[Bug c++/84222] [[deprecated]] class complains about internal class usage

[gcc-bugzilla at daryl dot haresign.com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84222

--- Comment #1 from Daryl Haresign <gcc-bugzilla at daryl dot haresign.com> ---
Additionally, any external use of a static method of a deprecated class should
probably (but does not currently) emit a warning (Clang emits a warning).

class [[deprecated]] C {
  public:
    void fn() {}
};

int main()
{
    C::fn();  // does not emit a deprecation warning
}