Crasher in Term.show for Skolem type

[jrudolph]

Compiler version

3.0.1

Reproducer

With branch https://github.com/jrudolph/parboiled2/tree/skkolem-crasher run parboiledCoreJVM/Test/compile in sbt.

Output

scala.MatchError: Skolem(1943876506) (of class dotty.tools.dotc.core.Types$SkolemType)
	at scala.quoted.runtime.impl.printers.Extractors$ExtractorsPrinter.visitType(Extractors.scala:233)
	at scala.quoted.runtime.impl.printers.Extractors$.showType(Extractors.scala:12)
	at scala.quoted.runtime.impl.QuotesImpl$$anon$17.show(QuotesImpl.scala:2898)
	at scala.quoted.runtime.impl.QuotesImpl$$anon$17.show(QuotesImpl.scala:2897)
	at scala.quoted.runtime.impl.QuotesImpl$reflect$TypeReprMethods$.show(QuotesImpl.scala:1660)
	at scala.quoted.runtime.impl.QuotesImpl$reflect$TypeReprMethods$.show(QuotesImpl.scala:1660)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.printType(SourceCode.scala:1228)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.printType(SourceCode.scala:1102)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.printTypeAndAnnots$1(SourceCode.scala:1003)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.printTypeTree(SourceCode.scala:1005)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.printTree(SourceCode.scala:528)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.printTrees$$anonfun$1(SourceCode.scala:656)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.printSeparated$3(SourceCode.scala:647)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.printList(SourceCode.scala:651)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.printTrees(SourceCode.scala:656)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.printTree$$anonfun$8(SourceCode.scala:418)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.inSquare(SourceCode.scala:88)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.printTree(SourceCode.scala:418)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.printQualTree(SourceCode.scala:546)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.printTree(SourceCode.scala:399)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.printQualTree(SourceCode.scala:546)
	at scala.quoted.runtime.impl.printers.SourceCode$SourceCodePrinter.printTree(SourceCode.scala:399)
	at scala.quoted.runtime.impl.printers.SourceCode$.showTree(SourceCode.scala:10)
	at scala.quoted.runtime.impl.QuotesImpl$$anon$10.show(QuotesImpl.scala:2870)
	at scala.quoted.runtime.impl.QuotesImpl$$anon$10.show(QuotesImpl.scala:2869)
	at scala.quoted.runtime.impl.QuotesImpl$reflect$TreeMethods$.show(QuotesImpl.scala:95)
	at scala.quoted.runtime.impl.QuotesImpl$reflect$TreeMethods$.show(QuotesImpl.scala:95)

[nicolasstucki]

I could not start SBT on that project

error: error while loading AnnotatedElement, class file '/usr/local/Cellar/openjdk@8/1.8.0+282/libexec/openjdk.jdk/Contents/Home/jre/lib/rt.jar(java/lang/reflect/AnnotatedElement.class)' is broken
(bad constant pool tag 18 at byte 76)
error: error while loading CharSequence, class file '/usr/local/Cellar/openjdk@8/1.8.0+282/libexec/openjdk.jdk/Contents/Home/jre/lib/rt.jar(java/lang/CharSequence.class)' is broken
(bad constant pool tag 18 at byte 10)

@jrudolph what version of the JDK are you using? Or could you help me minimize the issue?

[nicolasstucki]

Self contained version

Macro_1.scala

package org.parboiled2

import scala.annotation.unchecked.uncheckedVariance
import scala.annotation.compileTimeOnly
import scala.collection.immutable
import org.parboiled2.support._
import org.parboiled2.support.hlist.HList
import org.parboiled2.support.hlist.ops.hlist.Prepend
import org.parboiled2.support._
import org.parboiled2.support.hlist._

inline def rule(inline r: Any): Unit = ${ ParserMacros.ruleImpl('r) }

object ParserMacros {
  import scala.quoted._

  def ruleImpl(r: Expr[Any])(using Quotes): Expr[Unit] = {
    import quotes.reflect.*
    r.asTerm.show
    throw new Throwable("OK")
  }
}

sealed class Rule[-I <: HList, +O <: HList] {

  def ~[I2 <: HList, O2 <: HList](that: Rule[I2, O2])(implicit
      i: TailSwitch[I2, O @uncheckedVariance, I @uncheckedVariance],
      o: TailSwitch[O @uncheckedVariance, I2, O2]
  ): Rule[i.Out, o.Out] = ???

}

package support {

  import org.parboiled2.support.hlist._
  import org.parboiled2.Rule
  import org.parboiled2.support.hlist.ops.hlist.Prepend

  sealed trait FCapture[T]

  object FCapture {
    implicit def apply[T]: FCapture[T] = ???
  }

  sealed trait Join[I <: HList, L <: HList, R] {
    type In <: HList
    type Out <: HList
  }

  object Join extends LowPrioJoin {

    implicit def forHList[I <: HList, L <: HList, R <: HList, O <: HList](implicit
        x: Prepend.Aux[L, R, O]
    ): Aux[I, L, R, I, O] = ???

