Implement LWG Paper n3887: Consistent Metafunction Aliases. This adds std::tuple_element_t<> as an alias for tuple_element<>::type. Clean up the synopsis for tuple_element in <utility> as well.

llvm-svn: 202673

1 files changed, 7 insertions, 0 deletions

diff --git a/libcxx/test/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp b/libcxx/test/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp
index 7b1ff8bb183..f3f8f2b109d 100644
--- a/libcxx/test/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp
+++ b/libcxx/test/utilities/tuple/tuple.tuple/tuple.helper/tuple_element.pass.cpp
@@ -28,7 +28,14 @@ void test()
     static_assert((std::is_same<typename std::tuple_element<N, const T>::type, const U>::value), "");
     static_assert((std::is_same<typename std::tuple_element<N, volatile T>::type, volatile U>::value), "");
     static_assert((std::is_same<typename std::tuple_element<N, const volatile T>::type, const volatile U>::value), "");
+#if _LIBCPP_STD_VER > 11
+    static_assert((std::is_same<typename std::tuple_element_t<N, T>, U>::value), "");
+    static_assert((std::is_same<typename std::tuple_element_t<N, const T>, const U>::value), "");
+    static_assert((std::is_same<typename std::tuple_element_t<N, volatile T>, volatile U>::value), "");
+    static_assert((std::is_same<typename std::tuple_element_t<N, const volatile T>, const volatile U>::value), "");
+#endif
 }
+
 int main()
 {
     test<std::tuple<int>, 0, int>();