[Bug c++/113286] New: GCC accepts invalid program involving cast to protected base class

[jlame646 at gmail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113286

            Bug ID: 113286
           Summary: GCC accepts invalid program involving cast to
                    protected base class
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jlame646 at gmail dot com
  Target Milestone: ---

The following invalid program is accepted only by gcc.
https://godbolt.org/z/73Mh9bres

```
struct A {};
struct B: public A {int stuff() {return 5;} };  
struct C: protected B { using B::A; };

void call(A &) {}

int main()
{
    C c; 
    call(c);
}
```