src/jdk/nashorn/internal/codegen/CodeGenerator.java

@@ -1449,11 +1449,14 @@
             final String       key          = propertyNode.getKeyName();
             final Symbol       symbol       = value == null ? null : propertyNode.getKey().getSymbol();
 
             if (value == null) {
                 hasGettersSetters = true;
-            } else if (key.equals(ScriptObject.PROTO_PROPERTY_NAME)) {
+            } else if (propertyNode.getKey() instanceof IdentNode &&
+                       key.equals(ScriptObject.PROTO_PROPERTY_NAME)) {
+                // ES6 draft compliant __proto__ inside object literal
+                // Identifier key and name is __proto__
                 protoNode = value;
                 continue;
             }
 
             keys.add(key);