301.lean:1:9-1:17: error: missing cases:
(Nat.succ _)
301.lean:1:21-1:24: error: type mismatch
   ( fun (x : Nat) => ?m x)
has type
  (n : Nat) → ?m ( fun (x : Nat) => ?m x) n : Type ?u
but is expected to have type
  ?m x n : Type ?u