Storey = storey;

				Parent.PartialContainer.Members.Add (this);
				Block = new ToplevelBlock (am.block, parameters);
			}

			public override EmitContext CreateEmitContext (ILGenerator ig, SourceMethodBuilder sourceMethod)
			{
				EmitContext ec = new EmitContext (this, ig, ReturnType, sourceMethod);
				ec.CurrentAnonymousMethod = AnonymousMethod;
				return ec;
			}

			protected override void DefineTypeParameters ()
			{
				// Type parameters were cloned
			}

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

				if (Storey != null && Storey.Mutator != null) {
					if (!parameters.IsEmpty) {
						var mutated = Storey.Mutator.Mutate (parameters.Types);
						if (mutated != parameters.Types)
							parameters = ParametersCompiled.CreateFullyResolved ((Parameter[]) parameters.FixedParameters, mutated);
					}

					member_type = Storey.Mutator.Mutate (member_type);
				}

				return true;
			}

			public override void Emit ()
			{
				if (MethodBuilder == null) {
					Define ();
				}

				base.Emit ();
			}
		}

		protected readonly ParametersBlock block;

		public TypeSpec ReturnType;

		protected AnonymousExpression (ParametersBlock block, TypeSpec return_type, Location loc)
		{
			this.ReturnType = return_type;
			this.block = block;
			this.loc = loc;
		}

		public abstract string ContainerType { get; }
		public abstract bool IsIterator { get; }
		public abstract AnonymousMethodStorey Storey { get; }

		//
		// The block that makes up the body for the anonymous method
		//
		public ParametersBlock Block {
			get {
				return block;
			}
		}

		public AnonymousExpression Compatible (ResolveContext ec)
		{
			return Compatible (ec, this);
		}

		public AnonymousExpression Compatible (ResolveContext ec, AnonymousExpression ae)
		{
			if (block.Resolved)
				return this;

			// TODO: Implement clone
			BlockContext aec = new BlockContext (ec, block, ReturnType);
			aec.CurrentAnonymousMethod = ae;

			var am = this as AnonymousMethodBody;

			if (ec.HasSet (ResolveContext.Options.InferReturnType) && am != null) {
				am.ReturnTypeInference = new TypeInferenceContext ();
			}

			var bc = ec as BlockContext;

			if (bc != null) {
				aec.AssignmentInfoOffset = bc.AssignmentInfoOffset;
				aec.EnclosingLoop = bc.EnclosingLoop;
				aec.EnclosingLoopOrSwitch = bc.EnclosingLoopOrSwitch;
				aec.Switch = bc.Switch;
			}

			var errors = ec.Report.Errors;

			bool res = Block.Resolve (aec);

			if (res && errors == ec.Report.Errors) {
				MarkReachable (new Reachability ());

				if (!CheckReachableExit (ec.Report)) {
					return null;
				}

				if (bc != null)
					bc.AssignmentInfoOffset = aec.AssignmentInfoOffset;
			}

			if (am != null && am.ReturnTypeInference != null) {
				am.ReturnTypeInference.FixAllTypes (ec);
				ReturnType = am.ReturnTypeInference.InferredTypeArguments [0];
				am.ReturnTypeInference = null;

				//
				// If e is synchronous the inferred return type is T
				// If e is asynchronous and the body of F is either an expression classified as nothing
				// or a statement block where no return statements have expressions, the inferred return type is Task
				// If e is async and has an inferred result type T, the inferred return type is Task<T>
				//
				if (block.IsAsync && ReturnType != null) {
					ReturnType = ReturnType.Kind == MemberKind.Void ?
						ec.Module.PredefinedTypes.Task.TypeSpec :
						ec.Module.PredefinedTypes.TaskGeneric.TypeSpec.MakeGenericType (ec, new [] { ReturnType });
				}
			}

			if (res && errors != ec.Report.Errors)
				return null;

			return res ? this : null;
		}

		public override bool ContainsEmitWithAwait ()
		{
			return false;
		}

		bool CheckReachableExit (Report report)
		{
			if (block.HasReachableClosingBrace && ReturnType.Kind != MemberKind.Void) {
				// FIXME: Flow-analysis on MoveNext generated code
				if (!IsIterator) {
					report.Error (1643, StartLocation,
							"Not all code paths return a value in anonymous method of type `{0}'", GetSignatureForError ());

					return false;
				}
			}

			return true;
		}

		public override void FlowAnalysis (FlowAnalysisContext fc)
		{
			// We are reachable, mark block body reachable too
			MarkReachable (new Reachability ());

