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From: Jacob Sparre Andersen <jacob@jacob-sparre.dk>
Newsgroups: comp.lang.ada
Subject: Re: Community Input for the Maintenance and Revision of the Ada
 Programming Language
Date: Wed, 06 Sep 2017 17:57:32 +0200
Organization: JSA Research & Innovation
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Xref: news.eternal-september.org comp.lang.ada:47949
Date: 2017-09-06T17:57:32+02:00
List-Id: <comp.lang.ada>

Johan Söderlind Åström wrote:

> I do not think that accessing a element from a array is a complicated
> thing and starting from a zero indexed array is even simpler, then why
> would a compiler not guarantee such a simple thing to work?

One possibility is that constrained and unconstrained subtypes of the
same subtype may have slightly different memory layouts.

Or maybe the bounds of the array are stored at the beginning of the
memory structure (where else can we put them?), and your overlaying
changes the subtype of the (possibly constant) array passed to it, by
overwriting the bounds.

Randy has written a part of at least one Ada compiler, so he can
probably come up with some more concrete examples.

Greetings,

Jacob
-- 
"Good enough for physics" -- Ridcully