https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121250
Bug ID: 121250
Summary: Accepts invalid program containing function call via
member pointer to member in derived class during
constant evaluation
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: keinfluegeltier at posteo dot de
Target Milestone: ---
The following program is ill-formed, but accepted by GCC (see
https://godbolt.org/z/rYEq8ndbz):
struct A { };
struct B : A { constexpr void foo() {} };
consteval void test() {
auto p = &B::foo;
auto q = static_cast<void (A::*)()>(p);
A a;
(a.*q)();
}
int main() { test(); }
The call via member function pointer would have undefined behavior because the
member `B::foo` to which `q` refers is not a direct or indirect member of the
most derived class `A` of `a`. Therefore the constant evaluation of `test()`
must fail and the program is ill-formed.
