GNU bug report logs - #51982
Erroneous handling of local variables in byte-compiled nested lambdas

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Package: emacs;

Reported by: Paul Pogonyshev <pogonyshev <at> gmail.com>

Date: Fri, 19 Nov 2021 20:32:02 UTC

Severity: normal

Tags: patch

Fixed in version 29.1

Done: Lars Ingebrigtsen <larsi <at> gnus.org>

Bug is archived. No further changes may be made.

Full log

Message #8 received at 51982 <at> debbugs.gnu.org (full text, mbox):

From: Michael Heerdegen <michael_heerdegen <at> web.de>
To: Paul Pogonyshev <pogonyshev <at> gmail.com>
Cc: mattiase <at> acm.org, Stefan Monnier <monnier <at> iro.umontreal.ca>,
 51982 <at> debbugs.gnu.org
Subject: Re: bug#51982: Erroneous handling of local variables in
 byte-compiled nested lambdas
Date: Sat, 20 Nov 2021 05:44:38 +0100

Hello Paul,

thanks for the report, I can reproduce the issue, there is something
going wrong when compiling.  I guess this is something for Mattias or
Stefan maybe? (CC'd)

#+begin_src emacs-lisp
; -*- lexical-binding: t -*-

(defun wtf (x)
  (let ((it 0))
    #'(lambda ()
        (let ((fn #'(lambda () it)))
          (if x
              (let ((it x))
                it)
            (funcall fn))))))
#+end_src

Byte compile:

>     wtf.el:9:17:Warning: reference to free variable ‘it’

(funcall (wtf 1))

>     Symbol’s value as variable is void: it

while expected result is 1.  Uncompiled code works as expected.

TIA,

Michael.
This bug report was last modified 2 years and 250 days ago.

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