The code generates an access violation error when trying to execute TFoo methods that are private (just change to...

The code generates an access violation error when trying to execute TFoo methods that are private (just change to public to work as espected).

How can I solve this without changing the visibility of TFoo methods?

https://gist.github.com/dipold/7b871788222dd7eb94962a9cc92d2e9a