@@ -2902,59 +2902,7 @@ namespace ranges
inline constexpr __set_symmetric_difference_fn set_symmetric_difference{};
- struct __min_fn
- {
- template<typename _Tp, typename _Proj = identity,
- indirect_strict_weak_order<projected<const _Tp*, _Proj>>
- _Comp = ranges::less>
- constexpr const _Tp&
- operator()(const _Tp& __a, const _Tp& __b,
- _Comp __comp = {}, _Proj __proj = {}) const
- {
- if (std::__invoke(__comp,
- std::__invoke(__proj, __b),
- std::__invoke(__proj, __a)))
- return __b;
- else
- return __a;
- }
-
- template<input_range _Range, typename _Proj = identity,
- indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>>
- _Comp = ranges::less>
- requires indirectly_copyable_storable<iterator_t<_Range>,
- range_value_t<_Range>*>
- constexpr range_value_t<_Range>
- operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
- {
- auto __first = ranges::begin(__r);
- auto __last = ranges::end(__r);
- __glibcxx_assert(__first != __last);
- auto __result = *__first;
- while (++__first != __last)
- {
- auto __tmp = *__first;
- if (std::__invoke(__comp,
- std::__invoke(__proj, __tmp),
- std::__invoke(__proj, __result)))
- __result = std::move(__tmp);
- }
- return __result;
- }
-
- template<copyable _Tp, typename _Proj = identity,
- indirect_strict_weak_order<projected<const _Tp*, _Proj>>
- _Comp = ranges::less>
- constexpr _Tp
- operator()(initializer_list<_Tp> __r,
- _Comp __comp = {}, _Proj __proj = {}) const
- {
- return (*this)(ranges::subrange(__r),
- std::move(__comp), std::move(__proj));
- }
- };
-
- inline constexpr __min_fn min{};
+ // min is defined in <bits/ranges_util.h>.
struct __max_fn
{
@@ -649,6 +649,61 @@ namespace ranges
};
inline constexpr __search_fn search{};
+
+ struct __min_fn
+ {
+ template<typename _Tp, typename _Proj = identity,
+ indirect_strict_weak_order<projected<const _Tp*, _Proj>>
+ _Comp = ranges::less>
+ constexpr const _Tp&
+ operator()(const _Tp& __a, const _Tp& __b,
+ _Comp __comp = {}, _Proj __proj = {}) const
+ {
+ if (std::__invoke(__comp,
+ std::__invoke(__proj, __b),
+ std::__invoke(__proj, __a)))
+ return __b;
+ else
+ return __a;
+ }
+
+ template<input_range _Range, typename _Proj = identity,
+ indirect_strict_weak_order<projected<iterator_t<_Range>, _Proj>>
+ _Comp = ranges::less>
+ requires indirectly_copyable_storable<iterator_t<_Range>,
+ range_value_t<_Range>*>
+ constexpr range_value_t<_Range>
+ operator()(_Range&& __r, _Comp __comp = {}, _Proj __proj = {}) const
+ {
+ auto __first = ranges::begin(__r);
+ auto __last = ranges::end(__r);
+ __glibcxx_assert(__first != __last);
+ auto __result = *__first;
+ while (++__first != __last)
+ {
+ auto __tmp = *__first;
+ if (std::__invoke(__comp,
+ std::__invoke(__proj, __tmp),
+ std::__invoke(__proj, __result)))
+ __result = std::move(__tmp);
+ }
+ return __result;
+ }
+
+ template<copyable _Tp, typename _Proj = identity,
+ indirect_strict_weak_order<projected<const _Tp*, _Proj>>
+ _Comp = ranges::less>
+ constexpr _Tp
+ operator()(initializer_list<_Tp> __r,
+ _Comp __comp = {}, _Proj __proj = {}) const
+ {
+ return (*this)(ranges::subrange(__r),
+ std::move(__comp), std::move(__proj));
+ }
+ };
+
+ inline constexpr __min_fn min{};
+
} // namespace ranges
using ranges::get;
@@ -39,6 +39,7 @@
#if __cpp_lib_concepts
#include <compare>
+#include <cstdint>
#include <initializer_list>
#include <iterator>
#include <optional>
@@ -4352,6 +4353,450 @@ namespace views::__adaptor
inline constexpr auto values = elements<1>;
} // namespace views
+#if __cplusplus > 202002L
+ namespace __detail
+ {
+ template<typename... _Rs>
+ concept __zip_is_common = (sizeof...(_Rs) == 1 && (common_range<_Rs> && ...))
