39 class common_iterator {
57   common_iterator() requires default_initializable<_Iter> = default;
59   constexpr common_iterator(_Iter __i) : __hold_(in_place_type<_Iter>, _VSTD::move(__i)) {}  in common_iterator()  function
60   constexpr common_iterator(_Sent __s) : __hold_(in_place_type<_Sent>, _VSTD::move(__s)) {}  in common_iterator()  function
64   constexpr common_iterator(const common_iterator<_I2, _S2>& __other)  in common_iterator()  function
75   common_iterator& operator=(const common_iterator<_I2, _S2>& __other) {
127   common_iterator& operator++() {
150 …friend constexpr bool operator==(const common_iterator& __x, const common_iterator<_I2, _S2>& __y)…
168 …friend constexpr bool operator==(const common_iterator& __x, const common_iterator<_I2, _S2>& __y)…
189 …riend constexpr iter_difference_t<_I2> operator-(const common_iterator& __x, const common_iterator…
208   friend constexpr iter_rvalue_reference_t<_Iter> iter_move(const common_iterator& __i)  in iter_move()
217   friend constexpr void iter_swap(const common_iterator& __x, const common_iterator<_I2, _S2>& __y)  in iter_swap()
227 struct incrementable_traits<common_iterator<_Iter, _Sent>> {
237 concept __common_iter_has_ptr_op = requires(const common_iterator<_Iter, _Sent>& __a) {
249     using type = decltype(declval<const common_iterator<_Iter, _Sent>&>().operator->());
253 struct iterator_traits<common_iterator<_Iter, _Sent>> {