https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86480
Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|--- |8.2 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- What flags? GCC 7.3 doesn't compile it for me: > g++-7 -S t.C t.C:5:71: error: ‘tuple_size_v’ is not a member of ‘std’ template<typename Tuple, typename = std::make_index_sequence<std::tuple_size_v<Tuple>>> ^~~~~~~~~~~~ t.C:5:71: note: suggested alternative: ‘tuple_size’ can you please attach the testcase?