Scala.js: java.lang.AssertionError: assertion failed: Invalid functional interface trait FunctionXXL reached the back-end

[pshirshov]

Compiler fails on a lambda with long argument list.

Repro: https://scastie.scala-lang.org/tkeR8yJBROetPhTS2Hjz8w

Stack:

[error] java.lang.AssertionError: assertion failed: Invalid functional interface trait FunctionXXL reached the back-end
[error] 	at scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genClosure(JSCodeGen.scala:3511)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genStatOrExpr(JSCodeGen.scala:1913)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genStatOrExpr(JSCodeGen.scala:1845)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genExpr(JSCodeGen.scala:1637)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genStatOrExpr(JSCodeGen.scala:1717)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genStat(JSCodeGen.scala:1615)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.$anonfun$46(JSCodeGen.scala:1845)
[error] 	at scala.collection.immutable.List.map(List.scala:246)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genStatOrExpr(JSCodeGen.scala:1845)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genExpr(JSCodeGen.scala:1637)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genStatOrExpr(JSCodeGen.scala:1857)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genExpr(JSCodeGen.scala:1637)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genStatOrExpr(JSCodeGen.scala:1857)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genExpr(JSCodeGen.scala:1637)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genStatOrExpr(JSCodeGen.scala:1717)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genStat(JSCodeGen.scala:1615)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.$anonfun$46(JSCodeGen.scala:1845)
[error] 	at scala.collection.immutable.List.map(List.scala:246)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genStatOrExpr(JSCodeGen.scala:1845)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genExpr(JSCodeGen.scala:1637)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genBody$1(JSCodeGen.scala:1567)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genMethodDef(JSCodeGen.scala:1572)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genMethodWithCurrentLocalNameScope$$anonfun$1(JSCodeGen.scala:1539)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.withPerMethodBodyState$$anonfun$1(JSCodeGen.scala:106)
[error] 	at dotty.tools.backend.sjs.ScopedVar$.withScopedVars(ScopedVar.scala:33)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.withPerMethodBodyState(JSCodeGen.scala:107)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genMethodWithCurrentLocalNameScope(JSCodeGen.scala:1545)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genMethod$$anonfun$1(JSCodeGen.scala:1399)
[error] 	at dotty.tools.backend.sjs.ScopedVar$.withScopedVars(ScopedVar.scala:33)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genMethod(JSCodeGen.scala:1400)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genScalaClass$$anonfun$2(JSCodeGen.scala:368)
[error] 	at scala.collection.immutable.List.foreach(List.scala:333)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genScalaClass(JSCodeGen.scala:373)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genCompilationUnit$$anonfun$3$$anonfun$1(JSCodeGen.scala:238)
[error] 	at dotty.tools.backend.sjs.ScopedVar$.withScopedVars(ScopedVar.scala:33)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genCompilationUnit$$anonfun$3(JSCodeGen.scala:242)
[error] 	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
[error] 	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
[error] 	at scala.collection.immutable.List.foreach(List.scala:333)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.genCompilationUnit(JSCodeGen.scala:244)
[error] 	at dotty.tools.backend.sjs.JSCodeGen.run(JSCodeGen.scala:156)
[error] 	at dotty.tools.backend.sjs.GenSJSIR.run(GenSJSIR.scala:18)
[error] 	at dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:316)
[error] 	at scala.collection.immutable.List.map(List.scala:250)
[error] 	at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:320)
[error] 	at dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:233)
[error] 	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
[error] 	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
[error] 	at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1321)
[error] 	at dotty.tools.dotc.Run.runPhases$1(Run.scala:244)
[error] 	at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:252)
[error] 	at dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:261)
[error] 	at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:68)
[error] 	at dotty.tools.dotc.Run.compileUnits(Run.scala:261)
