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| author | Jonathan Wakely <jwakely@redhat.com> | 2024-06-11 11:08:12 +0100 |
|---|---|---|
| committer | Jonathan Wakely <jwakely@redhat.com> | 2024-06-13 14:08:36 +0100 |
| commit | cc38bdf093c44918edff819ae6c73d03c726b341 (patch) | |
| tree | a90c3cee080c5d2e7e519b186f95d62102024961 | |
| parent | 99a1fe6c12c733fe4923a75a79d09a66ff8abcec (diff) | |
| download | gcc-cc38bdf093c44918edff819ae6c73d03c726b341.zip gcc-cc38bdf093c44918edff819ae6c73d03c726b341.tar.gz gcc-cc38bdf093c44918edff819ae6c73d03c726b341.tar.bz2 | |
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.
| -rw-r--r-- | libstdc++-v3/include/bits/hashtable.h | 2 | ||||
| -rw-r--r-- | libstdc++-v3/testsuite/23_containers/unordered_map/115420.cc | 16 |
2 files changed, 18 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; diff --git a/libstdc++-v3/testsuite/23_containers/unordered_map/115420.cc b/libstdc++-v3/testsuite/23_containers/unordered_map/115420.cc new file mode 100644 index 0000000..5528bf8 --- /dev/null +++ b/libstdc++-v3/testsuite/23_containers/unordered_map/115420.cc @@ -0,0 +1,16 @@ +// { dg-do compile { target c++11 } } + +#include <unordered_map> + +struct S { }; + +void +test_pr115420() +{ + std::unordered_map<S, int> m; // { dg-error "here" } +} + +// { dg-error "hash function must be copy constructible" "" { target *-*-* } 0 } +// { dg-prune-output "use of deleted function" } +// { dg-prune-output "is private" } +// { dg-prune-output "no matching function" } |