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From: Lars Ingebrigtsen <larsi@gnus.org>
To: Pierre Rouleau <prouleau001@gmail.com>
Cc: 49749@debbugs.gnu.org
Subject: bug#49749: 26.3; 26.3 & 27.2: invalid byte compiler warning in short-circuited or form
Date: Wed, 28 Jul 2021 17:26:24 +0200	[thread overview]
Message-ID: <8735rycvdr.fsf@gnus.org> (raw)
In-Reply-To: <1B5C81C0-5D9A-4ED5-B56A-FC6AAA1A8A87@gmail.com> (Pierre Rouleau's message of "Tue, 27 Jul 2021 14:54:14 -0400")

Pierre Rouleau <prouleau001@gmail.com> writes:

> (defun f-or ()
>   "Use or."
>   (when (or (null (boundp 'foo))
>             (null foo))  ;=> ``Warning: reference to free variable ‘foo’``                          
>     (message "foo is not set")))

The message about invalid stuff is only discarded if Emacs is trivially
able to deduce that it'll never be evaluated -- and as you've found out,
it's easy to make that heuristic not be heeded (see
`byte-compile-maybe-guarded' for details).

So I'm not sure this is a bug -- Emacs can't determine all cases where
we won't be executing the code in question at compile time.

Anybody else think that this is something that should be improved?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no





  reply	other threads:[~2021-07-28 15:26 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-27 18:54 bug#49749: 26.3; 26.3 & 27.2: invalid byte compiler warning in short-circuited or form Pierre Rouleau
2021-07-28 15:26 ` Lars Ingebrigtsen [this message]
2021-07-31 13:59   ` Pierre Rouleau
2021-08-01  0:19     ` Michael Heerdegen
2021-08-01 10:26       ` Lars Ingebrigtsen

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