friend constexpr bool operator==(reference_wrapper x, reference_wrapper y);
friend constexpr bool operator==(reference_wrapper x, const T& y);
friend constexpr bool operator==(reference_wrapper x, reference_wrapper<const T> y);
friend constexpr synth-three-way-result<T> operator<=>(reference_wrapper x, reference_wrapper y);
friend constexpr synth-three-way-result<T> operator<=>(reference_wrapper x, const T& y);
friend constexpr synth-three-way-result<T> operator<=>(reference_wrapper x,
reference_wrapper<const T> y);