silencing warning "control reaches end of non-void function"

Hi,

Consider:

enum t {a, b};

OUString f(t i)
{
  switch(i)
  {
  case t::a;
    return "it was an a";
  case t::b;
    return "it was a b";
  }
}


gcc -Werror fails with
error: control reaches end of non-void function [-Werror=return-type]

But that is not true; since all possible values are treated and
return, it cannot fall through. How do I silence that spurious
warning-turned-error?

I tried adding "assert(false)", which solves the warning on my
machine, but not on Jenkins build linux_gcc_release_64, cf
https://ci.libreoffice.org/job/lo_gerrit/15859/Config=linux_gcc_release_64/

I don't want to add a fake
 return "never reached";
because I want compilation to fail if/when the switch is not
exhaustive (e.g. change of definition of enum t).

The "f" above is FilterManager::getFilterComponent in file
connectivity/source/commontools/filtermanager.cxx of
https://gerrit.libreoffice.org/40567

Thanks for you advice,

Lionel