diff --git a/include/boost/mp11/function.hpp b/include/boost/mp11/function.hpp
index 8ff66e5..3a2d549 100644
--- a/include/boost/mp11/function.hpp
+++ b/include/boost/mp11/function.hpp
@@ -87,7 +87,18 @@ template<class... T> using mp_and = typename detail::mp_and_impl<mp_list<T...>>:
 #endif
 
 // mp_all<T...>
-#if BOOST_WORKAROUND( BOOST_MSVC, <= 1910 ) || BOOST_WORKAROUND( BOOST_GCC, < 70200 )
+#if BOOST_WORKAROUND( BOOST_GCC, < 40900 )
+
+namespace detail
+{
+
+template<class T> using mp_to_true = mp_true;
+
+} // namespace detail
+
+template<class... T> using mp_all = mp_to_bool<std::is_same<mp_list<mp_to_bool<T>...>, mp_list<detail::mp_to_true<T>...>>>;
+
+#elif BOOST_WORKAROUND( BOOST_MSVC, <= 1910 ) || BOOST_WORKAROUND( BOOST_GCC, < 70200 )
 
 template<class... T> using mp_all = mp_bool< mp_count_if< mp_list<T...>, mp_not >::value == 0 >;