[Bug fortran/108369] FM509 Fails to compile with error

[sgk at troutmask dot apl.washington.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108369

--- Comment #4 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Wed, Jan 11, 2023 at 09:50:37PM +0000, kargl at gcc dot gnu.org wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108369
> 
> --- Comment #3 from kargl at gcc dot gnu.org ---
> (In reply to anlauf from comment #1)
> > (In reply to Ben Brewer from comment #0)
> > Workaround: either use -std=legacy or fix the above argument declaration to:
> > 
> >       CHARACTER C1D001(*)*8,CVD001*8
> 
> While the workaround will work, it does so because it disables
> -fallow-argument-mismatch.  But, that feature emitting a bogus
> error/warning.
> 
> Note the following all compile and execute.  TKR is satisfied
> as I discussion in comment #2.
> 

After looking into this a bit closer, Harald is indeed correct
with the need for -std=legacy (or -fallow-argument-mismatch).
In the line

      CALL SN512(C1N001(5)(2:9),CVCOMP)

'C1N001(5)(2:9)' is a substring of the array element 'C1N001(5)',
which is a scalar (ie., rank = 0).  The interface for SN512 is

      SUBROUTINE SN512(C1D001,CVD001)
      CHARACTER C1D001(6)*8,CVD001*8

The first dummy argument is a rank 1 array.  

Now, if the test is changed to pass an array section such as

      CALL SN512(C1N001(4:5)(2:9),CVCOMP)

then gfortran gives

%  gfcx -w -c fm509.f
fm509.f:378:17:

  378 |       CALL SN512(C1N001(4:5)(2:9),CVCOMP)                              
  03770509
      |                 1
Error: Actual argument contains too few elements for dummy
argument 'c1d001' (16/48) at (1)

which I believe may be wrong.