Issue: REST-LIST-ALLOCATION (Version 3)

[gz@spt.entity.com (Gail Zacharias)]

I would be (a little) more comfortable with MAY-SHARE if it explicitly stated
that the &rest argument is guaranteed to be a proper list.  I know this is not
directly related to rest list sharing, but in practical terms I'm
concerned about the following situation:

	(defun debugged-function (&rest args)
	   (declare (optimize (safety 0)))
	   ... (cadr args) ...)

	(apply #'debugged-function '(a . 17))

The error should be detected before debugged-function is called (or
put another way, whether this error is detected or not should be determined
by optimize settings in effect around apply, not in debugged-function).