diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/collections/Map-constructor-generator-2.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/collections/Map-constructor-generator-2.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,8 @@
+// The argument to Map can be a generator-expression.
+
+var arr = [1, 2, "green", "red"];
+var m = Map([v, v] for (v of arr));
+assertEq(m.size, 4);
+
+for (var i = 0; i < 4; i++)
+    assertEq(m.get(arr[i]), arr[i]);