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authorJonathan Wakely <jwakely@redhat.com>2024-06-11 11:08:12 +0100
committerJonathan Wakely <jwakely@redhat.com>2024-06-13 14:08:36 +0100
commitcc38bdf093c44918edff819ae6c73d03c726b341 (patch)
treea90c3cee080c5d2e7e519b186f95d62102024961 /libstdc++-v3/include/bits/hashtable.h
parent99a1fe6c12c733fe4923a75a79d09a66ff8abcec (diff)
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libstdc++: Improve diagnostics for invalid std::hash specializations [PR115420]
When using a key type without a valid std::hash specialization the unordered containers give confusing diagnostics about the default constructor being deleted. Add a static_assert that will fail for disabled std::hash specializations (and for a subset of custom hash functions). libstdc++-v3/ChangeLog: PR libstdc++/115420 * include/bits/hashtable.h (_Hashtable): Add static_assert to check that hash function is copy constructible. * testsuite/23_containers/unordered_map/115420.cc: New test.
Diffstat (limited to 'libstdc++-v3/include/bits/hashtable.h')
-rw-r--r--libstdc++-v3/include/bits/hashtable.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/libstdc++-v3/include/bits/hashtable.h b/libstdc++-v3/include/bits/hashtable.h
index 983aa90..361da2b 100644
--- a/libstdc++-v3/include/bits/hashtable.h
+++ b/libstdc++-v3/include/bits/hashtable.h
@@ -210,6 +210,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
static_assert(is_same<typename _Alloc::value_type, _Value>{},
"unordered container must have the same value_type as its allocator");
#endif
+ static_assert(is_copy_constructible<_Hash>::value,
+ "hash function must be copy constructible");
using __traits_type = _Traits;
using __hash_cached = typename __traits_type::__hash_cached;