What to do with argument mismatches in Fortran (was: [patch, fortran] Fix PR 91443)

[Steve Kargl]

On Tue, Aug 20, 2019 at 09:56:27PM +0200, Thomas Koenig wrote:
> I wrote:
> 
> > Committed as r274551.
> 
> Well, this revision appears to have woken quite a few bugs from their
> slumber.  While argument mismatch was always illegal, it seems to have
> been a common idiom at one time.  And, like almost all bad habits of
> the past, SPEC also has this (see PR 91473, where you can see thatt a
> rather large number of SPEC tests now require -std=legacy).
> 
> So, what to do?  Is -std=legacy the right option, or should we add
> something different (like -faccept-argument-mismatch), which we
> could then set by -std=legacy?  And is there anything special
> we should be doing after we have diagnoses the problem, if the
> user simply wants to run the code?

Perhaps, something along the lines of -fallow-invalid-boz
I recently introduced.  Issue an error be default, but 
have -fallow-argument-mismatch downgrades the error to a
warning.  The only way to disable the warning is with -w.

Personally, if gfortran can detect an error in code, I think
it should report the error to the user.

-- 
Steve