private static @Nullable PsiElement skipWhitespacesAndComments(@Nullable PsiElement at) {
    PsiElement nextLeaf = at;
    while (nextLeaf != null && (nextLeaf instanceof PsiWhiteSpace ||
                                nextLeaf instanceof PsiComment ||
                                nextLeaf instanceof PsiErrorElement ||
                                nextLeaf.getTextLength() == 0)) {
      nextLeaf = PsiTreeUtil.nextLeaf(nextLeaf, true);
    }
    return nextLeaf;
  }
private static @Nullable PsiElement skipWhitespacesAndComments(@Nullable PsiElement at)