ILSpy/ICSharpCode.NRefactory/CSharp/Parser/mcs/dynamic.cs

//
// dynamic.cs: support for dynamic expressions
//
// Authors: Marek Safar (marek.safar@gmail.com)
//
// Dual licensed under the terms of the MIT X11 or GNU GPL
//
// Copyright 2009 Novell, Inc
//

using System;
using System.Linq;
using SLE = System.Linq.Expressions;

#if NET_4_0
using System.Dynamic;
#endif

namespace Mono.CSharp
{
	//
	// A copy of Microsoft.CSharp/Microsoft.CSharp.RuntimeBinder/CSharpBinderFlags.cs
	// has to be kept in sync
	//
	[Flags]
	public enum CSharpBinderFlags
	{
		None = 0,
		CheckedContext = 1,
		InvokeSimpleName = 1 << 1,
		InvokeSpecialName = 1 << 2,
		BinaryOperationLogical = 1 << 3,
		ConvertExplicit = 1 << 4,
		ConvertArrayIndex = 1 << 5,
		ResultIndexed = 1 << 6,
		ValueFromCompoundAssignment = 1 << 7,
		ResultDiscarded = 1 << 8
	}

	//
	// Type expression with internal dynamic type symbol
	//
	class DynamicTypeExpr : TypeExpr
	{
		public DynamicTypeExpr (Location loc)
		{
			this.loc = loc;

			type = InternalType.Dynamic;
			eclass = ExprClass.Type;
		}

		protected override TypeExpr DoResolveAsTypeStep (IMemberContext ec)
		{
			return this;
		}
	}

	#region Dynamic runtime binder expressions

	//
	// Expression created from runtime dynamic object value by dynamic binder
	//
	public class RuntimeValueExpression : Expression, IDynamicAssign, IMemoryLocation
	{
#if !NET_4_0
		public class DynamicMetaObject
		{
			public TypeSpec RuntimeType;
			public TypeSpec LimitType;
			public SLE.Expression Expression;
		}
#endif

		readonly DynamicMetaObject obj;

		public RuntimeValueExpression (DynamicMetaObject obj, TypeSpec type)
		{
			this.obj = obj;
			this.type = type;
			this.eclass = ExprClass.Variable;
		}

		#region Properties

		public bool IsSuggestionOnly { get; set; }

		public DynamicMetaObject MetaObject {
			get { return obj; }
		}

		#endregion

		public void AddressOf (EmitContext ec, AddressOp mode)
		{
			throw new NotImplementedException ();
		}

		public override Expression CreateExpressionTree (ResolveContext ec)
		{
			throw new NotImplementedException ();
		}

		protected override Expression DoResolve (ResolveContext ec)
		{
			return this;
		}

		public override Expression DoResolveLValue (ResolveContext ec, Expression right_side)
		{
			return this;
		}

		public override void Emit (EmitContext ec)
		{
			throw new NotImplementedException ();
		}

		#region IAssignMethod Members

		public void Emit (EmitContext ec, bool leave_copy)
		{
			throw new NotImplementedException ();
		}

		public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
		{
			throw new NotImplementedException ();
		}

		#endregion

		public SLE.Expression MakeAssignExpression (BuilderContext ctx, Expression source)
		{
			return obj.Expression;
		}

		public override SLE.Expression MakeExpression (BuilderContext ctx)
		{
#if STATIC
			return base.MakeExpression (ctx);
#else

	#if NET_4_0		
				if (type.IsStruct && !obj.Expression.Type.IsValueType)
					return SLE.Expression.Unbox (obj.Expression, type.GetMetaInfo ());

				if (obj.Expression.NodeType == SLE.ExpressionType.Parameter) {
					if (((SLE.ParameterExpression) obj.Expression).IsByRef)
						return obj.Expression;
				}
	#endif

				return SLE.Expression.Convert (obj.Expression, type.GetMetaInfo ());
#endif
		}
	}

