diff --git a/util/collection/TypeFunctions.scala b/util/collection/TypeFunctions.scala
index c07ecce77..9a6d96b14 100644
--- a/util/collection/TypeFunctions.scala
+++ b/util/collection/TypeFunctions.scala
@@ -4,6 +4,7 @@ trait TypeFunctions
 {
 	type Id[X] = X
 	trait Const[A] { type Apply[B] = A }
+	trait P1of2[M[_,_], A] { type Apply[B] = M[A,B] }
 	trait Down[M[_]] { type Apply[B] = Id[M[B]] }
 
 	trait ~>[A[_], B[_]]