nil-pun.clj

; Before

(defn light-keys [symbol language]
  (let [states (light.resolve/resolve-states (psi/containing-file symbol) language)]
    (loop [current (psi/parent symbol)]               ; <- infinite loop if current is nil
      (if-let [state (get states current)]            ;    because psi/parent nil puns
        (light.resolve/resolve-keys symbol state)
        (if (psi/file? (psi/parent current))
          (recur (first (filter psi/significant? (psi/prev-siblings current)))) ; <- first can return nil
          (recur (psi/parent current)))))))

; After

(defn light-keys [symbol language]
  (let [states (light.resolve/resolve-states (psi/containing-file symbol) language)]
    (loop [current (psi/parent symbol)]
      (when current                                   ; <- fix
        (if-let [state (get states current)]
          (light.resolve/resolve-keys symbol state)
          (if (psi/file? (psi/parent current))
            (recur (first (filter psi/significant? (psi/prev-siblings current))))
            (recur (psi/parent current))))))))