trait Apply[F[_]]: extension [A](fa: F[A]) def map[B](f: A => B): F[B] def map2[B, Z](fb: F[B])(f: (A, B) => Z): F[Z] = ??? private case class IsMap[T <: Tuple](value: Tuple.Map[T, F]) private inline def tupledGeneric[T <: Tuple](tuple: Tuple.Map[T, F]): F[T] = inline IsMap(tuple) match case t: IsMap[h *: EmptyTuple] => t.value.head.map(_ *: EmptyTuple) case t: IsMap[h *: t] => val head = t.value.head val tail = tupledGeneric(t.value.tail) head.map2(tail)(_ *: _) trait Monad[F[_]] extends Apply[F]: extension [A](fa: F[A]) def flatMap[B](f: A => F[B]): F[B] extension [A](fa: F[A]) override def map[B](f: A => B): F[B] = ??? opaque type Kleisli[F[_], A, B] = A => F[B] given [F[_], A](using F: Monad[F]): Monad[[B] =>> Kleisli[F, A, B]] with extension [B](k: Kleisli[F, A, B]) def flatMap[C](f: B => Kleisli[F, A, C]) = ??? 

 unhandled exception while running MegaPhase{elimErasedValueType, pureStats, vcElideAllocations, etaReduce, arrayApply, elimPolyFunction, tailrec, completeJavaEnums, mixin, lazyVals, memoize, nonLocalReturns, capturedVars} on /Users/wmazur/projects/scala/community-build3/example.scala An unhandled exception was thrown in the compiler. Please file a crash report here: https://github.com/scala/scala3/issues/new/choose For non-enriched exceptions, compile with -Xno-enrich-error-messages. while compiling: /Users/wmazur/projects/scala/community-build3/example.scala during phase: MegaPhase{elimErasedValueType, pureStats, vcElideAllocations, etaReduce, arrayApply, elimPolyFunction, tailrec, completeJavaEnums, mixin, lazyVals, memoize, nonLocalReturns, capturedVars} mode: Mode(ImplicitsEnabled) library version: version 2.13.16 compiler version: version 3.7.3-RC1-bin-20250728-95b37a7-NIGHTLY-git-95b37a7 settings: -classpath /Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala3-library_3/3.7.3-RC1-bin-20250728-95b37a7-NIGHTLY/scala3-library_3-3.7.3-RC1-bin-20250728-95b37a7-NIGHTLY.jar:/Users/wmazur/.sdkman/candidates/scala/current/maven2/org/scala-lang/scala-library/2.13.16/scala-library-2.13.16.jar -d /Users/wmazur/projects/scala/community-build3/.scala-build/community-build3_8234e07519-990a7af3ef/classes/main -sourceroot /Users/wmazur/projects/scala/community-build3 Exception in thread "main" java.lang.AssertionError: assertion failed at scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:11) at dotty.tools.dotc.core.Types$MethodType.<init>(Types.scala:4160) at dotty.tools.dotc.core.Types$CachedMethodType.<init>(Types.scala:4183) at dotty.tools.dotc.core.Types$MethodTypeCompanion.apply(Types.scala:4263) at dotty.tools.dotc.core.Types$MethodTypeCompanion.apply(Types.scala:4262) at dotty.tools.dotc.core.Types$LambdaTypeCompanion.apply(Types.scala:4195) at dotty.tools.dotc.core.TypeErasure.eraseInfo(TypeErasure.scala:823) at dotty.tools.dotc.core.TypeErasure$.transformInfo(TypeErasure.scala:277) at dotty.tools.dotc.transform.Mixin.mkMixinForwarderSym$1(Mixin.scala:334) at dotty.tools.dotc.transform.Mixin.mixinForwarders$1$$anonfun$2(Mixin.scala:318) at scala.collection.Iterator$$anon$9.next(Iterator.scala:584) at scala.collection.immutable.List.prependedAll(List.scala:156) at scala.collection.immutable.List$.from(List.scala:685) at scala.collection.immutable.List$.from(List.scala:682) at scala.collection.IterableOps$WithFilter.map(Iterable.scala:900) at dotty.tools.dotc.transform.Mixin.mixinForwarders$1(Mixin.scala:315) at dotty.tools.dotc.transform.Mixin.$anonfun$6(Mixin.scala:354) at scala.collection.immutable.List.flatMap(List.scala:294) at dotty.tools.dotc.transform.Mixin.transformTemplate(Mixin.scala:346) at dotty.tools.dotc.transform.Mixin.transformTemplate(Mixin.scala:196) at dotty.tools.dotc.transform.MegaPhase.goTemplate(MegaPhase.scala:1071) at dotty.tools.dotc.transform.MegaPhase.goTemplate(MegaPhase.scala:1072) at dotty.tools.dotc.transform.MegaPhase.goTemplate(MegaPhase.scala:1072) at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:377) at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454) at dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:272) at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:452) at dotty.tools.dotc.transform.MegaPhase.loop$1(MegaPhase.scala:465) at dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:465) at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:376) at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454) at dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:272) at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:452) at dotty.tools.dotc.transform.MegaPhase.loop$1(MegaPhase.scala:465) at dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:465) at dotty.tools.dotc.transform.MegaPhase.mapPackage$1(MegaPhase.scala:396) at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:399) at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:454) at dotty.tools.dotc.transform.MegaPhase.transformUnit(MegaPhase.scala:481) at dotty.tools.dotc.transform.MegaPhase.run(MegaPhase.scala:493) at dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:386) at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15) at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10) at scala.collection.immutable.List.foreach(List.scala:334) at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:379) at dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:368) at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15) at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10) at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1324) at dotty.tools.dotc.Run.runPhases$1(Run.scala:361) at dotty.tools.dotc.Run.compileUnits$$anonfun$1$$anonfun$2(Run.scala:408) at dotty.tools.dotc.Run.compileUnits$$anonfun$1$$anonfun$adapted$1(Run.scala:408) at scala.Function0.apply$mcV$sp(Function0.scala:42) at dotty.tools.dotc.Run.showProgress(Run.scala:470) at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:408) at dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:420) at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:69) at dotty.tools.dotc.Run.compileUnits(Run.scala:420) at dotty.tools.dotc.Run.compileSources(Run.scala:307) at dotty.tools.dotc.Run.compile(Run.scala:292) at dotty.tools.dotc.Driver.doCompile(Driver.scala:37) at dotty.tools.dotc.Driver.process(Driver.scala:201) at dotty.tools.dotc.Driver.process(Driver.scala:169) at dotty.tools.dotc.Driver.process(Driver.scala:181) at dotty.tools.dotc.Driver.main(Driver.scala:211) at dotty.tools.dotc.Main.main(Main.scala) Compilation failed