private static boolean isInCaseNullDefaultLabel(@NotNull PsiElement element) {
    PsiCaseLabelElementList list = ObjectUtils.tryCast(element.getParent(), PsiCaseLabelElementList.class);
    if (list == null || list.getElementCount() != 2) return false;
    PsiCaseLabelElement[] elements = list.getElements();
    return elements[0] instanceof PsiExpression expr &&
           ExpressionUtils.isNullLiteral(expr) &&
           elements[1] instanceof PsiDefaultCaseLabelElement;
  }
private static boolean isInCaseNullDefaultLabel(@NotNull PsiElement element)