+namespace detail
+{
+
+// Type-unmarking class template -------------------------------------------//
+
+// Type-trait to get the raw type, i.e. the type without top-level reference nor
+// cv-qualification, from a type expression. Mainly for function arguments, any
+// reference part is stripped first.
+
+// Contributed by Daryle Walker
+
+template < typename T >
+struct remove_cv_ref
+{
+ typedef typename ::boost::remove_cv<typename
+ ::boost::remove_reference<T>::type>::type type;
+
+}; // boost::detail::remove_cv_ref
+
+// Unmarked-type comparison class template ---------------------------------//
+
+// Type-trait to check if two type expressions have the same raw type.
+
+// Contributed by Daryle Walker, based on a work-around by Luc Danton
+
+template < typename T, typename U >
+struct is_related
+ : public ::boost::is_same<
+ typename ::boost::detail::remove_cv_ref<T>::type,
+ typename ::boost::detail::remove_cv_ref<U>::type >
+{};
+
+// Enable-if-on-unidentical-unmarked-type class template -------------------//
+
+// Enable-if on the first two type expressions NOT having the same raw type.
+
+// Contributed by Daryle Walker, based on a work-around by Luc Danton
+
+#ifndef BOOST_NO_CXX11_VARIADIC_TEMPLATES
+template<typename ...T>
+struct enable_if_unrelated
+ : public ::boost::enable_if_c<true>
+{};
+
+template<typename T, typename U, typename ...U2>
+struct enable_if_unrelated<T, U, U2...>
+ : public ::boost::disable_if< ::boost::detail::is_related<T, U> >
+{};
+#endif
+
+} // namespace boost::detail
+
+