https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115846
--- Comment #9 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to 康桓瑋 from comment #7) > It seems like ~_Storage() doesn't call _M_value.~_Up(). > I could be wrong. Because the _Storage union doesn't know if there is an active member or not, so it doesn't know if anything needs to be destroyed. It's done in _Optional_payload_base::_M_destroy(). (In reply to 康桓瑋 from comment #8) > [optional.dtor] specifies to call val->T::~T(). But only if it has a contained value. You can't destroy something that doesn't exist.
