./tests/patmat/t9657.scala:29: warning: match may not be exhaustive.
It would fail on the following input: Bus(_)
  def refuel2[P <: Petrol.type](vehicle: Vehicle {type A = P} ): Vehicle = vehicle match {
                                                                                   ^
./tests/patmat/t9657.scala:38: warning: match may not be exhaustive.
It would fail on the following input: Bus(_)
  def foo2(vehicle: Vehicle {type A <: Petrol.type} ): Vehicle = vehicle match {
                                                                         ^
./tests/patmat/t9657.scala:49: warning: match may not be exhaustive.
It would fail on the following input: Bus(_)
  def bar2(vehicle: Vehicle {type A <: P} ): Vehicle = vehicle match {
                                                               ^
./tests/patmat/t9657.scala:58: warning: match may not be exhaustive.
It would fail on the following input: Bus(_)
  def qux2[P <: Petrol.type](vehicle: Vehicle {type A <: P} ): Vehicle = vehicle match {
                                                                                 ^
four warnings found