Assertion failed: duplicate attachment for key

[sir-wabbit]

Minimized code

// AE-6ca12c750b9a6e3dfc09fc327aa00146074fe260
@foo class foo[X]

Output (click arrow to expand)

-- [E046] Cyclic Error: test.scala:1:1 -----------------------------------------
1 |@foo class foo[X]
  | ^
  | Cyclic reference involving class foo

longer explanation available when compiling with `-explain`
exception occurred while typechecking test.scala
exception occurred while compiling test.scala
java.lang.AssertionError: assertion failed: duplicate attachment for key dotty.tools.dotc.util.Property$Key@3676ac27 while compiling test.scala
Exception in thread "main" java.lang.AssertionError: assertion failed: duplicate attachment for key dotty.tools.dotc.util.Property$Key@3676ac27
	at dotty.DottyPredef$.assertFail(DottyPredef.scala:17)
	at dotty.tools.dotc.util.Attachment$Container.pushAttachment(Attachment.scala:118)
	at dotty.tools.dotc.ast.Trees$Tree.pushAttachment(Trees.scala:56)
	at dotty.tools.dotc.typer.Namer.recordSym(Namer.scala:266)
	at dotty.tools.dotc.typer.Namer.createOrRefine$1(Namer.scala:382)
	at dotty.tools.dotc.typer.Namer.createSymbol(Namer.scala:435)
	at dotty.tools.dotc.typer.Namer.recur$1(Namer.scala:542)
	at dotty.tools.dotc.typer.Namer.indexExpanded(Namer.scala:552)
	at dotty.tools.dotc.typer.Namer.index(Namer.scala:525)
	at dotty.tools.dotc.typer.Namer$ClassCompleter.completeConstructor(Namer.scala:1225)
	at dotty.tools.dotc.typer.Namer$ClassCompleter.completeInCreationContext(Namer.scala:1308)
	at dotty.tools.dotc.typer.Namer$Completer.complete(Namer.scala:851)
	at dotty.tools.dotc.core.SymDenotations$SymDenotation.completeFrom(SymDenotations.scala:259)
	at dotty.tools.dotc.core.Denotations$Denotation.completeInfo$1(Denotations.scala:188)
	at dotty.tools.dotc.core.Denotations$Denotation.info(Denotations.scala:190)
	at dotty.tools.dotc.core.SymDenotations$SymDenotation.ensureCompleted(SymDenotations.scala:445)
	at dotty.tools.dotc.typer.Typer.retrieveSym(Typer.scala:2318)
	at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:2343)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2435)
	at dotty.tools.dotc.typer.Typer.op$1(Typer.scala:2502)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2511)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2514)
	at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:2536)
	at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:2581)
	at dotty.tools.dotc.typer.Typer.typedPackageDef(Typer.scala:2160)
	at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:2408)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2436)
	at dotty.tools.dotc.typer.Typer.op$1(Typer.scala:2502)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2511)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2514)
	at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:2625)
	at dotty.tools.dotc.typer.FrontEnd.liftedTree1$1(FrontEnd.scala:79)
	at dotty.tools.dotc.typer.FrontEnd.typeCheck$$anonfun$1(FrontEnd.scala:84)
	at dotty.runtime.function.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
	at dotty.tools.dotc.typer.FrontEnd.monitor(FrontEnd.scala:42)
	at dotty.tools.dotc.typer.FrontEnd.typeCheck(FrontEnd.scala:85)
	at dotty.tools.dotc.typer.FrontEnd.runOn$$anonfun$3(FrontEnd.scala:114)
	at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at scala.collection.immutable.List.foreach(List.scala:333)
	at dotty.tools.dotc.typer.FrontEnd.runOn(FrontEnd.scala:114)
	at dotty.tools.dotc.Run.runPhases$4$$anonfun$4(Run.scala:180)
	at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at dotty.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1323)
	at dotty.tools.dotc.Run.runPhases$5(Run.scala:190)
	at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:198)
	at dotty.runtime.function.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.java:12)
	at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:64)
	at dotty.tools.dotc.Run.compileUnits(Run.scala:205)
	at dotty.tools.dotc.Run.compileSources(Run.scala:142)
	at dotty.tools.dotc.Run.compile(Run.scala:124)
	at dotty.tools.dotc.Driver.doCompile(Driver.scala:38)
	at dotty.tools.dotc.Driver.process(Driver.scala:194)
	at dotty.tools.dotc.Driver.process(Driver.scala:163)
	at dotty.tools.dotc.Driver.process(Driver.scala:175)
	at dotty.tools.dotc.Driver.main(Driver.scala:202)
	at dotty.tools.dotc.Main.main(Main.scala)