https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102229
--- Comment #6 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Thanks. With the latter interpretation in mind, it seems my earlier fix should be mitigated so that we allow constexpr decltype(auto) but not constexpr const decltype(auto) Yes? Do you want me to raise this with the CWG?