GNU bug report logs - #14883
warning about unused returned value from some ert shoulds

Previous Next

Full log

View this message in rfc822 format

From: help-debbugs <at> gnu.org (GNU bug Tracking System)
To: Glenn Morris <rgm <at> gnu.org>
Subject: bug#14883: closed (Re: bug#14883: warning about unused returned
 value from some ert shoulds)
Date: Thu, 05 Sep 2013 03:07:02 +0000

[Message part 1 (text/plain, inline)]

Your bug report

#14883: warning about unused returned value from some ert shoulds

which was filed against the emacs package, has been closed.

The explanation is attached below, along with your original report.
If you require more details, please reply to 14883 <at> debbugs.gnu.org.

-- 
14883: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=14883
GNU Bug Tracking System
Contact help-debbugs <at> gnu.org with problems

[Message part 2 (message/rfc822, inline)]

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Glenn Morris <rgm <at> gnu.org>
Cc: 14883-done <at> debbugs.gnu.org
Subject: Re: bug#14883: warning about unused returned value from some ert
 shoulds
Date: Wed, 04 Sep 2013 23:06:38 -0400

> Compiling a file with contents:
>     ;; -*- lexical-binding: t; -*-
>     (require 'ert)
>     (require 'cl-lib)
>     (defvar foo-test 1)
>     (should foo-test)
>     (cl-assert foo-test)
> results in a warning (for some reason, only when lexical-binding is t):
>    foo.el:5:1:Warning: value returned from (car value-94600) is unused

This `car' came from the closure conversion.  I believe it is now fixed
in the trunk.  Thank you.


        Stefan

[Message part 3 (message/rfc822, inline)]

From: Glenn Morris <rgm <at> gnu.org>
To: submit <at> debbugs.gnu.org
Subject: warning about unused returned value from some ert shoulds
Date: Tue, 16 Jul 2013 16:17:05 -0400

Package: emacs
Version: 24.3
Severity: minor

Compiling a file with contents:

    ;; -*- lexical-binding: t; -*-
    (require 'ert)
    (require 'cl-lib)
    (defvar foo-test 1)
    (should foo-test)
    (cl-assert foo-test)

results in a warning (for some reason, only when lexical-binding is t):

   foo.el:5:1:Warning: value returned from (car value-94600) is unused

The warning is from the `should'. Obviously it is a bogus warning
because the whole point of the should is to test the return value.
The similar cl-assert does not trigger a warning, because internally
cl-assert is written differently.

This is the same issue as http://debbugs.gnu.org/10969, for what is now
cl-pop.

byte-optimize-form-code-walker has special handling for the standard
`pop' macro so as not to warn about unused return values from (pop foo).
It would be nice if there was a general way to get the same result for
arbitrary macros (sort of the opposite of side-effect-free?), but I
don't see how.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.