+ ;; Nodes whose type is NIL (i.e. don't return) such as calls to
+ ;; ERROR are never annotated as TAIL-P, in order to preserve
+ ;; debugging information.
+ ;;
+ ;; FIXME: It might be better to add another DEFKNOWN property
+ ;; (e.g. NO-TAIL-RECURSION) and use it for error-handling
+ ;; functions like ERROR, instead of spreading this special case
+ ;; net so widely.