outer-reference from object inside def referencing local class crasher

[bishabosha]

This is similar to code that would be generated for a Mirror - but I am using plain code to demonstrate that the problem is not to do with mirror synthesis itself.

derived from a shapeless test case at https://github.com/milessabin/shapeless/blob/ae9fc166082adb3fa590a604b256c9e87a467c56/core/src/test/scala/shapeless/generic.scala#L903

The crucial part is apparently the implementation of M_Rgb, and that it references TRgb - aka result of a match type.
If I replace TRgb by Inner.Rgb then it works.

Compiler version

3.2.1-RC1-bin-20220805-e560c2d-NIGHTLY

Minimized code

trait Mirr {
  type MirroredTp
  type Elems <: Tuple
}
trait MirrP extends Mirr {
  def fromProduct(x: Product): MirroredTp
}
trait MirrS extends Mirr

def outer3Local = {
  class Wrapper {
    object Nested {
      sealed trait Color
    }
  }
  val wrapper = new Wrapper
  import wrapper.Nested.Color

  object Inner {
    case object Red extends Color
    case object Green extends Color
    case object Blue extends Color
    case class Rgb(hex: Int) extends Color
    case object Rgb
  }

  object CallSite {
    def run =
      import Inner.*
      val M: (MirrS { type MirroredTp = Color; type Elems = (Inner.Red.type, Inner.Green.type, Inner.Blue.type, Inner.Rgb) }) =
        new MirrS {
          type MirroredTp = Color
          type Elems = (Inner.Red.type, Inner.Green.type, Inner.Blue.type, Inner.Rgb)
        }

      val M_Rgb =
        type TRgb = Tuple.Elem[M.Elems, 3]
        new MirrP {
          type MirroredTp = TRgb
          type Elems = Int *: EmptyTuple

          def fromProduct(x: Product): MirroredTp =
            new TRgb(x.productElement(0).asInstanceOf[Int])
        }: (MirrP {
          type MirroredTp = TRgb
          type Elems = Int *: EmptyTuple
        })
  }

  CallSite.run
}

@main def Test =
  outer3Local

Output (click arrow to expand)

exception occurred while compiling tests/run/i13332shapeless-c.scala
Exception in thread "main" java.lang.AssertionError: assertion failed: asTerm called on not-a-Term val <none>
	at scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8)
	at dotty.tools.dotc.core.Symbols$Symbol.asTerm(Symbols.scala:169)
	at dotty.tools.dotc.transform.ExplicitOuter$.dotty$tools$dotc$transform$ExplicitOuter$$$outerParamAccessor(ExplicitOuter.scala:230)
	at dotty.tools.dotc.transform.ExplicitOuter$OuterOps$.loop$1(ExplicitOuter.scala:438)
	at dotty.tools.dotc.transform.ExplicitOuter$OuterOps$.path$extension(ExplicitOuter.scala:447)
	at dotty.tools.dotc.transform.LambdaLift$Lifter.memberRef(LambdaLift.scala:161)
	at dotty.tools.dotc.transform.LambdaLift$Lifter.proxyRef(LambdaLift.scala:167)
	at dotty.tools.dotc.transform.LambdaLift$Lifter.addFreeArgs$$anonfun$1(LambdaLift.scala:172)
	at scala.collection.immutable.List.map(List.scala:246)
	at dotty.tools.dotc.transform.LambdaLift$Lifter.addFreeArgs(LambdaLift.scala:172)
	at dotty.tools.dotc.transform.LambdaLift.transformApply(LambdaLift.scala:310)
	at dotty.tools.dotc.transform.LambdaLift.transformApply(LambdaLift.scala:309)
	at dotty.tools.dotc.transform.MegaPhase.goApply(MegaPhase.scala:650)
	at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:280)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
	at dotty.tools.dotc.transform.MegaPhase.recur$1(MegaPhase.scala:459)
	at dotty.tools.dotc.transform.MegaPhase.transformTrees(MegaPhase.scala:459)
	at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:279)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
	at dotty.tools.dotc.transform.MegaPhase.mapDefDef$1(MegaPhase.scala:248)
	at dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:251)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
	at dotty.tools.dotc.transform.MegaPhase.loop$1(MegaPhase.scala:438)
	at dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:438)
	at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:359)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
	at dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:255)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
	at dotty.tools.dotc.transform.MegaPhase.loop$2(MegaPhase.scala:444)
	at dotty.tools.dotc.transform.MegaPhase.transformBlock(MegaPhase.scala:449)
	at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:298)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
	at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:320)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
	at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:320)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
	at dotty.tools.dotc.transform.MegaPhase.loop$2(MegaPhase.scala:447)
	at dotty.tools.dotc.transform.MegaPhase.transformBlock(MegaPhase.scala:449)
	at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:298)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
	at dotty.tools.dotc.transform.MegaPhase.mapValDef$1(MegaPhase.scala:234)
	at dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:239)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
	at dotty.tools.dotc.transform.MegaPhase.loop$2(MegaPhase.scala:444)
	at dotty.tools.dotc.transform.MegaPhase.transformBlock(MegaPhase.scala:449)
	at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:298)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
	at dotty.tools.dotc.transform.MegaPhase.mapDefDef$1(MegaPhase.scala:248)
	at dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:251)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
	at dotty.tools.dotc.transform.MegaPhase.loop$1(MegaPhase.scala:438)
	at dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:438)
	at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:359)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
	at dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:255)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
	at dotty.tools.dotc.transform.MegaPhase.loop$2(MegaPhase.scala:444)
	at dotty.tools.dotc.transform.MegaPhase.transformBlock(MegaPhase.scala:449)
	at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:298)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
	at dotty.tools.dotc.transform.MegaPhase.mapDefDef$1(MegaPhase.scala:248)
	at dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:251)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
	at dotty.tools.dotc.transform.MegaPhase.loop$1(MegaPhase.scala:438)
	at dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:438)
	at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:359)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
	at dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:255)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:425)
	at dotty.tools.dotc.transform.MegaPhase.loop$1(MegaPhase.scala:438)
	at dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:438)
	at dotty.tools.dotc.transform.MegaPhase.mapPackage$1(MegaPhase.scala:379)
	at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:382)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:427)
	at dotty.tools.dotc.transform.MegaPhase.transformUnit(MegaPhase.scala:454)
	at dotty.tools.dotc.transform.MegaPhase.run(MegaPhase.scala:466)
	at dotty.tools.dotc.transform.MegaPhase$MiniPhase.run(MegaPhase.scala:131)
	at dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:311)
	at scala.collection.immutable.List.map(List.scala:246)
	at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:312)
	at dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:234)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1328)
	at dotty.tools.dotc.Run.runPhases$1(Run.scala:245)
	at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:253)
	at dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:262)
	at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:68)
	at dotty.tools.dotc.Run.compileUnits(Run.scala:262)
	at dotty.tools.dotc.Run.compileSources(Run.scala:186)
	at dotty.tools.dotc.Run.compile(Run.scala:170)
	at dotty.tools.dotc.Driver.doCompile(Driver.scala:35)
	at dotty.tools.dotc.Driver.process(Driver.scala:195)
	at dotty.tools.dotc.Driver.process(Driver.scala:163)
	at dotty.tools.dotc.Driver.process(Driver.scala:175)
	at dotty.tools.dotc.Driver.main(Driver.scala:205)
	at dotty.tools.dotc.Main.main(Main.scala)
java.lang.AssertionError: assertion failed: asTerm called on not-a-Term val <none> while compiling tests/run/i13332shapeless-c.scala