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));
}