diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/collections/Map-constructor-4.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/collections/Map-constructor-4.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,6 @@
+// Map(x) throws if x is not iterable (unless x is undefined).
+
+load(libdir + "asserts.js");
+var nonIterables = [null, true, 1, -0, 3.14, NaN, {}, Math, this];
+for (let k of nonIterables)
+    assertThrowsInstanceOf(function () { Map(k); }, TypeError);