- ;; May be eliminated if value is unused. The function has no side effects
- ;; except possibly CONS. If a function is defined to signal errors, then it
- ;; is not flushable even if it is movable or foldable.
+ ;; may be eliminated if value is unused. The function has no side
+ ;; effects except possibly cons. If a function might signal errors,
+ ;; then it is not flushable even if it is movable, foldable or
+ ;; unsafely-flushable. Implies UNSAFELY-FLUSHABLE. (In safe code
+ ;; type checking of arguments is always performed by the caller, so
+ ;; a function which SHOULD signal an error if arguments are not of
+ ;; declared types may be FLUSHABLE.)