diff --git a/tapl/tests/stlc+sub-tests.rkt b/tapl/tests/stlc+sub-tests.rkt
index 4ecbf4a..ef50508 100644
--- a/tapl/tests/stlc+sub-tests.rkt
+++ b/tapl/tests/stlc+sub-tests.rkt
@@ -51,3 +51,7 @@
 (typecheck-fail (λ ([x : (→ Int Int)]) (+ x x))) ; x should be Int
 (typecheck-fail ((λ ([x : Int] [y : Int]) y) 1)) ; wrong number of args
 (check-type ((λ ([x : Int]) (+ x x)) 10) : Num ⇒ 20)
+
+(check-not-type (λ ([x : Int]) x) : Int)
+(check-not-type (λ ([x : Int] [y : Int]) x) : (→ Int Int))
+(check-not-type (λ ([x : Int]) x) : (→ Int Int Int Int))