checker/tests/nullness/java8inference/InLambdaAnnotated.java

import org.checkerframework.checker.nullness.qual.Nullable;

public class InLambdaAnnotated {
  static class Mine<T> {
    @SuppressWarnings("nullness") // just a utility
    static <S> Mine<S> some() {
      return null;
    }
  }

  interface Function<T, R> {
    R apply(T t);
  }

  interface Box<V> {}

  static class Boxes {
    @SuppressWarnings("nullness") // just a utility
    static <O> Box<O> transform(Function<String, ? extends O> function) {
      return null;
    }
  }

  class Infer {
    // The nested Mine.some() needs to infer the right type.
    Box<Mine<@Nullable Integer>> g =
        // TODO: This is a false positive.
        // :: error: (assignment)
        Boxes.transform(
            el -> {
              return Mine.some();
            });

    void bar(Function<String, Mine<@Nullable Integer>> fun) {
      Box<Mine<@Nullable Integer>> h = Boxes.transform(fun);
    }
  }
}