crash when trying completions on a specific library

[bishabosha]

So I was experimenting with my own enum-extensions library in amm and I managed to crash the shell with an autocompletion.

I could not replicate the crash in the standard dotty repl.

Here is the prelude:

amm
Loading...
Welcome to the Ammonite Repl 3.0.0-2-6342755f (Scala 3.5.1 Java 17)
@ import $ivy.`io.github.bishabosha::enum-extensions:0.1.1`
import $ivy.$

@ import enumextensions.EnumMirror
import enumextensions.EnumMirror

@ enum Foo derives EnumMirror:
    case A, B, C

defined class Foo

@ EnumMirror[Foo]
res3: EnumMirror[Foo] = ammonite.$sess.cmd2$Foo$$anon$2@72443081

now the crash happens when I try to tab-complete after EnumMirror[Foo].

tried to show that
  enumextensions.EnumMirror[ammonite.$sess.cmd2.Foo]
conforms to
  ammonite.$sess.cmd2.Foo

on the face of it, I don't know why this type comparison would be made, i.e. there are no F-bounds in the library.

Here is the full crash:

@ EnumMirror[Foo].Exception in thread "main" java.lang.AssertionError: assertion failed: type error: enumextensions.EnumMirror[ammonite.$sess.cmd2.Foo] does not conform to ammonite.$sess.cmd2.FooI tried to show that
  enumextensions.EnumMirror[ammonite.$sess.cmd2.Foo]
conforms to
  ammonite.$sess.cmd2.Foo
but none of the attempts shown below succeeded:

  ==> enumextensions.EnumMirror[ammonite.$sess.cmd2.Foo]  <:  ammonite.$sess.cmd2.Foo  = false

