framework/tests/framework/GenericTest8.java

// Test case for Issue 139:
// https://github.com/typetools/checker-framework/issues/139
abstract class GenericTest8 {
  interface A<S> {}

  void foo1(A<?> a) {
    foo2(a);
  }

  abstract <T> A<? extends T> foo2(A<? extends T> a);

  void bar1(A<? extends A<?>> a) {
    bar2(a);
  }

  abstract <U> A<A<? extends U>> bar2(A<? extends A<? extends U>> a);
}