Now that the frontend bug PR96805 is fixed, we can apply the proposed
resolution for this issue.
This slightly deviates from the proposed resolution by declaring _CI a
member of take_view instead of take_view::_Sentinel, since it doesn't
depend on anything within _Sentinel anymore.
Tested on x86_64-pc-linux-gnu, does this look OK for trunk?
libstdc++-v3/ChangeLog:
PR libstdc++/95322
* include/std/ranges (take_view::_CI): Define this alias
template as per LWG 3449 and remove ...
(take_view::_Sentinel::_CI): ... this type alias.
(take_view::_Sentinel::operator==): Adjust use of _CI
accordingly. Define a second overload that accepts an iterator
of the opposite constness as per LWG 3449.
(take_while_view::_Sentinel::operator==): Likewise.
* testsuite/std/ranges/adaptors/95322.cc: Add tests for LWG 3449.
---
libstdc++-v3/include/std/ranges | 23 +++++++++++++--
.../testsuite/std/ranges/adaptors/95322.cc | 28 ++++++++++++++++++-
2 files changed, 47 insertions(+), 4 deletions(-)
diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index 10f1f7b525b..19bc01a3b3a 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -1662,13 +1662,15 @@ namespace views
class take_view : public view_interface<take_view<_Vp>>
{
private:
+ template<bool _Const>
+ using _CI = counted_iterator<
+ iterator_t<__detail::__maybe_const_t<_Const, _Vp>>>;
+
template<bool _Const>
struct _Sentinel
{
private:
using _Base = __detail::__maybe_const_t<_Const, _Vp>;
- using _CI = counted_iterator<iterator_t<_Base>>;
-
sentinel_t<_Base> _M_end = sentinel_t<_Base>();
public:
@@ -1689,7 +1691,15 @@ namespace views
base() const
{ return _M_end; }
- friend constexpr bool operator==(const _CI& __y, const _Sentinel& __x)
+ friend constexpr bool
+ operator==(const _CI<_Const>& __y, const _Sentinel& __x)
+ { return __y.count() == 0 || __y.base() == __x._M_end; }
+
+ template<bool _OtherConst = !_Const,
+ typename _Base2 = __detail::__maybe_const_t<_OtherConst,
_Vp>>
+ requires sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
+ friend constexpr bool
+ operator==(const _CI<_OtherConst>& __y, const _Sentinel& __x)
{ return __y.count() == 0 || __y.base() == __x._M_end; }
friend _Sentinel<!_Const>;
@@ -1839,6 +1849,13 @@ namespace views
operator==(const iterator_t<_Base>& __x, const _Sentinel& __y)
{ return __y._M_end == __x || !std::__invoke(*__y._M_pred, *__x); }
+ template<bool _OtherConst = !_Const,
+ typename _Base2 = __detail::__maybe_const_t<_OtherConst,
_Vp>>
+ requires sentinel_for<sentinel_t<_Base>, iterator_t<_Base2>>
+ friend constexpr bool
+ operator==(const iterator_t<_Base2>& __x, const _Sentinel& __y)
+ { return __y._M_end == __x || !std::__invoke(*__y._M_pred, *__x); }
+
friend _Sentinel<!_Const>;
};
diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/95322.cc
b/libstdc++-v3/testsuite/std/ranges/adaptors/95322.cc
index 67bc7d33917..41785a0a8fa 100644
--- a/libstdc++-v3/testsuite/std/ranges/adaptors/95322.cc
+++ b/libstdc++-v3/testsuite/std/ranges/adaptors/95322.cc
@@ -26,7 +26,7 @@ using __gnu_test::test_forward_range;
void
test01()
{
- // PR libstdc++/95322 and LWG 3488
+ // PR libstdc++/95322 and LWG 3448
int a[2]{1, 2};
test_forward_range<int> v{a};
auto view1 = v | std::views::take(2);
@@ -51,8 +51,34 @@ test02()
VERIFY( !eq );
}
+void
+test03()
+{
+ // LWG 3449, for take_view
+ int a[2]{1, 2};
+ test_forward_range<int> v{a};
+ auto view1 = v | std::views::transform(std::identity{});
+ auto view2 = view1 | std::views::take(2);
+ const bool eq = std::ranges::cbegin(view2) == std::ranges::end(view2);
+ VERIFY( !eq );
+}
+
+void
+test04()
+{
+ // LWG 3449, for take_while_view
+ int a[2]{1, 2};
+ test_forward_range<int> v{a};
+ auto view1 = v | std::views::transform(std::identity{});
+ auto view2 = view1 | std::views::take_while([] (int i) { return true; });
+ const bool eq = std::ranges::cbegin(view2) == std::ranges::end(view2);
+ VERIFY( !eq );
+}
+
int main()
{
test01();
test02();
+ test03();
+ test04();
}
--
2.29.0.rc0
