https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105725
--- Comment #1 from tim blechmann <tim at klingt dot org> --- it also ICEs on valid code: ``` template <bool> struct enable_if; template <bool _Cond> using enable_if_t = typename enable_if<_Cond>::type; template <typename> bool is_class_v; template <class, class> bool IsPrivateSignalArg; template <class T> bool IsPrivateSignalArg<T, enable_if_t<is_class_v<class T::QPrivateSignal>>>; ```
