[Bug c++/63515] unused templated member can be instatiated

[luka.rahne at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63515

--- Comment #1 from Luka Rahne <luka.rahne at gmail dot com> ---
Created attachment 33704
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33704&action=edit
Shorter Example