> Yes, but we need to do that even on chunks of code that have not yet
 > been (and may never be) displayed and in buffers where font-lock
 > is disabled.  IOW I'm not talking about fontification but about parsing.

Sure.  But I was only talking about the possibility to highlight such
instances just like we do with column 0 parens in strings already.

 > Pretty much, yes, tho the error message should give more info (the OP
 > complained about lack of info in the error message).

That's what the ellipsis stands for.  But what info?  Guessing a good
buffer position seems next to impossible.  Where else can `forward-sexp'
go astray when called from a top-level position?

 >> But do we really have to scan the buffer in the first place?
 >
 > Don't know.  Maybe not, indeed.  Maybe it's just to detect the "too many
 > closing parens" case as well (i.e. rather than silently ignore trailing
 > code).

We could simply search for (concat "^(" (symbol-name symbol))) and do a
`forward-sexp' over the form starting there as in the attached patch.  I
see no reason why we should try to handle an .emacs broken before or
after that form.

martin