GNU bug report logs - #45619
No warning when pcase-let is binding dynamic variable

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From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: Michael Heerdegen <michael_heerdegen <at> web.de>, jixiuf <jixiuf <at> qq.com>, 45619 <at> debbugs.gnu.org
Subject: bug#45619: 28.0.50; pcase-let on MacOS doesn't work
Date: Sat, 12 Feb 2022 17:30:54 +0100

Stefan Monnier <monnier <at> iro.umontreal.ca> writes:

> Hmm... I doubt it's fixed in all cases.

Here's a more self-contained example:

;;;  -*- lexical-binding: t -*-

(defvar foo 1)

(defun zot ()
  (pcase-let ((`(,foo) '(2)))
    (bar)))

(defun bar ()
  (message "%s" foo))

M-: (zot) messages "2".

> I still think pcase should emit a warning when asked to bind
> a dynamically scoped variable.

If pcase-let currently does work fine for dynamic variables then it's
likely that people are depending on it, and it's too late to change...

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

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