Block scoped const variables.

src/v8globals.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 503 matching lines @@
 static const uint32_t kNaNOrInfinityLowerBoundUpper32 = 0x7FF00000;
 
 const uint64_t kHoleNanInt64 =
     (static_cast<uint64_t>(kHoleNanUpper32) << 32) | kHoleNanLower32;
 const uint64_t kLastNonNaNInt64 =
     (static_cast<uint64_t>(kNaNOrInfinityLowerBoundUpper32) << 32);
 
 
 enum VariableMode {
   // User declared variables:
-  VAR,       // declared via 'var', and 'function' declarations
+  VAR,             // declared via 'var', and 'function' declarations
 
-  CONST,     // declared via 'const' declarations
+  CONST,           // declared via 'const' declarations
 
-  LET,       // declared via 'let' declarations
+  CONST_HARMONY,   // declared via 'const' declarations in harmony mode
+
+  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
                    // has been shadowed by an eval-introduced
                    // variable
 
   INTERNAL,        // like VAR, but not user-visible (may or may not
                    // be in a context)
 
   TEMPORARY        // temporary variables (not user-visible), never
                    // in a context
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_V8GLOBALS_H_