diff --git a/include/__tuple/sfinae_helpers.h b/include/__tuple/sfinae_helpers.h
index 2fffac9..ee55576 100644
--- a/include/__tuple/sfinae_helpers.h
+++ b/include/__tuple/sfinae_helpers.h
@@ -49,22 +49,24 @@ struct __tuple_sfinae_base {
   static auto __do_test(...) -> false_type;
 
   template <class _FromArgs, class _ToArgs>
-  using __constructible = decltype(__do_test<is_constructible>(_ToArgs{}, _FromArgs{}));
+  using __constructible = decltype(__do_test<is_constructible>(declval<_ToArgs>(), declval<_FromArgs>()));
   template <class _FromArgs, class _ToArgs>
-  using __convertible = decltype(__do_test<is_convertible>(_FromArgs{}, _ToArgs{}));
+  using __convertible = decltype(__do_test<is_convertible>(declval<_FromArgs>(), declval<_ToArgs>()));
   template <class _FromArgs, class _ToArgs>
-  using __assignable = decltype(__do_test<is_assignable>(_ToArgs{}, _FromArgs{}));
+  using __assignable = decltype(__do_test<is_assignable>(declval<_ToArgs>(), declval<_FromArgs>()));
 };
 
 // __tuple_convertible
 
 template <class _Tp, class _Up, bool = __tuple_like_ext<__libcpp_remove_reference_t<_Tp> >::value,
-                                bool = __tuple_like_ext<_Up>::value>
+                                bool = __tuple_like_ext<_Up>::value,
+                class = void>
 struct __tuple_convertible
     : public false_type {};
 
 template <class _Tp, class _Up>
-struct __tuple_convertible<_Tp, _Up, true, true>
+struct __tuple_convertible<_Tp, _Up, true, true,
+                           typename enable_if<(tuple_size<typename remove_reference<_Tp>::type>::value == tuple_size<_Up>::value)>::type>
     : public __tuple_sfinae_base::__convertible<
       typename __make_tuple_types<_Tp>::type
     , typename __make_tuple_types<_Up>::type
diff --git a/include/__tuple/tuple_element.h b/include/__tuple/tuple_element.h
index 478dd08..5d2c38f 100644
--- a/include/__tuple/tuple_element.h
+++ b/include/__tuple/tuple_element.h
@@ -64,6 +64,7 @@ __indexed<_Idx, _Tp> __at_index(__indexed<_Idx, _Tp> const&);
 
 } // namespace __indexer_detail
 
+#if !defined(__CUDACC__) || !defined(_MSC_VER)
 template <size_t _Idx, class ..._Types>
 using __type_pack_element _LIBCPP_NODEBUG = typename decltype(
     __indexer_detail::__at_index<_Idx>(
@@ -72,7 +73,21 @@ using __type_pack_element _LIBCPP_NODEBUG = typename decltype(
             typename __make_tuple_indices<sizeof...(_Types)>::type
         >{})
   )::type;
-#endif
+#else // !defined(__CUDACC__) || !defined(_MSC_VER)
+template <size_t _Idx, class ..._Types>
+struct __y_type_pack_element {
+    using __t1 = typename __make_tuple_indices<sizeof...(_Types)>::type;
+    using __t2 = __indexer_detail::__indexer<__tuple_types<_Types...>, __t1>;
+    using __t3 = decltype(__indexer_detail::__at_index<_Idx>(__t2{}));
+    using __t4 = typename __t3::type;
+};
+
+template <size_t _Idx, class ..._Types>
+using __type_pack_element = typename __y_type_pack_element<_Idx, _Types...>::__t4;
+
+#endif // !defined(__CUDACC__) || !defined(_MSC_VER)
+
+#endif // __has_builtin(__type_pack_element)
 
 template <size_t _Ip, class ..._Types>
 struct _LIBCPP_TEMPLATE_VIS tuple_element<_Ip, __tuple_types<_Types...> >