[Bug fortran/69495] unused-label warning does not tell which flag triggered it

[janus at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69495

--- Comment #4 from janus at gcc dot gnu.org ---
Btw, I noticed another loosely related issue concerning misspellings of the
warning flags:


$ gfortran -Wunused-labels test.f90 
gfortran: error: unrecognized command line option ‘-Wunused-labels’

$ gfortran -Wno-unused-labels test.f90
(no error!)

$ gfortran -Wall -Wno-unused-labels test.f90 
f951: Warning: unrecognized command line option ‘-Wno-unused-labels’


This seems very inconsistent: All three calls involve an invalid flag, but the
diagnostics is very different for each of them (it's particularly bad that the
second case does not give any kind of feedback). Is there a reason for this
behavior?