  }

  sealed abstract class LowPrioJoin {

    type Aux[I <: HList, L <: HList, R, In0 <: HList, Out0 <: HList] =
      Join[I, L, R] { type In = In0; type Out = Out0 }

    implicit def forAny[I <: HList, L <: HList, R, In <: HList, Out <: HList](implicit
        x: Aux[I, L, R :: HNil, In, Out]
    ): Aux[I, L, R, In, Out] = ???
  }

  package hlist {

    sealed trait HList extends Product with Serializable

    final case class ::[+H, +T <: HList](head: H, tail: T) extends HList

    sealed trait HNil extends HList

    case object HNil extends HNil

    object HList {
      import org.parboiled2.support.hlist.syntax.HListOps
      implicit def hlistOps[L <: HList](l: L): HListOps[L] = new HListOps(l)

    }

    package ops {
      object hlist {

        trait DepFn2[T, U] {
          type Out
          def apply(t: T, u: U): Out
        }
        trait Prepend[P <: HList, S <: HList] extends DepFn2[P, S] with Serializable {
          type Out <: HList
        }

        trait LowestPriorityPrepend {
          type Aux[P <: HList, S <: HList, Out0 <: HList] = Prepend[P, S] { type Out = Out0 }

          implicit def hlistPrepend[PH, PT <: HList, S <: HList, PtOut <: HList](implicit
              pt: Prepend.Aux[PT, S, PtOut]
          ): Prepend.Aux[PH :: PT, S, PH :: PtOut] =
            new Prepend[PH :: PT, S] {
              type Out = PH :: PtOut
              def apply(prefix: PH :: PT, suffix: S): Out = prefix.head :: pt(prefix.tail, suffix)
            }
        }

        trait LowPriorityPrepend extends LowestPriorityPrepend {
          override type Aux[P <: HList, S <: HList, Out0 <: HList] = Prepend[P, S] { type Out = Out0 }

          implicit def hnilPrepend0[P <: HList, S >: HNil.type <: HNil]: Aux[P, S, P] =
            new Prepend[P, S] {
              type Out = P
              def apply(prefix: P, suffix: S): P = prefix
            }
        }

        object Prepend extends LowPriorityPrepend {
          def apply[P <: HList, S <: HList](implicit prepend: Prepend[P, S]): Aux[P, S, prepend.Out] = prepend

          implicit def hnilPrepend1[P >: HNil.type <: HNil, S <: HList]: Aux[P, S, S] =
            new Prepend[P, S] {
              type Out = S
              def apply(prefix: P, suffix: S): S = suffix
            }
        }

      }
    }

    package syntax {
      final class HListOps[L <: HList](l: L) extends Serializable {
        def ::[H](h: H): H :: L = org.parboiled2.support.hlist.::(h, l)
      }
    }
  }

  sealed trait Lifter[M[_], I <: HList, O <: HList] {
    type In <: HList
    type StrictOut <: HList
    type OptionalOut <: HList
  }

  object Lifter {
    implicit def forReduction[M[_], L <: HList, R <: L]: Lifter[M, L, R] {
      type In          = L
      type StrictOut   = R
      type OptionalOut = L
    } = ???
  }

  sealed trait TailSwitch[L <: HList, T <: HList, R <: HList] {
    type Out <: HList
  }
  object TailSwitch {

    type TailSwitch0[L <: HList, TI <: HList, R <: HList] <: HList = TI match {
      case L => R
    }

    type Aux[L <: HList, LI <: HList, T <: HList, TI <: HList, R <: HList, RI <: HList, Out <: HList] =
      TailSwitch[L, T, R] { type Out = R }

    implicit def tailSwitch[L <: HList, T <: HList, R <: HList]: TailSwitch[L, T, R] {
      type Out = T match {
        case L => R
      }
    } =
      ???
  }

  sealed trait ActionOps[I <: HList, O <: HList] { type Out }
  object ActionOps {

    implicit def ops1[II <: HList, A]: ActionOps[II, A :: HNil] { type Out = Ops1[II, A] } = ???
    sealed trait Ops1[II <: HList, A] {

      def apply[Z, RR](f: (Z, A) => RR)
          (implicit j: Join[Z :: II, HNil, RR],
                    c: FCapture[(Z, A) => RR]): Rule[j.In, j.Out]
    }
  }

}

Test_2.scala

package org.parboiled2

import org.parboiled2.support.hlist._
import org.parboiled2.support._

abstract class Calculator {
  def Expression = rule {
    (??? : Rule[HNil, Int :: HNil]) ~ zeroOrMore(
      rule2ActionOperator((??? : Rule[HNil, HNil]) ~ (??? : Rule[HNil, Int :: HNil])) ~> ((_: Int) + _)
    )
  }

  def zeroOrMore[I <: HList, O <: HList](r: Rule[I, O])(implicit
      l: Lifter[scala.collection.immutable.Seq, I, O]
  ): Rule[l.In, l.OptionalOut] = ???

  def rule2ActionOperator[I <: HList, O <: HList](r: Rule[I, O])(implicit
      ops: ActionOps[I, O]
  ): ActionOperator[I, O, ops.Out] = ???

  sealed trait ActionOperator[I <: HList, O <: HList, Ops] {
    def ~> : Ops
  }
}

