error while pickling type $param$1
error when pickling type $param$1
error while pickling type Null(Test.foo) & $param$1
error when pickling type (Null(Test.foo) & $param$1)^
error when pickling tree (Null(Test.foo) & $param$1)^
error when pickling tree Test.ident[(Null(Test.foo) & $param$1)^]
error when pickling tree Test.ident[(Null(Test.foo) & $param$1)^](Test.narrow(Test.foo))
error when pickling tree () extends Object() { this: Test.type => 
  def narrow(task: AnyRef): Contra[task.type] = new Contra[Any^](task)
  def ident[Before](elems: Contra[Before]): Contra[Before] = elems
  val foo: Null = null
  Test.ident[(Null(Test.foo) & $param$1)^](Test.narrow(Test.foo))
}
error when pickling tree @scala.annotation.internal.SourceFile(
  "core/src/main/scala/impromptu/framework.scala"
) final module class Test$() extends Object() { this: Test.type => 
  def narrow(task: AnyRef): Contra[task.type] = new Contra[Any^](task)
  def ident[Before](elems: Contra[Before]): Contra[Before] = elems
  val foo: Null = null
  Test.ident[(Null(Test.foo) & $param$1)^](Test.narrow(Test.foo))
}
error when pickling tree package <empty> {
  final lazy module val Test: Test$ = new Test$()
  @scala.annotation.internal.SourceFile(
    "core/src/main/scala/impromptu/framework.scala"
  ) final module class Test$() extends Object() { this: Test.type => 
    def narrow(task: AnyRef): Contra[task.type] = new Contra[Any^](task)
    def ident[Before](elems: Contra[Before]): Contra[Before] = elems
    val foo: Null = null
    Test.ident[(Null(Test.foo) & $param$1)^](Test.narrow(Test.foo))
  }
}

exception occurred while compiling core/src/main/scala/impromptu/examples.scala, core/src/main/scala/impromptu/framework.scala
Exception in thread "main" java.lang.AssertionError: assertion failed: orphan poly parameter: PolyParam($param$1)
	at scala.Predef$.assert(Predef.scala:165)
	at dotty.tools.dotc.core.tasty.TreePickler.pickleNewType(TreePickler.scala:269)
	at dotty.tools.dotc.core.tasty.TreePickler.pickleType(TreePickler.scala:145)
	at dotty.tools.dotc.core.tasty.TreePickler$$anonfun$pickleNewType$8.apply$mcV$sp(TreePickler.scala:252)
	at dotty.tools.dotc.core.tasty.TreePickler.dotty$tools$dotc$core$tasty$TreePickler$$withLength(TreePickler.scala:30)
	at dotty.tools.dotc.core.tasty.TreePickler.pickleNewType(TreePickler.scala:252)
	at dotty.tools.dotc.core.tasty.TreePickler.pickleType(TreePickler.scala:145)
	at dotty.tools.dotc.core.tasty.TreePickler.pickleTree(TreePickler.scala:530)
	at dotty.tools.dotc.core.tasty.TreePickler.pickleTpt(TreePickler.scala:305)
	at dotty.tools.dotc.core.tasty.TreePickler$$anonfun$pickleTree$2$$anonfun$apply$mcV$sp$4.apply(TreePickler.scala:390)
	at dotty.tools.dotc.core.tasty.TreePickler$$anonfun$pickleTree$2$$anonfun$apply$mcV$sp$4.apply(TreePickler.scala:390)
	at scala.collection.immutable.List.foreach(List.scala:381)
	at dotty.tools.dotc.core.tasty.TreePickler$$anonfun$pickleTree$2.apply$mcV$sp(TreePickler.scala:390)
	at dotty.tools.dotc.core.tasty.TreePickler.dotty$tools$dotc$core$tasty$TreePickler$$withLength(TreePickler.scala:30)
	at dotty.tools.dotc.core.tasty.TreePickler.pickleTree(TreePickler.scala:388)
	at dotty.tools.dotc.core.tasty.TreePickler$$anonfun$pickleTree$1.apply$mcV$sp(TreePickler.scala:383)
	at dotty.tools.dotc.core.tasty.TreePickler.dotty$tools$dotc$core$tasty$TreePickler$$withLength(TreePickler.scala:30)
	at dotty.tools.dotc.core.tasty.TreePickler.pickleTree(TreePickler.scala:382)
	at dotty.tools.dotc.core.tasty.TreePickler$$anonfun$pickleStats$2.apply(TreePickler.scala:342)
	at dotty.tools.dotc.core.tasty.TreePickler$$anonfun$pickleStats$2.apply(TreePickler.scala:342)
