Fixed the implementation, see my commits.

This pull request has been marked as ready for review.

Thank you.

Thank you. I more or less had the same in mind for handling unions (check of UnionType, iterate over its types and make a recursive call returning false if one is invalid / true if their all valid). But wanted to do to same for intersections (but obviously being true if any is valid, instead of all). And then "falling back" to what I had in case it was neither of those. But the resolved types (from the annotation) can indeed be combined into an intersection with the given type, and then doing the isSuperTypeOf check on that, dropping the need for an IntersectionType specific path.

does this PR also needs support in DependencyResolver, so types referenced via require-extends/require-implements from a throw-type will invalidate the result cache properly?

(similar how it was done with #2866)

I don't know. Maybe when the class in require-extends starts/stops being a Throwable we get a stale cache.

You can always verify your hypothesis with a failing test 😊