[committed] libstdc++: Add constexpr to std::counted_iterator post-increment (LWG 3643)
Commit Message
Tested powerpc64le-linux, pushed to trunk.
This can be backported to 11 and 12 too.
-- >8 --
libstdc++-v3/ChangeLog:
* include/bits/stl_iterator.h (counted_iterator::operator++(int)):
Add 'constexpr' as per LWG 3643.
* testsuite/24_iterators/counted_iterator/lwg3643.cc: New test.
---
libstdc++-v3/include/bits/stl_iterator.h | 3 +--
.../24_iterators/counted_iterator/lwg3643.cc | 27 +++++++++++++++++++
2 files changed, 28 insertions(+), 2 deletions(-)
create mode 100644 libstdc++-v3/testsuite/24_iterators/counted_iterator/lwg3643.cc
@@ -2341,7 +2341,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
return *this;
}
- decltype(auto)
+ constexpr decltype(auto)
operator++(int)
{
__glibcxx_assert(_M_length > 0);
@@ -2353,7 +2353,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
++_M_length;
__throw_exception_again;
}
-
}
constexpr counted_iterator
new file mode 100644
@@ -0,0 +1,27 @@
+// { dg-options "-std=gnu++20" }
+// { dg-do compile { target c++20 } }
+
+#include <iterator>
+
+struct InputIterator
+{
+ using difference_type = int;
+ using value_type = int;
+
+ constexpr int operator*() const noexcept { return 0; }
+ InputIterator& operator++() { return *this; }
+ constexpr void operator++(int) { }
+};
+
+static_assert( std::input_iterator<InputIterator> );
+static_assert( !std::forward_iterator<InputIterator> );
+
+constexpr bool
+test_lwg3643()
+{
+ std::counted_iterator<InputIterator> iter({}, 1);
+ iter++;
+ return iter == std::default_sentinel;
+}
+
+static_assert( test_lwg3643() );