/* { dg-do compile } */ /* { dg-options "-g -dA -std=gnu++11" } */ namespace std { template struct integral_constant { static constexpr _Tp value = 0; }; template using __bool_constant = integral_constant; struct __not_ : integral_constant { }; template class _Op, typename... _Args> struct __detector { using type = _Op<_Args...>; }; template class _Op, typename... _Args> using __detected_or = __detector<_Default, void, _Op, _Args...>; template class _Op, typename... _Args> using __detected_or_t = typename __detected_or<_Default, _Op, _Args...>::type; template