import org.chromium.build.annotations.NullMarked;
import org.chromium.build.annotations.Nullable;

@NullMarked
class Foo {
  interface Func<ParamT extends @Nullable Object, RetT extends @Nullable Object> {
    RetT apply(ParamT p);
  }

  public static <RetT extends @Nullable Object> RetT run(Func<String, RetT> func) {
    return func.apply("");
  }

  static void repro() {
      run(s -> s == null ? null : s);
  }
}

Foo.java:16: warning: [NullAway] returning @Nullable expression from method with @NonNull return type
      run(s -> s == null ? null : s);
          ^
    (see http://t.uber.com/nullaway )

      run(s -> null, "");