static boolean closure_header(PsiBuilder b, int l) {
    if (!recursion_guard_(b, l, "closure_header")) return false;
    boolean r;
    r = closure_header_with_arrow(b, l + 1);
    if (!r) r = empty_parameter_list(b, l + 1);
    return r;
  }
static boolean closure_header(PsiBuilder b, int l)