diff --git a/include/boost/mp11/detail/mp_void.hpp b/include/boost/mp11/detail/mp_void.hpp
index f7ab015..a7ac7b7 100644
--- a/include/boost/mp11/detail/mp_void.hpp
+++ b/include/boost/mp11/detail/mp_void.hpp
@@ -14,9 +14,6 @@ namespace mp11
 {
 
 // mp_void<T...>
-
-#if 0
-
 namespace detail
 {
 
@@ -29,12 +26,6 @@ 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