;;;; A slice taken before a push moved the Vec's storage still points at the
;;;; old block. In a dev build that block is filled with 0xDEADBEEF words when
;;;; the move happens, so the stale read shows a value nobody wrote; a release
;;;; build leaves the old values where they were.
;;;;
;;;; The Vec lives in an arena so the old block stays mapped and the read is of
;;;; live memory. A second arena allocation between the two pushes keeps the
;;;; first block from being grown in place.
(defn main [] i32
  (let [a (arena-new 4096)
        v (vec-new i32 a)]
    (dotimes [i 4] (push v (+ i 1)))
    (let [s (slice v)
          other (vec-new i32 a)]
      (push other 0)
      (push v 5)
      (println (at s 0))
      (println (at v 0))))
  0)