Version 3.5.6.

src/x64/full-codegen-x64.cc

 // 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 694 matching lines @@
           int offset = Context::SlotOffset(slot->index());
           __ movq(rbx, rsi);
           __ RecordWrite(rbx, offset, result_register(), rcx);
         }
         break;
 
       case Slot::LOOKUP: {
         __ push(rsi);
         __ Push(variable->name());
         // Declaration nodes are always introduced in one of two modes.
-        ASSERT(mode == Variable::VAR || mode == Variable::CONST);
-        PropertyAttributes attr = (mode == Variable::VAR) ? NONE : READ_ONLY;
+        ASSERT(mode == Variable::VAR ||
+               mode == Variable::CONST ||
+               mode == Variable::LET);
+        PropertyAttributes attr = (mode == Variable::CONST) ? READ_ONLY : NONE;
         __ Push(Smi::FromInt(attr));
         // Push initial value, if any.
         // Note: For variables we must not push an initial value (such as
         // 'undefined') because we may have a (legal) redeclaration and we
         // must not destroy the current value.
         if (mode == Variable::CONST) {
           __ PushRoot(Heap::kTheHoleValueRootIndex);
         } else if (function != NULL) {
           VisitForStackValue(function);
         } else {
@@ skipping 3508 matching lines @@
   __ jmp(rdx);
 }
 
 
 #undef __
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64