4.10.1.9 contains a lot of discussion and code to accomplish something relatively simple: decide whether a referenced method would resolve to a protected method declared in a superclass, and if so, and ensure the type on the stack is assignable to the current class type.

A few potential simplifications to consider:

- Define a single rule for the relevancy test, and use negation ('\+ foo()') to trivially succeed when all the preconditions aren't met

- Get rid of the 'classesInOtherPkgWithProtectedMember' result list, which never gets used—it's just a search to see if there is at least one match

- Rename the check to something more descriptive, and simplify the inputs—e.g., it looks like 'Target' might be a better input than an entire StackFrame