Introduce extended mode.

test/mjsunit/harmony/block-conflicts.js

 // Copyright 2011 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 11 matching lines @@
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 // Flags: --harmony-scoping
 
 // Test for conflicting variable bindings.
 
+// TODO(ES6): properly activate extended mode
+"use strict";
+
 function CheckException(e) {
   var string = e.toString();
   assertTrue(string.indexOf("has already been declared") >= 0 ||
              string.indexOf("redeclaration") >= 0);  return 'Conflict';
 }
 
 
 function TestFunction(s,e) {
   try {
     return eval("(function(){" + s + ";return " + e + "})")();
@@ skipping 80 matching lines @@
 
 // Test conflicting catch/var bindings.
 for (var v = 0; v < varbinds.length; ++v) {
   TestConflict('try {} catch (x) { ' + varbinds[v] + '; }');
 }
 
 // Test conflicting parameter/var bindings.
 for (var v = 0; v < varbinds.length; ++v) {
   TestConflict('(function (x) { ' + varbinds[v] + '; })()');
 }