diff --git a/libcxx/include/tuple b/libcxx/include/tuple
--- a/libcxx/include/tuple
+++ b/libcxx/include/tuple
@@ -1508,9 +1508,13 @@
     const __ignore_t& operator=(_Tp&&) const {return *this;}
 };
 
+#  if _LIBCPP_STD_VER >= 17
+inline constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
+#  else
 namespace {
   constexpr __ignore_t<unsigned char> ignore = __ignore_t<unsigned char>();
 } // namespace
+#  endif
 
 template <class... _Tp>
 inline _LIBCPP_INLINE_VISIBILITY _LIBCPP_CONSTEXPR_SINCE_CXX14