Cycle loading extends arguments from TASTy

Compiler version

Scala compiler version 3.1.1-RC1-bin-SNAPSHOT-git-8947f38 – Copyright 2002-2021, LAMP/EPFL

Minimized code

package bug

class RawXml(namespace2: String):
  class Value

object Body extends RawXml(Tei(null).namespace)

class Tei(text: Text):
  val namespace: String = ???

class Text(body: Body.Value):
  Text(null)

Then run:

bin/scalac -d here bug.scala 

Output: compiles successfully

Then run:

bin/scalac -d here2 -from-tasty here/bug/Body.tasty here/bug/RawXml.tasty here/bug/Tei.tasty here/bug/Text.tasty

Output:

cannot take signature of MethodType(List(body), List(TypeRef(TermRef(TermRef(ThisType(TypeRef(NoPrefix,module class <root>)),object bug),Body),Value)), TypeRef(ThisType(TypeRef(NoPrefix,module class bug)),class Text))
cannot resolve reference to type bug.Body.type.Value
the classfile defining the type might be missing from the classpath while compiling here/bug/Body.tasty, here/bug/RawXml.tasty, here/bug/Tei.tasty, here/bug/Text.tasty
Exception in thread "main" dotty.tools.dotc.core.MissingType: 
        at dotty.tools.dotc.core.TypeErasure.dotty$tools$dotc$core$TypeErasure$$sigName(TypeErasure.scala:782)
        at dotty.tools.dotc.core.TypeErasure$.sigName(TypeErasure.scala:204)
        at dotty.tools.dotc.core.Signature.$anonfun$2(Signature.scala:113)
        at scala.collection.immutable.List.map(List.scala:246)
        at dotty.tools.dotc.core.Signature.prependTermParams(Signature.scala:113)
        at dotty.tools.dotc.core.Types$MethodOrPoly.computeSignature$2(Types.scala:3521)
        at dotty.tools.dotc.core.Types$MethodOrPoly.signature(Types.scala:3538)
        at dotty.tools.dotc.core.Denotations$SingleDenotation.signature(Denotations.scala:612)
        at dotty.tools.dotc.core.Denotations$SingleDenotation.signature(Denotations.scala:602)
        at dotty.tools.dotc.core.Denotations$SingleDenotation.atSignature(Denotations.scala:644)
        at dotty.tools.dotc.core.Denotations$SingleDenotation.atSignature(Denotations.scala:642)
        at dotty.tools.dotc.core.tasty.TreeUnpickler$TreeReader.readLengthTerm$1(TreeUnpickler.scala:1225)
        at dotty.tools.dotc.core.tasty.TreeUnpickler$TreeReader.readTerm(TreeUnpickler.scala:1299)
        at dotty.tools.dotc.core.tasty.TreeUnpickler$TreeReader.readLengthTerm$1(TreeUnpickler.scala:1139)
        at dotty.tools.dotc.core.tasty.TreeUnpickler$TreeReader.readTerm(TreeUnpickler.scala:1299)
        at dotty.tools.dotc.core.tasty.TreeUnpickler.readRhs$1$$anonfun$1$$anonfun$1(TreeUnpickler.scala:810)
        at dotty.tools.dotc.core.tasty.TreeUnpickler$LazyReader.complete(TreeUnpickler.scala:1438)
        at dotty.tools.dotc.ast.Trees$WithLazyField.forceIfLazy(Trees.scala:1027)
        at dotty.tools.dotc.ast.Trees$WithLazyField.forceIfLazy$(Trees.scala:1022)
        at dotty.tools.dotc.ast.Trees$ValOrDefDef.forceIfLazy(Trees.scala:425)
        at dotty.tools.dotc.ast.Trees$ValOrDefDef.rhs(Trees.scala:430)
        at dotty.tools.dotc.ast.Trees$Instance$TreeAccumulator.foldOver(Trees.scala:1606)
        at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.traverseChildren(Trees.scala:1648)
        at dotty.tools.dotc.CompilationUnit$Force.traverse(CompilationUnit.scala:141)
        at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.apply(Trees.scala:1647)
        at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.apply(Trees.scala:1647)
        at dotty.tools.dotc.ast.Trees$Instance$TreeAccumulator.fold$1(Trees.scala:1522)
        at dotty.tools.dotc.ast.Trees$Instance$TreeAccumulator.apply(Trees.scala:1524)
