ES6: Map and Set needs to normalize minus zero

test/mjsunit/harmony/collections.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 466 matching lines @@
 
 // Test WeakSet clear
 (function() {
   var k = new Object();
   var w = new WeakSet();
   w.add(k);
   assertTrue(w.has(k));
   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));
+})();