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From: "Alejandro R. Mosteo" <alejandro@mosteo.com>
Newsgroups: comp.lang.ada
Subject: Re: Storage_Error: mine's or gnat's fault?
Date: Fri, 3 Jun 2016 23:43:25 +0200
Organization: A noiseless patient Spider
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Date: 2016-06-03T23:43:25+02:00
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On 03/06/16 23:01, Alejandro R. Mosteo wrote:
> I'm seeing this (sanitized) stack trace when using the
> *Ada.Containers.Holders* package (both 2015/2016 version):
>
> --8<--
> raised STORAGE_ERROR : stack overflow or erroneous memory access
>
> Ada.Tags.Displace at s-stoele.adb:97
> Rx.Producers.Holders.Definites.Reference at a-coinho.adb:379
> Rx.Examples.Strings.Subscribe at rx-observable.adb:33
> Rx.Examples.Strings."&" at rx-observable.adb:81
> Rx.Examples.Basic at rx-examples-basic.adb:14
> Main at b__rx-examples-basic.adb:345
> --8<--
>
> Since my code has not a single pointer, "new", unchecked operation or
> access I feel the responsibility might not be mine... Also the offending
> line is a bit of unfathomable (to me) Address arithmetic. I'd post a
> sample but the code is spread among several files right now. I could try
> to synthesize a self-contained example if it seems a legit bug in the
> sages' opinion.
>
> In the meantime I'm going to try with an indefinite list as container.

Using the Indefinite_Doubly_Linked_List the problem is equally suspect 
(this is code from a-cidlli.adb):

    function First_Element (Container : List) return Element_Type is
    begin
       if Checks and then Container.First = null then
          raise Constraint_Error with "list is empty";
       end if;

       return Container.First.Element.all; -- <-- RAISES
    end First_Element;

I'll try to produce a small trigger.

>
> Álex.