LWG 1385 [FCD] tuple_cat should be a single variadic signature (http://www.open-std.org/jtc1/sc22/wg21/docs/lwg-active.html#1385). This issue is only in Ready status, meaning it is not official, but probably will be this March in Madrid. It was tentatively accepted in Batavia with the previso that Bill and I didn't have any problems implementing it. This is my part of that agreement.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@121619 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/include/__tuple b/include/__tuple
index 72e36fb..9fc54d4 100644
--- a/include/__tuple
+++ b/include/__tuple
@@ -68,12 +68,13 @@
template <class _Tp> struct __tuple_like : false_type {};
+template <class _Tp> struct __tuple_like<const _Tp> : public __tuple_like<_Tp> {};
+template <class _Tp> struct __tuple_like<volatile _Tp> : public __tuple_like<_Tp> {};
+template <class _Tp> struct __tuple_like<const volatile _Tp> : public __tuple_like<_Tp> {};
+
template <class... _Tp> struct __tuple_like<tuple<_Tp...>> : true_type {};
-template <class... _Tp> struct __tuple_like<const tuple<_Tp...>> : true_type {};
template <class _T1, class _T2> struct __tuple_like<pair<_T1, _T2> > : true_type {};
-template <class _T1, class _T2> struct __tuple_like<const pair<_T1, _T2> > : true_type {};
template <class _Tp, size_t _Size> struct __tuple_like<array<_Tp, _Size> > : true_type {};
-template <class _Tp, size_t _Size> struct __tuple_like<const array<_Tp, _Size> > : true_type {};
template <size_t _Ip, class ..._Tp>
typename tuple_element<_Ip, tuple<_Tp...>>::type&