https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100739
Patrick Palka <ppalka at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |ppalka at gcc dot gnu.org --- Comment #1 from Patrick Palka <ppalka at gcc dot gnu.org> --- Reduced C++11 rejects-valid testcase: template<class T> struct array { }; template <class T, int = sizeof(T)> using debug_t = T; template<class T> struct X { auto f(T i) -> array<debug_t<decltype(i)>>; }; template<class T> auto X<T>::f(T i) -> array<debug_t<decltype(i)>> { return {}; }; Not a regression AFAICT