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Re: Possible patch for PR fortran/67806
- From: Louis Krupp <louis dot krupp at zoho dot com>
- To: Steve Kargl <sgk at troutmask dot apl dot washington dot edu>
- Cc: gcc-patches <gcc-patches at gcc dot gnu dot org>, fortran <fortran at gcc dot gnu dot org>
- Date: Mon, 12 Oct 2015 14:50:25 -0700
- Subject: Re: Possible patch for PR fortran/67806
- Authentication-results: sourceware.org; auth=none
- References: <1505a7c9fab dot f52df49364480 dot 2316667444406332595 at zoho dot com> <20151012154143 dot GA74102 at troutmask dot apl dot washington dot edu>
---- On Mon, 12 Oct 2015 08:41:43 -0700 Steve Kargl<sgk@troutmask.apl.washington.edu> wrote ----
> On Sun, Oct 11, 2015 at 10:18:48PM -0700, Louis Krupp wrote:
> > The problem involves a derived type with a character component declared CHARACTER(NULL()) or CHARACTER(NULL(n)), where mold argument n is an integer pointer.
> >
>
> I was looking at 67805 this weekend, which is somewhat
> related to this PR. AFAICT, gfortran does no checking
> for n in CHARACTER(LEN=n). n should be a scalar-int-expr
> (that is scalar INTEGER expression). NULL() is not
> an integer, and NULL(n) is a disassociated pointer. So,
> I believe neither can appear in an scalar-int-expr.
>
> Note, also that there is a table in 13.7.125 on where
> NULL() can appear.
>
> My patch for 67805 leads to one regression that I've been
> unable to resolve.
For what it's worth, my patch does absolutely nothing for 67805.
As to my error message, should I fold this misuse of NULL() into the existing message saying "Character length needs to be a constant specification expression" and not mention NULL()?
There are times I wish I knew the story behind the code in some of these bug reports. Were they written by someone looking for edge cases that might cause trouble, or was someone actually trying to do something?
Louis