TimeClip converts -0 to +0, following ES2015 spec

src/date.js

 // Copyright 2006-2008 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 var $createDate;
 
 // -------------------------------------------------------------------
 
 (function(global, utils) {
 
@@ skipping 98 matching lines @@
   // TimeClip to do it.
   if (MathAbs(time) > MAX_TIME_BEFORE_UTC) return NAN;
   return time;
 }
 
 
 // ECMA 262 - 15.9.1.14
 function TimeClip(time) {
   if (!IsFinite(time)) return NAN;
   if (MathAbs(time) > MAX_TIME_MS) return NAN;
-  return TO_INTEGER(time);
+  return TO_INTEGER(time) + 0;
 }
 
 
 // The Date cache is used to limit the cost of parsing the same Date
 // strings over and over again.
 var Date_cache = {
   // Cached time value.
   time: 0,
   // String input for which the cached time is valid.
   string: null
 };
 
 
 function DateConstructor(year, month, date, hours, minutes, seconds, ms) {
   if (!%_IsConstructCall()) {
     // ECMA 262 - 15.9.2
     return %_CallFunction(new GlobalDate(), DateToString);
   }
 
   // ECMA 262 - 15.9.3
   var argc = %_ArgumentsLength();
   var value;
   if (argc == 0) {
     value = %DateCurrentTime();
     SET_UTC_DATE_VALUE(this, value);
   } else if (argc == 1) {
     if (IS_NUMBER(year)) {
-      value = year;
+      value = TimeClip(year);
 
     } else if (IS_STRING(year)) {
       // Probe the Date cache. If we already have a time value for the
       // given time, we re-use that instead of parsing the string again.
       CheckDateCacheCurrent();
       var cache = Date_cache;
       if (cache.string === year) {
         value = cache.time;
       } else {
         value = DateParse(year);
@@ skipping 716 matching lines @@
   "toUTCString", DateToUTCString,
   "getYear", DateGetYear,
   "setYear", DateSetYear,
   "toISOString", DateToISOString,
   "toJSON", DateToJSON
 ]);
 
 %InstallToContext(["create_date_fun", CreateDate]);
 
 })