The __is_key_type specialization that matches a pair<key_type, T>
argument is intended for std::unordered_map, not for
std::unordered_set<std::pair<K,T>>.
This uses a pair<const Args&...> as the template argument for
__is_key_type, so that it won't match a set's key_type.
libstdc++-v3/ChangeLog:
PR libstdc++/117686
* include/bits/hashtable.h (_Hashtable::_M_emplace_uniq):
Adjust usage of __is_key_type to avoid false positive.
* testsuite/23_containers/unordered_set/insert/117686.cc:
New test.
---
Tested powerpc64le-linux. Pushed to trunk.
libstdc++-v3/include/bits/hashtable.h | 4 ++--
.../23_containers/unordered_set/insert/117686.cc | 16 ++++++++++++++++
2 files changed, 18 insertions(+), 2 deletions(-)
create mode 100644
libstdc++-v3/testsuite/23_containers/unordered_set/insert/117686.cc
diff --git a/libstdc++-v3/include/bits/hashtable.h
b/libstdc++-v3/include/bits/hashtable.h
index a704816573a..b8bd8c2f418 100644
--- a/libstdc++-v3/include/bits/hashtable.h
+++ b/libstdc++-v3/include/bits/hashtable.h
@@ -2286,9 +2286,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
}
else if constexpr (sizeof...(_Args) == 2)
{
- pair<const _Args&...> __refs(__args...);
- if constexpr (__is_key_type<pair<_Args...>>)
+ if constexpr (__is_key_type<pair<const _Args&...>>)
{
+ pair<const _Args&...> __refs(__args...);
const auto& __key = _ExtractKey{}(__refs);
__kp = std::__addressof(__key);
}
diff --git
a/libstdc++-v3/testsuite/23_containers/unordered_set/insert/117686.cc
b/libstdc++-v3/testsuite/23_containers/unordered_set/insert/117686.cc
new file mode 100644
index 00000000000..3baac16c2b4
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/unordered_set/insert/117686.cc
@@ -0,0 +1,16 @@
+// { dg-do compile { target c++11 } }
+// Bug 117686 - error in unordered_set::emplace
+
+#include <unordered_set>
+#include <utility>
+
+struct H {
+ std::size_t operator()(const std::pair<int, int>&) const { return 0; }
+};
+
+void
+test_117686()
+{
+ std::unordered_set<std::pair<int, int>, H> s;
+ s.emplace(1, 2);
+}
--
2.47.0
