private static @Nullable PsiCaseLabelElement findNullLabel(@NotNull List<? extends PsiCaseLabelElement> expressions) {
    return ContainerUtil.find(expressions, label -> label instanceof PsiExpression literal && TypeConversionUtil.isNullType(literal.getType()));
  }
private static @Nullable PsiCaseLabelElement findNullLabel(@NotNull List<? extends PsiCaseLabelElement> expressions)