Packages mixed type inference crashes compiler

[romanowski]

There is no import in scope and I found it out when I anciently copied piece of code that was missing value org.

Compiler version

3.0.0-M4-bin-SNAPSHOT-git-53a2dc5 (latest master) as well as 3.0.0-M3

Minimized code

// crashes the compiler
def a(o: String) = Seq(o, org)

// Reports problem property
def a2(o: String) = Seq[String](o, org) // package org is not a value
def a3(o: String): Seq[String] = Seq(o, org) // Found:    org.type Required: String
def a4(o: String): Seq[String] = Seq(o, org) // Found:    org.type Required: String

Output (click arrow to expand)

Exception in thread "main" java.lang.AssertionError: assertion failed
	at scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:11)
	at dotty.tools.dotc.core.TypeOps$.dominators$1(TypeOps.scala:210)
	at dotty.tools.dotc.core.TypeOps$.approximateOr$1(TypeOps.scala:330)
	at dotty.tools.dotc.core.TypeOps$.orDominator(TypeOps.scala:338)
	at dotty.tools.dotc.core.TypeOps$.approximateOr$1(TypeOps.scala:316)
	at dotty.tools.dotc.core.TypeOps$.orDominator(TypeOps.scala:338)
	at dotty.tools.dotc.core.Types$OrType.join(Types.scala:3119)
	at dotty.tools.dotc.core.Types$Type.widenUnionWithoutNull(Types.scala:1256)
	at dotty.tools.dotc.core.Types$Type.widenUnion(Types.scala:1251)
	at dotty.tools.dotc.core.ConstraintHandling.widenOr$1(ConstraintHandling.scala:402)
	at dotty.tools.dotc.core.ConstraintHandling.widenInferred(ConstraintHandling.scala:415)
	at dotty.tools.dotc.core.ConstraintHandling.widenInferred$(ConstraintHandling.scala:26)
	at dotty.tools.dotc.core.TypeComparer.widenInferred(TypeComparer.scala:30)
	at dotty.tools.dotc.core.ConstraintHandling.instanceType(ConstraintHandling.scala:432)
	at dotty.tools.dotc.core.ConstraintHandling.instanceType$(ConstraintHandling.scala:26)
	at dotty.tools.dotc.core.TypeComparer.instanceType(TypeComparer.scala:30)
	at dotty.tools.dotc.core.TypeComparer$.instanceType(TypeComparer.scala:2673)
	at dotty.tools.dotc.core.Types$TypeVar.instantiate(Types.scala:4394)
	at dotty.tools.dotc.typer.Inferencing.doInstantiate$1(Inferencing.scala:617)
	at dotty.tools.dotc.typer.Inferencing.interpolateTypeVars(Inferencing.scala:620)
	at dotty.tools.dotc.typer.Inferencing.interpolateTypeVars$(Inferencing.scala:488)
	at dotty.tools.dotc.typer.Typer.interpolateTypeVars(Typer.scala:102)
	at dotty.tools.dotc.typer.Typer.simplify(Typer.scala:2671)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2657)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2720)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2724)
	at dotty.tools.dotc.typer.Namer.typedAheadExpr$$anonfun$1(Namer.scala:1305)
	at dotty.tools.dotc.typer.Namer.typedAhead(Namer.scala:1292)
	at dotty.tools.dotc.typer.Namer.typedAheadExpr(Namer.scala:1305)
	at dotty.tools.dotc.typer.Namer.rhsType$1$$anonfun$1(Namer.scala:1447)
	at dotty.tools.dotc.typer.PrepareInlineable$.dropInlineIfError(PrepareInlineable.scala:223)
	at dotty.tools.dotc.typer.Namer.rhsType$2(Namer.scala:1447)
	at dotty.tools.dotc.typer.Namer.cookedRhsType$1(Namer.scala:1458)
	at dotty.tools.dotc.typer.Namer.lhsType$1(Namer.scala:1459)
	at dotty.tools.dotc.typer.Namer.inferredType$1(Namer.scala:1470)
	at dotty.tools.dotc.typer.Namer.valOrDefDefSig(Namer.scala:1479)
