bug#8711: 24.0.50; binding _ to unused values with lexical-binding

[Helmut Eller]

There seems be no way to avoid a warning in code like this:

;; -*- lexical-binding: t -*-
(eval-when-compile (require 'cl))
(defun foo (x) (destructuring-bind (_) x))
(defun bar (x) (destructuring-bind (_) x (ignore _)))

In foo the compiler complains because _ is never used and
it bar it complains because it is used.


In GNU Emacs 24.0.50.1 (i686-pc-linux-gnu, GTK+ Version 2.20.1)
 of 2011-05-21 on ix
Windowing system distributor `The X.Org Foundation', version 11.0.10707000
configured using `configure  '--with-gif=no' '--with-gnutls=no''