https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69223
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> --- Slightly reduced: #include <array> #include <vector> int main() { std::vector<std::array<int, 20>> out; auto saveChan = [&](auto && f) { f({}); }; saveChan([](decltype(out)::value_type const & i){ return i;}); }