Re: extended membership tests

[Dan <dan@irvine.com>]

On Mar 31, 12:34 am, AdaMagica <christ-usch.gr...@t-online.de> wrote:
> On 31 Mrz., 09:04, Dan <d...@irvine.com> wrote:
>
>
>
>
>
> > Here's a fun quiz to test your Ada2012 knowledge, based on an
> > observation by Yannick Moy.
>
> > Consider this Ada 2012 procedure:
>
> > with ada.containers.ordered_sets;
> > procedure membership is
> >     package int_sets is new ada.containers.ordered_sets(integer);
> >     function "="(x,y: integer) return boolean is begin return true;
> > end;
> >     x: integer := 6;
> >     y: integer := 12;
> >     b1: boolean := x in y;
> >     b2: boolean := x in int_sets.to_set(new_item => y);
> > begin
> >     null;
> > end;
>
> My first reaction was WTF!
>
> But RM 4.5.2 seems to make x in y legal, but false here.
>
> x in y | 1..7
>
> would be true.
>
> b2 is illegal, the simple expression must be of an elementary type.
>
> Hope this is correct.- Hide quoted text -
>
> - Show quoted text -

I think if the choice(s) resolve to the same type they don't have to
be elementary,
according to 4.5.2(3/3).  (other than that, good answer!)