Usage of by-name erased type class crashes

[Atry]

minimized code

object Test extends App {
  def upCast[A, B](a: A)(given erased evidence: => (A <:< B)): B = a.asInstanceOf[B]
  
  upCast("a")(given summon[String <:< AnyRef])
}

Stack trace

java.lang.UnsupportedOperationException: mkClosure(???)
	at dotty.tools.package$.unsupported(package.scala:25)
	at dotty.tools.dotc.transform.TransformByNameApply.mkByNameClosure(TransformByNameApply.scala:37)
	at dotty.tools.dotc.transform.TransformByNameApply.transformArg$1(TransformByNameApply.scala:54)
	at dotty.tools.dotc.transform.TransformByNameApply.$anonfun$1(TransformByNameApply.scala:61)
	at dotty.tools.dotc.core.Decorators$ListDecorator$.zipWithConserve$extension(Decorators.scala:110)
	at dotty.tools.dotc.transform.TransformByNameApply.transformApply(TransformByNameApply.scala:61)
	at dotty.tools.dotc.transform.MegaPhase.goApply(MegaPhase.scala:611)
	at dotty.tools.dotc.transform.MegaPhase.goApply(MegaPhase.scala:612)
	at dotty.tools.dotc.transform.MegaPhase.goApply(MegaPhase.scala:612)
	at dotty.tools.dotc.transform.MegaPhase.goApply(MegaPhase.scala:612)
	at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:272)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:396)
	at dotty.tools.dotc.transform.MegaPhase.transformStat$2(MegaPhase.scala:406)
	at dotty.tools.dotc.transform.MegaPhase.$anonfun$1(MegaPhase.scala:409)
	at scala.collection.immutable.List.mapConserve(List.scala:444)
	at dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:409)
	at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:339)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:396)
	at dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:251)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:394)
	at dotty.tools.dotc.transform.MegaPhase.transformStat$2(MegaPhase.scala:404)
	at dotty.tools.dotc.transform.MegaPhase.$anonfun$1(MegaPhase.scala:409)
	at scala.collection.immutable.List.mapConserve(List.scala:444)
	at dotty.tools.dotc.transform.MegaPhase.transformStats(MegaPhase.scala:409)
	at dotty.tools.dotc.transform.MegaPhase.mapPackage$1(MegaPhase.scala:356)
	at dotty.tools.dotc.transform.MegaPhase.transformUnnamed$1(MegaPhase.scala:359)
	at dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:396)
	at dotty.tools.dotc.transform.MegaPhase.transformUnit(MegaPhase.scala:415)
	at dotty.tools.dotc.transform.MegaPhase.run(MegaPhase.scala:427)
	at dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:315)
	at scala.collection.immutable.List.map(List.scala:219)
	at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:316)
	at dotty.tools.dotc.Run.runPhases$4$$anonfun$4(Run.scala:161)
	at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1323)
	at dotty.tools.dotc.Run.runPhases$5(Run.scala:171)
	at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:179)
	at dotty.runtime.function.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
	at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:65)
	at dotty.tools.dotc.Run.compileUnits(Run.scala:186)
	at dotty.tools.dotc.Run.compileSources(Run.scala:123)
	at dotty.tools.dotc.Run.compile(Run.scala:106)
	at dotty.tools.dotc.Driver.doCompile(Driver.scala:36)
	at dotty.tools.dotc.Driver.process(Driver.scala:189)
	at dotty.tools.dotc.Main.process(Main.scala)
	at xsbt.CachedCompilerImpl.run(CachedCompilerImpl.java:69)
	at xsbt.CompilerInterface.run(CompilerInterface.java:41)
	at sun.reflect.GeneratedMethodAccessor8.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at sbt.internal.inc.AnalyzingCompiler.call(AnalyzingCompiler.scala:248)
	at sbt.internal.inc.AnalyzingCompiler.compile(AnalyzingCompiler.scala:122)
	at sbt.internal.inc.AnalyzingCompiler.compile(AnalyzingCompiler.scala:95)
	at sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$4(MixedAnalyzingCompiler.scala:91)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:23)
	at sbt.internal.inc.MixedAnalyzingCompiler.timed(MixedAnalyzingCompiler.scala:186)
	at sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$3(MixedAnalyzingCompiler.scala:82)
	at sbt.internal.inc.MixedAnalyzingCompiler.$anonfun$compile$3$adapted(MixedAnalyzingCompiler.scala:77)
	at sbt.internal.inc.JarUtils$.withPreviousJar(JarUtils.scala:215)
	at sbt.internal.inc.MixedAnalyzingCompiler.compileScala$1(MixedAnalyzingCompiler.scala:77)
	at sbt.internal.inc.MixedAnalyzingCompiler.compile(MixedAnalyzingCompiler.scala:146)
	at sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1(IncrementalCompilerImpl.scala:343)
	at sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileInternal$1$adapted(IncrementalCompilerImpl.scala:343)
	at sbt.internal.inc.Incremental$.doCompile(Incremental.scala:120)
	at sbt.internal.inc.Incremental$.$anonfun$compile$4(Incremental.scala:100)
	at sbt.internal.inc.IncrementalCommon.recompileClasses(IncrementalCommon.scala:180)
	at sbt.internal.inc.IncrementalCommon.cycle(IncrementalCommon.scala:98)
	at sbt.internal.inc.Incremental$.$anonfun$compile$3(Incremental.scala:102)
	at sbt.internal.inc.Incremental$.manageClassfiles(Incremental.scala:155)
	at sbt.internal.inc.Incremental$.compile(Incremental.scala:92)
	at sbt.internal.inc.IncrementalCompile$.apply(Compile.scala:75)
	at sbt.internal.inc.IncrementalCompilerImpl.compileInternal(IncrementalCompilerImpl.scala:348)
	at sbt.internal.inc.IncrementalCompilerImpl.$anonfun$compileIncrementally$1(IncrementalCompilerImpl.scala:301)
	at sbt.internal.inc.IncrementalCompilerImpl.handleCompilationError(IncrementalCompilerImpl.scala:168)
	at sbt.internal.inc.IncrementalCompilerImpl.compileIncrementally(IncrementalCompilerImpl.scala:248)
	at sbt.internal.inc.IncrementalCompilerImpl.compile(IncrementalCompilerImpl.scala:74)
	at sbt.Defaults$.compileIncrementalTaskImpl(Defaults.scala:1761)
	at sbt.Defaults$.$anonfun$compileIncrementalTask$1(Defaults.scala:1734)
	at scala.Function1.$anonfun$compose$1(Function1.scala:49)
	at sbt.internal.util.$tilde$greater.$anonfun$$u2219$1(TypeFunctions.scala:62)
	at sbt.std.Transform$$anon$4.work(Transform.scala:67)
	at sbt.Execute.$anonfun$submit$2(Execute.scala:281)
	at sbt.internal.util.ErrorHandling$.wideConvert(ErrorHandling.scala:19)
	at sbt.Execute.work(Execute.scala:290)
	at sbt.Execute.$anonfun$submit$1(Execute.scala:281)
	at sbt.ConcurrentRestrictions$$anon$4.$anonfun$submitValid$1(ConcurrentRestrictions.scala:178)
	at sbt.CompletionService$$anon$2.call(CompletionService.scala:37)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.run(FutureTask.java:266)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
	at java.lang.Thread.run(Thread.java:748)

[nicolasstucki]

erased will be phased out in #7906. If added in the future, this issue will need to be fixed.