;; now SOMETHING is gc'ed and the binding stack looks like this: 0,
;; 0, SOMETHING, 0 (because the symbol slots are zeroed on
;; unbinding but values are not).
;; now SOMETHING is gc'ed and the binding stack looks like this: 0,
;; 0, SOMETHING, 0 (because the symbol slots are zeroed on
;; unbinding but values are not).