* [committed] libstdc++: Finish implementing LWG 3413 for propagate_const
@ 2021-06-08 14:01 Jonathan Wakely
0 siblings, 0 replies; only message in thread
From: Jonathan Wakely @ 2021-06-08 14:01 UTC (permalink / raw)
To: libstdc++, gcc-patches
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We already have conditional noexcept so this just constrains the
non-member swap overload.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/experimental/propagate_const (swap): Constrain.
* testsuite/experimental/propagate_const/swap/lwg3413.cc: New test.
Tested x86_64-linux. Committed to trunk.
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commit d319517e809ee50496db29e552f86a83a14c837c
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Tue Jun 8 14:56:57 2021
libstdc++: Finish implementing LWG 3413 for propagate_const
We already have conditional noexcept so this just constrains the
non-member swap overload.
Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:
* include/experimental/propagate_const (swap): Constrain.
* testsuite/experimental/propagate_const/swap/lwg3413.cc: New test.
diff --git a/libstdc++-v3/include/experimental/propagate_const b/libstdc++-v3/include/experimental/propagate_const
index 0d03c13c5e1..162b4783dd7 100644
--- a/libstdc++-v3/include/experimental/propagate_const
+++ b/libstdc++-v3/include/experimental/propagate_const
@@ -113,6 +113,7 @@ inline namespace fundamentals_v2
constexpr propagate_const() = default;
propagate_const(const propagate_const& __p) = delete;
constexpr propagate_const(propagate_const&& __p) = default;
+
template <typename _Up, typename
enable_if<__and_<is_constructible<_Tp, _Up&&>,
is_convertible<_Up&&, _Tp>>::value, bool
@@ -120,6 +121,7 @@ inline namespace fundamentals_v2
constexpr propagate_const(propagate_const<_Up>&& __pu)
: _M_t(std::move(get_underlying(__pu)))
{}
+
template <typename _Up, typename
enable_if<__and_<is_constructible<_Tp, _Up&&>,
__not_<is_convertible<_Up&&, _Tp>>>::value,
@@ -127,6 +129,7 @@ inline namespace fundamentals_v2
constexpr explicit propagate_const(propagate_const<_Up>&& __pu)
: _M_t(std::move(get_underlying(__pu)))
{}
+
template <typename _Up, typename
enable_if<__and_<is_constructible<_Tp, _Up&&>,
is_convertible<_Up&&, _Tp>,
@@ -136,6 +139,7 @@ inline namespace fundamentals_v2
constexpr propagate_const(_Up&& __u)
: _M_t(std::forward<_Up>(__u))
{}
+
template <typename _Up, typename
enable_if<__and_<is_constructible<_Tp, _Up&&>,
__not_<is_convertible<_Up&&, _Tp>>,
@@ -399,8 +403,10 @@ inline namespace fundamentals_v2
}
// [propagate_const.algorithms], specialized algorithms
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // 3413. propagate_const's swap [...] needs to be constrained and use a trait
template <typename _Tp>
- constexpr void
+ constexpr enable_if_t<__is_swappable<_Tp>::value, void>
swap(propagate_const<_Tp>& __pt, propagate_const<_Tp>& __pt2)
noexcept(__is_nothrow_swappable<_Tp>::value)
{
diff --git a/libstdc++-v3/testsuite/experimental/propagate_const/swap/lwg3413.cc b/libstdc++-v3/testsuite/experimental/propagate_const/swap/lwg3413.cc
new file mode 100644
index 00000000000..8dc13cfebdd
--- /dev/null
+++ b/libstdc++-v3/testsuite/experimental/propagate_const/swap/lwg3413.cc
@@ -0,0 +1,41 @@
+// { dg-do compile { target c++14 } }
+
+// LWG 3413
+// propagate_const's swap's noexcept specification needs to be constrained
+// and use a trait
+
+#include <experimental/propagate_const>
+
+using std::experimental::propagate_const;
+
+propagate_const<int*> i;
+static_assert( noexcept(i.swap(i)), "member swap is noexcept" );
+static_assert( noexcept(swap(i, i)), "non-member swap is noexcept" );
+
+struct P
+{
+ int i = 0;
+ int& operator*() const;
+};
+
+void swap(P&, P&) noexcept(false);
+
+propagate_const<P> p;
+static_assert( ! noexcept(p.swap(p)), "member swap is conditionally noexcept" );
+static_assert( ! noexcept(swap(p, p)), "non-member swap is conditionally noexcept" );
+
+// std::is_swappable not available for -std=c++14
+#if __cplusplus > 201402L || !defined(__STRICT_ANSI__)
+struct Q
+{
+ int i = 0;
+ int& operator*() const;
+
+ Q& operator=(Q&&) = delete;
+};
+
+static_assert( ! std::is_swappable<Q>::value, "" );
+
+static_assert( ! std::is_swappable<propagate_const<Q>>::value,
+ "non-member swap is constrained" );
+#endif
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