diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/debug/Environment-identity-02.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/debug/Environment-identity-02.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,29 @@
+// frame.environment is different for different activations of a scope.
+
+var g = newGlobal();
+var dbg = Debugger(g);
+g.eval("function h() { debugger; }");
+var arr;
+dbg.onDebuggerStatement = function (hframe) {
+    var e = hframe.older.environment;
+    assertEq(arr.indexOf(e), -1);
+    arr.push(e);
+};
+
+function test(code, expectedHits) {
+    arr = [];
+    g.eval(code);
+    assertEq(arr.length, expectedHits);
+}
+
+// two separate calls to a function
+test("(function () { var f = function (a) { h(); return a; }; f(1); f(2); })();", 2);
+
+// recursive calls to a function
+test("(function f(n) { h(); return n < 2 ? 1 : n * f(n - 1); })(3);", 3);
+
+// separate visits to a block in the same call frame
+test("(function () { for (var i = 0; i < 3; i++) { let j = i * 4; h(); }})();", 3);
+
+// two strict direct eval calls in the same function scope
+test("(function () { 'use strict'; for (var i = 0; i < 3; i++) eval('h();'); })();", 3);