bug#1059: 23.0.60; Error When Trying to Access Remote Files

[Chong Yidong]

> emacs -Q

> (setq debug-on-error t)
> C-x C-f /ftp:www.fbeck.net@ftp.strato.de:
> [TAB]

> Debugger entered--Lisp error: (wrong-type-argument char-or-string-p nil)
>   signal(wrong-type-argument (char-or-string-p nil))
>   completion--some(#[(style) "^H A@\n^K\f$" [style
>   completion-styles-alist

I can't reproduce this, also using latest CVS and `emacs -Q'.  Could you
try to debug the problem?