viewtest.scala:43: error: type mismatch;
 found   : List[a(in method compareTo)]
 required: List[a(in method view3)]
        case y1: List[a] => compareLists(x, y1)
                                            ^
viewtest.scala:104: error: ambiguous implicit values:
 both method view4 in object O of type [a](a)a
 and method identity in object Predef of type [a](a)a
 match expected type (test.Str) => test.Ordered[test.Str]
        t = t insert Str(s)
              ^
two errors found