src/jdk/nashorn/internal/objects/NativeError.java

@@ -72,11 +72,11 @@
     static final String COLUMNNUMBER = "__columnNumber__";
     // fileName property name
     static final String FILENAME = "__fileName__";
 
     /** Message property name */
-    @Property(name = NativeError.MESSAGE)
+    @Property(name = NativeError.MESSAGE, attributes = Attribute.NOT_ENUMERABLE)
     public Object instMessage;
 
     /** ECMA 15.11.4.2 Error.prototype.name */
     @Property(attributes = Attribute.NOT_ENUMERABLE, where = Where.PROTOTYPE)
     public Object name;