std::ranges::pair-like-convertible-from(C++20)

namespace std::ranges {
  // C++20
  template<class T, class U, class V>
    concept pair-like-convertible-from = // 説明専用コンセプト
      !range<T> && pair-like<T> &&
      constructible_from<T, U, V> &&
      convertible-to-non-slicing<U, tuple_element_t<0, T>> &&
      convertible_to<V, tuple_element_t<1, T>>;

  // C++23
  template<class T, class U, class V>
    concept pair-like-convertible-from = // 説明専用コンセプト
      !range<T> && !is_reference_v<T> && pair-like<T> &&
      constructible_from<T, U, V> &&
      convertible-to-non-slicing<U, tuple_element_t<0, T>> &&
      convertible_to<V, tuple_element_t<1, T>>;
}