[Bug fortran/109500] SIGABRT when calling a function that returns an unallocated value

["sgk at troutmask dot apl.washington.edu" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109500

--- Comment #7 from Steve Kargl <sgk at troutmask dot apl.washington.edu> ---
On Thu, Apr 13, 2023 at 07:44:36PM +0000, leandro.lupori at linaro dot org
wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109500
> 
> --- Comment #5 from Leandro Lupori <leandro.lupori at linaro dot org> ---
> Ok, thanks for the detailed explanations. Now I see that the standard doesn't
> allow the return of an unallocated value. This can be closed as invalid.
> 
> But may I just ask a last related question? As mentioned in the last comment
> and according to Note 1 in F2018 8.5.3 ALLOCATABLE attribute, the result of
> referencing a function cannot be used as an allocatable argument. This is
> however allowed by gfortran (and ifort), with the exception of intrinsic
> procedures, and seems to work correctly. Should this be considered an extension
> or does it just work by accident and there are no guarantees at all when using
> it?
> 

I suspect it works by accident, but I don't have enough
time at the moment to go read the gfortran source.  What 
is likely happening is gfortran checks that the actual
and dummy argument both have the allocatable attribute.
For the actual argument, the symbol is probably marked
an allocatable attribute and an internal attribute 
that designates this as a function-result, and gfortran
does not check for the latter.