From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Stefan Monnier via "Bug reports for GNU Emacs, the Swiss army knife of text editors" Newsgroups: gmane.emacs.bugs Subject: bug#26960: 26.0.50; Complaints about unused variable in cl-destructuring-bind Date: Sun, 08 May 2022 09:32:01 -0400 Message-ID: References: <871qx4i4pe.fsf@gnus.org> Reply-To: Stefan Monnier Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="31661"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/29.0.50 (gnu/linux) Cc: 26960@debbugs.gnu.org, 8711@debbugs.gnu.org, Helmut Eller To: Lars Ingebrigtsen Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Sun May 08 15:33:25 2022 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1nnh2L-00082K-58 for geb-bug-gnu-emacs@m.gmane-mx.org; Sun, 08 May 2022 15:33:25 +0200 Original-Received: from localhost ([::1]:56008 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nnh2K-0004cY-72 for geb-bug-gnu-emacs@m.gmane-mx.org; Sun, 08 May 2022 09:33:24 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:57558) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nnh1y-0004aw-O4 for bug-gnu-emacs@gnu.org; Sun, 08 May 2022 09:33:03 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:59821) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1nnh1y-0003Ks-F3 for bug-gnu-emacs@gnu.org; Sun, 08 May 2022 09:33:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1nnh1y-00089c-7U for bug-gnu-emacs@gnu.org; Sun, 08 May 2022 09:33:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Stefan Monnier Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sun, 08 May 2022 13:33:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 26960 X-GNU-PR-Package: emacs Original-Received: via spool by 26960-submit@debbugs.gnu.org id=B26960.165201673331261 (code B ref 26960); Sun, 08 May 2022 13:33:02 +0000 Original-Received: (at 26960) by debbugs.gnu.org; 8 May 2022 13:32:13 +0000 Original-Received: from localhost ([127.0.0.1]:53716 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1nnh1B-000888-27 for submit@debbugs.gnu.org; Sun, 08 May 2022 09:32:13 -0400 Original-Received: from mailscanner.iro.umontreal.ca ([132.204.25.50]:64218) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1nnh18-00087o-5k; Sun, 08 May 2022 09:32:11 -0400 Original-Received: from pmg1.iro.umontreal.ca (localhost.localdomain [127.0.0.1]) by pmg1.iro.umontreal.ca (Proxmox) with ESMTP id 7DD0910029F; Sun, 8 May 2022 09:32:04 -0400 (EDT) Original-Received: from mail01.iro.umontreal.ca (unknown [172.31.2.1]) by pmg1.iro.umontreal.ca (Proxmox) with ESMTP id 6EC12100118; Sun, 8 May 2022 09:32:02 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=iro.umontreal.ca; s=mail; t=1652016722; bh=bwEaiuLPK3lfPJ7EMHW9+8gUMfFgpddY1m+lLaIo3nk=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=ZLqO3HDStwGn35NYJEbil16JU1q3gC7aQwXGfjaVAr7UTvwtQVz7aws0S0pqQIvbA TJESaTJ8WHUzVvwnPAC6fJ6pV0LLbO1Fd9dUM61mbt4iIIDvF05vSHpruvswL4IXds oiKFpXHO6Zz6h9HFVfNjE8isK1xtyRTCOkrfGCzm4LHKDlkgH9riuSWP+EYNqiEU1N cnI421FyFDXM2/zdSPgrL1Y9v+lulkgA9kkhFEbxYS6EF5CSPPxeaQl0/kqRqCsQCF iX+zNzg3XlcrtdaUkPFfjekSk+I9iEEFSW/ukeoyDlmTHJWMI9Rt7+Z6fHGG0UK+cy roA94U/Icz2HQ== Original-Received: from pastel (unknown [45.72.221.51]) by mail01.iro.umontreal.ca (Postfix) with ESMTPSA id 399BF120263; Sun, 8 May 2022 09:32:02 -0400 (EDT) In-Reply-To: <871qx4i4pe.fsf@gnus.org> (Lars Ingebrigtsen's message of "Sun, 08 May 2022 14:33:49 +0200") X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:231651 Archived-At: > I can reproduce this in Emacs 25.1, but not in Emacs 29. That is, > there's no warning for `foo'. There's still a warning for `bar', but > that's correct, isn't it? Yes. > `ignore' is just a normal function, so _ is used there. It's not 100% normal, but yes. > However, this example from a merged bug report is giving a warning: > >> ;;; -*- lexical-binding: t; -*- >> (require 'cl-lib) >> (cl-destructuring-bind (&whole a b &rest _) '(1 2) >> (print (list a b))) > > And that seems like a bug? Indeed. If you look at the macroexpanded code, you see that `cl-destructuring-bind` uses: (let* ((_ '(1 2)) (a _) (b (if _ (pop _) (signal 'wrong-number-of-arguments (list '(&whole a b &rest _) (length _)))))) (print (list a b))) so, you can see that the problem is that `cl-destructuring-bind` tries to avoid using gensym and "abuses" the &rest var as the "iterator" variable while parsing the list. It might have been useful back in the dynbinding days because `setq` might have been a bit cheaper than `let`, but with lexical scoping `let` byte-compiles to virtually nothing. Stefan