./tests/patmat/t7020.scala:3: warning: match may not be exhaustive.
It would fail on the following input: List(_, _)
  List(5) match {
          ^
./tests/patmat/t7020.scala:10: warning: match may not be exhaustive.
It would fail on the following input: List(_, _)
  List(5) match {
          ^
./tests/patmat/t7020.scala:17: warning: match may not be exhaustive.
It would fail on the following input: List(_, _)
  List(5) match {
          ^
./tests/patmat/t7020.scala:24: warning: match may not be exhaustive.
It would fail on the following input: List(_, _)
  List(5) match {
          ^
four warnings found