[patch, fortran] PR31129 - warning on unused parameters

[Tobias Schlüter]

Daniel Franke wrote:
> 2007-07-09  Daniel Franke  <franke.daniel@gmail.com>
> 
>         PR fortran/31129
>         * trans-decl.c (generate_local_decl) Emit a warning if an unused
>         parameter is found.
> 
> 2007-07-09  Daniel Franke  <franke.daniel@gmail.com>
> 
>         PR fortran/31129
>         * gfortran.dg/parameter_unused.f90: New test.
> 
> Regtested on i686-pc-linux-gnu. Ok for trunk?

I think this is definitely ok, but since I've not done much work lately, 
you may want to wait for someone else to chime in.

I'd like to take the opportunity to suggest something related that I 
wanted to do for some time, but never got around to doing: currently the 
frontend only keeps track of whether a symbol is at all referenced. 
Instead we should introduce independent attributes attr.written and 
attr.read, and then use these to print more accurate warnings for unused 
variables from inside the frontend, and no longer (at least for 
non-character scalars) rely on the middleend.

This will allow us to fix PR 13615, and (to some extent at least) PRs 
20520 and 28004.  Also, the middleend will never know that
   print *, x
   end
makes use of an uninitialized x, as it only sees that x' address is 
taken, but it can't tell whether x is written or read in the I/O 
function.  For the FE this is fairly obvious with my suggested change.

Cheers,
- Tobi