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From: "pentek.imre at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/18635] use of uninitialised reference accepted in C++ front end
Date: Fri, 26 Nov 2010 17:28:00 -0000	[thread overview]
Message-ID: <bug-18635-4-p6UsW3QWgT@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-18635-4@http.gcc.gnu.org/bugzilla/>

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18635

--- Comment #12 from Imre Pentek <pentek.imre at gmail dot com> 2010-11-26 17:18:26 UTC ---
(In reply to comment #11)
> (In reply to comment #10)
> > (In reply to comment #9)
> > > (In reply to comment #2)
> > > > int &a = a;
> > > > i don't believe this is valid code.  i believe g++ should reject the code.
> > > 
> > > I'm not convinced the compiler must reject it. EDG accepts it too.
> > 
> > Without warning? What about clang 2.8?
> 
> Yes, without warning (G++ at least warns)
> I don't know about clang

This code is as valid as unset references are valid. The standards doesn't
allow 'unset' or 'extremal' references. In this way there's no point to query
the reference from a yet-unset reference, as there's no such a state as unset
reference. If you somehow manage to query the reference from an unset reference
you actually navigated your compiler to a state which doesn't even exist. It's
like division by zero to be accepted without any (runtime/compiletime) error
messages/crashes. Briefly, I consider this code as invalid, as it generates a
state which is invalid, and has no semantic meaning, and doesn't really exist.


  parent reply	other threads:[~2010-11-26 17:18 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-18635-4@http.gcc.gnu.org/bugzilla/>
2010-11-26  1:05 ` adam.rak at streamnovation dot com
2010-11-26 11:23 ` redi at gcc dot gnu.org
2010-11-26 11:29 ` manu at gcc dot gnu.org
2010-11-26 12:00 ` redi at gcc dot gnu.org
2010-11-26 17:28 ` pentek.imre at gmail dot com [this message]
2010-11-26 18:40 ` redi at gcc dot gnu.org
2010-11-27 14:53 ` adam.rak at streamnovation dot com
2011-05-22 19:11 ` redi at gcc dot gnu.org
2011-06-27 11:55 ` [Bug c++/18635] [DR 504] " redi at gcc dot gnu.org
2021-04-08  0:20 ` [Bug c++/18635] [DR 504] use of uninitialised reference accepted (without -Wuninitialized) " msebor at gcc dot gnu.org
2021-04-08  8:16 ` manu at gcc dot gnu.org
2021-04-08 14:24 ` msebor at gcc dot gnu.org
2021-08-10 19:46 ` redi at gcc dot gnu.org
2024-04-12  0:06 ` mpolacek at gcc dot gnu.org
     [not found] <bug-18635-9680@http.gcc.gnu.org/bugzilla/>
2005-11-27 21:18 ` [Bug c++/18635] use of uninitialised reference accepted " gdr at gcc dot gnu dot org
2009-05-29 14:36 ` pinskia at gcc dot gnu dot org
2004-11-23 23:11 [Bug c++/18635] New: " ajo at acm dot org
2004-11-23 23:19 ` [Bug c++/18635] " pinskia at gcc dot gnu dot org
2004-11-24  2:11 ` llib at computer dot org
2004-11-24 19:07 ` pinskia at gcc dot gnu dot org
2004-11-26  2:56 ` llib at computer dot org
2004-11-26 10:17 ` giovannibajo at libero dot it
2004-11-29  0:56 ` llib at computer dot org
2004-11-29 11:26 ` giovannibajo at libero dot it
2004-11-29 11:41 ` giovannibajo at libero dot it

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