-;;; What we do is call CONTINUATION-PROVEN-TYPE and check whether the
-;;; result is a subtype of the assertion. If so, return the proven
-;;; type and set TYPE-CHECK to NIL. Otherwise, return the intersection
-;;; of the asserted and proven types, and set TYPE-CHECK T. If
-;;; TYPE-CHECK already has a non-null value, then preserve it. Only in
-;;; the somewhat unusual circumstance of a newly discovered assertion
-;;; will we change TYPE-CHECK from NIL to T.
-;;;
-;;; The result value is cached in the CONTINUATION-%DERIVED-TYPE slot.
-;;; If the slot is true, just return that value, otherwise recompute
-;;; and stash the value there.
+;;; The result value is cached in the LVAR-%DERIVED-TYPE slot. If the
+;;; slot is true, just return that value, otherwise recompute and
+;;; stash the value there.