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

scala> 

scala> :type List[1, 2, 3]
<console>:2: error: identifier expected but integer literal found.
       List[1, 2, 3]
            ^


scala> :type List(1, 2, 3)
List[Int]

scala> :type def foo[T](x: T) = List(x)
[T](x: T)List[T]

scala> :type val bar = List(Set(1))
List[scala.collection.immutable.Set[Int]]

scala> :type lazy val bar = Set(Set(1))
scala.collection.immutable.Set[scala.collection.immutable.Set[Int]]

scala> :type def f[T >: Null, U <: String](x: T, y: U) = Set(x, y)
[T >: Null, U <: String](x: T, y: U)scala.collection.immutable.Set[Any]

scala> :type def x = 1 ; def bar[T >: Null <: AnyRef](xyz: T) = 5
[T >: Null <: AnyRef](xyz: T)Int

scala> 

scala> :type 5
Int

scala> :type val f = 5
Int

scala> :type lazy val f = 5
Int

scala> :type protected lazy val f = 5
Int

scala> :type def f = 5
Int

scala> :type def f() = 5
()Int

scala> 

scala> :type def g[T](xs: Set[_ <: T]) = Some(xs.head)
[T](xs: Set[_ <: T])Some[T]

scala> 

scala>