Proper handling of future reserved words in strict and normal mode.

src/messages.js

 // Copyright 2006-2008 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 130 matching lines @@
   if (kMessages === 0) {
     kMessages = {
       // Error
       cyclic_proto:                 ["Cyclic __proto__ value"],
       code_gen_from_strings:        ["Code generation from strings disallowed for this context"],
       // TypeError
       unexpected_token:             ["Unexpected token ", "%0"],
       unexpected_token_number:      ["Unexpected number"],
       unexpected_token_string:      ["Unexpected string"],
       unexpected_token_identifier:  ["Unexpected identifier"],
+      unexpected_reserved:          ["Unexpected reserved word"],
       unexpected_strict_reserved:   ["Unexpected strict mode reserved word"],
       unexpected_eos:               ["Unexpected end of input"],
       malformed_regexp:             ["Invalid regular expression: /", "%0", "/: ", "%1"],
       unterminated_regexp:          ["Invalid regular expression: missing /"],
       regexp_flags:                 ["Cannot supply flags when constructing one RegExp from another"],
       incompatible_method_receiver: ["Method ", "%0", " called on incompatible receiver ", "%1"],
       invalid_lhs_in_assignment:    ["Invalid left-hand side in assignment"],
       invalid_lhs_in_for_in:        ["Invalid left-hand side in for-in"],
       invalid_lhs_in_postfix_op:    ["Invalid left-hand side expression in postfix operation"],
       invalid_lhs_in_prefix_op:     ["Invalid left-hand side expression in prefix operation"],
@@ skipping 952 matching lines @@
     else throw e;
   }
 }
 
 
 InstallFunctions($Error.prototype, DONT_ENUM, ['toString', errorToString]);
 
 // Boilerplate for exceptions for stack overflows. Used from
 // Isolate::StackOverflow().
 const kStackOverflowBoilerplate = MakeRangeError('stack_overflow', []);