Re: Compiler Bug

[Adam Beneschan <adam@irvine.com>]

On Dec 4, 2:45 pm, "Randy Brukardt" <ra...@rrsoftware.com> wrote:
> "REH" <spamj...@stny.rr.com> wrote in message
>
> news:97d0825d-ee08-45ef-b736-ca005caf1a81@e23g2000prf.googlegroups.com...
>
>
>
> > No, I can't, sorry.  But the gist of it is:
>
> > function F1 return T1;
> > pragma Inline(F1);
>
> > function F1 return T1 is
> >   R : T1;
> > begin
> >   -- do stuff
> >   return R;
> > end F1;
>
> > function F2 return T2 is
> >   V : T1 := F1;
> >   R : T2;
> > begin
> >   -- do stuff
> >   return R;
> > end F2;
>
> > The compiler and debugger treat the R in F2 as if it is of type T1,
> > not T2.  Exceeding the bounds of T1 cause F2 to raise a
> > constraint_error.  The problem goes away if the pragma inline is
> > removed.
>
> The way you describe it, it sounds like a compiler bug. But without seeing
> the actual code, it is impossible to tell for sure. (It's not unusual for a
> compiler-bug-reporter to see one problem when something totally different is
> going on -- it even happens to me from time-to-time.) Ada's visibility rules
> are complex enough that you could be getting some other kind of conflict
> without realizing it.

Right... but pragma Inline isn't supposed to affect the visibility
rules at all.  So no matter what he's doing, if he's actually seeing a
case where a program with an Inline pragma raises a Constraint_Error,
and removing the pragma (without doing anything else to the program)
causes the Constraint_Error to go away, then I can't think of any way
that this could happen with a correct compiler.  (That's not true in
reverse, by the way... there are legitimate cases when adding an
Inline pragma could make a Constraint_Error go away, if an optimizer
determines that some of the inlined code can be eliminated for a
particular call.  But adding an Inline pragma should never make a
Constraint_Error appear that didn't appear before, I don't think.)

                            -- Adam