diff --git a/doc/emacs/vc1-xtra.texi b/doc/emacs/vc1-xtra.texi
index b4e1e82dcb9..975499cc787 100644
--- a/doc/emacs/vc1-xtra.texi
+++ b/doc/emacs/vc1-xtra.texi
@@ -388,10 +388,10 @@ slow, such as Git repositories where you check in changes to very large
 files, or Mercurial repositories with a very large number of files.
 
   For those backends which support it, setting @code{vc-async-checkin}
-to non-nil switches to doing checkin operations asynchronously.  This is
-particularly useful as a directory local variable in repositories where
-checkin operations are slow
-(@pxref{Directory Local Variables,,,elisp,GNU Emacs Lisp Reference Manual}).
+to non-@code{nil} switches to doing checkin operations asynchronously.
+This is particularly useful as a directory local variable in
+repositories where checkin operations are slow (@pxref{Directory Local
+Variables,,,elisp,GNU Emacs Lisp Reference Manual}).
 
   While an asynchronous checkin operation is in progress, if you use
 @kbd{C-x C-s} to save a buffer visiting any file within the current VC