	//
	// Wraps runtime dynamic expression into expected type. Needed
	// to satify expected type check by dynamic binder and no conversion
	// is required (ResultDiscarded).
	//
	public class DynamicResultCast : ShimExpression
	{
		public DynamicResultCast (TypeSpec type, Expression expr)
			: base (expr)
		{
			this.type = type;
		}

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

#if NET_4_0
		public override SLE.Expression MakeExpression (BuilderContext ctx)
		{
#if STATIC
			return base.MakeExpression (ctx);
#else
			return SLE.Expression.Block (expr.MakeExpression (ctx), SLE.Expression.Default (type.GetMetaInfo ()));
#endif
		}
#endif
	}

	#endregion

	//
	// Creates dynamic binder expression
	//
	interface IDynamicBinder
	{
		Expression CreateCallSiteBinder (ResolveContext ec, Arguments args);
	}

	//
	// Extends standard assignment interface for expressions
	// supported by dynamic resolver
	//
	interface IDynamicAssign : IAssignMethod
	{
		SLE.Expression MakeAssignExpression (BuilderContext ctx, Expression source);
	}

	//
	// Base dynamic expression statement creator
	//
	class DynamicExpressionStatement : ExpressionStatement
	{
		//
		// Binder flag dynamic constant, the value is combination of
		// flags known at resolve stage and flags known only at emit
		// stage
		//
		protected class BinderFlags : EnumConstant
		{
			DynamicExpressionStatement statement;
			CSharpBinderFlags flags;

			public BinderFlags (CSharpBinderFlags flags, DynamicExpressionStatement statement)
				: base (statement.loc)
			{
				this.flags = flags;
				this.statement = statement;
			}

			protected override Expression DoResolve (ResolveContext ec)
			{
				Child = new IntConstant ((int) (flags | statement.flags), statement.loc).Resolve (ec);

				type = ec.Module.PredefinedTypes.BinderFlags.Resolve (loc);
				eclass = Child.eclass;
				return this;
			}
		}

		readonly Arguments arguments;
		protected IDynamicBinder binder;
		protected Expression binder_expr;

		// Used by BinderFlags
		protected CSharpBinderFlags flags;

		TypeSpec binder_type;

		public DynamicExpressionStatement (IDynamicBinder binder, Arguments args, Location loc)
		{
			this.binder = binder;
			this.arguments = args;
			this.loc = loc;
		}

		public Arguments Arguments {
			get {
				return arguments;
			}
		}

		FieldSpec CreateSiteField (EmitContext ec, FullNamedExpression type)
		{
			var site_container = ec.CreateDynamicSite ();
			return site_container.CreateCallSiteField (type, loc);
		}

		public override Expression CreateExpressionTree (ResolveContext ec)
		{
			ec.Report.Error (1963, loc, "An expression tree cannot contain a dynamic operation");
			return null;
		}

		protected override Expression DoResolve (ResolveContext ec)
		{
			if (DoResolveCore (ec))
				binder_expr = binder.CreateCallSiteBinder (ec, arguments);

			return this;
		}

		protected bool DoResolveCore (ResolveContext rc)
		{
			int errors = rc.Report.Errors;
			var pt = rc.Module.PredefinedTypes;

			binder_type = pt.Binder.Resolve (loc);
			pt.CallSite.Resolve (loc);
			pt.CallSiteGeneric.Resolve (loc);

			eclass = ExprClass.Value;

			if (type == null)
				type = InternalType.Dynamic;

			if (rc.Report.Errors == errors)
				return true;

			rc.Report.Error (1969, loc,
				"Dynamic operation cannot be compiled without `Microsoft.CSharp.dll' assembly reference");
			return false;
		}

		public override void Emit (EmitContext ec)
		{
			EmitCall (ec, binder_expr, arguments,  false);
		}

		public override void EmitStatement (EmitContext ec)
		{
			EmitCall (ec, binder_expr, arguments, true);
		}

		protected void EmitCall (EmitContext ec, Expression binder, Arguments arguments, bool isStatement)
		{
			int dyn_args_count = arguments == null ? 0 : arguments.Count;
			TypeExpr site_type = CreateSiteType (ec, arguments, dyn_args_count, isStatement);
			var field = CreateSiteField (ec, site_type);
			if (field == null)
				return;

