set-visited-file-name with null buffer-file-name

[Trent Buck]

In files.el~CVS-1.778~:2548,25 is the call
        (file-name-nondirectory buffer-file-name)

If buffer-file-name is nil, this creates an error:
        (wrong-type-argument stringp nil)

You can reproduce this behaviour as follows:
        C-x b asdfasdf RET C-x C-w /tmp/tmp RET

assuming that there is no buffer "asdfasdf" and no file "/tmp/tmp".

In GNU Emacs 22.0.50.1 (powerpc-unknown-linux-gnu, GTK+ Version 2.6.2)
 of 2005-07-10 on rocinante, modified by Debian
configured using `configure '--build' 'powerpc-linux' '--host' 'powerpc-linux' 
'--prefix=/usr' '--sharedstatedir=/var/lib' '--libexecdir=/usr/lib' 
'--localstatedir=/var' '--infodir=/usr/share/info' '--mandir=/usr/share/man' 
'--with-pop=yes' '--with-gif' 
'--enable-locallisppath=/etc/emacs-snapshot:/etc/emacs:/usr/local/share/emacs/22.0.50/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/22.0.50/site-lisp:/usr/share/emacs/site-lisp:/usr/share/emacs/22.0.50/leim'
 '--with-x=yes' '--with-x-toolkit=gtk' 'CFLAGS=-DDEBIAN -g -O2' 
'build_alias=powerpc-linux' 'host_alias=powerpc-linux''

-- 
Trent Buck, Student Errant