(shell-chdrive-regexp): Likewise.

diff --git a/lisp/shell.el b/lisp/shell.el
index c28f1649eb69ad5092112f7358c687ed8c122d80..1b8c9da313aa5388dfe660aa2eec22fea71b0110 100644 (file)
--- a/lisp/shell.el
+++ b/lisp/shell.el
@@ -235,7 +235,8 @@ This mirrors the optional behavior of tcsh."
       "[]a-zA-Z^_`\\[\\\\]:"
     nil)
   "*If non-nil, is regexp used to track drive changes."
-  :type 'regexp
+  :type '(choice regexp
+                (const nil))
   :group 'shell-directories)
 
 (defcustom explicit-shell-file-name nil