Subject: bug#23926: defcustom with STANDARD=<non-pure-expression> gives confusing results

From: Noam Postavsky <[email-masked]>
Date: Fri, 8 Jul 2016 23:11:02 -0400

A trivial example:

(defcustom time (current-time-string)
  "the time"
  :type 'string)

Then try to M-x customize-options RET time RET, it will show with
state "CHANGED outside Customize." Similarly, doing <f1> v time RET
shows the "original value" as the current time, not the actual value
when `time' was defined.

See also http://debbugs.gnu.org/cgi/bugreport.cgi?bug=4755#25