diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/jaeger/bug583672.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/jaeger/bug583672.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,30 @@
+(function () {
+    function f()
+    {
+        this.y = w
+        this.y = (void 0)
+        Object
+    }
+    for (a in [0, 0, 0, 0])
+    {
+        new f
+    }
+    let w = {}
+})()
+
+/* Make sure that MICs don't have the same bug. */
+x = Object();
+(function () {
+    function f()
+    {
+        x = w
+        x = (void 0)
+        Object
+    }
+    for (a in [0, 0, 0, 0])
+    {
+        new f
+    }
+    let w = {}
+})()
+/* Don't assert. */