Block scoped const variables.

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 62 matching lines @@
   TestAll('NoConflict', 'eval("' + s + '")', "'NoConflict'");
 }
 
 var letbinds = [ "let x",
                  "let x = 0",
                  "let x = undefined",
                  "function x() { }",
                  "let x = function() {}",
                  "let x, y",
                  "let y, x",
+                 "const x = 0",
+                 "const x = undefined",
+                 "const x = function() {}",
+                 "const x = 2, y = 3",
+                 "const y = 4, x = 5",
                  ];
 var varbinds = [ "var x",
                  "var x = 0",
                  "var x = undefined",
                  "var x = function() {}",
                  "var x, y",
                  "var y, x",
                  ];
 
 
@@ skipping 24 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] + '; })()');
 }