			CheckReachableExit (fc.Report);

			var das = fc.BranchDefiniteAssignment ();
			var prev_pb = fc.ParametersBlock;
			fc.ParametersBlock = Block;
			var da_ontrue = fc.DefiniteAssignmentOnTrue;
			var da_onfalse = fc.DefiniteAssignmentOnFalse;

			fc.DefiniteAssignmentOnTrue = fc.DefiniteAssignmentOnFalse = null;
			block.FlowAnalysis (fc);

			fc.ParametersBlock = prev_pb;
			fc.DefiniteAssignment = das;
			fc.DefiniteAssignmentOnTrue = da_ontrue;
			fc.DefiniteAssignmentOnFalse = da_onfalse;
		}

		public override void MarkReachable (Reachability rc)
		{
			block.MarkReachable (rc);
		}

		public void SetHasThisAccess ()
		{
			ExplicitBlock b = block;
			do {
				if (b.HasCapturedThis)
					return;

				b.HasCapturedThis = true;
				b = b.Parent == null ? null : b.Parent.Explicit;
			} while (b != null);
		}
	}

	public class AnonymousMethodBody : AnonymousExpression
	{
		protected readonly ParametersCompiled parameters;
		AnonymousMethodStorey storey;

		AnonymousMethodMethod method;
		Field am_cache;
		string block_name;
		TypeInferenceContext return_inference;

		public AnonymousMethodBody (ParametersCompiled parameters,
					ParametersBlock block, TypeSpec return_type, TypeSpec delegate_type,
					Location loc)
			: base (block, return_type, loc)
		{
			this.type = delegate_type;
			this.parameters = parameters;
		}

		#region Properties

		public override string ContainerType {
			get { return "anonymous method"; }
		}

		//
		// Method-group instance for lambdas which can be replaced with
		// simple method group call
		//
		public MethodGroupExpr DirectMethodGroupConversion {
			get; set;
		}

		public override bool IsIterator {
			get {
				return false;
			}
		}

		public ParametersCompiled Parameters {
			get {
				return parameters;
			}
		}

		public TypeInferenceContext ReturnTypeInference {
			get {
				return return_inference;
			}
			set {
				return_inference = value;
			}
		}

		public override AnonymousMethodStorey Storey {
			get {
				return storey;
			}
		}

		#endregion

		public override Expression CreateExpressionTree (ResolveContext ec)
		{
			ec.Report.Error (1945, loc, "An expression tree cannot contain an anonymous method expression");
			return null;
		}

		bool Define (ResolveContext ec)
		{
			if (!Block.Resolved && Compatible (ec) == null)
				return false;

			if (block_name == null) {
				MemberCore mc = (MemberCore) ec.MemberContext;
				block_name = mc.MemberName.Basename;
			}

			return true;
		}

		//
		// Creates a host for the anonymous method
		//
		AnonymousMethodMethod DoCreateMethodHost (EmitContext ec)
		{
			//
			// Anonymous method body can be converted to
			//
			// 1, an instance method in current scope when only `this' is hoisted
			// 2, a static method in current scope when neither `this' nor any variable is hoisted
			// 3, an instance method in compiler generated storey when any hoisted variable exists
			//

			Modifiers modifiers;
			TypeDefinition parent = null;
			TypeParameters hoisted_tparams = null;
			ParametersCompiled method_parameters = parameters;

			var src_block = Block.Original.Explicit;
			if (src_block.HasCapturedVariable || src_block.HasCapturedThis) {
				parent = storey = FindBestMethodStorey ();

				if (storey == null) {
					var top_block = src_block.ParametersBlock.TopBlock;
					var sm = top_block.StateMachine;

					if (src_block.HasCapturedThis) {
						//
						// Remove hoisted 'this' request when simple instance method is
						// enough. No hoisted variables only 'this' and don't need to
						// propagate this to value type state machine.…