https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99909
--- Comment #2 from 康桓瑋 <hewillk at gmail dot com> --- (In reply to Christopher Yeleighton from comment #1) > (In reply to 康桓瑋 from comment #0) > > template <template <std::integral auto> class> > > constexpr auto f() {} > > That means auto is void, doesn’t it? Yes, the second auto just means void.