Recently I discovered an issue with reader-conditional fontification.

I open a new buffer, type `(iter)' in it, and then I move the point to the beginning and start typing `#+ nil'. When I type `#+ ' (so the buffer contains text `#+(iter)'), *Warnings* buffer appears with text in it:

`Warning (slime): "f.lisp":1:8 (pt=9). Caught error during fontification while searching for forms that are suppressed by reader-conditionals. The error was: (error "ecase failed: :iter, (:and :or :not)").

This is a bug in Slime itself. Please report this to the mailinglist slime-devel@common-lisp.net and include your Emacs version, the guilty Lisp source file, and the header of this message.'

I'm using emacs-23 from CVS in gentoo and SLIME from CVS. File f.lisp contains only one line `#+(iter)'

If I ignore this buffer, everything works fine.