remove PositionRef from valid types in Variables

libwccl/variables.h

@@ -150,7 +150,6 @@ protected:
 class Variables : detail::Vmap<Value>
 	, detail::Vmap<Bool>
 	, detail::Vmap<Position>
-	, detail::Vmap<PositionRef>
 	, detail::Vmap<StrSet>
 	, detail::Vmap<TSet>
 {
@@ -158,7 +157,7 @@ public:
 	/// Valid value types, should match the inheritance.
 	/// the type Value must be first, order of other items is not important
 	typedef boost::mpl::list<Value,
-		Bool, Position, PositionRef, StrSet, TSet> types;
+		Bool, Position, StrSet, TSet> types;
 
 	/// Constructor, creates an empty instance.
 	Variables();