diff --git a/racket/src/cs/rumble/error-rewrite.ss b/racket/src/cs/rumble/error-rewrite.ss
index ca71aa4263..55d9cc3542 100644
--- a/racket/src/cs/rumble/error-rewrite.ss
+++ b/racket/src/cs/rumble/error-rewrite.ss
@@ -100,18 +100,18 @@
                               irritants))]
    [(and (or (eq? who 'list-ref) (eq? who 'list-tail))
          (equal? str "index ~s is out of range for list ~s"))
-    (values (string-append "index too large for list\n"
-                           "  index: ~s\n"
-                           "  in: ~s")
-            irritants)]
+    (format-error-values (string-append "index too large for list\n"
+                                        "  index: ~s\n"
+                                        "  in: ~s")
+                         irritants)]
    [(and (or (eq? who 'list-ref) (eq? who 'list-tail))
          (equal? str "index ~s reaches a non-pair in ~s"))
-    (values (string-append "index reaches a non-pair\n"
-                           "  index: ~s\n"
-                           "  in: ~s")
-            irritants)]
+    (format-error-values (string-append "index reaches a non-pair\n"
+                                        "  index: ~s\n"
+                                        "  in: ~s")
+                         irritants)]
    [(or (eq? who 'memq) (eq? who 'memv))
-    (values "not a proper list\n  in: ~s" irritants)]
+    (format-error-values "not a proper list\n  in: ~s" irritants)]
    [(equal? str  "~s is not a valid index for ~s")
     (cond
      [(exact-nonnegative-integer? (car irritants))