-;;; the old physical environment, removing/flagging variables that
-;;; have no sets or refs. If a var has no references, we remove it
-;;; from the closure. We always clear the INDIRECT flag. This is
-;;; necessary because pre-analysis is done before optimization.
+;;; the old physical environment and the INDIRECT flag on LAMBDA-VARs.
+;;; This is necessary because pre-analysis is done before
+;;; optimization.