diff --git a/collects/typed-scheme/private/base-env.ss b/collects/typed-scheme/private/base-env.ss
index 27d7a009..55e0a681 100644
--- a/collects/typed-scheme/private/base-env.ss
+++ b/collects/typed-scheme/private/base-env.ss
@@ -278,6 +278,8 @@
 [call-with-current-continuation (-poly (a b) (((a . -> . (Un)) . -> . b) . -> . (Un a b)))]
 [call-with-escape-continuation (-poly (a b) (((a . -> . (Un)) . -> . b) . -> . (Un a b)))]
 
+[struct->vector (Univ . -> . (-vec Univ))]
+
 [quotient (-Integer -Integer . -> . -Integer)]
 [remainder (-Integer -Integer . -> . -Integer)]
 [quotient/remainder