When the top calls on the execution stack are native code methods, these methods are not showing up in the error tracebacks, which can make it difficult to figure out where things are failing. For example, this simple program:
c = .TestClass~new("Abc")
Will give an error because the Object init method does not allow any arguments. The traceback is showing the source of the error as the first line, omitting display of the class NEW method and the Object INIT method.