diff --git a/pkgs/racket-test-core/tests/racket/module.rktl b/pkgs/racket-test-core/tests/racket/module.rktl
index 0891a0abd5..f54ce74b47 100644
--- a/pkgs/racket-test-core/tests/racket/module.rktl
+++ b/pkgs/racket-test-core/tests/racket/module.rktl
@@ -1434,7 +1434,7 @@ case of module-leve bindings; it doesn't cover local bindings.
   (delete-file zo-path))
 
 ;; Check that module-code caching works
-(let ([saved-namespace #f])
+(let ()
   (define dir (find-system-path 'temp-dir))
   (define tmx (build-path dir "tmx2.rkt"))
   (define e (compile '(module tmx2 racket/kernel
@@ -1474,7 +1474,7 @@ case of module-leve bindings; it doesn't cover local bindings.
   (delete-file zo-path)
 
   ;; Need to retain the namespace until here
-  (set! saved-namespace first-namespace))
+  (ephemeron-value (make-ephemeron first-namespace 7) first-namespace))
 
 ;; ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 ;; Check that `provide` doesn't run enclosed expanders until within a