[strong] Implement static restrictions on binding/assignment to 'undefined' identifier.

src/parser.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_PARSER_H_
 #define V8_PARSER_H_
 
 #include "src/allocation.h"
 #include "src/ast.h"
 #include "src/compiler.h"  // TODO(titzer): remove this include dependency
@@ skipping 551 matching lines @@
     // For constructing objects returned by the traversing functions.
     typedef AstNodeFactory Factory;
   };
 
   explicit ParserTraits(Parser* parser) : parser_(parser) {}
 
   // Helper functions for recursive descent.
   bool IsEval(const AstRawString* identifier) const;
   bool IsArguments(const AstRawString* identifier) const;
   bool IsEvalOrArguments(const AstRawString* identifier) const;
+  bool IsUndefined(const AstRawString* identifier) const;
   V8_INLINE bool IsFutureStrictReserved(const AstRawString* identifier) const;
 
   // Returns true if the expression is of type "this.foo".
   static bool IsThisProperty(Expression* expression);
 
   static bool IsIdentifier(Expression* expression);
 
   bool IsPrototype(const AstRawString* identifier) const;
 
   bool IsConstructor(const AstRawString* identifier) const;
@@ skipping 540 matching lines @@
 }
 
 
 Expression* ParserTraits::CloseTemplateLiteral(TemplateLiteralState* state,
                                                int start, Expression* tag) {
   return parser_->CloseTemplateLiteral(state, start, tag);
 }
 } }  // namespace v8::internal
 
 #endif  // V8_PARSER_H_