The Tor Browser / file revision

 // Test Debugger.Object.prototype.callable.

 var g = newGlobal();

 var dbg = new Debugger(g);

 var hits = 0;

 dbg.onDebuggerStatement = function (frame) {

     assertEq(frame.arguments[0].callable, frame.arguments[1]);

     hits++;

 };

 g.eval("function f(obj, iscallable) { debugger; }");

 g.eval("f({}, false);");

 g.eval("f(Function.prototype, true);");

 g.eval("f(f, true);");

 g.eval("f(Proxy.create({}), false);");

 g.eval("f(Proxy.createFunction(f, f), true);");

 assertEq(hits, 5);