diff --git a/collects/lang/private/rewrite-error-message.rkt b/collects/lang/private/rewrite-error-message.rkt
index 1cda5e5d87..8799658aa9 100644
--- a/collects/lang/private/rewrite-error-message.rkt
+++ b/collects/lang/private/rewrite-error-message.rkt
@@ -133,6 +133,8 @@
                 (lambda (all one) "expects a "))
           (list #rx"list or cyclic list"
                 (lambda (all) "list"))
+          (list #rx"cannot set variable before its definition\n  variable:"
+                (lambda (all) "cannot set variable before its definition:"))
           ;; When do these show up? I see only `#<image>' errors, currently.
           (list (regexp-quote "#(struct:object:image% ...)")
                 (lambda (all) "an image"))
diff --git a/collects/tests/htdp-lang/advanced.rktl b/collects/tests/htdp-lang/advanced.rktl
index 95520ca92f..56236decb9 100644
--- a/collects/tests/htdp-lang/advanced.rktl
+++ b/collects/tests/htdp-lang/advanced.rktl
@@ -70,9 +70,12 @@
 (htdp-syntax-test #'(set! set! 2) "set!: expected a variable after set!, but found a set!")
 (htdp-syntax-test #'(set! x 1) "x: this variable is not defined")
 (htdp-syntax-test #'(lambda (x) (set! x 2)) "set!: expected a mutable variable after set!, but found a variable that cannot be modified: x")
-
 (htdp-syntax-test #'(let ([x 5]) (lambda (x) (set! x 2))) "set!: expected a mutable variable after set!, but found a variable that cannot be modified")
 
+(htdp-top (set! x 5))
+(htdp-err/rt-test (define x 10) "set!: cannot set variable before its definition: x")
+(htdp-top-pop 1)
+
 (htdp-top (define x 5))
 (htdp-top (set! x 'hello))
 (htdp-test 'hello 'access-x x)