t5878.scala:1: error: value class may not unbox to itself
case class Foo(x: Bar) extends AnyVal
           ^
t5878.scala:2: error: value class may not unbox to itself
case class Bar(x: Foo) extends AnyVal
           ^
t5878.scala:4: error: value class may not unbox to itself
class Foo1(val x: Bar1) extends AnyVal
      ^
t5878.scala:5: error: value class may not unbox to itself
class Bar1(val x: Foo1) extends AnyVal
      ^
four errors found