diff --git a/collects/tests/typed-scheme/succeed/empty-or.ss b/collects/tests/typed-scheme/succeed/empty-or.ss
index ba96025d..f0195a6e 100644
--- a/collects/tests/typed-scheme/succeed/empty-or.ss
+++ b/collects/tests/typed-scheme/succeed/empty-or.ss
@@ -1,22 +1,25 @@
-#lang typed/scheme
+#lang typed-scheme
+
+(require scheme/bool scheme/list typed/test-engine/scheme-tests)
 
-(require scheme/list)
 (define-type-alias Atom (U Number #f))
 
 (: mrg ([Listof Atom] [Listof Atom] -> [Listof Number]))
 ;; add corresponding numbers, drop false, stop at end of shortest list
 
-;(check-expect (mrg (list 1 false 2) (list 3 4 5 false 10)) (list 4 4 7))
+(check-expect (mrg (list 1 false 2) (list 3 4 5 false 10)) (list 4 4 7))
 
 (define (mrg l k)
  (cond
-   [(if (empty? l) #t (empty? k))
+   [(or (empty? l) (empty? k))
     empty]
-   [(and (number? (first l)) (number? (first k)))
-    (cons (+ (first l) (first k)) (mrg (rest l) (rest k)))]
-   [(number? (first l))
-    (cons (first l) (mrg (rest l) (rest k)))]
+   [(and (not (car l)) (not (car k)))
+    (cons 0 (mrg (rest l) (rest k)))]
+   [(not (car l))
+    (cons (car k) (mrg (rest l) (rest k)))]
+   [(not (car k))
+    (cons (car l) (mrg (rest l) (rest k)))]
    [else
-    (error 'fail)]))
+    (cons (+ (car l) (car k)) (mrg (rest l) (rest k)))]))
 
-;(test)
\ No newline at end of file
+(test)
\ No newline at end of file