Aladdin - Scala Bugtracking

	[#811]	project: compiler	priority: low	category: bug
	submitter	assigned to	status	date submitted
	Sean	Burak	fixed	2006-11-10 12:19:29.0
subject	match broken for traits (again???)
code	package test; trait Core { trait NodeImpl; trait OtherImpl extends NodeImpl; trait DoubleQuoteImpl extends NodeImpl; def asDQ(node : OtherImpl) = node match { case dq : DoubleQuoteImpl => dq; } }
what happened	Could be a bad check-in as I would be surprised if there was not a test case for this. Anyways, the current comp\ iler is recently very broken (this crash wasn't in my pull last week): sean-mcdirmid:~/workspace/test32/src mcdirmid$ ../../scala/build/quick/bin/scalac -sourcepath . -d ../bin t\ est/Test.scala exception when transforming def asDQ(node: Core.this.OtherImpl): Core.this.OtherImpl with Core.this.DoubleQuoteI\ mpl = node match { case (dq @ (_) : Core.this.DoubleQuoteImpl) => dq } exception when transforming java.lang.Object with scala.ScalaObject { abstract trait NodeImpl extends java.lang.Object with scala.ScalaObject; abstract trait OtherImpl extends java.lang.Object with Core.this.NodeImpl with scala.ScalaObject; abstract trait DoubleQuoteImpl extends java.lang.Object with Core.this.NodeImpl with scala.ScalaObject; def asDQ(node: Core.this.OtherImpl): Core.this.OtherImpl with Core.this.DoubleQuoteImpl = node match { case (dq @ (_) : Core.this.DoubleQuoteImpl) => dq } } exception when transforming abstract trait Core extends java.lang.Object with scala.ScalaObject { abstract trait NodeImpl extends java.lang.Object with scala.ScalaObject; abstract trait OtherImpl extends java.lang.Object with Core.this.NodeImpl with scala.ScalaObject; abstract trait DoubleQuoteImpl extends java.lang.Object with Core.this.NodeImpl with scala.ScalaObject; def asDQ(node: Core.this.OtherImpl): Core.this.OtherImpl with Core.this.DoubleQuoteImpl = node match { case (dq @ (_) : Core.this.DoubleQuoteImpl) => dq } } exception when transforming package test { abstract trait Core extends java.lang.Object with scala.ScalaObject { abstract trait NodeImpl extends java.lang.Object with scala.ScalaObject; abstract trait OtherImpl extends java.lang.Object with Core.this.NodeImpl with scala.ScalaObject; abstract trait DoubleQuoteImpl extends java.lang.Object with Core.this.NodeImpl with scala.ScalaObject; def asDQ(node: Core.this.OtherImpl): Core.this.OtherImpl with Core.this.DoubleQuoteImpl = node match { case (dq @ (_) : Core.this.DoubleQuoteImpl) => dq } } } Exception in thread "main" scala.tools.nsc.symtab.Types$TypeError: type mismatch; found : Core.this.DoubleQuoteImpl required: Core.this.OtherImpl with Core.this.DoubleQuoteImpl at scala.tools.nsc.typechecker.Contexts$Context.error(Contexts.scala:252) at scala.tools.nsc.typechecker.Infer$Inferencer.error(Infer.scala:245) at scala.tools.nsc.typechecker.Infer$Inferencer.typeError(Infer.scala:254) at scala.tools.nsc.typechecker.Infer$Inferencer.typeErrorTree(Infer.scala:263) at scala.tools.nsc.typechecker.Typers$Typer.adapt(Typers.scala:652) at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:2215) at scala.tools.nsc.typechecker.Typers$Typer.typedArg(Typers.scala:1285) at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$52.apply(Typers.scala:1302) at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$52.apply(Typers.scala:1302) at scala.List$.map2(List.scala:276) at scala.tools.nsc.typechecker.Typers$Typer.typedArgs(Typers.scala:1302) at scala.tools.nsc.typechecker.Typers$Typer.typedApply(Typers.scala:1337) at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:2069) at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:2213) at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:2245) at scala.tools.nsc.typechecker.Typers$Typer.typedStat$0(Typers.scala:1258) at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$48.apply(Typers.scala:1279) at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$48.apply(Typers.scala:1279) at scala.List$.loop$0(List.scala:243) at scala.List$.mapConserve(List.scala:260) at