@Contract("null, null -> true; null, !null -> false")
  private static boolean sameReference(PsiExpression expr1, PsiExpression expr2) {
    if (expr1 == null && expr2 == null) return true;
    if (!(expr1 instanceof PsiReferenceExpression ref1) || !(expr2 instanceof PsiReferenceExpression ref2)) return false;
    return Objects.equals(ref1.getReferenceName(), ref2.getReferenceName()) && 
           sameReference(ref1.getQualifierExpression(), ref2.getQualifierExpression());
  }
@Contract("null, null -> true; null, !null -> false")
  private static boolean sameReference(PsiExpression expr1, PsiExpression expr2)