			FieldExpr site_field_expr = new FieldExpr (field, loc);

			SymbolWriter.OpenCompilerGeneratedBlock (ec);

			Arguments args = new Arguments (1);
			args.Add (new Argument (binder));
			StatementExpression s = new StatementExpression (new SimpleAssign (site_field_expr, new Invocation (new MemberAccess (site_type, "Create"), args)));
			
			BlockContext bc = new BlockContext (ec.MemberContext, null, TypeManager.void_type);		
			if (s.Resolve (bc)) {
				Statement init = new If (new Binary (Binary.Operator.Equality, site_field_expr, new NullLiteral (loc), loc), s, loc);
				init.Emit (ec);
			}

			args = new Arguments (1 + dyn_args_count);
			args.Add (new Argument (site_field_expr));
			if (arguments != null) {
				foreach (Argument a in arguments) {
					if (a is NamedArgument) {
						// Name is not valid in this context
						args.Add (new Argument (a.Expr, a.ArgType));
						continue;
					}

					args.Add (a);
				}
			}

			Expression target = new DelegateInvocation (new MemberAccess (site_field_expr, "Target", loc).Resolve (bc), args, loc).Resolve (bc);
			if (target != null)
				target.Emit (ec);

			SymbolWriter.CloseCompilerGeneratedBlock (ec);
		}

		public static MemberAccess GetBinderNamespace (Location loc)
		{
			return new MemberAccess (new MemberAccess (
				new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "Microsoft", loc), "CSharp", loc), "RuntimeBinder", loc);
		}

		protected MemberAccess GetBinder (string name, Location loc)
		{
			return new MemberAccess (new TypeExpression (binder_type, loc), name, loc);
		}

		TypeExpr CreateSiteType (EmitContext ec, Arguments arguments, int dyn_args_count, bool is_statement)
		{
			int default_args = is_statement ? 1 : 2;
			var module = ec.MemberContext.Module;

			bool has_ref_out_argument = false;
			var targs = new TypeExpression[dyn_args_count + default_args];
			targs [0] = new TypeExpression (module.PredefinedTypes.CallSite.TypeSpec, loc);
			for (int i = 0; i < dyn_args_count; ++i) {
				Argument a = arguments [i];
				if (a.ArgType == Argument.AType.Out || a.ArgType == Argument.AType.Ref)
					has_ref_out_argument = true;

				var t = a.Type;

				// Convert any internal type like dynamic or null to object
				if (t.Kind == MemberKind.InternalCompilerType)
					t = TypeManager.object_type;

				targs [i + 1] = new TypeExpression (t, loc);
			}

			TypeExpr del_type = null;
			if (!has_ref_out_argument) {
				string d_name = is_statement ? "Action" : "Func";

				TypeExpr te = null;
				Namespace type_ns = module.GlobalRootNamespace.GetNamespace ("System", true);
				if (type_ns != null) {
					te = type_ns.LookupType (module.Compiler, d_name, dyn_args_count + default_args, true, Location.Null);
				}
			
				if (te != null) {
					if (!is_statement)
						targs [targs.Length - 1] = new TypeExpression (type, loc);

					del_type = new GenericTypeExpr (te.Type, new TypeArguments (targs), loc);
				}
			}

			//
			// Create custom delegate when no appropriate predefined one is found
			//
			if (del_type == null) {
				TypeSpec rt = is_statement ? TypeManager.void_type : type;
				Parameter[] p = new Parameter [dyn_args_count + 1];
				p[0] = new Parameter (targs [0], "p0", Parameter.Modifier.NONE, null, loc);

				var site = ec.CreateDynamicSite ();
				int index = site.Types == null ? 0 : site.Types.Count;

				if (site.Mutator != null)
					rt = site.Mutator.Mutate (rt);

				for (int i = 1; i < dyn_args_count + 1; ++i) {
					var t = targs[i];
					if (site.Mutator != null)
						t.Type = site.Mutator.Mutate (t.Type);

					p[i] = new Parameter (t, "p" + i.ToString ("X"), arguments[i - 1].Modifier, null, loc);
				}