The tests were made under the empty constraint
	at scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8)
	at dotty.tools.dotc.typer.Implicits.inferImplicit(Implicits.scala:1086)
	at dotty.tools.dotc.typer.Implicits.inferImplicit$(Implicits.scala:860)
	at dotty.tools.dotc.typer.Typer.inferImplicit(Typer.scala:145)
	at dotty.tools.dotc.typer.Implicits.inferView(Implicits.scala:900)
	at dotty.tools.dotc.typer.Implicits.inferView$(Implicits.scala:860)
	at dotty.tools.dotc.typer.Typer.inferView(Typer.scala:145)
	at dotty.tools.dotc.typer.Typer.adaptToSubType$1(Typer.scala:4551)
	at dotty.tools.dotc.typer.Typer.adaptNoArgsOther$1(Typer.scala:4372)
	at dotty.tools.dotc.typer.Typer.adaptNoArgs$1(Typer.scala:4452)
	at dotty.tools.dotc.typer.Typer.adapt1(Typer.scala:4682)
	at dotty.tools.dotc.typer.Typer.adapt(Typer.scala:3954)
	at dotty.tools.dotc.typer.ProtoTypes$FunProto.typedArg(ProtoTypes.scala:534)
	at dotty.tools.dotc.typer.Applications$ApplyToUntyped.typedArg(Applications.scala:996)
	at dotty.tools.dotc.typer.Applications$ApplyToUntyped.typedArg(Applications.scala:996)
	at dotty.tools.dotc.typer.Applications$Application.addTyped$1(Applications.scala:688)
	at dotty.tools.dotc.typer.Applications$Application.matchArgs(Applications.scala:752)
	at dotty.tools.dotc.typer.Applications$Application.init(Applications.scala:574)
	at dotty.tools.dotc.typer.Applications$TypedApply.<init>(Applications.scala:878)
	at dotty.tools.dotc.typer.Applications$ApplyToUntyped.<init>(Applications.scala:995)
	at dotty.tools.dotc.typer.Applications.ApplyTo(Applications.scala:1257)
	at dotty.tools.dotc.typer.Applications.ApplyTo$(Applications.scala:434)
	at dotty.tools.dotc.typer.Typer.ApplyTo(Typer.scala:145)
	at dotty.tools.dotc.typer.Applications.simpleApply$1(Applications.scala:1068)
	at dotty.tools.dotc.typer.Applications.realApply$1$$anonfun$2(Applications.scala:1178)
	at dotty.tools.dotc.typer.Typer$.tryEither(Typer.scala:118)
	at dotty.tools.dotc.typer.Applications.realApply$1(Applications.scala:1193)
	at dotty.tools.dotc.typer.Applications.typedApply(Applications.scala:1231)
	at dotty.tools.dotc.typer.Applications.typedApply$(Applications.scala:434)
	at dotty.tools.dotc.typer.Typer.typedApply(Typer.scala:145)
	at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3414)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3499)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3576)
	at dotty.tools.dotc.typer.Applications.extMethodApply(Applications.scala:2591)
	at dotty.tools.dotc.typer.Applications.extMethodApply$(Applications.scala:434)
	at dotty.tools.dotc.typer.Typer.extMethodApply(Typer.scala:145)
	at dotty.tools.dotc.typer.Applications.tryApplyingExtensionMethod(Applications.scala:2636)
	at dotty.tools.dotc.typer.Applications.tryApplyingExtensionMethod$(Applications.scala:434)
	at dotty.tools.dotc.typer.Typer.tryApplyingExtensionMethod(Typer.scala:145)
	at dotty.tools.dotc.interactive.Completion$Completer.tryApplyingReceiverToExtension$1(Completion.scala:526)
	at dotty.tools.dotc.interactive.Completion$Completer.$anonfun$23(Completion.scala:569)
	at scala.collection.immutable.List.flatMap(List.scala:294)
	at scala.collection.immutable.List.flatMap(List.scala:79)
	at dotty.tools.dotc.interactive.Completion$Completer.extensionCompletions(Completion.scala:566)
	at dotty.tools.dotc.interactive.Completion$Completer.selectionCompletions(Completion.scala:446)
	at dotty.ammonite.compiler.AmmCompletion$.computeCompletions(AmmCompletion.scala:44)
	at dotty.ammonite.compiler.AmmCompletion$.completions(AmmCompletion.scala:26)
	at ammonite.compiler.Compiler.complete(Compiler.scala:392)
	at ammonite.compiler.CompilerLifecycleManager.complete(CompilerLifecycleManager.scala:112)
	at ammonite.repl.Repl.action$$anonfun$2$$anonfun$2$$anonfun$1(Repl.scala:199)
	at ammonite.repl.Repl.action$$anonfun$2$$anonfun$2$$anonfun$adapted$1(Repl.scala:199)
	at ammonite.repl.AmmoniteFrontEnd.$anonfun$3(AmmoniteFrontEnd.scala:57)
	at ammonite.terminal.TTY$.withSttyOverride(Utils.scala:120)
	at ammonite.repl.AmmoniteFrontEnd.$anonfun$1(AmmoniteFrontEnd.scala:58)
	at ammonite.terminal.Filter$$anon$3$$anon$4.applyOrElse(Filter.scala:71)
	at ammonite.terminal.Filter$$anon$3$$anon$4.applyOrElse(Filter.scala:71)
	at scala.collection.IterableOnceOps.collectFirst(IterableOnce.scala:1256)
	at scala.collection.IterableOnceOps.collectFirst$(IterableOnce.scala:1248)
	at scala.collection.AbstractIterator.collectFirst(Iterator.scala:1303)
	at ammonite.terminal.Filter$$anon$3.op(Filter.scala:71)
	at ammonite.terminal.Filter$.ammonite$terminal$Filter$$anon$7$$_$op$$anonfun$3(Filter.scala:92)
	at scala.collection.Iterator$$anon$9.next(Iterator.scala:584)
	at scala.collection.IterableOnceOps.find(IterableOnce.scala:677)
	at scala.collection.IterableOnceOps.find$(IterableOnce.scala:674)
	at scala.collection.AbstractIterator.find(Iterator.scala:1303)
	at ammonite.terminal.Filter$$anon$7.op(Filter.scala:92)
	at ammonite.terminal.LineReader.readChar(LineReader.scala:155)
	at ammonite.terminal.Terminal$.readLine$$anonfun$2(Terminal.scala:36)
	at ammonite.terminal.TTY$.withSttyOverride(Utils.scala:120)
	at ammonite.terminal.Terminal$.readLine(Terminal.scala:38)
	at ammonite.repl.AmmoniteFrontEnd.readLine(AmmoniteFrontEnd.scala:137)
	at ammonite.repl.AmmoniteFrontEnd.action(AmmoniteFrontEnd.scala:30)
	at ammonite.repl.Repl.action$$anonfun$2$$anonfun$2(Repl.scala:201)
	at ammonite.repl.Scoped.flatMap$$anonfun$1(Signaller.scala:45)
	at ammonite.repl.Signaller.apply(Signaller.scala:28)
	at ammonite.repl.Scoped.flatMap(Signaller.scala:45)
	at ammonite.repl.Scoped.flatMap$(Signaller.scala:42)
	at ammonite.repl.Signaller.flatMap(Signaller.scala:16)
	at ammonite.repl.Repl.action$$anonfun$2(Repl.scala:185)
	at ammonite.util.Res$Success.flatMap(Res.scala:58)
	at ammonite.repl.Repl.action(Repl.scala:175)
	at ammonite.repl.Repl.loop$1(Repl.scala:218)
	at ammonite.repl.Repl.run(Repl.scala:233)
	at ammonite.Main.run(Main.scala:249)
	at ammonite.MainRunner.runRepl$$anonfun$1(MainRunner.scala:76)
	at ammonite.MainRunner.watchLoop(MainRunner.scala:57)
	at ammonite.MainRunner.runRepl(MainRunner.scala:76)
	at ammonite.AmmoniteMain$.main0(AmmoniteMain.scala:98)
	at ammonite.AmmoniteMain$.main(AmmoniteMain.scala:31)
	at ammonite.AmmoniteMain.main(AmmoniteMain.scala)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
	at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.base/java.lang.reflect.Method.invoke(Method.java:568)
	at coursier.bootstrap.launcher.a.a(Unknown Source)
	at coursier.bootstrap.launcher.Launcher.main(Unknown Source)