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The Scala 3 compiler, also known as Dotty.
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Crash in match type with wildcards when using `-Xkind-projector:underscores` #21400

Open WojciechMazur opened 3 weeks ago

WojciechMazur commented 3 weeks ago

Compiler version

Works in 3.0.0 Fails in every other version

Minimized code

//> using options -Ykind-projector:underscores
import scala.compiletime.ops.int.S

type IndexOf[T <: Tuple, E] <: Int = T match
  case E *: _  => 0
  case _ *: es => 1 // S[IndexOf[es, E]]

Output (click arrow to expand)

```scala exception occurred while typechecking /Users/wmazur/projects/sandbox/test.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/sandbox/test.scala during phase: typer mode: Mode(ImplicitsEnabled) library version: version 2.13.14 compiler version: version 3.6.0-RC1-bin-20240819-b64afad-NIGHTLY-git-b64afad settings: -Xkind-projector underscores -classpath /Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala3-library_3/3.6.0-RC1-bin-20240819-b64afad-NIGHTLY/scala3-library_3-3.6.0-RC1-bin-20240819-b64afad-NIGHTLY.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala-library/2.13.14/scala-library-2.13.14.jar -d /Users/wmazur/projects/sandbox/.scala-build/sandbox_1f4505af95-92b0ef3e72/classes/main -java-output-version 17 -sourceroot /Users/wmazur/projects/sandbox Exception in thread "main" java.lang.AssertionError: assertion failed at scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:11) at dotty.tools.dotc.typer.Typer$$anon$5.transform(Typer.scala:2158) at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform$$anonfun$1(Trees.scala:1643) at scala.collection.immutable.List.mapConserve(List.scala:473) at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1643) at dotty.tools.dotc.ast.Trees$Instance$TreeMap.transform(Trees.scala:1579) at dotty.tools.dotc.typer.Typer$$anon$5.transform(Typer.scala:2155) at dotty.tools.dotc.typer.Typer.caseRest$2(Typer.scala:2229) at dotty.tools.dotc.typer.Typer.typedTypeCase(Typer.scala:2236) at dotty.tools.dotc.typer.Typer.$anonfun$56(Typer.scala:2606) at dotty.tools.dotc.core.Decorators$.loop$1(Decorators.scala:99) at dotty.tools.dotc.core.Decorators$.mapconserve(Decorators.scala:115) at dotty.tools.dotc.typer.Typer.typedMatchTypeTree(Typer.scala:2606) at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3474) at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3529) at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3606) at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3610) at dotty.tools.dotc.typer.Typer.typedType(Typer.scala:3724) at dotty.tools.dotc.typer.Namer.typedAheadType$$anonfun$1(Namer.scala:1761) at dotty.tools.dotc.typer.Namer.typedAhead(Namer.scala:1754) at dotty.tools.dotc.typer.Namer.typedAheadType(Namer.scala:1761) at dotty.tools.dotc.typer.Namer$TypeDefCompleter.typeSig(Namer.scala:1093) at dotty.tools.dotc.typer.Namer$Completer.completeInCreationContext(Namer.scala:990) at dotty.tools.dotc.typer.Namer$Completer.complete(Namer.scala:859) at dotty.tools.dotc.core.SymDenotations$SymDenotation.completeFrom(SymDenotations.scala:175) at dotty.tools.dotc.core.Denotations$Denotation.completeInfo$1(Denotations.scala:190) at dotty.tools.dotc.core.Denotations$Denotation.info(Denotations.scala:192) at dotty.tools.dotc.core.SymDenotations$SymDenotation.ensureCompleted(SymDenotations.scala:393) at dotty.tools.dotc.typer.Typer.retrieveSym(Typer.scala:3391) at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3416) at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3528) at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3606) at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3610) at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3632) at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3678) at dotty.tools.dotc.typer.Typer.typedClassDef(Typer.scala:3126) at dotty.tools.dotc.typer.Typer.typedTypeOrClassDef$1(Typer.scala:3432) at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3436) at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3528) at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3606) at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3610) at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3632) at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3678) at dotty.tools.dotc.typer.Typer.typedPackageDef(Typer.scala:3259) at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3478) at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3529) at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3606) at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3610) at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:3721) at dotty.tools.dotc.typer.TyperPhase.typeCheck$$anonfun$1(TyperPhase.scala:47) at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15) at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10) at dotty.tools.dotc.core.Phases$Phase.monitor(Phases.scala:503) at dotty.tools.dotc.typer.TyperPhase.typeCheck(TyperPhase.scala:53) at dotty.tools.dotc.typer.TyperPhase.$anonfun$4(TyperPhase.scala:99) at scala.collection.Iterator$$anon$6.hasNext(Iterator.scala:479) at scala.collection.Iterator$$anon$9.hasNext(Iterator.scala:583) at scala.collection.immutable.List.prependedAll(List.scala:152) at scala.collection.immutable.List$.from(List.scala:685) at scala.collection.immutable.List$.from(List.scala:682) at scala.collection.IterableOps$WithFilter.map(Iterable.scala:900) at dotty.tools.dotc.typer.TyperPhase.runOn(TyperPhase.scala:98) at dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:343) at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15) at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10) at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1323) at dotty.tools.dotc.Run.runPhases$1(Run.scala:336) at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:384) at dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:396) at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:69) at dotty.tools.dotc.Run.compileUnits(Run.scala:396) at dotty.tools.dotc.Run.compileSources(Run.scala:282) at dotty.tools.dotc.Run.compile(Run.scala:267) 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 ```
xuwei-k commented 3 weeks ago

Maybe same issue 🤔

https://github.com/tarao/record4s/blob/3f127ed33099c485e08ccd1df1261c38d641e1fe/modules/core/src/main/scala/com/github/tarao/record4s/InternalMacros.scala#L215-L219

https://github.com/tarao/record4s/blob/3f127ed33099c485e08ccd1df1261c38d641e1fe/modules/core/src/main/scala/com/github/tarao/record4s/InternalMacros.scala#L429-L433

xuwei-k commented 3 weeks ago

minimized record4s issue

//> using options -Ykind-projector:underscores

import scala.quoted.Type
import scala.quoted.Quotes

def x[A](t: Type[A])(using Quotes): Boolean = t match
  case '[_ *: _] =>
    true
  case _ =>
    false
xuwei-k commented 3 weeks ago