diff --git a/turnstile/examples/stlc+union.rkt b/turnstile/examples/stlc+union.rkt
index c30d7ca..2ce4e34 100644
--- a/turnstile/examples/stlc+union.rkt
+++ b/turnstile/examples/stlc+union.rkt
@@ -27,7 +27,8 @@
                     [* : (→ Num Num Num)]
                     [add1 : (→ Int Int)]
                     [sub1 : (→ Int Int)])
-         #%datum #%app)
+         #%datum #%app
+         (for-syntax ~True ~False))
 
 (define-syntax define-named-type-alias
   (syntax-parser