https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122661
Bug ID: 122661
Summary: Incorrect value category handling in
forward_list::assign
Product: gcc
Version: 15.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: nedimsehic50 at gmail dot com
Target Milestone: ---
#include <forward_list>
struct S {
S() = default;
S& operator=(S const&) & = delete;
S& operator=(S const&) && { return *this; }
};
int main() {
std::forward_list<S> l;
S s;
l.assign(&s, &s + 1);
}
Godbolt: https://godbolt.org/z/xKdMsxjcq
The above code does not compile with an error complaining about "use of deleted
function 'S& S::operator=(const S&) &'".
The problem is in this check in assign:
if constexpr (is_assignable<_Tp, decltype(*__first)>::value)
but then later there is
*__curr = *__first;
where __curr is an lvalue of type _Tp.
The fix would be to just replace _Tp with _Tp& inside the is_assignable check.