+ || (!(bidirectional_range<_Rs> && ...) && (common_range<_Rs> && ...))
+ || ((random_access_range<_Rs> && ...) && (sized_range<_Rs> && ...));
+
+ template<typename... _Ts>
+ struct __tuple_or_pair
+ { using type = std::tuple<_Ts...>; };
+
+ template<typename _Tp, typename _Up>
+ struct __tuple_or_pair<_Tp, _Up>
+ { using type = pair<_Tp, _Up>; };
+
+ template<typename... _Ts>
+ using __tuple_or_pair_t = typename __tuple_or_pair<_Ts...>::type;
+
+ template<typename _Fp, typename _Tuple>
+ constexpr auto
+ __tuple_transform(_Fp&& __f, _Tuple&& __tuple)
+ {
+ return std::apply([&]<typename... _Ts>(_Ts&&... __elts) {
+ return __tuple_or_pair_t<invoke_result_t<_Fp&, _Ts>...>
+ (std::__invoke(__f, std::forward<_Ts>(__elts))...);
+ }, std::forward<_Tuple>(__tuple));
+ }
+
+ template<typename _Fp, typename _Tuple>
+ constexpr void
+ __tuple_for_each(_Fp&& __f, _Tuple&& __tuple)
+ {
+ std::apply([&]<typename... _Ts>(_Ts&&... __elts) {
+ (std::__invoke(__f, std::forward<_Ts>(__elts)), ...);
+ }, std::forward<_Tuple>(__tuple));
+ }
+ } // namespace __detail
+
+ template<input_range... _Vs>
+ requires (view<_Vs> && ...) && (sizeof...(_Vs) > 0)
+ class zip_view : public view_interface<zip_view<_Vs...>>
+ {
+ tuple<_Vs...> _M_views;
+
+ template<bool> class iterator;
+ template<bool> class sentinel;
+
+ public:
+ zip_view() = default;
+
+ constexpr explicit
+ zip_view(_Vs... views)
+ : _M_views(std::move(views)...)
+ { }
+
+ constexpr auto
+ begin() requires (!(__detail::__simple_view<_Vs> && ...))
+ { return iterator<false>(__detail::__tuple_transform(ranges::begin, _M_views)); }
+
+ constexpr auto
+ begin() const requires (range<const _Vs> && ...)
+ { return iterator<true>(__detail::__tuple_transform(ranges::begin, _M_views)); }
+
+ constexpr auto
+ end() requires (!(__detail::__simple_view<_Vs> && ...))
+ {
+ if constexpr (!__detail::__zip_is_common<_Vs...>)
+ return sentinel<false>(__detail::__tuple_transform(ranges::end, _M_views));
+ else if constexpr ((random_access_range<_Vs> && ...))
+ return begin() + iter_difference_t<iterator<false>>(size());
+ else
+ return iterator<false>(__detail::__tuple_transform(ranges::end, _M_views));
+ }
+
+ constexpr auto
+ end() const requires (range<const _Vs> && ...)
+ {
+ if constexpr (!__detail::__zip_is_common<const _Vs...>)
+ return sentinel<true>(__detail::__tuple_transform(ranges::end, _M_views));
+ else if constexpr ((random_access_range<const _Vs> && ...))
+ return begin() + iter_difference_t<iterator<true>>(size());
+ else
+ return iterator<true>(__detail::__tuple_transform(ranges::end, _M_views));
+ }
+
+ constexpr auto
+ size() requires (sized_range<_Vs> && ...)
+ {
+ return std::apply([](auto... sizes) {
+ using _CT = __detail::__make_unsigned_like_t<common_type_t<decltype(sizes)...>>;
+ return ranges::min({_CT(sizes)...});
+ }, __detail::__tuple_transform(ranges::size, _M_views));
+ }
+
+ constexpr auto
+ size() const requires (sized_range<const _Vs> && ...)
