AssertionError: Unexpected alias type from the interaction of higher kinded types, AnyVal and partial functions

[doczir]

Compiler version

3.0.0-RC2

Minimized code

trait ReproTrait[F[_], E] {
  def reproFunction[A](pf: PartialFunction[E, F[Unit]]): Unit = ???
}

class ReproExtensionClass[F[_], A](val dummy: Boolean) extends AnyVal {
  def reproExtensionFunction(me: ReproTrait[F, Throwable]): Unit =
    me.reproFunction { case _ =>
      ???
    }
}

(https://scastie.scala-lang.org/npkKBWceTcCajTIL9lPsKw)

Output (click arrow to expand)

java.lang.AssertionError: assertion failed: Unexpected alias type: type F
	at scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8)
	at dotty.tools.dotc.transform.GenericSignatures$.jsig$1(GenericSignatures.scala:261)
	at dotty.tools.dotc.transform.GenericSignatures$.boxedSig$1(GenericSignatures.scala:67)
	at dotty.tools.dotc.transform.GenericSignatures$.argSig$1(GenericSignatures.scala:201)
	at dotty.tools.dotc.transform.GenericSignatures$.classSig$1$$anonfun$1(GenericSignatures.scala:233)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at scala.collection.immutable.List.foreach(List.scala:333)
	at dotty.tools.dotc.transform.GenericSignatures$.classSig$2(GenericSignatures.scala:233)
	at dotty.tools.dotc.transform.GenericSignatures$.jsig$1(GenericSignatures.scala:288)
	at dotty.tools.dotc.transform.GenericSignatures$.boxedSig$1(GenericSignatures.scala:67)
	at dotty.tools.dotc.transform.GenericSignatures$.superSig$1$$anonfun$1(GenericSignatures.scala:64)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at scala.collection.immutable.List.foreach(List.scala:333)
	at dotty.tools.dotc.transform.GenericSignatures$.superSig$2(GenericSignatures.scala:64)
	at dotty.tools.dotc.transform.GenericSignatures$.jsig$1(GenericSignatures.scala:355)
	at dotty.tools.dotc.transform.GenericSignatures$.javaSig0(GenericSignatures.scala:372)
	at dotty.tools.dotc.transform.GenericSignatures$.javaSig(GenericSignatures.scala:39)
	at dotty.tools.backend.jvm.BCodeHelpers.dotty$tools$backend$jvm$BCodeHelpers$$getGenericSignatureHelper(BCodeHelpers.scala:867)
	at dotty.tools.backend.jvm.BCodeHelpers$BCJGenSigGen.getGenericSignature(BCodeHelpers.scala:497)
	at dotty.tools.backend.jvm.BCodeHelpers$BCJGenSigGen.getGenericSignature$(BCodeHelpers.scala:478)
	at dotty.tools.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.getGenericSignature(BCodeSkelBuilder.scala:63)
	at dotty.tools.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.initJClass(BCodeSkelBuilder.scala:274)
	at dotty.tools.backend.jvm.BCodeSkelBuilder$PlainSkelBuilder.genPlainClass(BCodeSkelBuilder.scala:113)
	at dotty.tools.backend.jvm.GenBCodePipeline$Worker1.visit(GenBCode.scala:229)
	at dotty.tools.backend.jvm.GenBCodePipeline$Worker1.run(GenBCode.scala:194)
	at dotty.tools.backend.jvm.GenBCodePipeline.buildAndSendToDisk(GenBCode.scala:529)
	at dotty.tools.backend.jvm.GenBCodePipeline.run(GenBCode.scala:495)
	at dotty.tools.backend.jvm.GenBCode.run(GenBCode.scala:60)
	at dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:303)
	at scala.collection.immutable.List.map(List.scala:246)
	at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:304)
	at dotty.tools.backend.jvm.GenBCode.runOn(GenBCode.scala:64)
	at dotty.tools.dotc.Run.runPhases$4$$anonfun$4(Run.scala:205)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1323)
	at dotty.tools.dotc.Run.runPhases$5(Run.scala:215)
	at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:223)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.scala:18)