scala.tools.nsc.typechecker.Typers$Typer.typedStats(Typers.scala:1279) at scala.tools.nsc.typechecker.Typers$Typer.typedBlock(Typers.scala:1122) at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:1870) at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:2213) at scala.tools.nsc.typechecker.Typers$Typer.typedArg(Typers.scala:1285) at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$52.apply(Typers.scala:1302) at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$52.apply(Typers.scala:1302) at scala.List$.map2(List.scala:276) at scala.tools.nsc.typechecker.Typers$Typer.typedArgs(Typers.scala:1302) at scala.tools.nsc.typechecker.Typers$Typer.typedApply(Typers.scala:1337) at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:2069) at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:2213) at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:2245) at scala.tools.nsc.typechecker.Typers$Typer.typedStat$0(Typers.scala:1258) at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$48.apply(Typers.scala:1279) at scala.tools.nsc.typechecker.Typers$Typer$$anonfun$48.apply(Typers.scala:1279) at scala.List$.loop$0(List.scala:243) at scala.List$.mapConserve(List.scala:260) at scala.tools.nsc.typechecker.Typers$Typer.typedStats(Typers.scala:1279) at scala.tools.nsc.typechecker.Typers$Typer.typedBlock(Typers.scala:1122) at scala.tools.nsc.typechecker.Typers$Typer.typed1(Typers.scala:1870) at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:2213) at scala.tools.nsc.typechecker.Typers$Typer.typed(Typers.scala:2256) at scala.tools.nsc.transform.ExplicitOuter$ExplicitOuterTransformer.transform(ExplicitOuter.scala:404) at scala.tools.nsc.ast.Trees$Transformer$$anonfun$20.apply(Trees.scala:1082) at scala.tools.nsc.ast.Trees$Transformer$$anonfun$20.apply(Trees.scala:1081) at scala.tools.nsc.ast.Trees$Transformer.atOwner(Trees.scala:1189) at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:33) at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:27) at scala.tools.nsc.ast.Trees$Transformer.transform(Trees.scala:1080) at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:46) at scala.tools.nsc.transform.ExplicitOuter$OuterPathTransformer.transform(ExplicitOuter.scala:191) at scala.tools.nsc.transform.ExplicitOuter$ExplicitOuterTransformer.transform(ExplicitOuter.scala:354) at scala.tools.nsc.ast.Trees$Transformer$$anonfun$30.apply(Trees.scala:1183) at scala.tools.nsc.ast.Trees$Transformer$$anonfun$30.apply(Trees.scala:1181) at scala.List$.loop$0(List.scala:243) at scala.List$.mapConserve(List.scala:260) at scala.tools.nsc.ast.Trees$Transformer.transformStats(Trees.scala:1181) at scala.tools.nsc.ast.Trees$Transformer.transform(Trees.scala:1101) at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.scala$tools$nsc$transform$TypingTransformers$\ TypingTransformer$$super$transform(TypingTransformers.scala:44) at scala.tools.nsc.transform.TypingTransformers$TypingTransformer$$anonfun$0.apply(TypingTransformers.scala:44)\ at scala.tools.nsc.transform.TypingTransformers$TypingTransformer$$anonfun$0.apply(TypingTransformers.scala:44)\ at scala.tools.nsc.ast.Trees$Transformer.atOwner(Trees.scala:1189) at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:33) at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:27) at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:44) at scala.tools.nsc.transform.ExplicitOuter$OuterPathTransformer.transform(ExplicitOuter.scala:191) at scala.tools.nsc.transform.ExplicitOuter$ExplicitOuterTransformer.transform(ExplicitOuter.scala:331) at scala.tools.nsc.ast.Trees$Transformer.transformTemplate(Trees.scala:1169) at scala.tools.nsc.ast.Trees$Transformer$$anonfun$17.apply(Trees.scala:1069) at scala.tools.nsc.ast.Trees$Transformer$$anonfun$17.apply(Trees.scala:1068) at scala.tools.nsc.ast.Trees$Transformer.atOwner(Trees.scala:1189) at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:33) at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:27) at scala.tools.nsc.ast.Trees$Transformer.transform(Trees.scala:1067) at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:46) at