[error] 	at dotty.tools.dotc.Run.compileSources(Run.scala:185)
[error] 	at dotty.tools.dotc.Run.compile(Run.scala:169)
[error] 	at dotty.tools.dotc.Driver.doCompile(Driver.scala:35)
[error] 	at dotty.tools.xsbt.CompilerBridgeDriver.run(CompilerBridgeDriver.java:88)
[error] 	at dotty.tools.xsbt.CompilerBridge.run(CompilerBridge.java:22)
[error] 	at sbt.internal.inc.AnalyzingCompiler.compile(AnalyzingCompiler.scala:91)
[error] 	at sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$7(MixedAnalyzingCompiler.scala:193)
[error] 	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
[error] 	at sbt.internal.inc.MixedAnalyzingCompiler.timed(MixedAnalyzingCompiler.scala:248)
[error] 	at sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4(MixedAnalyzingCompiler.scala:183)
[error] 	at sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4$adapted(MixedAnalyzingCompiler.scala:163)
[error] 	at sbt.internal.inc.JarUtils$.withPreviousJar(JarUtils.scala:239)
[error] 	at sbt.internal.inc.MixedAnalyzingCompiler.compileScala$1(MixedAnalyzingCompiler.scala:163)
[error] 	at sbt.internal.inc.MixedAnalyzingCompiler.compile(MixedAnalyzingCompiler.scala:211)
[error] 	at sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1(IncrementalCompilerImpl.scala:534)
[error] 	at sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1$adapted(IncrementalCompilerImpl.scala:534)
[error] 	at sbt.internal.inc.Incremental$.$anonfun$apply$5(Incremental.scala:179)
[error] 	at sbt.internal.inc.Incremental$.$anonfun$apply$5$adapted(Incremental.scala:177)
[error] 	at sbt.internal.inc.Incremental$$anon$2.run(Incremental.scala:463)
[error] 	at sbt.internal.inc.IncrementalCommon$CycleState.next(IncrementalCommon.scala:116)
[error] 	at sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:56)
[error] 	at sbt.internal.inc.IncrementalCommon$$anon$1.next(IncrementalCommon.scala:52)
[error] 	at sbt.internal.inc.IncrementalCommon.cycle(IncrementalCommon.scala:263)
[error] 	at sbt.internal.inc.Incremental$.$anonfun$incrementalCompile$8(Incremental.scala:418)
[error] 	at sbt.internal.inc.Incremental$.withClassfileManager(Incremental.scala:506)
[error] 	at sbt.internal.inc.Incremental$.incrementalCompile(Incremental.scala:405)
[error] 	at sbt.internal.inc.Incremental$.apply(Incremental.scala:171)
[error] 	at sbt.internal.inc.IncrementalCompilerImpl.compileInternal(IncrementalCompilerImpl.scala:534)
[error] 	at sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileIncrementally$1(IncrementalCompilerImpl.scala:488)
[error] 	at sbt.internal.inc.IncrementalCompilerImpl.handleCompilationError(IncrementalCompilerImpl.scala:332)
[error] 	at sbt.internal.inc.IncrementalCompilerImpl.compileIncrementally(IncrementalCompilerImpl.scala:425)
[error] 	at sbt.internal.inc.IncrementalCompilerImpl.compile(IncrementalCompilerImpl.scala:137)
[error] 	at sbt.Defaults$.compileIncrementalTaskImpl(Defaults.scala:2363)
[error] 	at sbt.Defaults$.$anonfun$compileIncrementalTask$2(Defaults.scala:2313)
[error] 	at sbt.internal.server.BspCompileTask$.$anonfun$compute$1(BspCompileTask.scala:30)
[error] 	at sbt.internal.io.Retry$.apply(Retry.scala:46)
[error] 	at sbt.internal.io.Retry$.apply(Retry.scala:28)
[error] 	at sbt.internal.io.Retry$.apply(Retry.scala:23)
[error] 	at sbt.internal.server.BspCompileTask$.compute(BspCompileTask.scala:30)
[error] 	at sbt.Defaults$.$anonfun$compileIncrementalTask$1(Defaults.scala:2311)
[error] 	at scala.Function1.$anonfun$compose$1(Function1.scala:49)
[error] 	at sbt.internal.util.$tilde$greater.$anonfun$$u2219$1(TypeFunctions.scala:62)
[error] 	at sbt.std.Transform$$anon$4.work(Transform.scala:68)
[error] 	at sbt.Execute.$anonfun$submit$2(Execute.scala:282)
[error] 	at sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:23)
[error] 	at sbt.Execute.work(Execute.scala:291)
[error] 	at sbt.Execute.$anonfun$submit$1(Execute.scala:282)
[error] 	at sbt.ConcurrentRestrictions$$anon$4.$anonfun$submitValid$1(ConcurrentRestrictions.scala:265)
[error] 	at sbt.CompletionService$$anon$2.call(CompletionService.scala:64)
[error] 	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
[error] 	at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
[error] 	at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
[error] 	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
[error] 	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
[error] 	at java.base/java.lang.Thread.run(Thread.java:833)

ScalaJS developers say that this is a dotty problem.

[sjrd]

Thanks for the report here.

[pshirshov]

Thanks. Is there any chance it may be released soon?

[sjrd]

Look up the Scala 3 release schedule. I'm not in charge. There's supposed to be a release every 6 weeks (first RC, then 6 weeks later the stable version).