constexpr auto f()
{
    std::optional<size_t> index;
    static_for<0, 7>([&index](auto i) {
        if (!index) // The index of the first occurrence is stored
        {
            if constexpr (std::is_same_v < char, pack::type_by_index < static_cast<size_t>(decltype(i){}), char, int, float, double, int64_t, uint64_t, void >> )
                index = static_cast<size_t>(decltype(i){});
        }
        });

    return index;
}

    static constexpr auto idOf = *f();
    static_assert(idOf == 0);

constexpr auto f() noexcept
{
    constexpr auto index = pack::index_for_type<char, char, int, float, double, int64_t, uint64_t, void>();
    static_assert (index, "Type not found in pack");
    return *index;
}
static constexpr auto idOf = f();
static_assert(!idOf);