	at scala.collection.immutable.List.foreach(List.scala:381)
	at dotty.tools.dotc.core.tasty.TreePickler.pickleStats(TreePickler.scala:342)
	at dotty.tools.dotc.core.tasty.TreePickler$$anonfun$pickleTree$22.apply$mcV$sp(TreePickler.scala:512)
	at dotty.tools.dotc.core.tasty.TreePickler.dotty$tools$dotc$core$tasty$TreePickler$$withLength(TreePickler.scala:30)
	at dotty.tools.dotc.core.tasty.TreePickler.pickleTree(TreePickler.scala:493)
	at dotty.tools.dotc.core.tasty.TreePickler$$anonfun$pickleDef$1.apply$mcV$sp(TreePickler.scala:318)
	at dotty.tools.dotc.core.tasty.TreePickler.dotty$tools$dotc$core$tasty$TreePickler$$withLength(TreePickler.scala:30)
	at dotty.tools.dotc.core.tasty.TreePickler.pickleDef(TreePickler.scala:314)
	at dotty.tools.dotc.core.tasty.TreePickler.pickleTree(TreePickler.scala:483)
	at dotty.tools.dotc.core.tasty.TreePickler$$anonfun$pickleStats$2.apply(TreePickler.scala:342)
	at dotty.tools.dotc.core.tasty.TreePickler$$anonfun$pickleStats$2.apply(TreePickler.scala:342)
	at scala.collection.immutable.List.foreach(List.scala:381)
	at dotty.tools.dotc.core.tasty.TreePickler.pickleStats(TreePickler.scala:342)
	at dotty.tools.dotc.core.tasty.TreePickler$$anonfun$pickleTree$24.apply$mcV$sp(TreePickler.scala:528)
	at dotty.tools.dotc.core.tasty.TreePickler.dotty$tools$dotc$core$tasty$TreePickler$$withLength(TreePickler.scala:30)
	at dotty.tools.dotc.core.tasty.TreePickler.pickleTree(TreePickler.scala:528)
	at dotty.tools.dotc.core.tasty.TreePickler$$anonfun$pickle$1.apply(TreePickler.scala:629)
	at dotty.tools.dotc.core.tasty.TreePickler$$anonfun$pickle$1.apply(TreePickler.scala:629)
	at scala.collection.immutable.List.foreach(List.scala:381)
	at dotty.tools.dotc.core.tasty.TreePickler.pickle(TreePickler.scala:629)
	at dotty.tools.dotc.transform.Pickler$$anonfun$run$2$$anonfun$apply$1.apply(Pickler.scala:51)
	at dotty.tools.dotc.transform.Pickler$$anonfun$run$2$$anonfun$apply$1.apply(Pickler.scala:44)
	at scala.collection.immutable.List.foreach(List.scala:381)
	at dotty.tools.dotc.transform.Pickler$$anonfun$run$2.apply(Pickler.scala:44)
	at dotty.tools.dotc.transform.Pickler$$anonfun$run$2.apply(Pickler.scala:43)
	at scala.collection.immutable.List.foreach(List.scala:381)
	at dotty.tools.dotc.transform.Pickler.run(Pickler.scala:43)
	at dotty.tools.dotc.core.Phases$Phase$$anonfun$runOn$1.apply(Phases.scala:283)
	at dotty.tools.dotc.core.Phases$Phase$$anonfun$runOn$1.apply(Phases.scala:281)
	at scala.collection.immutable.List.map(List.scala:277)
	at dotty.tools.dotc.core.Phases$Phase$class.runOn(Phases.scala:281)
	at dotty.tools.dotc.transform.Pickler.runOn(Pickler.scala:75)
	at dotty.tools.dotc.Run$$anonfun$compileUnits$1$$anonfun$apply$mcV$sp$1.apply(Run.scala:76)
	at dotty.tools.dotc.Run$$anonfun$compileUnits$1$$anonfun$apply$mcV$sp$1.apply(Run.scala:73)
	at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33)
	at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:186)
	at dotty.tools.dotc.Run$$anonfun$compileUnits$1.apply$mcV$sp(Run.scala:73)
	at dotty.tools.dotc.Run$$anonfun$compileUnits$1.apply(Run.scala:67)
	at dotty.tools.dotc.Run$$anonfun$compileUnits$1.apply(Run.scala:67)
	at dotty.tools.dotc.util.Stats$.monitorHeartBeat(Stats.scala:76)
	at dotty.tools.dotc.Run.compileUnits(Run.scala:67)
	at dotty.tools.dotc.Run.compileSources(Run.scala:64)
	at dotty.tools.dotc.Run.compile(Run.scala:48)
	at dotty.tools.dotc.Driver.doCompile(Driver.scala:26)
	at dotty.tools.dotc.Driver.process(Driver.scala:124)
	at dotty.tools.dotc.Driver.process(Driver.scala:93)
	at dotty.tools.dotc.Driver.process(Driver.scala:105)
	at dotty.tools.dotc.Driver.main(Driver.scala:132)
	at dotty.tools.dotc.Main.main(Main.scala)