public @NotNull Set<PsiElement> computeUnreachable(@NotNull BitSet reached) {
    Set<PsiElement> result = new HashSet<>();
    myElementToStartOffsetMap.forEach((element, start) -> {
      int end = myElementToEndOffsetMap.getOrDefault(element, -1);
      if (end == -1) return;
      int nextReached = reached.nextSetBit(start);
      if (nextReached == -1 || nextReached >= end) {
        result.add(element);
      }
    });
    return result;
  }
public @NotNull Set<PsiElement> computeUnreachable(@NotNull BitSet reached)