+ {
+ return std::apply([](auto... sizes) {
+ using _CT = __detail::__make_unsigned_like_t<common_type_t<decltype(sizes)...>>;
+ return ranges::min({_CT(sizes)...});
+ }, __detail::__tuple_transform(ranges::size, _M_views));
+ }
+ };
+
+ template<typename... _Rs>
+ zip_view(_Rs&&...) -> zip_view<views::all_t<_Rs>...>;
+
+ template<typename... _Views>
+ inline constexpr bool enable_borrowed_range<zip_view<_Views...>>
+ = (enable_borrowed_range<_Views> && ...);
+
+ namespace __detail
+ {
+ template<bool _Const, typename... _Vs>
+ concept __all_random_access
+ = (random_access_range<__maybe_const_t<_Const, _Vs>> && ...);
+
+ template<bool _Const, typename... _Vs>
+ concept __all_bidirectional
+ = (bidirectional_range<__maybe_const_t<_Const, _Vs>> && ...);
+
+ template<bool _Const, typename... _Vs>
+ concept __all_forward
+ = (forward_range<__maybe_const_t<_Const, _Vs>> && ...);
+
+ template<bool _Const, typename... _Views>
+ struct __zip_view_iter_cat
+ { };
+
+ template<bool _Const, typename... _Views>
+ requires __all_forward<_Const, _Views...>
+ struct __zip_view_iter_cat<_Const, _Views...>
+ { using iterator_category = input_iterator_tag; };
+ } // namespace __detail
+
+ template<input_range... _Vs>
+ requires (view<_Vs> && ...) && (sizeof...(_Vs) > 0)
+ template<bool _Const>
+ class zip_view<_Vs...>::iterator
+ : public __detail::__zip_view_iter_cat<_Const, _Vs...>
+ {
+ __detail::__tuple_or_pair_t<iterator_t<__detail::__maybe_const_t<_Const, _Vs>>...> _M_current;
+
+ constexpr explicit
+ iterator(decltype(_M_current) __current)
+ : _M_current(std::move(__current))
+ { }
+
+ static auto
+ _S_iter_concept()
+ {
+ if constexpr (__detail::__all_random_access<_Const, _Vs...>)
+ return random_access_iterator_tag{};
+ else if constexpr (__detail::__all_bidirectional<_Const, _Vs...>)
+ return bidirectional_iterator_tag{};
+ else if constexpr (__detail::__all_forward<_Const, _Vs...>)
+ return forward_iterator_tag{};
+ else
+ return input_iterator_tag{};
+ }
+
+ public:
+ // iterator_category defined in __zip_view_iter_cat
+ using iterator_concept = decltype(_S_iter_concept());
+ using value_type
+ = __detail::__tuple_or_pair_t<range_value_t<__detail::__maybe_const_t<_Const, _Vs>>...>;
+ using difference_type
+ = common_type_t<range_difference_t<__detail::__maybe_const_t<_Const, _Vs>>...>;
+
+ iterator() = default;
+
+ constexpr
+ iterator(iterator<!_Const> __i)
+ requires _Const
+ && (convertible_to<iterator_t<_Vs>,
+ iterator_t<__detail::__maybe_const_t<_Const, _Vs>>> && ...)
