diff --git a/test-uniquify.scm b/test-uniquify.scm
index abb327f..df45c20 100644
--- a/test-uniquify.scm
+++ b/test-uniquify.scm
@@ -25,6 +25,15 @@
                     (let ([x.1 32])
                       (+ (let ([x.2 10]) x.2) x.1)))))
 
+(test-eq (uniquify
+           `(program ()
+              (let ([x 32])
+                (- x))))
+         `(#hash((x . 1))
+           (program ()
+                    (let ([x.1 32])
+                      (- x.1)))))
+
 
 (test-eq (uniquify
            `(program ()
diff --git a/uniquify.scm b/uniquify.scm
index 00fde74..70eb782 100644
--- a/uniquify.scm
+++ b/uniquify.scm
@@ -46,7 +46,7 @@
        (begin
         (define-values (new-symtable res) 
           (for/fold ([cur-symtable symtable]
-                     [res (list '+)])
+                     [res (list op)])
                     ([exp es])
             (let ([uniquify-result ((uniquify-exp cur-symtable ctxtable) exp)])
               (values (car uniquify-result) (append res (list (cadr uniquify-result)))))))