Double binding error when compiling Option and Seq together

[smarter]

Note that this does not happen if you reverse the order of the arguments and run -Yno-double-bindings ./scala-scala/src/library/scala/collection/Seq.scala ./scala-scala/src/library/scala/Option.scala instead.

% ./bin/dotc -Yno-double-bindings ./scala-scala/src/library/scala/Option.scala ./scala-scala/src/library/scala/collection/Seq.scala
exception occurred while indexing ./scala-scala/src/library/scala/collection/Seq.scala
exception occurred while compiling ./scala-scala/src/library/scala/Option.scala, ./scala-scala/src/library/scala/collection/Seq.scala
Exception in thread "main" java.lang.AssertionError: assertion failed: data race? overwriting symbol of scala.collection.Seq / TypeRef(ThisType(TypeRef(NoPrefix,collection)),Seq) / class dotty.tools.dotc.core.Types$CachedTypeRef / 2918 / 4702 / module class collection / module class collection / frontend at run 2
        at scala.Predef$.assert(Predef.scala:165)
        at dotty.tools.dotc.core.Types$NamedType.checkSymAssign(Types.scala:1379)
        at dotty.tools.dotc.core.Types$NamedType.setDenot(Types.scala:1407)
        at dotty.tools.dotc.core.Types$NamedType.withDenot(Types.scala:1400)
        at dotty.tools.dotc.core.Types$TypeRef$.apply(Types.scala:1794)
        at dotty.tools.dotc.core.SymDenotations$SymDenotation.typeRef(SymDenotations.scala:1051)
        at dotty.tools.dotc.core.SymDenotations$ClassDenotation.typeRef(SymDenotations.scala:1297)
        at dotty.tools.dotc.core.Symbols$$anonfun$synthesizeCompanionMethod$1.apply(Symbols.scala:188)
        at dotty.tools.dotc.core.Symbols$$anonfun$synthesizeCompanionMethod$1.apply(Symbols.scala:188)
        at dotty.tools.dotc.core.Symbols$Symbol.orElse(Symbols.scala:450)
        at dotty.tools.dotc.core.Symbols$class.synthesizeCompanionMethod(Symbols.scala:187)
        at dotty.tools.dotc.core.Contexts$Context.synthesizeCompanionMethod(Contexts.scala:53)
        at dotty.tools.dotc.typer.Namer.dotty$tools$dotc$typer$Namer$$createLinks$1(Namer.scala:458)
        at dotty.tools.dotc.typer.Namer$$anonfun$createCompanionLinks$1$2.apply(Namer.scala:466)
        at dotty.tools.dotc.typer.Namer$$anonfun$createCompanionLinks$1$2.apply(Namer.scala:463)
        at scala.collection.TraversableLike$WithFilter$$anonfun$foreach$1.apply(TraversableLike.scala:778)
        at scala.collection.mutable.HashMap$$anon$2$$anonfun$foreach$3.apply(HashMap.scala:108)
        at scala.collection.mutable.HashMap$$anon$2$$anonfun$foreach$3.apply(HashMap.scala:108)
        at scala.collection.mutable.HashTable$class.foreachEntry(HashTable.scala:230)
        at scala.collection.mutable.HashMap.foreachEntry(HashMap.scala:40)
        at scala.collection.mutable.HashMap$$anon$2.foreach(HashMap.scala:108)
        at scala.collection.TraversableLike$WithFilter.foreach(TraversableLike.scala:777)
        at dotty.tools.dotc.typer.Namer.createCompanionLinks$1(Namer.scala:463)
        at dotty.tools.dotc.typer.Namer.index(Namer.scala:475)
        at dotty.tools.dotc.typer.Namer.indexExpanded(Namer.scala:401)
        at dotty.tools.dotc.typer.Namer$$anonfun$6.apply(Namer.scala:474)
        at dotty.tools.dotc.typer.Namer$$anonfun$6.apply(Namer.scala:474)
        at scala.collection.LinearSeqOptimized$class.foldLeft(LinearSeqOptimized.scala:124)
        at scala.collection.immutable.List.foldLeft(List.scala:84)
        at scala.collection.TraversableOnce$class.$div$colon(TraversableOnce.scala:136)
        at scala.collection.AbstractTraversable.$div$colon(Traversable.scala:104)
        at dotty.tools.dotc.typer.Namer.index(Namer.scala:474)
        at dotty.tools.dotc.typer.Namer.indexExpanded(Namer.scala:401)
        at dotty.tools.dotc.typer.Namer.index(Namer.scala:392)
        at dotty.tools.dotc.typer.FrontEnd$$anonfun$enterSyms$1.apply$mcV$sp(FrontEnd.scala:41)
        at dotty.tools.dotc.typer.FrontEnd.monitor(FrontEnd.scala:23)
        at dotty.tools.dotc.typer.FrontEnd.enterSyms(FrontEnd.scala:39)
        at dotty.tools.dotc.typer.FrontEnd$$anonfun$runOn$2.apply(FrontEnd.scala:68)
        at dotty.tools.dotc.typer.FrontEnd$$anonfun$runOn$2.apply(FrontEnd.scala:68)
        at scala.collection.immutable.List.foreach(List.scala:381)
        at dotty.tools.dotc.typer.FrontEnd.runOn(FrontEnd.scala:68)
        at dotty.tools.dotc.Run$$anonfun$compileUnits$1$$anonfun$apply$mcV$sp$1.apply(Run.scala:60)
        at dotty.tools.dotc.Run$$anonfun$compileUnits$1$$anonfun$apply$mcV$sp$1.apply(Run.scala:57)
        at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33)
        at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:186)
        at dotty.tools.dotc.Run$$anonfun$compileUnits$1.apply$mcV$sp(Run.scala:57)
        at dotty.tools.dotc.Run$$anonfun$compileUnits$1.apply(Run.scala:52)
        at dotty.tools.dotc.Run$$anonfun$compileUnits$1.apply(Run.scala:52)
        at dotty.tools.dotc.util.Stats$.monitorHeartBeat(Stats.scala:69)
        at dotty.tools.dotc.Run.compileUnits(Run.scala:52)
        at dotty.tools.dotc.Run.compileSources(Run.scala:49)
        at dotty.tools.dotc.Run.compile(Run.scala:33)
        at dotty.tools.dotc.Driver.doCompile(Driver.scala:21)
        at dotty.tools.dotc.Driver.process(Driver.scala:44)
        at dotty.tools.dotc.Driver.process(Driver.scala:50)
        at dotty.tools.dotc.Driver.main(Driver.scala:58)
        at dotty.tools.dotc.Main.main(Main.scala)