gistfile1.txt

trait Foo{
    val id: String
}

trait SubFoo extends Foo{
    val id = "1234"
}

abstract class Bar{
    def save[T <: Foo](foo: T): Unit
}

class BarImpl extends Bar{
    def save(foo: SubFoo) = println(foo.id)
}

object Tmp extends Application{
    
    object Foop extends SubFoo
    
    val bar = new BarImpl
    bar.save(Foop)
    
}