optimize_bug.scm

scheme@(cunning-bot plugins)> ,optimize (define (foo f arg)
  (define l '())
  (define m
    (if (pair? arg)
        (begin
          (set! l (cdr arg))
          (car arg))
        arg))
  (lambda (x) (apply f m l)))
$6 = (define (foo f arg)
  (let ((m (if #f #f)))
    (set! m
      (if (pair? arg)
        (begin (begin (cdr arg) (if #f #f)) (car arg))
        arg))
    (lambda (x) (f m))))
scheme@(cunning-bot plugins)> ,optimize (define (foo f arg)
  (define l '())
  (define m
    (if (pair? arg)
        (begin
          (set! l (cdr arg))
          (car arg))
        arg))
  (lambda (x) (apply f m l)))
$7 = (define (foo f arg)
  (let ((m (if #f #f)))
    (set! m
      (if (pair? arg)
        (begin (begin (cdr arg) (if #f #f)) (car arg)) ;; no set!, so l never becomes (cdr arg)
        arg))
    (lambda (x) (f m)))) ;; note, l has turned into '()
scheme@(cunning-bot plugins)> ,optimize (define (foo f arg)
  (define l '())
  (define m
    (if (pair? arg)
        (begin
          (set! l (cdr arg))
          (car arg))
        arg))
  (lambda (x) (apply f m (pk l))))
$8 = (define (foo f arg)
  (let ((l (if #f #f)) (m (if #f #f)))
    (begin
      (set! l '())
      (set! m
        (if (pair? arg)
          (begin (set! l (cdr arg)) (car arg))
          arg)))
    (lambda (x) (apply f m (pk l)))))
scheme@(cunning-bot plugins)>