[Patch, Fortran] Add is_coarray() function, use it

[Tobias Burnus]

On 07/19/2011 05:24 PM, Mikael Morin wrote:
> On Monday 18 July 2011 21:37:24 Tobias Burnus wrote:
> Now about your request:
>> I would be happy if someone could carefully read the function in expr.c
>> - and confirm that the second test case ("dg-error" line) is indeed
>> invalid. I think it is invalid because one has an array element of a
>> coarray, which is a coarray but which is not simply contiguous.
> I don't understand what is your concern here; the standard seems pretty clear

Well, I was confused about it as passing an array element as actual 
argument to a dummy argument is OK, while it is not for coarrays. 
Additionally, there is a test case, which is supposedly valid (and 
accepted by some compilers) but fails. - And it is not the first time 
that I fail either to read something obvious as such (mind too much 
twisted) - or to miss some constraint elsewhere (mind too little twisted).

However, in this case, the F2008 standard seems to relatively clearly 
reject it - though not clearly enough as J3 suggested to edit the text 
to make it even clearer:
   http://j3-fortran.org/doc/meeting/193/10-226r2.txt

However, in the J3 ballot the modified proposal was rejected - and some 
want to have the original version back:
   http://j3-fortran.org/doc/meeting/193/10-226.txt
(Cf. comments for F08/0048 at 
http://j3-fortran.org/doc/year/11/11-006A.txt )

Thus, the standard is not as obvious as one might think ;-)

> So, to sum up, if one sticks to fortran 2008, the test is clearly 
> invalid and..

... thus the current version rejects it. I think we leave it like that 
and keep PR 45859 as tracking bug.

>> Build and regtested on x86-64-linux.
>> OK for the trunk?
> ... the patch is ok with the two minor changes suggested above.

Committed with the two changes as Rev. 176467. Thanks for the review!

Tobias