diff --git a/include/proxy/v4/proxy.h b/include/proxy/v4/proxy.h
index b4f5495..a3a1d9b 100644
--- a/include/proxy/v4/proxy.h
+++ b/include/proxy/v4/proxy.h
@@ -152,8 +152,15 @@ template <template <class...> class T, class TL, std::size_t... Is,
 struct instantiated_traits<T, TL, std::index_sequence<Is...>, Args...>
     : std::type_identity<T<Args..., std::tuple_element_t<Is, TL>...>> {};
 template <template <class...> class T, class TL, class... Args>
-using instantiated_t = typename instantiated_traits<
-    T, TL, std::make_index_sequence<std::tuple_size_v<TL>>, Args...>::type;
+struct instantiated_traits_helper
+    : instantiated_traits<
+          T, TL, std::make_index_sequence<std::tuple_size_v<TL>>, Args...> {};
+template <template <class...> class T, class... Ts, class... Args>
+struct instantiated_traits_helper<T, std::tuple<Ts...>, Args...>
+    : std::type_identity<T<Args..., Ts...>> {};
+template <template <class...> class T, class TL, class... Args>
+using instantiated_t =
+    typename instantiated_traits_helper<T, TL, Args...>::type;
 
 enum class qualifier_type { lv, const_lv, rv, const_rv };
 template <class T, qualifier_type Q>