ES6: Map and Set needs to normalize minus zero

test/mjsunit/harmony/collections.js

Index: test/mjsunit/harmony/collections.js
diff --git a/test/mjsunit/harmony/collections.js b/test/mjsunit/harmony/collections.js
index 04a5cdca369bddfe2d0aab63ee1e0662ba5512fd..7e95b9e110749f3b83efddef13c8c092d8adc714 100644
--- a/test/mjsunit/harmony/collections.js
+++ b/test/mjsunit/harmony/collections.js
@@ -484,3 +484,25 @@ for (var i = 9; i >= 0; i--) {
   w.clear();
   assertFalse(w.has(k));
 })();
+
+
+(function TestMinusZeroSet() {
+  var m = new Set();
+  m.add(0);
+  m.add(-0);
+  assertEquals(1, m.size);
+  assertTrue(m.has(0));
+  assertTrue(m.has(-0));
+})();
+
+
+(function TestMinusZeroMap() {
+  var m = new Map();
+  m.set(0, 'plus');
+  m.set(-0, 'minus');
+  assertEquals(1, m.size);
+  assertTrue(m.has(0));
+  assertTrue(m.has(-0));
+  assertEquals('minus', m.get(0));
+  assertEquals('minus', m.get(-0));
+})();