diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/collections/Set-scale.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/collections/Set-scale.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,8 @@
+// Sets can hold at least 64K values.
+
+var N = 1 << 16;
+var s = new Set;
+for (var i = 0; i < N; i++)
+    assertEq(s.add(i), undefined);
+for (var i = 0; i < N; i++)
+    assertEq(s.has(i), true);