[Bug fortran/46846] Bogus warning: "Interface mismatch in dummy procedure .* has the wrong number of arguments" for intrinsic functions with optional arguments

[dominiq at lps dot ens.fr]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=46846

Dominique d'Humieres <dominiq at lps dot ens.fr> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-12-19
            Summary|Warning of AINT as actual   |Bogus warning: "Interface
                   |argument ain't right        |mismatch in dummy procedure
                   |                            |.* has the wrong number of
                   |                            |arguments" for intrinsic
                   |                            |functions with optional
                   |                            |arguments
     Ever confirmed|0                           |1

--- Comment #4 from Dominique d'Humieres <dominiq at lps dot ens.fr> ---
This PR is a real mess.

> lnblnk is a GNU extension.
> char, ichar, int, and len_trim are also rejected by other compilers.

I think gfortran is correct when rejecting the intrinsic functions in

Table 13.3: Restricted specific intrinsic functions

(Fortran 2015 draft).

> The problem is that all those functions have an optional KIND= argument -
> which, however, is not included in the specific functions (as backward
> compatibility to Fortran 77). Thus, the warning is bogus - 

I agree and I have changed the summary.

> but another question is whether this can lead to wrong code by not passing
> NULL as second argument.

I did not find such wrong codes, however I have opened pr68433 for wrong codes
when including the optional argument in the interfaces.

> I have not checked, but maybe the documentation should also be improved
> (cf. James' posting to c.l.f)

If so, I think it deserves a separate PR.