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

[marc.mutz at kdab dot com]

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

--- Comment #2 from Marc Mutz <marc.mutz at kdab dot com> ---
Created attachment 39772
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=39772&action=edit
Expanded version of test-case for 77886, adding an unused inline non-template
overload of the function template

Findings:

  l.30 \ l.29           template specialisation      overload
  inline                 - doesn"t warn          - doesn't warn
  non-inline             + warns                 + warns