Re: limited allocated classwide types

[Adam Beneschan <adam@irvine.com>]

On Nov 4, 2:53 am, Brian Drummond <br...@shapes.demon.co.uk> wrote:
>
> But this bug (assuming it is confirmed, as it looks to be) is much closer
> to the core of the language ... to me it raises the question: has ACATS
> (test suite) not kept up with the language additions in Ada-2005? And is
> it being maintained and updated alongside Ada-2012?

I should probably let Randy answer this, but I think the answer to
your questions is that it hasn't kept up, due to insufficient funding.

But what I really wanted to point out was that it's not reasonable to
expect ACATS to catch everything; and the fact that one simple test
breaks a compiler that passes ACATS isn't itself evidence that there's
a flaw in ACATS.  I believe ACATS is set up to check each feature and
rule defined in the language (or something like that), but it can't
test every combination of every feature.  And this case seems to
involve a combination of limited controlled types and interfaces (and
perhaps extended return).  Even if there is, or should be, an ACATS
test that tests interfaces in conjunction with controlled types, it
may not occur to the test suite maintainer that there needs to be a
separate test to do the same thing with limited controlled types,
because they may not envision that a compiler could work with non-
limited controlled types but blow up with limited ones.

Also, I suspect that a major purpose of ACATS is to ensure that the
compiler vendors understand the language rules and have implemented
them.  It is not, and cannot, be to ensure that the implementation is
correct and bug-free in every case.

I'm posting this because the "Why didn't ACATS test for this??"
sentiment has come up more than once, but I don't think it's
justified.


> Is there a mechanism for adding ad-hoc test cases like this one to ACATS?
> One would like to think there is a more systematic effort to add tests
> alongside features as they are developed.

I'm wondering if there might be a need for some other public test
suite that users can contribute to.  I don't think ACATS would be an
appropriate suite to for just dumping any test cases users find--that
just doesn't seem like the right place--but perhaps someone could
start a web site.

                             -- Adam