--- a/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/AssignSymbols.java	Thu Dec 14 20:19:34 2017 +0800
+++ b/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/codegen/AssignSymbols.java	Thu Dec 14 13:42:59 2017 +0100
@@ -796,7 +796,7 @@
             args.add(strictFlagNode);
 
         } else {
-            return LiteralNode.newInstance(unaryNode, true);
+            throw new AssertionError("Unexpected delete with " + rhs.getClass().getName() + " expression");
         }
         return new RuntimeNode(unaryNode, request, args);
     }