This results in a deprecated warning for fn>. Posting here to link to a Jira ticket.

core.typed-deprecated-warning.clj

(ann get-number-of-cleared-spaces
     [(IPersistentVector (IPersistentVector Any))
      ->
      AnyInteger])
(defn get-number-of-cleared-spaces
  "Returns the number of cleared spaces in the grid."
  [grid]
  (inc (reduce (fn> [[cleared :- AnyInteger]
                     [row :- (IPersistentVector Any)]]
                 (let [result (inc (reduce (fn> [[row-cleared :- AnyInteger]
                                                [grid-item :- Any]]
                                             (if (or (= grid-item 0)
                                                     (= grid-item "@"))
                                               (inc row-cleared)
                                               row-cleared))
                                           -1 row))]
                   (+ cleared result)))
               -1 grid)))

;; "DEPRECATED WARNING: fn> syntax has changed, use [b :- t i] for clauses" "ns: " #<Namespace greed.grid>