Merge pull request #387 from benedekkupper/fix-empty-pack-indexing

type_traits: fix empty pack indexing

Author: elbeno

include/stdx/type_traits.hpp

@@ -300,10 +300,10 @@ STDX_PRAGMA(diagnostic ignored "-Wc++26-extensions")
 #endif
 template <unsigned int N, typename... Ts>
 using nth_t =
-#if __cpp_pack_indexing >= 202311L
-    Ts...[N];
-#elif __has_builtin(__type_pack_element)
+#if __has_builtin(__type_pack_element)
     __type_pack_element<N, Ts...>;
+#elif __cpp_pack_indexing >= 202311L
+    Ts...[N];
 #else
     boost::mp11::mp_at_c<type_list<Ts...>, N>;
 #endif