Introduce extended mode.

test/mjsunit/harmony/block-let-semantics.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
 //       with the distribution.
 //     * Neither the name of Google Inc. nor the names of its
 //       contributors may be used to endorse or promote products derived
 //       from this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // 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
 
+// TODO(ES6): properly activate extended mode
+"use strict";
+
 // Test temporal dead zone semantics of let bound variables in
 // function and block scopes.
 
 function TestFunctionLocal(s) {
   try {
     eval("(function(){" + s + "; })")();
   } catch (e) {
     assertInstanceof(e, ReferenceError);
     return;
   }
@@ skipping 80 matching lines @@
     return 3;
   }
 }
 f();
 
 // Test that a function declaration introduces a block scoped variable.
 TestAll('{ function k() { return 0; } }; k(); ');
 
 // Test that a function declaration sees the scope it resides in.
 function f2() {
-  let m, n;
+  let m, n, o, p;
   {
     m = g;
     function g() {
       return a;
     }
     let a = 1;
   }
   assertEquals(1, m());
 
   try {
@@ skipping 37 matching lines @@
     }
     eval("1 + 1");
     return x + inner();
   }
 
   let x = 1;
   return middle();
 }
 
 assertEquals(2, outer());