diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/debug/Object-01.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/debug/Object-01.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,17 @@
+// Debugger.Object basics
+
+var g = newGlobal();
+var dbg = Debugger(g);
+var hits = 0;
+dbg.onDebuggerStatement = function (frame) {
+    assertEq(frame.arguments[0], frame.callee);
+    assertEq(Object.getPrototypeOf(frame.arguments[0]), Debugger.Object.prototype);
+    assertEq(frame.arguments[0] instanceof Debugger.Object, true);
+    assertEq(frame.arguments[0] !== frame.arguments[1], true);
+    assertEq(Object.getPrototypeOf(frame.arguments[1]), Debugger.Object.prototype);
+    assertEq(frame.arguments[1] instanceof Debugger.Object, true);
+    hits++;
+};
+
+g.eval("var obj = {}; function f(a, b) { debugger; } f(f, obj);");
+assertEq(hits, 1);