				Delegate d = new Delegate (site.NamespaceEntry, site, new TypeExpression (rt, loc),
					Modifiers.INTERNAL | Modifiers.COMPILER_GENERATED,
					new MemberName ("Container" + index.ToString ("X")),
					new ParametersCompiled (p), null);

				d.CreateType ();
				d.DefineType ();
				d.Define ();
				d.Emit ();

				var inflated = site.AddDelegate (d);
				del_type = new TypeExpression (inflated, loc);
			}

			TypeExpr site_type = new GenericTypeExpr (module.PredefinedTypes.CallSiteGeneric.TypeSpec, new TypeArguments (del_type), loc);
			return site_type;
		}
	}

	//
	// Dynamic member access compound assignment for events
	//
	class DynamicEventCompoundAssign : ExpressionStatement
	{
		class IsEvent : DynamicExpressionStatement, IDynamicBinder
		{
			string name;

			public IsEvent (string name, Arguments args, Location loc)
				: base (null, args, loc)
			{
				this.name = name;
				binder = this;
			}

			public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
			{
				type = TypeManager.bool_type;

				Arguments binder_args = new Arguments (3);

				binder_args.Add (new Argument (new BinderFlags (0, this)));
				binder_args.Add (new Argument (new StringLiteral (name, loc)));
				binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));

				return new Invocation (GetBinder ("IsEvent", loc), binder_args);
			}
		}

		Expression condition;
		ExpressionStatement invoke, assign;

		public DynamicEventCompoundAssign (string name, Arguments args, ExpressionStatement assignment, ExpressionStatement invoke, Location loc)
		{
			condition = new IsEvent (name, args, loc);
			this.invoke = invoke;
			this.assign = assignment;
			this.loc = loc;
		}

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

		protected override Expression DoResolve (ResolveContext rc)
		{
			type = InternalType.Dynamic;
			eclass = ExprClass.Value;
			condition = condition.Resolve (rc);
			return this;
		}

		public override void Emit (EmitContext ec)
		{
			var rc = new ResolveContext (ec.MemberContext);
			var expr = new Conditional (new BooleanExpression (condition), invoke, assign, loc).Resolve (rc);
			expr.Emit (ec);
		}

		public override void EmitStatement (EmitContext ec)
		{
			var stmt = new If (condition, new StatementExpression (invoke), new StatementExpression (assign), loc);
			stmt.Emit (ec);
		}
	}

	class DynamicConversion : DynamicExpressionStatement, IDynamicBinder
	{
		public DynamicConversion (TypeSpec targetType, CSharpBinderFlags flags, Arguments args, Location loc)
			: base (null, args, loc)
		{
			type = targetType;
			base.flags = flags;
			base.binder = this;
		}

		public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
		{
			Arguments binder_args = new Arguments (3);

			flags |= ec.HasSet (ResolveContext.Options.CheckedScope) ? CSharpBinderFlags.CheckedContext : 0;

			binder_args.Add (new Argument (new BinderFlags (flags, this)));
			binder_args.Add (new Argument (new TypeOf (new TypeExpression (type, loc), loc)));
			binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
			return new Invocation (GetBinder ("Convert", loc), binder_args);
		}
	}

	class DynamicConstructorBinder : DynamicExpressionStatement, IDynamicBinder
	{
		public DynamicConstructorBinder (TypeSpec type, Arguments args, Location loc)
			: base (null, args, loc)
		{
			this.type = type;
			base.binder = this;
		}

		public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
		{
			Arguments binder_args = new Arguments (3);

			binder_args.Add (new Argument (new BinderFlags (0, this)));
			binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
			binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc)));

