diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/collections/Set-iterator-remove-1.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/collections/Set-iterator-remove-1.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,26 @@
+// A set iterator can cope with removing the current entry.
+
+function test(letters, toRemove) {
+    var set = Set(letters);
+    toRemove = Set(toRemove);
+
+    var leftovers = [x for (x of set) if (!toRemove.has(x))].join("");
+
+    var log = "";
+    for (let x of set) {
+        log += x;
+        if (toRemove.has(x))
+            set.delete(x);
+    }
+    assertEq(log, letters);
+
+    var remaining = [x for (x of set)].join("");
+    assertEq(remaining, leftovers);
+}
+
+test('a', 'a');    // removing the only entry
+test('abc', 'a');  // removing the first entry
+test('abc', 'b');  // removing a middle entry
+test('abc', 'c');  // removing the last entry
+test('abc', 'abc') // removing all entries
+