+ : _M_current(std::move(__i._M_current))
+ { }
+
+ constexpr auto
+ operator*() const
+ {
+ auto __f = [](auto& __i) -> decltype(auto) {
+ return *__i;
+ };
+ return __detail::__tuple_transform(__f, _M_current);
+ }
+
+ constexpr iterator&
+ operator++()
+ {
+ __detail::__tuple_for_each([](auto& __i) { ++__i; }, _M_current);
+ return *this;
+ }
+
+ constexpr void
+ operator++(int)
+ { ++*this; }
+
+ constexpr iterator
+ operator++(int)
+ requires __detail::__all_forward<_Const, _Vs...>
+ {
+ auto __tmp = *this;
+ ++*this;
+ return __tmp;
+ }
+
+ constexpr iterator&
+ operator--()
+ requires __detail::__all_bidirectional<_Const, _Vs...>
+ {
+ __detail::__tuple_for_each([](auto& __i) { --__i; }, _M_current);
+ return *this;
+ }
+
+ constexpr iterator
+ operator--(int)
+ requires __detail::__all_bidirectional<_Const, _Vs...>
+ {
+ auto __tmp = *this;
+ --*this;
+ return __tmp;
+ }
+
+ constexpr iterator&
+ operator+=(difference_type __x)
+ requires __detail::__all_random_access<_Const, _Vs...>
+ {
+ auto __f = [&]<typename _It>(_It& __i) {
+ __i += iter_difference_t<_It>(__x);
+ };
+ __detail::__tuple_for_each(__f, _M_current);
+ return *this;
+ }
+
+ constexpr iterator&
+ operator-=(difference_type __x)
+ requires __detail::__all_random_access<_Const, _Vs...>
+ {
+ auto __f = [&]<typename _It>(_It& __i) {
+ __i -= iter_difference_t<_It>(__x);
+ };
+ __detail::__tuple_for_each(__f, _M_current);
+ return *this;
+ }
+
+ constexpr auto
+ operator[](difference_type __n) const
+ requires __detail::__all_random_access<_Const, _Vs...>
+ {
+ auto __f = [&]<typename _It>(_It& __i) -> decltype(auto) {
+ return __i[iter_difference_t<_It>(__n)];
+ };
+ return __detail::__tuple_transform(__f, _M_current);
+ }
+
+ friend constexpr bool
+ operator==(const iterator& __x, const iterator& __y)
+ requires (equality_comparable<iterator_t<__detail::__maybe_const_t<_Const, _Vs>>> && ...)
+ {
+ if constexpr (__detail::__all_bidirectional<_Const, _Vs...>)
+ return __x._M_current == __y._M_current;
+ else
+ return [&]<size_t... _Is>(index_sequence<_Is...>) {
+ return ((std::get<_Is>(__x._M_current) == std::get<_Is>(__y._M_current)) || ...);
+ }(make_index_sequence<sizeof...(_Vs)>{});
+ }
+
+ friend constexpr bool
+ operator<(const iterator& __x, const iterator& __y)
+ requires __detail::__all_random_access<_Const, _Vs...>
+ { return __x._M_current < __y._M_current; }
+
+ friend constexpr bool
+ operator>(const iterator& __x, const iterator& __y)
+ requires __detail::__all_random_access<_Const, _Vs...>
+ { return __y < __x; }
+
+ friend constexpr bool
+ operator<=(const iterator& __x, const iterator& __y)
+ requires __detail::__all_random_access<_Const, _Vs...>
+ { return !(__y < __x); }
+
+ friend constexpr bool
+ operator>=(const iterator& __x, const iterator& __y)
+ requires __detail::__all_random_access<_Const, _Vs...>
+ { return !(__x < __y); }
+
+ friend constexpr auto
+ operator<=>(const iterator& __x, const iterator& __y)
+ requires __detail::__all_random_access<_Const, _Vs...>
+ && (three_way_comparable<iterator_t<__detail::__maybe_const_t<_Const, _Vs>>> && ...)
+ { return __x._M_current <=> __y._M_current; }
+
+ friend constexpr iterator
+ operator+(const iterator& __i, difference_type __n)
+ requires __detail::__all_random_access<_Const, _Vs...>
+ {
+ auto __r = __i;
+ __r += __n;
+ return __r;
+ }
+
+ friend constexpr iterator
+ operator+(difference_type __n, const iterator& __i)
+ requires __detail::__all_random_access<_Const, _Vs...>
+ {
+ auto __r = __i;
+ __r += __n;
+ return __r;
+ }
+
+ friend constexpr iterator
+ operator-(const iterator& __i, difference_type __n)
+ requires __detail::__all_random_access<_Const, _Vs...>
+ {
+ auto __r = __i;
+ __r -= __n;
+ return __r;
+ }
+
+ friend constexpr difference_type
+ operator-(const iterator& __x, const iterator& __y)
+ requires (sized_sentinel_for<iterator_t<__detail::__maybe_const_t<_Const, _Vs>>,
+ iterator_t<__detail::__maybe_const_t<_Const, _Vs>>> && ...)
