@NotNull
  private static PsiElement findAnchor(@NotNull PsiElement element) {
    PsiElement last = element.getLastChild();
    assert last != null;
    while (true) {
      PsiElement prevSibling = last.getPrevSibling();
      if (prevSibling instanceof PsiWhiteSpace || prevSibling instanceof PsiErrorElement) {
        last = prevSibling;
      }
      else {
        break;
      }
    }
    return last;
  }
@NotNull
  private static PsiElement findAnchor(@NotNull PsiElement element)