Accessing private field gives MissingPropertyException, not

When accessing a private field of some other class, Groovy gives a MissingPropertyException. This can be confusing to the user; better would be to throw an exception that says it's private. Perhaps create a PrivatePropertyException as a subclass of MissingPropertyException? Alsoo, I'm aware that even if we find a private property we have to keep looking for the property elsewhere. But if we can't find it, it make sense to me to say we found a private one during the search.