diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/collections/Map-iterator-remove-5.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/collections/Map-iterator-remove-5.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,22 @@
+// Removing a Map entry already visited by an iterator does not cause any
+// entries to be skipped.
+
+var map = Map();
+for (var i = 0; i < 20; i++)
+    map.set(String.fromCharCode('A'.charCodeAt(0) + i), i);
+
+var log = '';
+for (var [k, v] of map) {
+    log += k;
+    if (v % 5 === 4) {
+        // Delete all entries preceding this one.
+        for (let [k1, v1] of map) {
+            if (k1 === k)
+                break;
+            map.delete(k1);
+        }
+    }
+}
+assertEq(log, 'ABCDEFGHIJKLMNOPQRST');
+assertEq(map.size, 1);  // Only the last entry remains.
+assertEq(map.get('T'), 19);