#include <iostream>
#include <array>

template <typename T, T ... S>
constexpr std::array<T, sizeof...(S)> operator "" _ar ()
{ return {S ...}; }

template <std::array S>
struct TAG
{};

//

int main()
{
    static_assert(std::is_same_v< TAG<"123"_ar>, TAG<"123"_ar> >);
    return 0;
}