(SETF (FIXNUM-IDENTITY ...) ...)

[Jon L White <JONL at MIT-MC>]

So finally I've gone in and fixed this cretinous loser!
    Date: 12 May 1981 13:40-EDT
    From: Alan Bawden <ALAN at MIT-MC>
	Date: 12 May 1981 05:44-EDT
	From: Gail Zacharias <GZ at MIT-MC>
	(SETF (FIXNUM-IDENTITY (CAR SOME-LIST)) 17.)
	wants that SOME-LIST should be a fixnum...
    .  .  .
    While you people are fixing this, could you make it expand into:
    (fixnum-identity (progn (rplaca some-list (fixnum-identity 17.)) 17.))
    or some other variation that does a fixnum-identity BEFORE performing
    the side-effect?  This would be a useful error check to have in the
    interpreter.
(SETF (FIXNUM-IDENTITY foo) bar) ==> 
	(FIXNUM-IDENTITY (SETF foo (FIXNUM-IDENTITY bar)))
So ALAN get's his interpretive error checking, and GZ's bug is fixed.