tweak for readability (no functionality change)

llvm-svn: 124192
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 2a3f1bc13f4d835ddfca9f8c0f536fd36d2cdb76
diff --git a/include/tuple b/include/tuple
index 3f67ff8..63ce4cc 100644
--- a/include/tuple
+++ b/include/tuple
@@ -589,7 +589,7 @@
 get(tuple<_Tp...>&& __t)
 {
     typedef typename tuple_element<_Ip, tuple<_Tp...> >::type type;
-    return static_cast<typename tuple_element<_Ip, tuple<_Tp...> >::type&&>(
+    return static_cast<type&&>(
              static_cast<__tuple_leaf<_Ip, type>&&>(__t.base_).get());
 }