[nicolasstucki]

Slightly minimized

Macro_1.scala

package org.parboiled2

import scala.annotation.unchecked.uncheckedVariance
import org.parboiled2.support._
import org.parboiled2.support.hlist._

inline def rule(inline r: Any): Unit = ${ ParserMacros.ruleImpl('r) }

object ParserMacros {
  import scala.quoted._

  def ruleImpl(r: Expr[Any])(using Quotes): Expr[Unit] = {
    import quotes.reflect.*
    r.asTerm.show
    throw new Throwable("OK")
  }
}

sealed class Rule[-I <: HList, +O <: HList] {

  def ~[I2 <: HList, O2 <: HList](that: Rule[I2, O2])(implicit
      i: TailSwitch[I2, O @uncheckedVariance, I @uncheckedVariance],
      o: TailSwitch[O @uncheckedVariance, I2, O2]
  ): Rule[i.Out, o.Out] = ???

}

package support {

  sealed trait FCapture[T]

  object FCapture {
    implicit def apply[T]: FCapture[T] = ???
  }

  sealed trait Join[I <: HList, L <: HList, R] {
    type In <: HList
    type Out <: HList
  }

  object Join extends LowPrioJoin {

    implicit def forHList[I <: HList, L <: HList, R <: HList, O <: HList](implicit
        x: Prepend.Aux[L, R, O]
    ): Aux[I, L, R, I, O] = ???

  }

  sealed abstract class LowPrioJoin {

    type Aux[I <: HList, L <: HList, R, In0 <: HList, Out0 <: HList] =
      Join[I, L, R] { type In = In0; type Out = Out0 }

    implicit def forAny[I <: HList, L <: HList, R, In <: HList, Out <: HList](implicit
        x: Aux[I, L, R :: HNil, In, Out]
    ): Aux[I, L, R, In, Out] = ???
  }

  package hlist {

    sealed trait HList extends Product with Serializable

    final case class ::[+H, +T <: HList](head: H, tail: T) extends HList

    sealed trait HNil extends HList

    case object HNil extends HNil

    trait Prepend[P <: HList, S <: HList] {
      type Out <: HList
    }

    object Prepend {
      type Aux[P <: HList, S <: HList, Out0 <: HList] = Prepend[P, S] { type Out = Out0 }
      implicit def hlistPrepend[PH, PT <: HList, S <: HList, PtOut <: HList](implicit pt: Prepend.Aux[PT, S, PtOut]): Prepend.Aux[PH :: PT, S, PH :: PtOut] = ???
      implicit def hnilPrepend1[P >: HNil.type <: HNil, S <: HList]: Aux[P, S, S] = ???
    }

  }



  sealed trait TailSwitch[L <: HList, T <: HList, R <: HList] {
    type Out <: HList
  }
  object TailSwitch {

    type TailSwitch0[L <: HList, TI <: HList, R <: HList] <: HList = TI match {
      case L => R
    }

    type Aux[L <: HList, LI <: HList, T <: HList, TI <: HList, R <: HList, RI <: HList, Out <: HList] =
      TailSwitch[L, T, R] { type Out = R }

    implicit def tailSwitch[L <: HList, T <: HList, R <: HList]: TailSwitch[L, T, R] {
      type Out = T match {
        case L => R
      }
    } = ???
  }

  sealed trait ActionOps[I <: HList, O <: HList] { type Out }
  object ActionOps {

    def ops1[II <: HList, A]: ActionOps[II, A :: HNil] { type Out = Ops1[II, A] } = ???
    sealed trait Ops1[II <: HList, A] {

      def apply[Z, RR](f: (Z, A) => RR)
          (implicit j: Join[Z :: II, HNil, RR],
                    c: FCapture[(Z, A) => RR]): Rule[j.In, j.Out]
    }
  }

}

Test_2.scala

package org.parboiled2

import org.parboiled2.support.hlist._
import org.parboiled2.support._

abstract class Calculator {
  def Expression = rule {
      rule2ActionOperator((??? : Rule[HNil, HNil]).~[HNil, Int :: HNil](???))(ActionOps.ops1)
  }

  def zeroOrMore[I <: HList, O <: HList](r: Rule[I, O]): Rule[Nothing, Nothing] = ???

  def rule2ActionOperator[I <: HList, O <: HList](r: Rule[I, O])(ops: ActionOps[I, O]): ActionOperator[I, O, ops.Out] = ???

  sealed trait ActionOperator[I <: HList, O <: HList, Ops] {
    def ~> : Ops
  }
}

[nicolasstucki]

Minimized

import scala.quoted._

inline def rule(inline r: Any): Unit = ${ ruleImpl('r) }

def ruleImpl(r: Expr[Any])(using Quotes): Expr[Unit] = {
  import quotes.reflect.*
  r.asTerm.show
  throw new Throwable("OK")
}

def test = rule {
  foo(bar(baz))
}

def foo[I](r: I): Nothing = ???

def bar(i: Baz): i.Out = ???

sealed trait Baz:
  type Out = Nothing match { case Nothing => Nothing }

def baz: Baz = ???