Version 3.5.6.

src/variables.h

 // 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 28 matching lines @@
 // after binding and variable allocation.
 
 class Variable: public ZoneObject {
  public:
   enum Mode {
     // User declared variables:
     VAR,       // declared via 'var', and 'function' declarations
 
     CONST,     // declared via 'const' declarations
 
+    LET,       // declared via 'let' declarations
+
     // Variables introduced by the compiler:
     DYNAMIC,         // always require dynamic lookup (we don't know
                      // the declaration)
 
     DYNAMIC_GLOBAL,  // requires dynamic lookup, but we know that the
                      // variable is global unless it has been shadowed
                      // by an eval-introduced variable
 
     DYNAMIC_LOCAL,   // requires dynamic lookup, but we know that the
                      // variable is local and where it is unless it
@@ skipping 99 matching lines @@
 
   // Usage info.
   bool is_accessed_from_inner_function_scope_;  // set by variable resolver
   bool is_used_;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_VARIABLES_H_