Method max_size_impl

external/parallel_hashmap/phmap_base.h:1564–1566

    template <typename A>
    static auto max_size_impl(int, const A& a) -> decltype(a.max_size()) {
        return a.max_size();
    }
    static size_type max_size_impl(char, const Alloc&) {
        return (std::numeric_limits<size_type>::max)() / sizeof(value_type);
    }