diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/collections/Set-constructor-3.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/collections/Set-constructor-3.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,11 @@
+// The argument to Set may contain a value multiple times. Duplicates are discarded.
+
+assertEq(Set(["testing", "testing", 123]).size, 2);
+
+var values = [undefined, null, false, NaN, 0, -0, 6.022e23, -Infinity, "", "xyzzy", {}, Math.sin];
+for (let v of values) {
+    var a = [v, {}, {}, {}, v, {}, v, v];
+    var s = Set(a);
+    assertEq(s.size, 5);
+    assertEq(s.has(v), true);
+}