[Bug c++/90895] __attribute__((warning(""))) doesn't work for dynamically dispatched calls to virtual functions

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90895

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Of course, if the code is optimized then no warnigns are issued at all, because
b.f() and b2.g() get inlined to nothing, and so no calls to the functions
remain.