Package: emacs;
Reported by: Pierre Rouleau <prouleau001 <at> gmail.com>
Date: Tue, 27 Jul 2021 18:55:02 UTC
Severity: wishlist
Tags: moreinfo, notabug
Found in version 26.3
Done: Lars Ingebrigtsen <larsi <at> gnus.org>
Bug is archived. No further changes may be made.
Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):
From: Pierre Rouleau <prouleau001 <at> gmail.com> To: bug-gnu-emacs <at> gnu.org Subject: 26.3; 26.3 & 27.2: invalid byte compiler warning in short-circuited or form Date: Tue, 27 Jul 2021 14:54:14 -0400
Paste the following code inside the scratch buffer (nothing else):
(defun f-and ()
"Use and."
(when (null (and (boundp 'foo)
foo)) ; no warning here, as expected.
(message "foo is not set")))
(defun f-or ()
"Use or."
(when (or (null (boundp 'foo))
(null foo)) ;=> ``Warning: reference to free variable ‘foo’``
(message "foo is not set")))
Then do:
- ``M-x compile-defun`` with point over f-and.
No warning is reported as expected.
- ``M-x compile-defun`` with point over f-or.
This time the byte compiler (of both Emacs 26.3 and 27.2) reports a
"Warning: reference to free variable ‘foo’" on the line identified in
the code.
I believe the byte compiler warning to be invalid.
The symbol `foo' is not bound but the code checks if it is
bound first with the line just above.
The ``or`` form is short-circuiting and will not eval
the (null foo) at that point.
Furthermore the code in `f-or' is a De Morgan equivalent boolean
expression of the one inside the `f-and' function.
Both functions `f-and' and `f-or' will run to completion when called and
both issue the "foo is not set" message.
In GNU Emacs 26.3 (build 1, x86_64-apple-darwin18.6.0)
of 2019-08-30 built on Mojave.local
Recent messages:
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Configured using:
'configure --disable-dependency-tracking --disable-silent-rules
--enable-locallisppath=/usr/local/share/emacs/site-lisp
--infodir=/usr/local/Cellar/emacs/26.3/share/info/emacs
--prefix=/usr/local/Cellar/emacs/26.3 --with-gnutls --without-x
--with-xml2 --without-dbus --with-modules --without-ns
--without-imagemagick'
Configured features:
NOTIFY ACL GNUTLS LIBXML2 ZLIB MODULES THREADS
Important settings:
value of $LANG: en_CA.UTF-8
locale-coding-system: utf-8-unix
Major mode: Debbugs
Minor modes in effect:
eros-mode: t
global-undo-tree-mode: t
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tooltip-mode: t
global-eldoc-mode: t
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file-name-shadow-mode: t
global-font-lock-mode: t
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auto-composition-mode: t
auto-encryption-mode: t
auto-compression-mode: t
buffer-read-only: t
column-number-mode: t
line-number-mode: t
transient-mark-mode: t
Load-path shadows:
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/Users/roup/.emacs.d/utils/sr-speedbar hides /Users/roup/.emacs.d/elpa/sr-speedbar-20161025.831/sr-speedbar
/Users/roup/.emacs.d/elpa/lispy-20210121.926/elpa hides /Users/roup/.emacs.d/elpa/ivy-20210311.1638/elpa
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/Users/roup/.emacs.d/elpa/lfe-mode-20201007.2214/lfe-mode hides /usr/local/share/emacs/site-lisp/lfe/lfe-mode
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/Users/roup/.emacs.d/elpa/soap-client-3.2.0/soap-client hides /usr/local/Cellar/emacs/26.3/share/emacs/26.3/lisp/net/soap-client
/Users/roup/.emacs.d/elpa/soap-client-3.2.0/soap-inspect hides /usr/local/Cellar/emacs/26.3/share/emacs/26.3/lisp/net/soap-inspect
/Users/roup/.emacs.d/elpa/let-alist-1.0.6/let-alist hides /usr/local/Cellar/emacs/26.3/share/emacs/26.3/lisp/emacs-lisp/let-alist
/Users/roup/.emacs.d/elpa/seq-2.22/seq hides /usr/local/Cellar/emacs/26.3/share/emacs/26.3/lisp/emacs-lisp/seq
/Users/roup/.emacs.d/elpa/nadvice-0.3/nadvice hides /usr/local/Cellar/emacs/26.3/share/emacs/26.3/lisp/emacs-lisp/nadvice
Features:
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Memory information:
((conses 16 840205 372854)
(symbols 48 54699 97)
(miscs 40 697 2352)
(strings 32 229530 157598)
(string-bytes 1 6394735)
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