diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/debug/Environment-setVariable-11.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/debug/Environment-setVariable-11.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,16 @@
+// setVariable cannot modify the binding for a FunctionExpression's name.
+
+load(libdir + "asserts.js");
+
+var g = newGlobal();
+var dbg = Debugger(g);
+var hits = 0;
+dbg.onDebuggerStatement = function (frame) {
+    var env = frame.environment.find("f");
+    assertEq(env.getVariable("f"), frame.callee);
+    assertThrowsInstanceOf(function () { env.setVariable("f", 0) }, TypeError);
+    assertThrowsInstanceOf(function () { env.setVariable("f", frame.callee) }, TypeError);
+    hits++;
+};
+g.eval("(function f() { debugger; })();");
+assertEq(hits, 1);