Dotty deviation: failing to compile case class & package object with same name

[DarkDimius]

case class FooBar(){}
package object FooBar{}

exception occured while indexing packageCase.scala
Exception in thread "main" scala.MatchError: PackageDef(Ident(FooBar),List(ModuleDef(package,Template(DefDef(<init>,List(),List(),TypeTree(EmptyTree),EmptyTree),List(),ValDef(_,EmptyTree,EmptyTree),List(EmptyTree))))) (of class dotty.tools.dotc.ast.Trees$PackageDef)
    at dotty.tools.dotc.typer.Namer$$anonfun$mergeCompanionDefs$1$4.apply(Namer.scala:408)
    at dotty.tools.dotc.typer.Namer$$anonfun$mergeCompanionDefs$1$4.apply(Namer.scala:405)
    at scala.collection.TraversableLike$WithFilter$$anonfun$foreach$1.apply(TraversableLike.scala:778)
    at scala.collection.immutable.List.foreach(List.scala:381)
    at scala.collection.TraversableLike$WithFilter.foreach(TraversableLike.scala:777)
    at dotty.tools.dotc.typer.Namer.mergeCompanionDefs$1(Namer.scala:405)
    at dotty.tools.dotc.typer.Namer.index(Namer.scala:422)
    at dotty.tools.dotc.typer.Namer.indexExpanded(Namer.scala:380)
    at dotty.tools.dotc.typer.Namer.index(Namer.scala:371)
    at dotty.tools.dotc.typer.FrontEnd$$anonfun$enterSyms$1.apply$mcV$sp(FrontEnd.scala:35)
    at dotty.tools.dotc.typer.FrontEnd.monitor(FrontEnd.scala:18)
    at dotty.tools.dotc.typer.FrontEnd.enterSyms(FrontEnd.scala:33)
    at dotty.tools.dotc.typer.FrontEnd$$anonfun$runOn$2.apply(FrontEnd.scala:51)
    at dotty.tools.dotc.typer.FrontEnd$$anonfun$runOn$2.apply(FrontEnd.scala:51)
    at scala.collection.immutable.List.foreach(List.scala:381)
    at dotty.tools.dotc.typer.FrontEnd.runOn(FrontEnd.scala:51)
    at dotty.tools.dotc.Run$$anonfun$compileSources$1$$anonfun$apply$mcV$sp$3.apply(Run.scala:50)
    at dotty.tools.dotc.Run$$anonfun$compileSources$1$$anonfun$apply$mcV$sp$3.apply(Run.scala:47)
    at scala.collection.IndexedSeqOptimized$class.foreach(IndexedSeqOptimized.scala:33)
    at scala.collection.mutable.ArrayOps$ofRef.foreach(ArrayOps.scala:186)
    at dotty.tools.dotc.Run$$anonfun$compileSources$1.apply$mcV$sp(Run.scala:47)
    at dotty.tools.dotc.Run$$anonfun$compileSources$1.apply(Run.scala:42)
    at dotty.tools.dotc.Run$$anonfun$compileSources$1.apply(Run.scala:42)
    at dotty.tools.dotc.util.Stats$.monitorHeartBeat(Stats.scala:68)
    at dotty.tools.dotc.Run.compileSources(Run.scala:41)
    at dotty.tools.dotc.Run.compile(Run.scala:32)
    at dotty.tools.dotc.Driver.doCompile(Driver.scala:20)
    at dotty.tools.dotc.Main$.doCompile(Main.scala:26)
    at dotty.tools.dotc.Driver.process(Driver.scala:31)
    at dotty.tools.dotc.Driver.main(Driver.scala:40)
    at dotty.tools.dotc.Main.main(Main.scala)

[DarkDimius]

I was able to fix failure in namer in 78af8a4, but now it fails in typer.

[DarkDimius]

failure in typer:
https://github.com/lampepfl/dotty/blob/master/src/dotty/tools/dotc/typer/Typer.scala#L966

packageCase.scala:2: error: object FooBar is not a package
package object FooBar{}
                     ^
one error found

[odersky]

I don't think we should permit this, but #1079 improves the error message.