diff --git a/collects/typed-scheme/types/abbrev.rkt b/collects/typed-scheme/types/abbrev.rkt
index c2608c17..0ab61f3d 100644
--- a/collects/typed-scheme/types/abbrev.rkt
+++ b/collects/typed-scheme/types/abbrev.rkt
@@ -58,8 +58,8 @@
 (define-match-expander Listof:
   (lambda (stx)
     (syntax-parse stx
-      [(_ elem-pat)
-       #'(Mu: var (Union: (list (Value: '()) (Pair: elem-pat (F: var)))))])))
+      [(_ elem-pat (~optional var-pat #:defaults ([var-pat #'var])))
+       (syntax/loc stx (Mu: var-pat (Union: (list (Value: '()) (Pair: elem-pat (F: var-pat))))))])))
 
 (define-match-expander List:
   (lambda (stx)