StreamEx<NullabilityProblemKind.NullabilityProblem<?>> problems() {
    return EntryStream.of(myStateInfos).filterValues(StateInfo::shouldReport).mapKeyValue((np, si) -> si.unknown ? np.makeUnknown() : np);
  }
StreamEx<NullabilityProblemKind.NullabilityProblem<?>> problems()