unhandled exception while running erasure, MatchError, Context Function inside implicit class

[maksymilianrozanski]

Compiler version

3.3.4
3.6.2

Minimized code

object Logger {
  case class Ctx(a: String)
  implicit final class MyLoggerInterpolator(private val sc: StringContext) extends AnyVal {
    def error(message: String*): Ctx ?=> Unit = {
      ???
    }
  }
}

In contrast, this similar code compiles correctly:

object Logger {
  case class Ctx(a: String)
  implicit final class MyLoggerInterpolator(private val sc: StringContext) extends AnyVal {
    def error(message: String*)(using Ctx): Unit = {
      ???
    }
  }
}

Output (click arrow to expand)

unhandled exception while running erasure on /tmp/scastie13405439581228603105/src/main/scala/main.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: /tmp/scastie13405439581228603105/src/main/scala/main.scala
    during phase: erasure
            mode: Mode(ImplicitsEnabled)
 library version: version 2.13.15
compiler version: version 3.6.2
        settings: -bootclasspath /home/sbtRunnerContainer/.cache/coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala3-library_3/3.6.2/scala3-library_3-3.6.2.jar:/home/sbtRunnerContainer/.cache/coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala-library/2.13.15/scala-library-2.13.15.jar -classpath /tmp/scastie13405439581228603105/target/scala-3.6.2/classes:/home/sbtRunnerContainer/.ivy2/local/org.scastie/runtime-scala_3/1.0.0-SNAPSHOT/jars/runtime-scala_3.jar:/home/sbtRunnerContainer/.ivy2/local/org.scastie/api_3/0.30.0-SNAPSHOT/jars/api_3.jar:/home/sbtRunnerContainer/.cache/coursier/v1/https/repo1.maven.org/maven2/com/typesafe/play/play-json_3/2.10.0-RC5/play-json_3-2.10.0-RC5.jar:/home/sbtRunnerContainer/.cache/coursier/v1/https/repo1.maven.org/maven2/com/typesafe/play/play-functional_3/2.10.0-RC5/play-functional_3-2.10.0-RC5.jar:/home/sbtRunnerContainer/.cache/coursier/v1/https/repo1.maven.org/maven2/com/fasterxml/jackson/core/jackson-core/2.11.4/jackson-core-2.11.4.jar:/home/sbtRunnerContainer/.cache/coursier/v1/https/repo1.maven.org/maven2/com/fasterxml/jackson/core/jackson-annotations/2.11.4/jackson-annotations-2.11.4.jar:/home/sbtRunnerContainer/.cache/coursier/v1/https/repo1.maven.org/maven2/com/fasterxml/jackson/datatype/jackson-datatype-jdk8/2.11.4/jackson-datatype-jdk8-2.11.4.jar:/home/sbtRunnerContainer/.cache/coursier/v1/https/repo1.maven.org/maven2/com/fasterxml/jackson/datatype/jackson-datatype-jsr310/2.11.4/jackson-datatype-jsr310-2.11.4.jar:/home/sbtRunnerContainer/.cache/coursier/v1/https/repo1.maven.org/maven2/com/fasterxml/jackson/core/jackson-databind/2.11.4/jackson-databind-2.11.4.jar -d /tmp/scastie13405439581228603105/target/scala-3.6.2/classes -deprecation true -feature true

