Remove unnecessary hack for HKT

Apparently it was fixed along the way.

compiler/src/dotty/tools/dotc/core/Contexts.scala

@@ -829,11 +829,6 @@ object Contexts {
  res
  }
 
- def isEmptyBounds(tp: Type) = tp match {
- case TypeBounds(lo, hi) => (lo eq defn.NothingType) && (hi eq defn.AnyType)
- case _ => false
- }
-
  def unify(tv: TypeVar, tp: Type): Unit = {
  gadts.println(i"manually unifying $tv with $tp")
  constraint = constraint.updateEntry(tv.origin, tp)
@@ -843,9 +838,6 @@ object Contexts {
  val res = tvarBound match {
  case boundTvar: TypeVar =>
  doAddBound(boundTvar)
- // hack to normalize T and T[_]
- case AppliedType(boundTvar: TypeVar, args) if args forall isEmptyBounds =>
- doAddBound(boundTvar)
  case tp => doAddBound(tp)
  }
 

tests/gadt/i5068.scala

@@ -4,8 +4,21 @@ object i5068 {
  final case class ReflK[F[_]]() extends IsK[F, F]
 
  def foo[F[_], G[_]](r: F IsK G, a: Box[F]): Box[G] = r match { case ReflK() => a }
+}
+
+object i5068b {
+ type WeirdShape[A[_], B] = A[B]
+ // type WeirderShape[S[_[_], _], I, M] = Any
+ case class Box[ F[_[_[_], _], _, _[_]] ](value: F[WeirdShape, Int, Option])
+ sealed trait IsK[F[_[_[_], _], _, _[_]], G[_[_[_], _], _, _[_]]]
+ final case class ReflK[ F[_[_[_], _], _, _[_]] ]() extends IsK[F, F]
+
+ def foo[F[_[_[_], _], _, _[_]], G[_[_[_], _], _, _[_]]](
+ r: F IsK G,
+ a: Box[F]
+ ): Box[G] = r match { case ReflK() => a }
 
- def main(args: Array[String]): Unit = {
-  println(foo(ReflK(), Box(Option(10))))
- }
+ // def main(args: Array[String]): Unit = {
+ // println(foo(ReflK(), Box[WeirderShape](???)))
+ // }
 }