        at dotty.tools.dotc.ast.Trees$Instance$TreeAccumulator.foldOver(Trees.scala:1617)
        at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.traverseChildren(Trees.scala:1648)
        at dotty.tools.dotc.CompilationUnit$Force.traverse(CompilationUnit.scala:141)
        at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.apply(Trees.scala:1647)
        at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.apply(Trees.scala:1647)
        at dotty.tools.dotc.ast.Trees$Instance$TreeAccumulator.foldOver(Trees.scala:1614)
        at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.traverseChildren(Trees.scala:1648)
        at dotty.tools.dotc.CompilationUnit$Force.traverse(CompilationUnit.scala:141)
        at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.apply(Trees.scala:1647)
        at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.apply(Trees.scala:1647)
        at dotty.tools.dotc.ast.Trees$Instance$TreeAccumulator.fold$1(Trees.scala:1522)
        at dotty.tools.dotc.ast.Trees$Instance$TreeAccumulator.apply(Trees.scala:1524)
        at dotty.tools.dotc.ast.Trees$Instance$TreeAccumulator.foldOver(Trees.scala:1623)
        at dotty.tools.dotc.ast.Trees$Instance$TreeAccumulator.foldOver(Trees.scala:1528)
        at dotty.tools.dotc.ast.Trees$Instance$TreeTraverser.traverseChildren(Trees.scala:1648)
        at dotty.tools.dotc.CompilationUnit$Force.traverse(CompilationUnit.scala:141)
        at dotty.tools.dotc.CompilationUnit$.apply(CompilationUnit.scala:105)
        at dotty.tools.dotc.CompilationUnit$.apply(CompilationUnit.scala:96)
        at dotty.tools.dotc.fromtasty.ReadTasty.compilationUnit$1(ReadTasty.scala:42)
        at dotty.tools.dotc.fromtasty.ReadTasty.readTASTY(ReadTasty.scala:70)
        at dotty.tools.dotc.fromtasty.ReadTasty.runOn$$anonfun$1(ReadTasty.scala:25)
        at scala.collection.immutable.List.flatMap(List.scala:293)
        at dotty.tools.dotc.fromtasty.ReadTasty.runOn(ReadTasty.scala:25)
        at dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:261)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1323)
        at dotty.tools.dotc.Run.runPhases$1(Run.scala:272)
        at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:280)
        at scala.runtime.java8.JFunction0$mcV$sp.apply(JFunction0$mcV$sp.scala:18)
        at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:68)
        at dotty.tools.dotc.Run.compileUnits(Run.scala:289)
        at dotty.tools.dotc.Run.compileUnits(Run.scala:228)
        at dotty.tools.dotc.fromtasty.TASTYRun.compile(TASTYRun.scala:12)
        at dotty.tools.dotc.Driver.doCompile(Driver.scala:39)
        at dotty.tools.dotc.Driver.process(Driver.scala:199)
        at dotty.tools.dotc.Driver.process(Driver.scala:167)
        at dotty.tools.dotc.Driver.process(Driver.scala:179)
        at dotty.tools.dotc.Driver.main(Driver.scala:209)
        at dotty.tools.dotc.Main.main(Main.scala)

Expectation

Compiles successfully

Disclaimer

I know this minimization is not very obvious but it is as most self-contained as I could achieve. The error comes from opentorah project and has been reported at Gradle. The sbt reproduction can be found at this branch https://github.com/BarkingBad/opentorah/blob/repro/base/src/main/scala/org/opentorah/tei/Body.scala though as you can see you can reproduce it using the compiler from dotty directly.

[nicolasstucki]

Indeed, looks like the cause is similar to #12872. But it fails in a different way, in #12872 we detect the cycle while here we fail to see a symbol that should be there while unpickling.

[nicolasstucki]

Nice minimization