diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/debug/Frame-arguments-05.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/debug/Frame-arguments-05.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,19 @@
+// frame.arguments is "live" (it reflects assignments to arguments).
+
+var g = newGlobal();
+var dbg = new Debugger(g);
+var log = '';
+var args;
+dbg.onDebuggerStatement = function (frame) {
+    if (args === undefined)
+        args = frame.arguments;
+    else
+        assertEq(frame.arguments, args);
+    log += args[0];
+    assertEq(frame.eval("x = '0';").return, '0');
+    log += args[0];
+};
+
+g.eval("function f(x) { x = '2'; debugger; x = '3'; debugger; }");
+g.f("1");
+assertEq(log, "2030");