+ {
+ return [&]<size_t... _Is>(index_sequence<_Is...>) {
+ return ranges::min({difference_type(std::get<_Is>(__x._M_current)
+ - std::get<_Is>(__y._M_current))...},
+ ranges::less{},
+ [](difference_type __i) -> make_unsigned_t<difference_type> {
+ // TODO: use constexpr std::abs from P0533R9 once implemented
+ return __i < 0 ? -__i : __i;
+ });
+ }(make_index_sequence<sizeof...(_Vs)>{});
+ }
+
+ friend constexpr auto
+ iter_move(const iterator& __i)
+ { return __detail::__tuple_transform(ranges::iter_move, __i._M_current); }
+
+ friend constexpr void
+ iter_swap(const iterator& __l, const iterator& __r)
+ requires (indirectly_swappable<iterator_t<__detail::__maybe_const_t<_Const, _Vs>>> && ...)
+ {
+ [&]<size_t... _Is>(index_sequence<_Is...>) {
+ (ranges::iter_swap(std::get<_Is>(__l._M_current), std::get<_Is>(__r._M_current)), ...);
+ }(make_index_sequence<sizeof...(_Vs)>{});
+ }
+
+ friend class zip_view;
+ };
+
+ template<input_range... _Vs>
+ requires (view<_Vs> && ...) && (sizeof...(_Vs) > 0)
+ template<bool _Const>
+ class zip_view<_Vs...>::sentinel
+ {
+ __detail::__tuple_or_pair_t<sentinel_t<__detail::__maybe_const_t<_Const, _Vs>>...> _M_end;
+
+ constexpr explicit
+ sentinel(decltype(_M_end) __end)
+ : _M_end(__end)
+ { }
+
+ friend class zip_view;
+
+ public:
+ sentinel() = default;
+
+ constexpr
+ sentinel(sentinel<!_Const> __i)
+ requires _Const
+ && (convertible_to<sentinel_t<_Vs>,
+ sentinel_t<__detail::__maybe_const_t<_Const, _Vs>>> && ...)
+ : _M_end(std::move(__i._M_end))
+ { }
+
+ template<bool _OtherConst>
+ requires (sentinel_for<sentinel_t<__detail::__maybe_const_t<_Const, _Vs>>,
+ iterator_t<__detail::__maybe_const_t<_OtherConst, _Vs>>> && ...)
+ friend constexpr bool
+ operator==(const iterator<_OtherConst>& __x, const sentinel& __y)
+ {
+ return [&]<size_t... _Is>(index_sequence<_Is...>) {
+ return ((std::get<_Is>(__x._M_current) == std::get<_Is>(__y._M_end)) || ...);
+ }(make_index_sequence<sizeof...(_Vs)>{});
+ }
+
+ template<bool _OtherConst>
+ requires (sized_sentinel_for<sentinel_t<__detail::__maybe_const_t<_Const, _Vs>>,
+ iterator_t<__detail::__maybe_const_t<_OtherConst, _Vs>>> && ...)
+ friend constexpr auto
+ operator-(const iterator<_OtherConst>& __x, const sentinel& __y)
+ {
+ using _Ret
+ = common_type_t<range_difference_t<__detail::__maybe_const_t<_OtherConst, _Vs>>...>;
+ return [&]<size_t... _Is>(index_sequence<_Is...>) {
+ return ranges::min({_Ret(std::get<_Is>(__x._M_current) - std::get<_Is>(__y._M_end))...},
+ ranges::less{},
+ [](_Ret __i) -> make_unsigned_t<_Ret> {
+ // TODO: use constexpr std::abs from P0533R9 once implemented
+ return __i < 0 ? -__i : __i;
+ });
+ }(make_index_sequence<sizeof...(_Vs)>{});
+ }
+
+ template<bool _OtherConst>
+ requires (sized_sentinel_for<sentinel_t<__detail::__maybe_const_t<_Const, _Vs>>,
+ iterator_t<__detail::__maybe_const_t<_OtherConst, _Vs>>> && ...)
