`Some` in a macro reflect-based unapply method can crash the compiler

[jchyb]

Compiler version

3.3.1, 3.4.0-RC1-bin-20231223-938d405-NIGHTLY (and presumably other)

Minimized code

UnapplyErrorMain.scala

@main def main() =
  val Unapplier(result) = Some(5)

UnapplyErrorMacro.scala

import scala.quoted._

object Unapplier:
  inline def unapplySeq(arg: Any): Option[Seq[Any]] = ${unapplyImpl('arg)}

  def unapplyImpl(using Quotes)(argExpr: Expr[Any]): Expr[Option[Seq[Any]]] =
    import quotes.reflect._
    Match(
      '{Option.empty[Int]}.asTerm,
      List(
        CaseDef(Unapply(TypeApply(Select.unique(Ref(Symbol.classSymbol("scala.Some").companionModule), "unapply"), List(TypeTree.of[Int])), Nil, List('{5}.asTerm)), None, '{Some(Seq(0))}.asTerm),
        CaseDef(Wildcard(), None, '{Some(Seq(0))}.asTerm)
      )
    ).asExprOf[Option[Seq[Any]]]

Output (click arrow to expand)

  exception while retyping x1.value of class Select # -1

  An unhandled exception was thrown in the compiler.
  Please file a crash report here:
  https://github.com/lampepfl/dotty/issues/new/choose
  For non-enriched exceptions, compile with -Yno-enrich-error-messages.

     while compiling: /Users/jchyb/Documents/workspace/dotty/UnapplyErrorMain.scala
        during phase: MegaPhase{elimErasedValueType, pureStats, vcElideAllocations, etaReduce, arrayApply, elimPolyFunction, tailrec, completeJavaEnums, mixin, lazyVals, memoize, nonLocalReturns, capturedVars}
                mode: Mode(ImplicitsEnabled)
     library version: version 2.13.12
    compiler version: version 3.4.0-RC1-bin-20231223-938d405-NIGHTLY-git-938d405
            settings: -classpath /Users/jchyb/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala3-library_3/3.4.0-RC1-bin-20231223-938d405-NIGHTLY/scala3-library_3-3.4.0-RC1-bin-20231223-938d405-NIGHTLY.jar:/Users/jchyb/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala-library/2.13.12/scala-library-2.13.12.jar -d /Users/jchyb/Documents/workspace/dotty/.scala-build/dotty_3200b05eac-8d90288d6d/classes/main -java-output-version 17 -sourceroot /Users/jchyb/Documents/workspace/dotty


  Exception while compiling /Users/jchyb/Documents/workspace/dotty/UnapplyErrorMacro.scala, /Users/jchyb/Documents/workspace/dotty/UnapplyErrorMain.scala

  An unhandled exception was thrown in the compiler.
  Please file a crash report here:
  https://github.com/lampepfl/dotty/issues/new/choose
  For non-enriched exceptions, compile with -Yno-enrich-error-messages.

     while compiling: <no file>
        during phase: parser
                mode: Mode()
     library version: version 2.13.12
    compiler version: version 3.4.0-RC1-bin-20231223-938d405-NIGHTLY-git-938d405
            settings: -classpath /Users/jchyb/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala3-library_3/3.4.0-RC1-bin-20231223-938d405-NIGHTLY/scala3-library_3-3.4.0-RC1-bin-20231223-938d405-NIGHTLY.jar:/Users/jchyb/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala-library/2.13.12/scala-library-2.13.12.jar -d /Users/jchyb/Documents/workspace/dotty/.scala-build/dotty_3200b05eac-8d90288d6d/classes/main -java-output-version 17 -sourceroot /Users/jchyb/Documents/workspace/dotty

