https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63362
--- Comment #21 from Jason Merrill <jason at gcc dot gnu.org> ---
(In reply to Ville Voutilainen from comment #20)
> template <bool b> struct bool_
> {
> };
>
> template <typename T, class... Args>
> struct mytrait : bool_<__is_trivially_constructible(T, Args...)>
> {
> };
>
> template <typename T, class... Args>
> struct mytrait2 : bool_<__is_trivially_constructible(T, Args...)>
> {
> };
Fixed.
