diff --git a/internal/util-collection/src/main/scala/sbt/internal/util/AList.scala b/internal/util-collection/src/main/scala/sbt/internal/util/AList.scala
index 3ab98f72e..7685f9c5f 100644
--- a/internal/util-collection/src/main/scala/sbt/internal/util/AList.scala
+++ b/internal/util-collection/src/main/scala/sbt/internal/util/AList.scala
@@ -59,7 +59,7 @@ object AList {
   }
 
   /** AList for the arbitrary arity data structure KList. */
-  def klist[KL[M[_]] <: KList[M] { type Transform[N[_]] = KL[N] }]: AList[KL] = new AList[KL] {
+  def klist[KL[M[_]] <: KList.Aux[M, KL]]: AList[KL] = new AList[KL] {
     def transform[M[_], N[_]](k: KL[M], f: M ~> N) = k.transform(f)
     def foldr[M[_], T](k: KL[M], f: (M[_], T) => T, init: T): T = k.foldr(f, init)
     override def apply[M[_], C](k: KL[M], f: KL[Id] => C)(implicit app: Applicative[M]): M[C] = k.apply(f)(app)
diff --git a/internal/util-collection/src/main/scala/sbt/internal/util/KList.scala b/internal/util-collection/src/main/scala/sbt/internal/util/KList.scala
index 42ad69bb9..a68b61788 100644
--- a/internal/util-collection/src/main/scala/sbt/internal/util/KList.scala
+++ b/internal/util-collection/src/main/scala/sbt/internal/util/KList.scala
@@ -29,6 +29,9 @@ sealed trait KList[+M[_]] {
   /** Discards the heterogeneous type information and constructs a plain List from this KList's elements. */
   def toList: List[M[_]]
 }
+object KList {
+  type Aux[+M[_], Transform0[N[_]]] = KList[M] { type Transform[N[_]] = Transform0[N] }
+}
 
 final case class KCons[H, +T <: KList[M], +M[_]](head: M[H], tail: T) extends KList[M] {
   final type Transform[N[_]] = KCons[H, tail.Transform[N], N]