scala.MatchError: Apply(Apply(Ident(error$extension),List(This(Ident(MyLoggerInterpolator)))),List(Ident(message))) (of class dotty.tools.dotc.ast.Trees$Apply)
	at dotty.tools.dotc.transform.Erasure$Typer.skipContextClosures$1(Erasure.scala:952)
	at dotty.tools.dotc.transform.Erasure$Typer.typedDefDef(Erasure.scala:954)
	at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3478)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3580)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3658)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3662)
	at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3684)
	at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3730)
	at dotty.tools.dotc.transform.Erasure$Typer.typedStats(Erasure.scala:1085)
	at dotty.tools.dotc.typer.Typer.typedClassDef(Typer.scala:3160)
	at dotty.tools.dotc.transform.Erasure$Typer.typedClassDef(Erasure.scala:1061)
	at dotty.tools.dotc.typer.Typer.typedTypeOrClassDef$1(Typer.scala:3484)
	at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3488)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3580)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3658)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3662)
	at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3684)
	at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3730)
	at dotty.tools.dotc.transform.Erasure$Typer.typedStats(Erasure.scala:1085)
	at dotty.tools.dotc.typer.Typer.typedClassDef(Typer.scala:3160)
	at dotty.tools.dotc.transform.Erasure$Typer.typedClassDef(Erasure.scala:1061)
	at dotty.tools.dotc.typer.Typer.typedTypeOrClassDef$1(Typer.scala:3484)
	at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3488)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3580)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3658)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3662)
	at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3684)
	at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3730)
	at dotty.tools.dotc.transform.Erasure$Typer.typedStats(Erasure.scala:1085)
	at dotty.tools.dotc.typer.Typer.typedClassDef(Typer.scala:3160)
	at dotty.tools.dotc.transform.Erasure$Typer.typedClassDef(Erasure.scala:1061)
	at dotty.tools.dotc.typer.Typer.typedTypeOrClassDef$1(Typer.scala:3484)
	at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:3488)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3580)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3658)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3662)
	at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:3684)
	at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:3730)
	at dotty.tools.dotc.transform.Erasure$Typer.typedStats(Erasure.scala:1085)
	at dotty.tools.dotc.typer.Typer.typedPackageDef(Typer.scala:3293)
	at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:3530)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:3581)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3658)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:3662)
	at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:3773)
	at dotty.tools.dotc.transform.Erasure.run(Erasure.scala:146)
	at dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:380)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at scala.collection.immutable.List.foreach(List.scala:334)
	at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:373)
	at dotty.tools.dotc.Run.runPhases$1$$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.xsbt.CompilerBridgeDriver.run(CompilerBridgeDriver.java:141)
	at dotty.tools.xsbt.CompilerBridge.run(CompilerBridge.java:22)
	at sbt.internal.inc.AnalyzingCompiler.compile(AnalyzingCompiler.scala:91)
	at sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$7(MixedAnalyzingCompiler.scala:193)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
	at sbt.internal.inc.MixedAnalyzingCompiler.timed(MixedAnalyzingCompiler.scala:248)
	at sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4(MixedAnalyzingCompiler.scala:183)
	at sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4$adapted(MixedAnalyzingCompiler.scala:163)
	at sbt.internal.inc.JarUtils$.withPreviousJar(JarUtils.scala:239)
	at sbt.internal.inc.MixedAnalyzingCompiler.compileScala$1(MixedAnalyzingCompiler.scala:163)
	at sbt.internal.inc.MixedAnalyzingCompiler.compile(MixedAnalyzingCompiler.scala:211)
	at sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1(IncrementalCompilerImpl.scala:534)
	at sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1$adapted(IncrementalCompilerImpl.scala:534)
	at sbt.internal.inc.Incremental$.$anonfun$apply$5(Incremental.scala:180)
	at sbt.internal.inc.Incremental$.$anonfun$apply$5$adapted(Incremental.scala:178)
	at sbt.internal.inc.Incremental$$anon$2.run(Incremental.scala:464)
	at sbt.internal.inc.IncrementalCommon$CycleState.next(IncrementalCommon.scala:116)
	at sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:56)
	at sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:52)
	at sbt.internal.inc.IncrementalCommon.cycle(IncrementalCommon.scala:263)
	at sbt.internal.inc.Incremental$.$anonfun$incrementalCompile$8(Incremental.scala:419)
	at sbt.internal.inc.Incremental$.withClassfileManager(Incremental.scala:506)
	at sbt.internal.inc.Incremental$.incrementalCompile(Incremental.scala:406)
	at sbt.internal.inc.Incremental$.apply(Incremental.scala:172)
	at sbt.internal.inc.IncrementalCompilerImpl.compileInternal(IncrementalCompilerImpl.scala:534)
	at sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileIncrementally$1(IncrementalCompilerImpl.scala:488)
	at sbt.internal.inc.IncrementalCompilerImpl.handleCompilationError(IncrementalCompilerImpl.scala:332)
	at sbt.internal.inc.IncrementalCompilerImpl.compileIncrementally(IncrementalCompilerImpl.scala:425)
	at sbt.internal.inc.IncrementalCompilerImpl.compile(IncrementalCompilerImpl.scala:137)
	at sbt.Defaults$.compileIncrementalTaskImpl(Defaults.scala:2371)
	at sbt.Defaults$.$anonfun$compileIncrementalTask$2(Defaults.scala:2321)
	at sbt.internal.server.BspCompileTask$.$anonfun$compute$1(BspCompileTask.scala:31)
	at sbt.internal.io.Retry$.apply(Retry.scala:47)
	at sbt.internal.io.Retry$.apply(Retry.scala:29)
	at sbt.internal.io.Retry$.apply(Retry.scala:24)
	at sbt.internal.server.BspCompileTask$.compute(BspCompileTask.scala:31)
	at sbt.Defaults$.$anonfun$compileIncrementalTask$1(Defaults.scala:2319)
	at scala.Function1.$anonfun$compose$1(Function1.scala:49)
	at sbt.internal.util.$tilde$greater.$anonfun$$u2219$1(TypeFunctions.scala:63)
	at sbt.std.Transform$$anon$4.work(Transform.scala:69)
	at sbt.Execute.$anonfun$submit$2(Execute.scala:283)
	at sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:24)
	at sbt.Execute.work(Execute.scala:292)
	at sbt.Execute.$anonfun$submit$1(Execute.scala:283)
	at sbt.ConcurrentRestrictions$$anon$4.$anonfun$submitValid$1(ConcurrentRestrictions.scala:265)
	at sbt.CompletionService$$anon$2.call(CompletionService.scala:65)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
	at java.base/java.lang.Thread.run(Thread.java:840)

[soronpo]

You do know that you can use extension methods instead, right?

[maksymilianrozanski]

I didn’t realize that extension methods can be used with StringContext. Thanks!