Apparent bug in filling docstrings in Emacs-Lisp mode

[Luc Teirlinck]

After emacs -q, visit the (changed since a few minutes ago) source
docstring of `write-abbrev-file':

(defun write-abbrev-file (&optional file)
  "Write all user-level abbrev definitions to a file of Lisp code.
This does not include system abbrevs; it includes only the abbrev tables
listed in listed in `abbrev-table-name-list'.
The file written can be loaded in another session to define the same abbrevs.
The argument FILE is the file name to write.  If omitted or nil, the file
specified in `abbrev-file-name' is used."

Doing M-q on any line of the docstring except the second will fill in
a reasonable way (although not necessarily an improvement over the
hand-filled version).

However doing M-q with point on the second line (containing the `;')
produces: 
 
(defun write-abbrev-file (&optional file)
  "Write all user-level abbrev definitions to a file of Lisp code.
This does not include system abbrevs; it includes only the abbrev
                                    ; tables
listed in listed in `abbrev-table-name-list'.
The file written can be loaded in another session to define the same abbrevs.
The argument FILE is the file name to write.  If omitted or nil, the file
specified in `abbrev-file-name' is used."

This can be avoided by quoting the semi-colon.  But I am not aware of
any convention that semi-colons need to be quoted in docstrings.  The
fact that they are inside strings should make them loose their comment
syntax.  Or should that semi-colon be quoted anyway?

Sincerely,

Luc.