This is a function I can't annotate correctly. The given annotation is how the function is currently used.

zero-path-between.clj

(ann zero-path-between
     [(IPersistentVector (IPersistentVector Any)) Symbol (Vector* Number Number)
      (Vector* Number Number)
      ->
      (IPersistentVector (IPersistentVector Any))])
(defn zero-path-between
  "Traverses the path between start and end and changes each position to 0."
  [grid direction start end]
  (let [next (get-next-coordinate grid start direction)]
    (if (and next (not= next end))
      (zero-path-between (assoc-in grid (reverse next) 0) direction next end)
      grid)))