ES6 symbols: enable symbols as weak map keys

test/mjsunit/harmony/symbols.js

 // Copyright 2013 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 96 matching lines @@
     assertEquals(undefined, symbols[i].a)
     symbols[i]["a" + "b"] = 0
     assertEquals(undefined, symbols[i]["a" + "b"])
     symbols[i][62] = 0
     assertEquals(undefined, symbols[i][62])
   }
 }
 TestSet()
 
 
-function TestMap() {
+function TestCollections() {
+  var set = new Set
   var map = new Map
+  var weakmap = new WeakMap
   for (var i in symbols) {
+    set.add(symbols[i])
     map.set(symbols[i], i)
+    weakmap.set(symbols[i], i)
+  }
+  assertEquals(symbols.length, set.size)
+  assertEquals(symbols.length, map.size)
+  for (var i in symbols) {
+    assertTrue(set.has(symbols[i]))
+    assertTrue(map.has(symbols[i]))
+    assertTrue(weakmap.has(symbols[i]))
+    assertEquals(i, map.get(symbols[i]))
+    assertEquals(i, weakmap.get(symbols[i]))
   }
   for (var i in symbols) {
-    assertTrue(map.has(symbols[i]))
-    assertEquals(i, map.get(symbols[i]))
+    assertTrue(set.delete(symbols[i]))
+    assertTrue(map.delete(symbols[i]))
+    assertTrue(weakmap.delete(symbols[i]))
   }
+  assertEquals(0, set.size)
+  assertEquals(0, map.size)
 }
-TestMap()
+TestCollections()
 
 
 
 function TestKeySet(obj) {
   // Set the even symbols via assignment.
   for (var i = 0; i < symbols.length; i += 2) {
     obj[symbols[i]] = i
   }
 }
 
@@ skipping 77 matching lines @@
   var obj = objs[i]
   TestKeySet(obj)
   TestKeyDefine(obj)
   TestKeyGet(obj)
   TestKeyHas(obj)
   TestKeyEnum(obj)
   TestKeyKeys(obj)
   TestKeyDescriptor(obj)
   TestKeyDelete(obj)
 }