	at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:67)
	at dotty.tools.dotc.Run.compileUnits(Run.scala:230)
	at dotty.tools.dotc.Run.compileSources(Run.scala:166)
	at dotty.tools.dotc.Run.compile(Run.scala:150)
	at dotty.tools.dotc.Driver.doCompile(Driver.scala:39)
	at dotty.tools.dotc.Driver.process(Driver.scala:199)
	at dotty.tools.dotc.Main.process(Main.scala)
	at xsbt.CachedCompilerImpl.run(CachedCompilerImpl.java:64)
	at xsbt.CompilerInterface.run(CompilerInterface.java:59)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at sbt.internal.inc.AnalyzingCompiler.call(AnalyzingCompiler.scala:248)
	at sbt.internal.inc.AnalyzingCompiler.compile(AnalyzingCompiler.scala:122)
	at sbt.internal.inc.AnalyzingCompiler.compile(AnalyzingCompiler.scala:95)
	at sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4(MixedAnalyzingCompiler.scala:91)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
	at sbt.internal.inc.MixedAnalyzingCompiler.timed(MixedAnalyzingCompiler.scala:186)
	at sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$3(MixedAnalyzingCompiler.scala:82)
	at sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$3$adapted(MixedAnalyzingCompiler.scala:77)
	at sbt.internal.inc.JarUtils$.withPreviousJar(JarUtils.scala:215)
	at sbt.internal.inc.MixedAnalyzingCompiler.compileScala$1(MixedAnalyzingCompiler.scala:77)
	at sbt.internal.inc.MixedAnalyzingCompiler.compile(MixedAnalyzingCompiler.scala:146)
	at sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1(IncrementalCompilerImpl.scala:343)
	at sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1$adapted(IncrementalCompilerImpl.scala:343)
	at sbt.internal.inc.Incremental$.doCompile(Incremental.scala:120)
	at sbt.internal.inc.Incremental$.$anonfun$compile$4(Incremental.scala:100)
	at sbt.internal.inc.IncrementalCommon.recompileClasses(IncrementalCommon.scala:180)
	at sbt.internal.inc.IncrementalCommon.cycle(IncrementalCommon.scala:98)
	at sbt.internal.inc.Incremental$.$anonfun$compile$3(Incremental.scala:102)
	at sbt.internal.inc.Incremental$.manageClassfiles(Incremental.scala:155)
	at sbt.internal.inc.Incremental$.compile(Incremental.scala:92)
	at sbt.internal.inc.IncrementalCompile$.apply(Compile.scala:75)
	at sbt.internal.inc.IncrementalCompilerImpl.compileInternal(IncrementalCompilerImpl.scala:348)
	at sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileIncrementally$1(IncrementalCompilerImpl.scala:301)
	at sbt.internal.inc.IncrementalCompilerImpl.handleCompilationError(IncrementalCompilerImpl.scala:168)
	at sbt.internal.inc.IncrementalCompilerImpl.compileIncrementally(IncrementalCompilerImpl.scala:248)
	at sbt.internal.inc.IncrementalCompilerImpl.compile(IncrementalCompilerImpl.scala:74)
	at sbt.Defaults$.compileIncrementalTaskImpl(Defaults.scala:1765)
	at sbt.Defaults$.$anonfun$compileIncrementalTask$1(Defaults.scala:1738)
	at scala.Function1.$anonfun$compose$1(Function1.scala:49)
	at sbt.internal.util.$tilde$greater.$anonfun$$u2219$1(TypeFunctions.scala:62)
	at sbt.std.Transform$$anon$4.work(Transform.scala:67)
	at sbt.Execute.$anonfun$submit$2(Execute.scala:281)
	at sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:19)
	at sbt.Execute.work(Execute.scala:290)
	at sbt.Execute.$anonfun$submit$1(Execute.scala:281)
	at sbt.ConcurrentRestrictions$$anon$4.$anonfun$submitValid$1(ConcurrentRestrictions.scala:178)
	at sbt.CompletionService$$anon$2.call(CompletionService.scala:37)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)

[griggt]

Regressed in #10936