Re: How many Ada compiler bugs are here?

["Randy Brukardt" <randy@rrsoftware.com>]

"Maciej Sobczak" <see.my.homepage@gmail.com> wrote in message 
news:01dd6341-9c3c-4dcb-90f8-6ac66c65eb66@z1g2000vbx.googlegroups.com...
...
> 1. Adjust should not be allowed to be declared (it is a *limited*
> type). But I have defined it to trace the remaining bugs:

There's nothing wrong with defining "Adjust" (you can define any named 
subprogram you want, of course), but (A) "overriding" shouldn't be allowed 
on it, and (B) it shouldn't be called automatically if it is defined without 
"overriding", because it is not special for a limited type.

> 2. The return statement in Make_T should not be required, because it
> is unreachable anyway.

Ada requires all functions to have a return statement. 6.5(5/2). This was an 
Ada 83 rule; we've discussed removing it, but the feeling was that it 
catches as many errors as it creates, and we just couldn't justify a change 
to the language that didn't seem to be an obvious improvement. (In my 
personal work, it has been about 50-50 as to whether it helps or hinders.)

So the requirement for a return statement is not a bug, it's a language 
rule.

> 3. Logically, Tmp is never created, because Make_T raises an
> exception. Somehow some object is finalized. Apparently it is Tmp,
> which should not exist.
> 4. Somehow Tmp.initialized = True, even though its default value is
> defined to be False.

I'm not sure if these are actually bugs or not; the fact that Adjust is 
being called for a limited object means to me that nothing that happens 
afterwards makes any sense from a formal language perspective, so you can't 
really say if there is a bug. Garbage-in, garbage-out! Does the same thing 
happen without Adjust being defined? That would seem more like a bug.

                                                Randy.