diff --git a/include/boost/mp11/function.hpp b/include/boost/mp11/function.hpp
index 3a2d549..8ff66e5 100644
--- a/include/boost/mp11/function.hpp
+++ b/include/boost/mp11/function.hpp
@@ -87,18 +87,7 @@ template<class... T> using mp_and = typename detail::mp_and_impl<mp_list<T...>>:
 #endif
 
 // mp_all<T...>
-#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 )
+#if 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 >;
 
diff --git a/test/mp_all.cpp b/test/mp_all.cpp
index 9974cfb..64c40e8 100644
--- a/test/mp_all.cpp
+++ b/test/mp_all.cpp
@@ -58,7 +58,12 @@ int main()
     BOOST_TEST_TRAIT_TRUE((std::is_same<mp_all<mp_size_t<1>, mp_size_t<2>, mp_size_t<114>, mp_size_t<0>, mp_size_t<94>>, mp_false>));
 
     BOOST_TEST_TRAIT_TRUE((std::is_same<check1<void, int, float>, mp_true>));
+
+#if !BOOST_WORKAROUND( BOOST_GCC, < 40900 )
+
     BOOST_TEST_TRAIT_TRUE((std::is_same<check2<void, int, float>, mp_true>));
 
+#endif
+
     return boost::report_errors();
 }