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From: bobduff@world.std.com (Robert A Duff)
Subject: Re: Rules for Representation of Subtypes
Date: 1996/09/30
Message-ID: <DyKCIG.KE6@world.std.com>#1/1
X-Deja-AN: 186301367
references: <mheaney-ya023080002209961353500001@news.ni.net>
 <1996Sep28.155354.1@eisner> <DyGwtp.Bs1@world.std.com>
 <mheaney-ya023180002909961030520001@news.ni.net>
organization: The World Public Access UNIX, Brookline, MA
newsgroups: comp.lang.ada
Date: 1996-09-30T00:00:00+00:00
List-Id: <comp.lang.ada>


In article <mheaney-ya023180002909961030520001@news.ni.net>,
Matthew Heaney <mheaney@ni.net> wrote:
>I think his comment was in reaction a previous post, which stated that the
>compiler would make all kinds of optimizations based on what it knew was an
>illegal program as a result of a call to unchecked_conversion.  If the
 ^^^^^^^ You mean "erroneous".
>compiler does something "special" to handle a "bad" program because of
>unchecked_conversion, well, the conversion is not really "unchecked,"
>right?

No, no, the compiler doesn't *know* the program is bad.  It just does an
optimization that will work if the program is good, and might not work
if the program is bad.

If the compiler *knows* the program is bad, then it should of course
give a warning message.  But usually such things aren't knowable.

- Bob