Re: Overriding discriminants perplexes GNAT 3.14p

["Per Sandbergs" <prsa@cntw.com>]

I am using GNAT(pro) and when ever i got som problems or questions with  i
send it to ACT (the GNAT people).
And the are real fast in solving our problems (We pay them for that).

So my advice to you would be:
    Report the bug in acordance with the crash printout so that other users
may benefit from your findings.

/Regards
/Per Sandberg

"Dmitry A.Kazakov" <mailbox@dmitry-kazakov.de> wrote in message
news:ama2bm$404hu$1@ID-77047.news.dfncis.de...
> Hi!
>
> The following primitive code causes "GNAT bug detected" report:
> --------
> with Ada.Finalization; use Ada.Finalization;
>
> package Test1 is
>    type X (N : Natural) is
>       new Ada.Finalization.Limited_Controlled with private;
>    procedure Initialize (Obj : in out X);
> private
>    type X (N : Natural) is
>       new Ada.Finalization.Limited_Controlled with
>    record
>       NS : String (1..N);
>    end record;
> end Test1;
> ----------
> package body Test1 is
>    procedure Initialize (Obj : in out X) is
>    begin
>       null;
>    end Initialize;
> end Test1;
> ----------
> package Test1.Test2 is
>    type XX (M : Natural; N : Natural)  is new X with private;
>    procedure Initialize (Obj : in out XX);
> private
>    type XX (M : Natural; N : Natural)  is new X (N) with
>    record
>       MS : String (1..M);
>    end record;
> end Test1.Test2;
> ----------
> package body Test1.Test2 is
>    procedure Initialize (Obj : in out XX) is
>    begin
>       Initialize (X (Obj));
>    end Initialize;
> end Test1.Test2;
> ----------
> package Test1.Test2.Test3 is
>    type XXX is new XX (10, 20) with private;
>    procedure Initialize (Obj : in out XXX);
> private
>    type XXX is new XX (10, 20) with null record;
> end Test1.Test2.Test3;
> ----------
> package body Test1.Test2.Test3 is
>    procedure Initialize (Obj : in out XXX) is
>    begin
>       Initialize (XX (Obj));
>    end Initialize;
> end Test1.Test2.Test3;
> ----------
> 1. Unconstrained type X has a discriminant
> 2. Unconstrained XX (derived from X) has two disriminants. It overrides
the
> discriminant of X
> 3. Constrained XXX is derived from XX.
>
> This results in a bug report (crash)  under Windows.
>
> What wonders me is which sort of validation uses ACT if such bugs go
> through? People rightly criticize MS VC++, but the situation with Ada
> compilers isn't much better. I judge from my experience with GNAT and
> Object Ada. It is a permanent battle of finding work-arounds for countless
> compiler bugs. Is there any good Ada compilers since DEC gone?
>
> --
> Regards,
> Dmitry Kazakov
> www.dmitry-kazakov.de