[Bug c++/66934] Compiler accepting ill-formed program with extern variable declarations and using-declaration

[anders.granlund.0 at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66934

--- Comment #6 from Anders Granlund <anders.granlund.0 at gmail dot com> ---
(In reply to Jonathan Wakely from comment #3)
> Problem report i.e. bugzilla bug.

Ok. Done.