sbool anyOverlap_intRanges(Collection<IntRange> l) {
  if (empty(l)) false;
  L<IntRange> l = sortedByCalculatedField start(l);
  int x = first(l).start;
  for (int i = 1; i < l(l); i++) {
    IntRange r = l.get(i);
    if (r.start < x) true;
    x = r.end;
  }
  false;
}