Type in expressions to have them evaluated.
Type :help for more information.

scala> 

scala> import scala.reflect.mirror._
import scala.reflect.mirror._

scala> def foo[T]{
  val tt = implicitly[TypeTag[List[T]]]
  println(tt)
}
<console>:11: free type: Ident(newTypeName("T")) defined by foo in <console>:10:16
         val tt = implicitly[TypeTag[List[T]]]
                            ^
foo: [T]=> Unit

scala> foo[Int]
ConcreteTypeTag[List[T]]

scala> 

scala>