+ friend constexpr auto
+ operator-(const sentinel& __y, const iterator<_OtherConst>& __x)
+ { return -(__x - __y); }
+ };
+
+ namespace views
+ {
+ namespace __detail
+ {
+ template<typename... _Ts>
+ concept __can_zip_view
+ = requires { zip_view<all_t<_Ts>...>(std::declval<_Ts>()...); };
+ }
+
+ struct _Zip
+ {
+ template<typename... _Ts>
+ requires (sizeof...(_Ts) == 0 || __detail::__can_zip_view<_Ts...>)
+ [[nodiscard]]
+ constexpr auto
+ operator()(_Ts&&... __ts) const
+ {
+ if constexpr (sizeof...(_Ts) == 0)
+ return views::empty<tuple<>>;
+ else
+ return zip_view<all_t<_Ts>...>(std::forward<_Ts>(__ts)...);
+ }
+ };
+
+ inline constexpr _Zip zip;
+ }
+#endif // C++23
} // namespace ranges
namespace views = ranges::views;
new file mode 100644
@@ -0,0 +1,101 @@
+// { dg-options "-std=gnu++23" }
+// { dg-do run { target c++23 } }
+
+#include <ranges>
+#include <algorithm>
+#include <utility>
+#include <vector>
+#include <testsuite_hooks.h>
+#include <testsuite_iterators.h>
+
+namespace ranges = std::ranges;
+namespace views = std::views;
+
+constexpr bool
+test01()
+{
+ static_assert(ranges::empty(views::zip()));
+ static_assert(ranges::empty(views::empty<int>));
+
+ auto z1 = views::zip(std::array{1, 2});
+ const auto i0 = z1.begin(), i1 = z1.begin() + 1;
+ VERIFY( i0 + 1 - 1 == i0 );
+ VERIFY( i0 < i1 );
+ VERIFY( i1 < z1.end() );
+ VERIFY( i1 - i0 == 1 );
+ VERIFY( i0 - i1 == -1 );
+ VERIFY( z1.end() - i1 == 1 );
+ VERIFY( i1 - z1.end() == -1 );
+ ranges::iter_swap(i0, i1);
+ VERIFY( ranges::equal(std::move(z1) | views::keys, (int[]){2, 1}) );
+
+ auto z2 = views::zip(std::array{1, 2}, std::array{3, 4, 5});
+ VERIFY( ranges::size(z2) == 2 );
+ VERIFY( ranges::size(std::as_const(z2)) == 2 );
+ VERIFY( z2[0].first == 1 && z2[0].second == 3 );
+ VERIFY( z2[1].first == 2 && z2[1].second == 4 );
+ for (const auto [x, y] : z2)
+ {
+ VERIFY( y - x == 2 );
+ std::swap(x, y);
+ }
+
+ int x[2] = {1, 2}, y[2] = {3, 4}, z[2] = {5, 6};
+ const auto z3 = views::zip(x, y, z);
+ VERIFY( ranges::size(z3) == 2 );
+ for (int i = 0; i < ranges::size(x); i++)
+ {
+ VERIFY( &std::get<0>(z3[i]) == &x[i] );
+ VERIFY( &std::get<1>(z3[i]) == &y[i] );
+ VERIFY( &std::get<2>(z3[i]) == &z[i] );
+ }
+
+ return true;
+}
+
+constexpr bool
+test02()
+{
+ using __gnu_test::test_input_range;
+ using __gnu_test::test_forward_range;
+ using __gnu_test::test_random_access_range;
+
+ using ty1 = ranges::zip_view<views::all_t<test_forward_range<int>>,
+ views::all_t<test_random_access_range<int>>>;
+ static_assert(ranges::forward_range<ty1>);
+ static_assert(!ranges::random_access_range<ty1>);
+ static_assert(!ranges::sized_range<ty1>);
+
+ using ty2 = ranges::zip_view<views::all_t<test_forward_range<int>>,
+ views::all_t<test_input_range<int>>,
+ views::all_t<test_forward_range<int>>>;
+ static_assert(ranges::input_range<ty2>);
+ static_assert(!ranges::forward_range<ty2>);
+ static_assert(!ranges::sized_range<ty2>);
+
+ return true;
+}
+
+constexpr bool
+test03()
+{
+ int u[] = {1, 2, 3, 4}, v[] = {4, 5, 6}, w[] = {7, 8, 9, 10};
+ auto z = views::zip(u | views::filter([](auto) { return true; }), v, w);
+ using ty = decltype(z);
+ static_assert(ranges::forward_range<ty>);
+ static_assert(!ranges::common_range<ty>);
+ static_assert(!ranges::sized_range<ty>);
+ VERIFY( z.begin() == z.begin() );
+ VERIFY( z.begin() != z.end() );
+ VERIFY( ranges::next(z.begin(), 3) == z.end() );
+
+ return true;
+}
+
+int
+main()
+{
+ static_assert(test01());
+ static_assert(test02());
+ static_assert(test03());
+}