[Bug c++/77887] -Wimplicit-fallthrough fails to trigger in an unused function template specialisation

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77887

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Complete testcase please.

(In reply to Marc Mutz from comment #0)
> This specialisation ends up not being instantiated, but I'd expect a warning
> from a full specialisation nonetheless.

This is the case for *loads* of warnings. GCC doesn't do very much with
uninstantiated templates.

> Hmm. If I change from specialisation to overloading (ie. to a non-template),
> the switch still doesn't trigger.

Probably because it's inline.