Re: [PATCH] Fortran: fixes for procedures with ALLOCATABLE,INTENT(OUT) arguments [PR92178]

[Steve Kargl <sgk@troutmask.apl.washington.edu>]

On Tue, Jul 04, 2023 at 11:26:26AM +0200, Mikael Morin wrote:
> Le 04/07/2023 à 01:56, Steve Kargl a écrit :
> > On Mon, Jul 03, 2023 at 10:49:36PM +0200, Harald Anlauf via Fortran wrote:
> > > 
> > > Indeed, this is a nice demonstration.
> > > 
> > > While playing, I was wondering whether the following code is conforming:
> > > 
> > > program p
> > >    call s ((1))
> > > contains
> > >    subroutine s (x)
> > >      integer :: x
> > >      x = 42
> > >    end subroutine
> > > end
> > > 
> > > (It crashes with gfortran, but not with any foreign brand tested).
> > > 
> > 
> > It's not conforming.  '(1)' is an expression and it cannot appear
> > in a variable definition condition.  I am not aware of any numbered
> > constraint tha would require a Fortran processor to generate an
> > error.
> > 
> 
> I think you would be right if X had INTENT(OUT) or INTENT(INOUT) attribute.
> This is F2023, 15.5.2.4 (no mention of variable definition context here):
> > If a dummy argument has INTENT (OUT) or INTENT (INOUT), the actual
> > argument shall be definable.
> 
> However, with unspecified intent, I can't find the rule explicitly
> forbidding the above example.
> I'm tempted to say it is conforming.

I thought it was in Sec. 19, but failed to locate any prohibition.
The best I can find is

23-007r1.pdf

8.5.10 INTENT attribute

pg. 114 (following Note 1) 

If no INTENT attribute is specified for a dummy argument,
its use is subject to the limitations of its effective
argument (15.5.2).

pg. 115 (within Note 4, so non-normative text)

INTENT (INOUT) is not equivalent to omitting the INTENT attribute.
The actual argument corresponding to an INTENT (INOUT) dummy argument
is always required to be definable, while an actual argument corresponding
to a dummy argument without an INTENT attribute need be definable only
if the dummy argument is actually redefined.

Searching for "definable" does not lead to a prohibition of the form
"An expression is not definable."

-- 
Steve