diff --git a/scheme/cyclone/transforms.sld b/scheme/cyclone/transforms.sld
index e0062cd4..1289904d 100644
--- a/scheme/cyclone/transforms.sld
+++ b/scheme/cyclone/transforms.sld
@@ -705,12 +705,15 @@ if (acc) {
         (difference (reduce union (map search (ast:lambda-body exp)) '())
                     (ast:lambda-formals->list exp)))
       ((const? exp)    '())
-      ((prim? exp)     '())    
       ((quote? exp)    '())    
       ((ref? exp)      
-       (if (member exp let-vars)
-           '()
-           (if bound-only? '() (list exp))))
+       (cond
+        ((prim? exp)     
+         '())    
+        (else
+         (if (member exp let-vars)
+             '()
+             (if bound-only? '() (list exp))))))
       ((lambda? exp)   
         (difference (reduce union (map search (lambda->exp exp)) '())
                     (lambda-formals->list exp)))