ES6 Unscopables

src/contexts.h

Index: src/contexts.h
diff --git a/src/contexts.h b/src/contexts.h
index d2f97141df0106010b1dc3e384e9b0401d0493ab..0f8bf77b53d2fbf1ca11bdb48500c944af29215a 100644
--- a/src/contexts.h
+++ b/src/contexts.h
@@ -200,7 +200,8 @@ enum BindingFlags {
   V(ITERATOR_RESULT_MAP_INDEX, Map, iterator_result_map)                       \
   V(MAP_ITERATOR_MAP_INDEX, Map, map_iterator_map)                             \
   V(SET_ITERATOR_MAP_INDEX, Map, set_iterator_map)                             \
-  V(ITERATOR_SYMBOL_INDEX, Symbol, iterator_symbol)
+  V(ITERATOR_SYMBOL_INDEX, Symbol, iterator_symbol)                            \
+  V(UNSCOPABLES_SYMBOL_INDEX, Symbol, unscopables_symbol)
 
 // JSFunctions are pairs (context, function code), sometimes also called
 // closures. A Context object is used to represent function contexts and
@@ -394,6 +395,7 @@ class Context: public FixedArray {
     MAP_ITERATOR_MAP_INDEX,
     SET_ITERATOR_MAP_INDEX,
     ITERATOR_SYMBOL_INDEX,
+    UNSCOPABLES_SYMBOL_INDEX,
 
     // Properties from here are treated as weak references by the full GC.
     // Scavenge treats them as strong references.