template<class T, T lhs, T rhs>
struct Refl
{
    Refl() = delete;
    Refl(const Refl<T, lhs, rhs>&) = delete;
    Refl<T, lhs, rhs>& operator=(const Refl<T, lhs, rhs>&) = delete;
};

template<class T, T both>
struct Refl<T, both, both>
{
};

static constexpr Refl<int, 1 + 1, 2> proof;
// static constexpr Refl<int, 1 + 1, 3> dumb;
// static constexpr Refl<int, 1 + 1, 3> dumber(dumber);