Allocatable components to the right of a nonzero-rank part reference

[Steve Kargl]

On Thu, Nov 16, 2006 at 10:53:09PM +0200, erik.edelmann@iki.fi wrote:
> 
> According to the standard, "A part-name to the right of a part-ref with
> nonzero rank shall not have the ALLOCATABLE or POINTER attribute."
> (F2003 draft standard, page 105, lines 12-13).
> 
> Currently we accept it for ALLOCATABLEs for some cases (e.g. as procedure
> arguments, and in WHEREs), but get ICEs for other cases (e.g. plain
> array assignments).
> 
> The question now is what we should do about this. We could
> 
>         (a) Allways reject (attached patch does that).
> 
>         (b) Accept it as an extension.  Those cases that don't work can be
>         implemented eventually (I can open a PR).  This would be a nice
>         extension, but it has the downside that it could get quite
>         complicated.  I haven't thought a lot about it, but I guess that
>         e.g.
> 
>                 p => x(:)%y(1)
> 
>         where y is an allocatable component, is somewhere between
>         difficult and impossible to implement.
> 
>         (c) Like (b), but reject the most difficult cases.
> 
> Perhaps we could do (a) for 4.2, and (c) for 4.3?  Opinions?
> 

I think (a) is the preferred solution.  (b) and (c) seem to
lead to a dangerously slippery slope.

-- 
Steve