https://gcc.gnu.org/bugzilla/show_bug.cgi?id=128456
Bug ID: 128456
Summary: using-declaration skips access check when the member
is also reachable via another public path
Product: gcc
Version: 16.2.1
Status: UNCONFIRMED
Keywords: accepts-invalid
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: fchelnokov at gmail dot com
Target Milestone: ---
```
struct A { static int x; };
class B : A {};
struct C : A {};
struct D : B, C {
using B::x; // must be rejected, GCC accepts
using B::A; // same for the injected-class-name
};
```
The naming class of `B::x` and `B::A` is B ([class.access.base]/5), where both
are private, so the using-declarations in D are ill-formed
([namespace.udecl]/19). The public path through C must not matter (without C,
GCC rejects them). Clang and EDG reject both:
https://gcc.godbolt.org/z/91doaq6Wo
Related: https://stackoverflow.com/q/69311086/7325599