scala.tools.nsc.transform.ExplicitOuter$OuterPathTransformer.transform(ExplicitOuter.scala:191) at scala.tools.nsc.transform.ExplicitOuter$ExplicitOuterTransformer.transform(ExplicitOuter.scala:415) at scala.tools.nsc.ast.Trees$Transformer$$anonfun$30.apply(Trees.scala:1183) at scala.tools.nsc.ast.Trees$Transformer$$anonfun$30.apply(Trees.scala:1181) at scala.List$.loop$0(List.scala:243) at scala.List$.mapConserve(List.scala:260) at scala.tools.nsc.ast.Trees$Transformer.transformStats(Trees.scala:1181) at scala.tools.nsc.ast.Trees$Transformer$$anonfun$16.apply(Trees.scala:1064) at scala.tools.nsc.ast.Trees$Transformer$$anonfun$16.apply(Trees.scala:1064) at scala.tools.nsc.ast.Trees$Transformer.atOwner(Trees.scala:1189) at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:33) at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.atOwner(TypingTransformers.scala:27) at scala.tools.nsc.ast.Trees$Transformer.transform(Trees.scala:1063) at scala.tools.nsc.transform.TypingTransformers$TypingTransformer.transform(TypingTransformers.scala:46) at scala.tools.nsc.transform.ExplicitOuter$OuterPathTransformer.transform(ExplicitOuter.scala:191) at scala.tools.nsc.transform.ExplicitOuter$ExplicitOuterTransformer.transform(ExplicitOuter.scala:415) at scala.tools.nsc.ast.Trees$Transformer.transformUnit(Trees.scala:1184) at scala.tools.nsc.transform.ExplicitOuter$ExplicitOuterTransformer.scala$tools$nsc$transform$ExplicitOuter$Exp\ licitOuterTransformer$$super$transformUnit(ExplicitOuter.scala:422) at scala.tools.nsc.transform.ExplicitOuter$ExplicitOuterTransformer$$anonfun$7.apply(ExplicitOuter.scala:422) at scala.tools.nsc.transform.ExplicitOuter$ExplicitOuterTransformer$$anonfun$7.apply(ExplicitOuter.scala:422) at scala.tools.nsc.symtab.SymbolTable.atPhase(SymbolTable.scala:71) at scala.tools.nsc.transform.ExplicitOuter$ExplicitOuterTransformer.transformUnit(ExplicitOuter.scala:422) at scala.tools.nsc.transform.Transform$Phase.apply(Transform.scala:30) at scala.tools.nsc.Global$GlobalPhase.applyPhase(Global.scala:219) at scala.tools.nsc.Global$GlobalPhase$$anonfun$1.apply(Global.scala:208) at scala.tools.nsc.Global$GlobalPhase$$anonfun$1.apply(Global.scala:208) at scala.Iterator$class.foreach(Iterator.scala:319) at scala.collection.mutable.ListBuffer$$anon$0.foreach(ListBuffer.scala:244) at scala.tools.nsc.Global$GlobalPhase.run(Global.scala:208) at scala.tools.nsc.Global$Run.compileSources(Global.scala:473) at scala.tools.nsc.Global$Run.compile(Global.scala:542) at scala.tools.nsc.Main$.process(Main.scala:74) at scala.tools.nsc.Main$.main(Main.scala:96) at scala.tools.nsc.Main.main(Main.scala)
what expected
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Changes of this bug report

Sean edited on 2006-11-10 12:26:08.0

Maybe a duplicate of #806, but I thought this bug went away for awhile without #806 being closed. At anyrate, I'm still running into this problem.

Martin edited on 2006-11-10 18:36:11.0

It's code generated by pattern matcher so I reassign to Burak.

Burak edited on 2006-11-10 18:55:00.0

I can tell without looking at any code that the reason for this are Martin's latest GADT hacks (why would we require an OtherImpl with DoubleQuotedImpl?) The following problem works, so it is not clear to me what I should do fix:

  def asDQ(node : OtherImpl) = node match {
    case dq : DoubleQuoteImpl => dq:DoubleQuoteImpl;
  }

IMHO the "better" types that the typer spits out after inference must be communicated to the pattern matcher somehow. I guess it is just a matter of assigning the right type to the typed pattern in the typer, but have to check.

Burak edited on 2006-11-13 13:20:10.0

I fixed this in a way that is robust again typer - behavior by using the type of the symbol rather than the type in the tree. However, I still think it odd that the tree does not fully reflect the type, the tree should be rewritten to

//after typer
case dq: OtherImpl with DoubleQuoteImpl =>

but that's just a maintainability issue.