private static String hasAmbiguitiesSoFar(@NotNull PsiClass psiClass, String oldFqn) {
    if (Strings.areSameInstance(oldFqn, AMBIGUITY_FOUND)) return AMBIGUITY_FOUND;
    String qName = Objects.requireNonNullElse(psiClass.getQualifiedName(), LOCAL_CLASS_FOUND);
    return oldFqn == null || oldFqn.equals(qName) && !oldFqn.equals(LOCAL_CLASS_FOUND) ? qName : AMBIGUITY_FOUND;
  }
private static String hasAmbiguitiesSoFar(@NotNull PsiClass psiClass, String oldFqn)