	at dotty.tools.dotc.typer.Namer.defDefSig(Namer.scala:1562)
	at dotty.tools.dotc.typer.Namer$Completer.typeSig(Namer.scala:703)
	at dotty.tools.dotc.typer.Namer$Completer.completeInCreationContext(Namer.scala:826)
	at dotty.tools.dotc.typer.Namer$Completer.complete(Namer.scala:727)
	at dotty.tools.dotc.core.SymDenotations$SymDenotation.completeFrom(SymDenotations.scala:167)
	at dotty.tools.dotc.core.Denotations$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:369)
	at dotty.tools.dotc.typer.Typer.retrieveSym(Typer.scala:2535)
	at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:2560)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2654)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2720)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2724)
	at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:2746)
	at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:2796)
	at dotty.tools.dotc.typer.Typer.typedClassDef(Typer.scala:2226)
	at dotty.tools.dotc.typer.Typer.typedTypeOrClassDef$2(Typer.scala:2581)
	at dotty.tools.dotc.typer.Typer.typedNamed$1(Typer.scala:2585)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2654)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2720)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2724)
	at dotty.tools.dotc.typer.Typer.traverse$1(Typer.scala:2746)
	at dotty.tools.dotc.typer.Typer.typedStats(Typer.scala:2796)
	at dotty.tools.dotc.typer.Typer.typedPackageDef(Typer.scala:2378)
	at dotty.tools.dotc.typer.Typer.typedUnnamed$1(Typer.scala:2626)
	at dotty.tools.dotc.typer.Typer.typedUnadapted(Typer.scala:2655)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2720)
	at dotty.tools.dotc.typer.Typer.typed(Typer.scala:2724)
	at dotty.tools.dotc.typer.Typer.typedExpr(Typer.scala:2840)
	at dotty.tools.dotc.typer.FrontEnd.liftedTree1$1(FrontEnd.scala:79)
	at dotty.tools.dotc.typer.FrontEnd.typeCheck$$anonfun$1(FrontEnd.scala:84)
	at dotty.tools.dotc.typer.FrontEnd.monitor(FrontEnd.scala:43)
	at dotty.tools.dotc.typer.FrontEnd.typeCheck(FrontEnd.scala:85)
	at dotty.tools.repl.REPLFrontEnd.runOn(ReplFrontEnd.scala:24)
	at dotty.tools.dotc.Run.runPhases$4$$anonfun$4(Run.scala:205)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
	at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
	at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1323)
	at dotty.tools.dotc.Run.runPhases$5(Run.scala:215)
	at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:223)
	at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.scala:18)
	at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:67)
	at dotty.tools.dotc.Run.compileUnits(Run.scala:230)
	at dotty.tools.dotc.Run.compileUnits(Run.scala:172)
	at dotty.tools.repl.ReplCompiler.runCompilationUnit(ReplCompiler.scala:151)
	at dotty.tools.repl.ReplCompiler.compile(ReplCompiler.scala:161)
	at dotty.tools.repl.ReplDriver.compile(ReplDriver.scala:234)
	at dotty.tools.repl.ReplDriver.interpret(ReplDriver.scala:197)
	at dotty.tools.repl.ReplDriver.loop$1(ReplDriver.scala:130)
	at dotty.tools.repl.ReplDriver.runUntilQuit$$anonfun$1(ReplDriver.scala:133)
	at dotty.tools.repl.ReplDriver.withRedirectedOutput(ReplDriver.scala:152)
	at dotty.tools.repl.ReplDriver.runUntilQuit(ReplDriver.scala:133)
	at dotty.tools.repl.Main$.main(Main.scala:6)
	at dotty.tools.repl.Main.main(Main.scala)