Re: Bug in GNAT GPL 2006?

["Adam Beneschan" <adam@irvine.com>]

On Feb 21, 12:19 pm, "Randy Brukardt" <r...@rrsoftware.com> wrote:
> Bill Findlay writes:
> > Using GNAT GPL 2006 (20060522-34) I get warning messages
> > like the following when using extended return statements:
>
> >     function is_empty (the_table : a_safe_table) return Boolean is
> >     begin
> >        return result : Boolean do
> >               |
> >  >>> warning: variable "result" is assigned but never read
>
> >           lock_table;
> >              result := is_empty(a_basic_table(the_table));
> >           unlock_table;
> >        end return;
> >     end is_empty;
>
> > I'm inclined to assume that this is a compiler bug, but can
> > anyone more knowledgeable about Ada 200[57] confirm this?
>
> Sure looks like a (harmless) compiler bug to me. It's hard to imagine why
> you would be required to read the result of a function before returning it.

Looks to me like the compiler is (incorrectly) pretending it's a
normal variable.  If you had declared "result : Boolean" before the
"begin", and then assigned it but never used it, I can imagine the
compiler being suspicious that something was perhaps mistyped
somewhere, and displaying a warning.  Just a very understandable
implementation bug.

                              -- Adam