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From: Ludovic Brenta <ludovic@ludovic-brenta.org>
Newsgroups: comp.lang.ada
Subject: Re: Extending discriminant types
Date: Fri, 21 Nov 2008 04:00:50 -0800 (PST)
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Date: 2008-11-21T04:00:50-08:00
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On Nov 21, 8:25 am, a...@anon.org (anon) wrote:
> Adam,
>
> Try an explain this. Since I downloaded my binary version of GNAT-3.15p
> direct from Adacore. And someone else has said the GNAT-3.15p is old but
> it has been fully tested and found to be correct. So, that means that time
> Adacore agreed that "Base" attribute could be used outside of scalars and
> that was years after the RM and AARM for Ada 95 was written.

Your reasoning is incorrect because (a) it is impossible to "fully
test" a program as complex as a compiler and (b) testing can prove the
presence of bugs but not their absence. Therefore, even though GNAT
3.15p did pass the ACATS and many thousands of tests beyond the ACATS,
you may not assume that it contains no bugs. In fact, during my years
maintaining GNAT 3.15p in Debian, various people reported
approximately 110 bugs in it. A few of these bugs are still present in
the latest releases of GNAT; yet, the ACATS does not find them.

It would be nice to add a test to the ACATS so that compilers that
accept T'Base where T is non-scalar get rejected.

--
Ludovic Brenta.