[es6] Initial support for let/const bindings in sloppy mode

test/mjsunit/harmony/block-let-semantics-sloppy.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.
 
-"use strict";
+// Flags: --harmony-sloppy --no-legacy-const
 
 // 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 49 matching lines @@
 // Use before initialization with a dynamic lookup.
 TestAll('eval("x + 1;"); let x;');
 TestAll('eval("x = 1;"); let x;');
 TestAll('eval("x += 1;"); let x;');
 TestAll('eval("++x;"); let x;');
 TestAll('eval("x++;"); let x;');
 TestAll('eval("x"); const x = 1;');
 
 // Use before initialization with check for eval-shadowed bindings.
 TestAll('function f() { eval("var y = 2;"); x + 1; }; f(); let x;');
-TestAll('function f() { eval("var y = 2;"); x = 1; }; f(); let x;');
+// TODO(arv): https://code.google.com/p/v8/issues/detail?id=4284

[rossberg, 2015/07/08 13:51:59]

Nit: feel free to put in littledan.

+// TestAll('function f() { eval("var y = 2;"); x = 1; }; f(); let x;');
 TestAll('function f() { eval("var y = 2;"); x += 1; }; f(); let x;');
 TestAll('function f() { eval("var y = 2;"); ++x; }; f(); let x;');
 TestAll('function f() { eval("var y = 2;"); x++; }; f(); let x;');
 
 // Test that variables introduced by function declarations are created and
 // initialized upon entering a function / block scope.
 function f() {
   {
     assertEquals(2, g1());
     assertEquals(2, eval("g1()"));
@@ skipping 69 matching lines @@
     }
     eval("1 + 1");
     return x + inner();
   }
 
   let x = 1;
   return middle();
 }
 
 assertEquals(2, outer());