[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 #5 from Anders Granlund <anders.granlund.0 at gmail dot com> ---
*** Bug 66935 has been marked as a duplicate of this bug. ***