From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Christopher Wellons Newsgroups: gmane.emacs.bugs Subject: bug#15326: 24.3; Incorrect "variable not left unused" in destructuring cl-loop Date: Wed, 11 Sep 2013 00:47:54 -0400 Message-ID: <874n9s9d6t.fsf@susie.zeus.nullprogram.com> References: <87a9jkttya.fsf@wellocc1-ld1.jhuapl.edu> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain X-Trace: ger.gmane.org 1378874958 10761 80.91.229.3 (11 Sep 2013 04:49:18 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Wed, 11 Sep 2013 04:49:18 +0000 (UTC) To: 15326@debbugs.gnu.org Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Wed Sep 11 06:49:20 2013 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VJcMg-0002lM-Qu for geb-bug-gnu-emacs@m.gmane.org; Wed, 11 Sep 2013 06:49:18 +0200 Original-Received: from localhost ([::1]:32928 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VJcMg-0007rg-65 for geb-bug-gnu-emacs@m.gmane.org; Wed, 11 Sep 2013 00:49:18 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:40678) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VJcMX-0007rX-Ka for bug-gnu-emacs@gnu.org; Wed, 11 Sep 2013 00:49:14 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VJcMQ-00023g-NI for bug-gnu-emacs@gnu.org; Wed, 11 Sep 2013 00:49:09 -0400 Original-Received: from debbugs.gnu.org ([140.186.70.43]:45804) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VJcMQ-00023c-JL for bug-gnu-emacs@gnu.org; Wed, 11 Sep 2013 00:49:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.80) (envelope-from ) id 1VJcMQ-0001Wl-7B for bug-gnu-emacs@gnu.org; Wed, 11 Sep 2013 00:49:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Christopher Wellons Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Wed, 11 Sep 2013 04:49:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 15326 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 15326-submit@debbugs.gnu.org id=B15326.13788749015811 (code B ref 15326); Wed, 11 Sep 2013 04:49:02 +0000 Original-Received: (at 15326) by debbugs.gnu.org; 11 Sep 2013 04:48:21 +0000 Original-Received: from localhost ([127.0.0.1]:54092 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1VJcLk-0001Ve-Jh for submit@debbugs.gnu.org; Wed, 11 Sep 2013 00:48:21 -0400 Original-Received: from mail.nullprogram.com ([192.241.191.137]:42194) by debbugs.gnu.org with esmtp (Exim 4.80) (envelope-from ) id 1VJcLh-0001VN-Hx for 15326@debbugs.gnu.org; Wed, 11 Sep 2013 00:48:18 -0400 Original-Received: from localhost ([127.0.0.1] helo=susie.zeus.nullprogram.com) by mail.nullprogram.com with esmtp (Exim 4.80) (envelope-from ) id 1VJcLg-0000S9-5M; Wed, 11 Sep 2013 04:48:16 +0000 In-Reply-To: User-Agent: Notmuch/0.16 (http://notmuchmail.org) Emacs/24.3.1 (x86_64-pc-linux-gnu) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.15 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 140.186.70.43 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.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:78204 Archived-At: Stefan Monnier writes: > A `setq' does not *use* a variable. It just sets it, affecting > later uses. I mean that the compiler counts the setq as a use even in this simple expression: (let (_) (setq _ t)) ;; Warning: variable `_' not left unused > If there's no later uses, the setq is just a no-op. Without bothering to dig into the bytecode for it, it seems that the compiler is still emitting code for the setq: (defun foo () (let (_) (setq _ t))) (defun bar () (let (_))) (equal (byte-compile 'foo) (byte-compile 'bar)) ;; => nil Maybe I'm not understanding what you mean by "no-op" here.