(SETF (CDR X) Y) ...

[KMP at MIT-MC (Kent M. Pitman)]

This is also `fixed' in Lisp if you have done a complex SETF that causes
SETF FASL to load. Eg,

  (LIST (SETQ A '(A B))
	(SETF (CDR A) 'C)
	(SETF (SFA-GET (SFA-CREATE #'(LAMBDA N NIL) 1 "FOO") 0) 'A)
	(SETQ A '(A B))
	(SETF (CDR A) 'C))
  ;Loading SHARPM 66
  ;Loading SETF 272
  ;Loading DEFMAX 64
  ;Loading MACAID 98
  ((A . C) (A . C) A (A . C) C)

Note the 2nd and 5th elements are different. Sigh. I bring this up not because
I care about this instance, but it does bother me that we have no mechanism
for filenaming or autoloading which allows us to separate the FASL files used
by XLisp from the FASL files used by Lisp. I think this should be thought out
more carefully and a real solution worked out.