code: public boolean isSubtypesUnchecked(List<Type> ts, List<Type> ss, Warner warn) {
          while (ts.tail != null && ss.tail != null
                 /*inlined: ts.nonEmpty() && ss.nonEmpty()*/ &&
                 isSubtypeUnchecked(ts.head, ss.head, warn)) {
              ts = ts.tail;
              ss = ss.tail;
          }
          return ts.tail == null && ss.tail == null;
          /*inlined: ts.isEmpty() && ss.isEmpty();*/
      }
docs: Are corresponding elements of ts subtypes of ss, allowing
  unchecked conversions?  If lists are of different length,
  return false.