diff --git a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/optimizer/hidden-costs.rkt b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/optimizer/hidden-costs.rkt
index d3ff094c3b..a76dcb150e 100644
--- a/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/optimizer/hidden-costs.rkt
+++ b/pkgs/typed-racket-pkgs/typed-racket-lib/typed-racket/optimizer/hidden-costs.rkt
@@ -10,7 +10,7 @@
 
 ;; not an exhaustive list
 (define-literal-syntax-class hidden-port-parameter-function
-  (display displayln newline write write-byte print printf))
+  (display displayln newline write write-byte write-bytes print printf))
 (define-literal-syntax-class hidden-random-parameter-function
   (random))