			return new Invocation (GetBinder ("InvokeConstructor", loc), binder_args);
		}
	}

	class DynamicIndexBinder : DynamicMemberAssignable
	{
		bool can_be_mutator;

		public DynamicIndexBinder (Arguments args, Location loc)
			: base (args, loc)
		{
		}

		public DynamicIndexBinder (CSharpBinderFlags flags, Arguments args, Location loc)
			: this (args, loc)
		{
			base.flags = flags;
		}

		protected override Expression DoResolve (ResolveContext ec)
		{
			can_be_mutator = true;
			return base.DoResolve (ec);
		}

		protected override Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet)
		{
			Arguments binder_args = new Arguments (3);

			binder_args.Add (new Argument (new BinderFlags (flags, this)));
			binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
			binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc)));

			isSet |= (flags & CSharpBinderFlags.ValueFromCompoundAssignment) != 0;
			return new Invocation (GetBinder (isSet ? "SetIndex" : "GetIndex", loc), binder_args);
		}

		protected override Arguments CreateSetterArguments (ResolveContext rc, Expression rhs)
		{
			//
			// Indexer has arguments which complicates things as the setter and getter
			// are called in two steps when unary mutator is used. We have to make a
			// copy of all variable arguments to not duplicate any side effect.
			//
			// ++d[++arg, Foo ()]
			//

			if (!can_be_mutator)
				return base.CreateSetterArguments (rc, rhs);

			var setter_args = new Arguments (Arguments.Count + 1);
			for (int i = 0; i < Arguments.Count; ++i) {
				var expr = Arguments[i].Expr;

				if (expr is Constant || expr is VariableReference || expr is This) {
					setter_args.Add (Arguments [i]);
					continue;
				}

				LocalVariable temp = LocalVariable.CreateCompilerGenerated (expr.Type, rc.CurrentBlock, loc);
				expr = new SimpleAssign (temp.CreateReferenceExpression (rc, expr.Location), expr).Resolve (rc);
				Arguments[i].Expr = temp.CreateReferenceExpression (rc, expr.Location).Resolve (rc);
				setter_args.Add (Arguments [i].Clone (expr));
			}

			setter_args.Add (new Argument (rhs));
			return setter_args;
		}
	}

	class DynamicInvocation : DynamicExpressionStatement, IDynamicBinder
	{
		ATypeNameExpression member;

		public DynamicInvocation (ATypeNameExpression member, Arguments args, Location loc)
			: base (null, args, loc)
		{
			base.binder = this;
			this.member = member;
		}

		//
		// When a return type is known not to be dynamic
		//
		public DynamicInvocation (ATypeNameExpression member, Arguments args, TypeSpec type, Location loc)
			: this (member, args, loc)
		{
			this.type = type;
		}

		public static DynamicInvocation CreateSpecialNameInvoke (ATypeNameExpression member, Arguments args, Location loc)
		{
			return new DynamicInvocation (member, args, loc) {
				flags = CSharpBinderFlags.InvokeSpecialName
			};
		}

		public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
		{
			Arguments binder_args = new Arguments (member != null ? 5 : 3);
			bool is_member_access = member is MemberAccess;

			CSharpBinderFlags call_flags;
			if (!is_member_access && member is SimpleName) {
				call_flags = CSharpBinderFlags.InvokeSimpleName;
				is_member_access = true;
			} else {
				call_flags = 0;
			}

			binder_args.Add (new Argument (new BinderFlags (call_flags, this)));

			if (is_member_access)
				binder_args.Add (new Argument (new StringLiteral (member.Name, member.Location)));

			if (member != null && member.HasTypeArguments) {
				TypeArguments ta = member.TypeArguments;
				if (ta.Resolve (ec)) {
					var targs = new ArrayInitializer (ta.Count, loc);
					foreach (TypeSpec t in ta.Arguments)
						targs.Add (new TypeOf (new TypeExpression (t, loc), loc));

					binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (targs, loc)));
				}
			} else if (is_member_access) {
				binder_args.Add (new Argument (new NullLiteral (loc)));
			}

			binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));

