diff --git a/include/boost/mp11/detail/mp_void.hpp b/include/boost/mp11/detail/mp_void.hpp
index a7ac7b7..f7ab015 100644
--- a/include/boost/mp11/detail/mp_void.hpp
+++ b/include/boost/mp11/detail/mp_void.hpp
@@ -14,6 +14,9 @@ namespace mp11
 {
 
 // mp_void<T...>
+
+#if 0
+
 namespace detail
 {
 
@@ -26,6 +29,12 @@ template<class... T> struct mp_void_impl
 
 template<class... T> using mp_void = typename detail::mp_void_impl<T...>::type;
 
+#else
+
+template<class... T> using mp_void = void;
+
+#endif
+
 } // namespace mp11
 } // namespace boost