Subject: 25.0.50; `setq' with only one argument

From: Drew Adams <[email-masked]>
Date: Wed, 1 Apr 2015 07:53:36 -0700 (PDT)

See for example: `(setq mark-active)' in `compilation-goto-locus'
(compile.el).

setq' should not be called with only one argument.  It "works", with the
effect of assigning a value of nil, but it is poor form.  Typically this
is a sign of a typo.

Beyond this particular occurrence, I think that a wrong-number-of-args
error should be raised when `setq' is called with an odd number of
arguments.  That certainly corresponds to the syntax that is documented.
And it corresponds to the doc explanations that using `setq' is the same
as using `set' and quoting the variable.  And it corresponds to the
definition and behavior of `setq' in Common Lisp.

In GNU Emacs 25.0.50.1 (i686-pc-mingw32)
 of 2014-10-20 on LEG570
Bzr revision: 118168 [email-masked]
Windowing system distributor `Microsoft Corp.', version 6.1.7601
Configured using:
 `configure --enable-checking=yes,glyphs CPPFLAGS=-DGLYPH_DEBUG=1'