[Patch, Fortran] (F2015) Permit ERROR STOP in PURE procedures

[Tobias Burnus]

Hi Janus,

Janus Weil wrote:
> looks (almost) ok to me. Just one thing about your test cases:
> Shouldn't the dg-error go into error_stop_4.f90 (where you have
> -std=f2008ts) instead of error_stop_3.f90 (with -std=gnu)?

Yes, I missed to re-diff it, after realizing that I mis-inserted the 
dg-error.

> And then:
> -/* Match a number or character constant after an (ALL) STOP or PAUSE
> statement.  */
> +/* Match a number or character constant after an (ERROR) STOP or PAUSE
> +   statement.  */
>
> I don't actually understand what the "(ALL)" was supposed to mean
> here.

The draft Fortran 2008 standard had "ALL STOP" to stop all images of a 
parallel coarray program when an error occurred. They later renamed it 
to ERROR STOP. In my coarray draft patches, I first had ALL STOP and 
then – before the merge (for GCC 4.6, 2010-03) – J3/WG5 renamed it to 
ERROR STOP. Seemingly, I missed that comment when doing the name change.

Committed as Rev. 219127.

> Btw: It's probably not worth to introduce an option like -std=f2015
> yet, but since there is an early draft document already, maybe it
> would make sense to start a wiki page to document which of those F15
> draft features are implemented already?

Currently, it's listed at https://gcc.gnu.org/gcc-5/changes.html#fortran 
and 
https://gcc.gnu.org/wiki/GFortran/News#gfortran_5_.28current_development_version.29 
; I think we should wait a bit before starting a 
https://gcc.gnu.org/wiki/Fortran2015Status page. (The "Introduction" of 
the F2015 standard lists the major new features.)

Regarding  -std=f2015: I think we should add that option once the GCC 6 
development starts.

Tobias