typeOf.lean:11:22-11:25: error: failed to synthesize instance
  HAdd Nat Nat Bool
typeOf.lean:12:0-12:5: error: failed to synthesize instance
  HAdd Bool Nat Nat
typeOf.lean:20:56-20:62: error: invalid reassignment, term has type
  Bool : Type
but is expected to have type
  Nat : Type
typeOf.lean:29:55-29:59: error: natural number expected, value has type
  Bool : Type
but is expected to have type
  Nat : Type