in fatal/container/tuple_tags.h [202:209]
static constexpr bool foreach(Tuple &&tuple, V &&visitor, VArgs &&...args) {
return fatal::foreach<list>(
detail::tuple_tags_impl::foreach_visitor(),
std::forward<Tuple>(tuple),
std::forward<V>(visitor),
std::forward<VArgs>(args)...
), !empty<list>::value;
}