https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115497
--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Ok, clang behavior is an odd one here: ``` template<typename _Tp, bool _IsPtr = __is_pointer(_Tp)> struct __is_pointer {}; template<typename _Tp> inline bool t = __is_pointer(_Tp); template<bool> struct ts{}; template<typename _Tp> struct is_pointer : ts<__is_pointer(_Tp)> {}; int tt = t<int>; ``` clang does not complain about the use of __is_pointer for variable template t but does for the base class of is_pointer.