			Expression real_args;
			if (args == null) {
				// Cannot be null because .NET trips over
				real_args = new ArrayCreation (
					new MemberAccess (GetBinderNamespace (loc), "CSharpArgumentInfo", loc),
					new ArrayInitializer (0, loc), loc);
			} else {
				real_args = new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc);
			}

			binder_args.Add (new Argument (real_args));

			return new Invocation (GetBinder (is_member_access ? "InvokeMember" : "Invoke", loc), binder_args);
		}

		public override void EmitStatement (EmitContext ec)
		{
			flags |= CSharpBinderFlags.ResultDiscarded;
			base.EmitStatement (ec);
		}
	}

	class DynamicMemberBinder : DynamicMemberAssignable
	{
		readonly string name;

		public DynamicMemberBinder (string name, Arguments args, Location loc)
			: base (args, loc)
		{
			this.name = name;
		}

		public DynamicMemberBinder (string name, CSharpBinderFlags flags, Arguments args, Location loc)
			: this (name, args, loc)
		{
			base.flags = flags;
		}

		protected override Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet)
		{
			Arguments binder_args = new Arguments (4);

			binder_args.Add (new Argument (new BinderFlags (flags, this)));
			binder_args.Add (new Argument (new StringLiteral (name, loc)));
			binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
			binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc)));

			isSet |= (flags & CSharpBinderFlags.ValueFromCompoundAssignment) != 0;
			return new Invocation (GetBinder (isSet ? "SetMember" : "GetMember", loc), binder_args);
		}
	}

	//
	// Any member binder which can be source and target of assignment
	//
	abstract class DynamicMemberAssignable : DynamicExpressionStatement, IDynamicBinder, IAssignMethod
	{
		Expression setter;
		Arguments setter_args;

		protected DynamicMemberAssignable (Arguments args, Location loc)
			: base (null, args, loc)
		{
			base.binder = this;
		}

		public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
		{
			//
			// DoResolve always uses getter
			//
			return CreateCallSiteBinder (ec, args, false);
		}

		protected abstract Expression CreateCallSiteBinder (ResolveContext ec, Arguments args, bool isSet);

		protected virtual Arguments CreateSetterArguments (ResolveContext rc, Expression rhs)
		{
			var setter_args = new Arguments (Arguments.Count + 1);
			setter_args.AddRange (Arguments);
			setter_args.Add (new Argument (rhs));
			return setter_args;
		}

		public override Expression DoResolveLValue (ResolveContext rc, Expression right_side)
		{
			if (right_side == EmptyExpression.OutAccess.Instance) {
				right_side.DoResolveLValue (rc, this);
				return null;
			}

			if (DoResolveCore (rc)) {
				setter_args = CreateSetterArguments (rc, right_side);
				setter = CreateCallSiteBinder (rc, setter_args, true);
			}

			eclass = ExprClass.Variable;
			return this;
		}

		public override void Emit (EmitContext ec)
		{
			// It's null for ResolveLValue used without assignment
			if (binder_expr == null)
				EmitCall (ec, setter, Arguments, false);
			else
				base.Emit (ec);
		}

		public override void EmitStatement (EmitContext ec)
		{
			// It's null for ResolveLValue used without assignment
			if (binder_expr == null)
				EmitCall (ec, setter, Arguments, true);
			else
				base.EmitStatement (ec);
		}

		#region IAssignMethod Members

		public void Emit (EmitContext ec, bool leave_copy)
		{
			throw new NotImplementedException ();
		}

		public void EmitAssign (EmitContext ec, Expression source, bool leave_copy, bool prepare_for_load)
		{
			EmitCall (ec, setter, setter_args, !leave_copy);
		}

