;; A dyn captured by an fn. The copy lives in the fn's environment, which the
;; collector allocated and marks through the environment's descriptor, so the
;; value it names stays alive for as long as the function value does.
(defn run [f (Fn [] i64)] i64 (f))

;; [d] is unannotated, which is what makes it a dyn.
(defn use [d] i64
  (run (fn [] (i64 d))))

(defn main [] i32 (println (use 7)) 0)