diff -r 5538c1eb03be -r 8ac637d7d62a rt/vm/src/test/java/org/apidesign/vm4brwsr/Instance.java
--- a/rt/vm/src/test/java/org/apidesign/vm4brwsr/Instance.java	Mon Feb 17 12:08:31 2014 +0100
+++ b/rt/vm/src/test/java/org/apidesign/vm4brwsr/Instance.java	Sun Jun 22 00:09:56 2014 +0200
@@ -135,6 +135,13 @@
         return jsgetbytes(new Instance());
     }
     
+    public static int noInstOfExposed() {
+        return countInstOf(10);
+    }
+    
+    @JavaScriptBody(args = "o", body = "var i = 0; for (p in o) { if (p.toString().indexOf('instOf') >= 0) i++; } return i;")
+    private static native int countInstOf(Object o);
+    
     @JavaScriptBody(args = { "instance" }, body = "return instance.getByte__B();")
     private static native int jsgetbytes(Instance instance);