https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99983
--- Comment #11 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This should fix it:
--- a/libstdc++-v3/include/bits/hashtable.h
+++ b/libstdc++-v3/include/bits/hashtable.h
@@ -1319,8 +1319,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_H1, _H2, _Hash, _RehashPolicy, _Traits>::
_Hashtable(_Hashtable&& __ht, __node_alloc_type&& __a,
true_type /* alloc always equal */)
- noexcept(std::is_nothrow_copy_constructible<_H1>::value &&
- std::is_nothrow_copy_constructible<_Equal>::value)
+ noexcept(_S_nothrow_move())
: __hashtable_base(__ht),
__map_base(__ht),
__rehash_base(__ht),
