auto-fill in c-mode messes up incomplete comments

[Toby Allsopp]

>From a shell prompt:

emacs -q /tmp/tmp.c
M-x auto-fill-mode
/*
* 

(That's / * <return> * SPC).

When typing the final space, the second line gets deleted.  Pressing
return instead messes it up differently.  This seems to be a problem
with c-mask-paragraph.

After space:
--8<---------------cut here---------------start------------->8---
/*
--8<---------------cut here---------------end--------------->8---


After return:
--8<---------------cut here---------------start------------->8---
/
**
--8<---------------cut here---------------end--------------->8---


In GNU Emacs 22.0.91.1 (i486-pc-linux-gnu, X toolkit, Xaw3d scroll bars)
 of 2006-11-24 on pacem, modified by Debian
 (Debian emacs-snapshot package, version 1:20061123-1)
X server distributor `The X.Org Foundation', version 11.0.70101000
configured using `configure  '--build' 'i486-linux-gnu' '--host' 
'i486-linux-gnu' '--prefix=/usr' '--sharedstatedir=/var/lib' 
'--libexecdir=/usr/lib' '--localstatedir=/var' '--infodir=/usr/share/info' 
'--mandir=/usr/share/man' '--with-pop=yes' 
'--enable-locallisppath=/etc/emacs-snapshot:/etc/emacs:/usr/local/share/emacs/22.0.91/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/22.0.91/site-lisp:/usr/share/emacs/site-lisp:/usr/share/emacs/22.0.91/leim'
 '--with-x=yes' '--with-x-toolkit=athena' '--with-toolkit-scroll-bars' 
'build_alias=i486-linux-gnu' 'host_alias=i486-linux-gnu' 'CFLAGS=-DDEBIAN 
-DSITELOAD_PURESIZE_EXTRA=5000 -g -O2''

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: en_NZ.UTF-8
  locale-coding-system: utf-8
  default-enable-multibyte-characters: t

Major mode: C/l

Minor modes in effect:
  tooltip-mode: t
  tool-bar-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  unify-8859-on-encoding-mode: t
  utf-translate-cjk-mode: t
  auto-compression-mode: t
  line-number-mode: t
  abbrev-mode: t

Recent input:
M-x a u t o - f i l l - m o d e <return> / * <return> 
* SPC M-x r e p o <tab> r <tab> <return>

Recent messages:
Loading /etc/emacs/site-start.d/60hyperspec.el (source)...done
Loading /etc/emacs/site-start.d/65bitmap-mule.el (source)...done
Loading /etc/emacs/site-start.d/70x-face-el.el (source)...done
For information about the GNU Project and its goals, type C-h C-p.
tmp.c has auto save data; consider M-x recover-this-file
Loading cc-mode...done
Loading tabify...done
c-mask-paragraph: Beginning of buffer
Making completion list...
Loading emacsbug...done