https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86728
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> --- Reduced: auto c = [](auto x ...) { }; 86728.cc:1:23: error: parameter packs not expanded with ‘...’: auto c = [](auto x ...) { }; ^ 86728.cc:1:23: note: ‘auto:1’