#if _HAS_CXX17
template <class _Iter, class _Hasher = hash<_Guide_key_t<_Iter>>, class _Keyeq = equal_to<_Guide_key_t<_Iter>>,
    class _Alloc = allocator<_Guide_pair_t<_Iter>>,
    enable_if_t<
        conjunction_v<_Is_iterator<_Iter>, _Is_hasher<_Hasher>, negation<_Is_allocator<_Keyeq>>, _Is_allocator<_Alloc>>,
        int> = 0>
unordered_map(_Iter, _Iter, _Guide_size_type_t<_Alloc> = 0, _Hasher = _Hasher(), _Keyeq = _Keyeq(), _Alloc = _Alloc())
    ->unordered_map<_Guide_key_t<_Iter>, _Guide_val_t<_Iter>, _Hasher, _Keyeq, _Alloc>;

template <class _Kty, class _Ty, class _Hasher = hash<_Kty>, class _Keyeq = equal_to<_Kty>,
    class _Alloc = allocator<pair<const _Kty, _Ty>>,
    enable_if_t<conjunction_v<_Is_hasher<_Hasher>, negation<_Is_allocator<_Keyeq>>, _Is_allocator<_Alloc>>, int> = 0>
unordered_map(initializer_list<pair<_Kty, _Ty>>, _Guide_size_type_t<_Alloc> = 0, _Hasher = _Hasher(), _Keyeq = _Keyeq(),
    _Alloc = _Alloc())
    ->unordered_map<_Kty, _Ty, _Hasher, _Keyeq, _Alloc>;

template <class _Iter, class _Alloc, enable_if_t<conjunction_v<_Is_iterator<_Iter>, _Is_allocator<_Alloc>>, int> = 0>
unordered_map(_Iter, _Iter, _Alloc)
    ->unordered_map<_Guide_key_t<_Iter>, _Guide_val_t<_Iter>, hash<_Guide_key_t<_Iter>>, equal_to<_Guide_key_t<_Iter>>,
        _Alloc>;

template <class _Iter, class _Alloc, enable_if_t<conjunction_v<_Is_iterator<_Iter>, _Is_allocator<_Alloc>>, int> = 0>
unordered_map(_Iter, _Iter, _Guide_size_type_t<_Alloc>, _Alloc)
    ->unordered_map<_Guide_key_t<_Iter>, _Guide_val_t<_Iter>, hash<_Guide_key_t<_Iter>>, equal_to<_Guide_key_t<_Iter>>,
        _Alloc>;

template <class _Iter, class _Hasher, class _Alloc,
    enable_if_t<conjunction_v<_Is_iterator<_Iter>, _Is_hasher<_Hasher>, _Is_allocator<_Alloc>>, int> = 0>
unordered_map(_Iter, _Iter, _Guide_size_type_t<_Alloc>, _Hasher, _Alloc)
    ->unordered_map<_Guide_key_t<_Iter>, _Guide_val_t<_Iter>, _Hasher, equal_to<_Guide_key_t<_Iter>>, _Alloc>;

template <class _Kty, class _Ty, class _Alloc, enable_if_t<_Is_allocator<_Alloc>::value, int> = 0>
unordered_map(initializer_list<pair<_Kty, _Ty>>, _Alloc)->unordered_map<_Kty, _Ty, hash<_Kty>, equal_to<_Kty>, _Alloc>;

template <class _Kty, class _Ty, class _Alloc, enable_if_t<_Is_allocator<_Alloc>::value, int> = 0>
unordered_map(initializer_list<pair<_Kty, _Ty>>, _Guide_size_type_t<_Alloc>, _Alloc)
    ->unordered_map<_Kty, _Ty, hash<_Kty>, equal_to<_Kty>, _Alloc>;

template <class _Kty, class _Ty, class _Hasher, class _Alloc,
    enable_if_t<conjunction_v<_Is_hasher<_Hasher>, _Is_allocator<_Alloc>>, int> = 0>
unordered_map(initializer_list<pair<_Kty, _Ty>>, _Guide_size_type_t<_Alloc>, _Hasher, _Alloc)
    ->unordered_map<_Kty, _Ty, _Hasher, equal_to<_Kty>, _Alloc>;
#endif // _HAS_CXX17