Re: Beginners question: Compound types, how-to?

[Adam Beneschan <adam@irvine.com>]

On Nov 1, 10:16 am, Yannick Duchêne (Hibou57)
<yannick_duch...@yahoo.fr> wrote:
> Le Mon, 01 Nov 2010 12:50:50 +0100, (see below)  
> <yaldni...@blueyonder.co.uk> a écrit:>> Children always have visibility into the specs of their ancestors, so  
> >> you
> >> never need to "with" said ancestors.
>
> > While the first claim is true, the second does not follow, as I am given  
> > to
> > understand it.
>
> > If you need:
>
> >   pragma Elaborate_All(<ancestor>);
>
> > Then you also need:
>
> >   with <ancestor>;
>
> I've just checked it with GNAT, it did not return an error.  <ancestor> is  
> implicitly withed even with Elaborate_All. No special case with this  
> pragma.

Then this version of GNAT is wrong.

The visibility rules for context clauses (the WITH and USE clauses and
pragmas appearing before the top-level PACKAGE, PROCEDURE, FUNCTION,
etc.) are different from the normal visibility rules.  See 10.1.6 and
especially paragraph 3.  Jeff was correct except with respect to
context clauses (an easy thing to forget).

Please don't rely on GNAT, or any other compiler, to determine whether
something is legal Ada or not.  None of them is perfect at getting the
language rules correct.

                                            -- Adam