(defconst xs [3 i32] [1 2 3])

;; (at xs 7) with a literal index does not reach the backend at all: check.ml
;; rejects it. This one goes through a local, so it is the runtime check that
;; catches it — the same message, and the program stops where it happened.
(defn main [] ()
  (let [i 7]
    (println "before")
    (print (at xs i))
    (println "unreachable")))