Exception in thread "main" java.lang.AssertionError: assertion failed: no owner from  <none>/ <none> in x1.value
        at scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8)
        at dotty.tools.dotc.transform.Erasure$Typer.typedSelect(Erasure.scala:717)
        at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3129)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3243)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:3437)
        at dotty.tools.dotc.transform.Erasure$Typer.$anonfun$7(Erasure.scala:855)
        at dotty.tools.dotc.core.Decorators$.zipWithConserve(Decorators.scala:160)
        at dotty.tools.dotc.transform.Erasure$Typer.typedApply(Erasure.scala:855)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3160)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3244)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:3437)
        at dotty.tools.dotc.transform.Erasure$Typer.$anonfun$7(Erasure.scala:855)
        at dotty.tools.dotc.core.Decorators$.zipWithConserve(Decorators.scala:160)
        at dotty.tools.dotc.transform.Erasure$Typer.typedApply(Erasure.scala:855)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3160)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3244)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.typedIf(Typer.scala:1267)
        at dotty.tools.dotc.transform.Erasure$Typer.typedIf(Erasure.scala:888)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3169)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3244)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3374)
        at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3393)
        at dotty.tools.dotc.transform.Erasure$Typer.typedStats(Erasure.scala:1058)
        at dotty.tools.dotc.typer.Typer.typedBlockStats(Typer.scala:1193)
        at dotty.tools.dotc.typer.Typer.typedBlock(Typer.scala:1197)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3168)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3244)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.typedLabeled(Typer.scala:1991)
        at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3153)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3243)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3318)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.transform.Erasure$Typer.typedTyped(Erasure.scala:632)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3165)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3244)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3318)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.ReTyper.typedInlined(ReTyper.scala:100)
        at dotty.tools.dotc.transform.Erasure$Typer.typedInlined(Erasure.scala:903)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3183)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3244)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:3437)
        at dotty.tools.dotc.typer.Typer.typedValDef(Typer.scala:2539)
        at dotty.tools.dotc.transform.Erasure$Typer.typedValDef(Erasure.scala:912)
        at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3133)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3243)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3347)
        at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3393)
        at dotty.tools.dotc.transform.Erasure$Typer.typedStats(Erasure.scala:1058)
        at dotty.tools.dotc.typer.Typer.typedBlockStats(Typer.scala:1193)
        at dotty.tools.dotc.typer.Typer.typedBlock(Typer.scala:1197)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3168)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3244)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.$anonfun$14(Typer.scala:1294)
        at dotty.tools.dotc.typer.Applications.harmonic(Applications.scala:2364)
        at dotty.tools.dotc.typer.Applications.harmonic$(Applications.scala:350)
        at dotty.tools.dotc.typer.Typer.harmonic(Typer.scala:121)
        at dotty.tools.dotc.typer.Typer.typedIf(Typer.scala:1297)
        at dotty.tools.dotc.transform.Erasure$Typer.typedIf(Erasure.scala:888)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3169)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3244)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3374)
        at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3393)
        at dotty.tools.dotc.transform.Erasure$Typer.typedStats(Erasure.scala:1058)
        at dotty.tools.dotc.typer.Typer.typedBlockStats(Typer.scala:1193)
        at dotty.tools.dotc.typer.Typer.typedBlock(Typer.scala:1197)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3168)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3244)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.typedLabeled(Typer.scala:1991)
        at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3153)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3243)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:3437)
        at dotty.tools.dotc.typer.Typer.typedValDef(Typer.scala:2539)
        at dotty.tools.dotc.transform.Erasure$Typer.typedValDef(Erasure.scala:912)
        at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3133)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3243)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3347)
        at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3393)
        at dotty.tools.dotc.transform.Erasure$Typer.typedStats(Erasure.scala:1058)
        at dotty.tools.dotc.typer.Typer.typedBlockStats(Typer.scala:1193)
        at dotty.tools.dotc.typer.Typer.typedBlock(Typer.scala:1197)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3168)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3244)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:3437)
        at dotty.tools.dotc.typer.Typer.$anonfun$62(Typer.scala:2602)
        at dotty.tools.dotc.inlines.PrepareInlineable$.dropInlineIfError(PrepareInlineable.scala:256)
        at dotty.tools.dotc.typer.Typer.typedDefDef(Typer.scala:2602)
        at dotty.tools.dotc.transform.Erasure$Typer.typedDefDef(Erasure.scala:959)
        at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3136)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3243)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3347)
        at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3393)
        at dotty.tools.dotc.transform.Erasure$Typer.typedStats(Erasure.scala:1058)
        at dotty.tools.dotc.typer.Typer.typedClassDef(Typer.scala:2789)
        at dotty.tools.dotc.transform.Erasure$Typer.typedClassDef(Erasure.scala:1047)
        at dotty.tools.dotc.typer.Typer.typedTypeOrClassDef$1(Typer.scala:3148)
        at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3152)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3243)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3347)
        at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3393)
        at dotty.tools.dotc.transform.Erasure$Typer.typedStats(Erasure.scala:1058)
        at dotty.tools.dotc.typer.Typer.typedPackageDef(Typer.scala:2922)
        at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3194)
        at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3244)
        at dotty.tools.dotc.typer.ReTyper.typedUnadapted(ReTyper.scala:174)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3321)
        at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3325)
        at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:3437)
        at dotty.tools.dotc.transform.Erasure.run(Erasure.scala:143)
        at dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:354)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.immutable.List.foreach(List.scala:333)
        at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:360)
        at dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:315)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1323)
        at dotty.tools.dotc.Run.runPhases$1(Run.scala:337)
        at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:348)
        at dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:357)
        at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:69)
        at dotty.tools.dotc.Run.compileUnits(Run.scala:357)
        at dotty.tools.dotc.Run.compileUnits(Run.scala:267)
        at dotty.tools.dotc.Driver.finish(Driver.scala:58)
        at dotty.tools.dotc.Driver.doCompile(Driver.scala:38)
        at dotty.tools.dotc.Driver.process(Driver.scala:197)
        at dotty.tools.dotc.Driver.process(Driver.scala:165)
        at dotty.tools.dotc.Driver.process(Driver.scala:177)
        at dotty.tools.dotc.Driver.main(Driver.scala:207)
        at dotty.tools.dotc.Main.main(Main.scala)

Notes:

• Writing reflect-based UnApply calls works for other classes and objects. It's just Some that is causing the issues.
• macro call has to be a part of the extractor for this to trigger
• -Xcheck-macros gives no additional hints
• When using Some in a quoted expression it compiles (and when converting that Expr to a Term and back), but we cannot match the representation of that Term exactly, as we cannot insert Unapply into Typed (as Typed requires a Term, and Unapply isn't that)

[jchyb]

This is correct behavior - back then, I did not realise we had the reflect' TypedOrTest abstraction on Typed that does indeed allow us to insert a Tree instead of a Term