Re: GROUP BY DISTINCT

On Fri, Mar 19, 2021 at 8:27 AM Tomas Vondra
<tomas(dot)vondra(at)enterprisedb(dot)com> wrote:
> Hmmm, this seems to fail on lapwing with this error:
>
> parse_agg.c: In function 'expand_grouping_sets':
> parse_agg.c:1851:23: error: value computed is not used
> [-Werror=unused-value]
> cc1: all warnings being treated as errors
>
> That line is this:
>
> foreach_delete_current(result, cell);
>
> and I don't see how any of the values close by could be unused ...
>
> The only possibility I can think of is some sort of issue in the old-ish
> gcc release (4.7.2).

No sure what's going on there, but data points: I tried a 32 bit build
here (that's the other special thing about lapwing) and didn't see the
warning. GCC 10. Also curculio (gcc 4.2) and snapper (gcc 4.7) are
also showing this warning, but they don't have -Werror so they don't
fail. sidewinder (gcc 4.8) is not showing the warning.