diff --git a/library/collection/List.scala b/library/collection/List.scala
index e4924f75e0db19f4bcd168949139cd97e373a2a3..11eccd24f6a4f14c1ee8b88ffe4a1ecb2cddeff0 100644
--- a/library/collection/List.scala
+++ b/library/collection/List.scala
@@ -250,14 +250,14 @@ sealed abstract class List[T] {
     case Cons(h, t) =>
       t.lastOption.orElse(Some(h))
     case Nil() =>
-      None()
+      None[T]()
   }} ensuring { _.isDefined != this.isEmpty }
 
   def firstOption: Option[T] = { this match {
     case Cons(h, t) =>
       Some(h)
     case Nil() =>
-      None()
+      None[T]()
   }} ensuring { _.isDefined != this.isEmpty }
 
   def unique: List[T] = this match {