The Tor Browser / file revision

 // env.names() lists nonenumerable names in with-statement environments.

 var g = newGlobal();

 var dbg = Debugger(g);

 var hits = 0;

 g.h = function () {

     var env = dbg.getNewestFrame().environment;

     var names = env.names();

     assertEq(names.indexOf("a") !== -1, true);

     // FIXME: Bug 748592 - proxies don't correctly propagate JSITER_HIDDEN

     //assertEq(names.indexOf("b") !== -1, true);

     //assertEq(names.indexOf("isPrototypeOf") !== -1, true);

     hits++;

 };

 g.eval("var obj = {a: 1};\n" +

        "Object.defineProperty(obj, 'b', {value: 2});\n" +

        "with (obj) h();");

 assertEq(hits, 1);