		#endregion
	}

	class DynamicUnaryConversion : DynamicExpressionStatement, IDynamicBinder
	{
		readonly string name;

		public DynamicUnaryConversion (string name, Arguments args, Location loc)
			: base (null, args, loc)
		{
			this.name = name;
			base.binder = this;
		}

		public static DynamicUnaryConversion CreateIsTrue (Arguments args, Location loc)
		{
			return new DynamicUnaryConversion ("IsTrue", args, loc) { type = TypeManager.bool_type };
		}

		public static DynamicUnaryConversion CreateIsFalse (Arguments args, Location loc)
		{
			return new DynamicUnaryConversion ("IsFalse", args, loc) { type = TypeManager.bool_type };
		}

		public Expression CreateCallSiteBinder (ResolveContext ec, Arguments args)
		{
			Arguments binder_args = new Arguments (4);

			MemberAccess sle = new MemberAccess (new MemberAccess (
				new QualifiedAliasMember (QualifiedAliasMember.GlobalAlias, "System", loc), "Linq", loc), "Expressions", loc);

			var flags = ec.HasSet (ResolveContext.Options.CheckedScope) ? CSharpBinderFlags.CheckedContext : 0;

			binder_args.Add (new Argument (new BinderFlags (flags, this)));
			binder_args.Add (new Argument (new MemberAccess (new MemberAccess (sle, "ExpressionType", loc), name, loc)));
			binder_args.Add (new Argument (new TypeOf (new TypeExpression (ec.CurrentType, loc), loc)));
			binder_args.Add (new Argument (new ImplicitlyTypedArrayCreation (args.CreateDynamicBinderArguments (ec), loc)));

			return new Invocation (GetBinder ("UnaryOperation", loc), binder_args);
		}
	}

	public class DynamicSiteClass : HoistedStoreyClass
	{
		//
		// Holds the type to access the site. It gets inflated
		// by MVARs for generic call sites
		//
		TypeSpec instance_type;

		public DynamicSiteClass (TypeContainer parent, MemberBase host, TypeParameter[] tparams)
			: base (parent, MakeMemberName (host, "DynamicSite", parent.DynamicSitesCounter, tparams, Location.Null), tparams, Modifiers.STATIC)
		{
			if (tparams != null) {
				mutator = new TypeParameterMutator (tparams, CurrentTypeParameters);
			}

			parent.DynamicSitesCounter++;
		}

		public override TypeSpec AddDelegate (Delegate d)
		{
			TypeSpec inflated;

			base.AddDelegate (d);

			// Inflated type instance has to be updated manually
			if (instance_type is InflatedTypeSpec) {
				var inflator = new TypeParameterInflator (instance_type, TypeParameterSpec.EmptyTypes, TypeSpec.EmptyTypes);
				inflated = (TypeSpec) d.CurrentType.InflateMember (inflator);
				instance_type.MemberCache.AddMember (inflated);

				//inflator = new TypeParameterInflator (d.Parent.CurrentType, TypeParameterSpec.EmptyTypes, TypeSpec.EmptyTypes);
				//d.Parent.CurrentType.MemberCache.AddMember (d.CurrentType.InflateMember (inflator));
			} else {
				inflated = d.CurrentType;
			}

			return inflated;
		}

		public FieldSpec CreateCallSiteField (FullNamedExpression type, Location loc)
		{
			int index = fields == null ? 0 : fields.Count;
			Field f = new HoistedField (this, type, Modifiers.PUBLIC | Modifiers.STATIC, "Site" + index.ToString ("X"), null, loc);
			f.Define ();

			AddField (f);

			var fs = f.Spec;
			if (mutator != null) {
				//
				// Inflate the field, no need to keep it in MemberCache as it's accessed only once
				//
				var inflator = new TypeParameterInflator (instance_type, spec.MemberDefinition.TypeParameters, instance_type.TypeArguments);
				fs = (FieldSpec) fs.InflateMember (inflator);
			}

			return fs;
		}

		protected override bool DoResolveTypeParameters ()
		{
			instance_type = spec;
			if (mutator != null)
				instance_type = instance_type.MakeGenericType (mutator.MethodTypeParameters.Select (l => l.Type).ToArray ());

			return true;
		}
	}
}