Crash in pickler when self type is intersection type

[WojciechMazur]

Based on OpenCB failure in scala-graph/scala-graph

Compiler version

Last good release: 3.3.1-RC1-bin-20230215-006e2e4-NIGHTLY
First bad release: 3.3.1-RC1-bin-20230216-2507577-NIGHTLY

Bisect points to 8d65f19

Minimized code

trait GraphTraversal:
  type NodeT
  trait Properties:
    def root: NodeT

  trait TraverserMethods[A, +CC <: TraverserMethods[A, CC]]:
    self: CC & Properties =>
      def root: NodeT

Output (click arrow to expand)

error when pickling tree def root: GraphTraversal.this.NodeT of class class dotty.tools.dotc.ast.Trees$DefDef
error when pickling tree [A >: Nothing <: Any, CC >: Nothing <: GraphTraversal.this.TraverserMethods[A, CC]]() extends Object { self: TraverserMethods.this.CC & GraphTraversal.this.Properties =>
  A
  +CC <: GraphTraversal.this.TraverserMethods[A, CC]
  def root: GraphTraversal.this.NodeT
} of class class dotty.tools.dotc.ast.Trees$Template
error when pickling tree trait TraverserMethods[A >: Nothing <: Any, CC >: Nothing <: GraphTraversal.this.TraverserMethods[A, CC]]() extends Object {
  self: TraverserMethods.this.CC & GraphTraversal.this.Properties =>
  A
  +CC <: GraphTraversal.this.TraverserMethods[A, CC]
  def root: GraphTraversal.this.NodeT
} of class class dotty.tools.dotc.ast.Trees$TypeDef
error when pickling tree () extends Object {
  type NodeT >: Nothing <: Any
  trait Properties() extends Object {
    def root: GraphTraversal.this.NodeT
  }
  trait TraverserMethods[A >: Nothing <: Any, CC >: Nothing <: GraphTraversal.this.TraverserMethods[A, CC]]() extends Object {
    self: TraverserMethods.this.CC & GraphTraversal.this.Properties =>
    A
    +CC <: GraphTraversal.this.TraverserMethods[A, CC]
    def root: GraphTraversal.this.NodeT
  }
} of class class dotty.tools.dotc.ast.Trees$Template
error when pickling tree @SourceFile("graphTraversal.scala") trait GraphTraversal() extends Object {
  type NodeT >: Nothing <: Any
  trait Properties() extends Object {
    def root: GraphTraversal.this.NodeT
  }
  trait TraverserMethods[A >: Nothing <: Any, CC >: Nothing <: GraphTraversal.this.TraverserMethods[A, CC]]() extends Object {
    self: TraverserMethods.this.CC & GraphTraversal.this.Properties =>
    A
    +CC <: GraphTraversal.this.TraverserMethods[A, CC]
    def root: GraphTraversal.this.NodeT
  }
} of class class dotty.tools.dotc.ast.Trees$TypeDef
error when pickling tree package <empty> {
  @SourceFile("graphTraversal.scala") trait GraphTraversal() extends Object {
    type NodeT >: Nothing <: Any
    trait Properties() extends Object {
      def root: GraphTraversal.this.NodeT
    }
    trait TraverserMethods[A >: Nothing <: Any, CC >: Nothing <: GraphTraversal.this.TraverserMethods[A, CC]]() extends Object {
      self: TraverserMethods.this.CC & GraphTraversal.this.Properties =>
      A
      +CC <: GraphTraversal.this.TraverserMethods[A, CC]
      def root: GraphTraversal.this.NodeT
    }
  }
} of class class dotty.tools.dotc.ast.Trees$PackageDef

  unhandled exception while running pickler on /Users/wmazur/projects/sandbox/graphTraversal.scala

  An unhandled exception was thrown in the compiler.
  Please file a crash report here:
  https://github.com/scala/scala3/issues/new/choose
  For non-enriched exceptions, compile with -Xno-enrich-error-messages.

     while compiling: /Users/wmazur/projects/sandbox/graphTraversal.scala
        during phase: pickler
                mode: Mode(ImplicitsEnabled)
     library version: version 2.13.15
    compiler version: version 3.6.1
            settings: -classpath /Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala3-library_3/3.6.1/scala3-library_3-3.6.1.jar:/Users/wmazur/Library/Caches/Coursier/v1/https/repo1.maven.org/maven2/org/scala-lang/scala-library/2.13.15/scala-library-2.13.15.jar -d /Users/wmazur/projects/sandbox/.scala-build/sandbox_755cda591f-33703b4d14/classes/main -java-output-version 17 -sourceroot /Users/wmazur/projects/sandbox

Exception in thread "main" java.lang.AssertionError: assertion failed: method root
        at scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8)
        at dotty.tools.dotc.core.tasty.TreePickler.pickleDef(TreePickler.scala:372)
        at dotty.tools.dotc.core.tasty.TreePickler.pickleTree(TreePickler.scala:662)
        at dotty.tools.dotc.core.tasty.TreePickler.pickleStats$$anonfun$2(TreePickler.scala:423)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.immutable.List.foreach(List.scala:334)
        at dotty.tools.dotc.core.tasty.TreePickler.pickleStats(TreePickler.scala:423)
        at dotty.tools.dotc.core.tasty.TreePickler.pickleTree(TreePickler.scala:698)
        at dotty.tools.dotc.core.tasty.TreePickler.pickleDef(TreePickler.scala:381)
        at dotty.tools.dotc.core.tasty.TreePickler.pickleTree(TreePickler.scala:664)
        at dotty.tools.dotc.core.tasty.TreePickler.pickleStats$$anonfun$2(TreePickler.scala:423)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.immutable.List.foreach(List.scala:334)
        at dotty.tools.dotc.core.tasty.TreePickler.pickleStats(TreePickler.scala:423)
        at dotty.tools.dotc.core.tasty.TreePickler.pickleTree(TreePickler.scala:698)
        at dotty.tools.dotc.core.tasty.TreePickler.pickleDef(TreePickler.scala:381)
        at dotty.tools.dotc.core.tasty.TreePickler.pickleTree(TreePickler.scala:664)
        at dotty.tools.dotc.core.tasty.TreePickler.pickleStats$$anonfun$2(TreePickler.scala:423)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.immutable.List.foreach(List.scala:334)
        at dotty.tools.dotc.core.tasty.TreePickler.pickleStats(TreePickler.scala:423)
        at dotty.tools.dotc.core.tasty.TreePickler.pickleTree(TreePickler.scala:714)
        at dotty.tools.dotc.core.tasty.TreePickler.pickle$$anonfun$1(TreePickler.scala:938)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.immutable.List.foreach(List.scala:334)
        at dotty.tools.dotc.core.tasty.TreePickler.pickle(TreePickler.scala:936)
        at dotty.tools.dotc.transform.Pickler.run$$anonfun$1$$anonfun$1(Pickler.scala:306)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.immutable.List.foreach(List.scala:334)
        at dotty.tools.dotc.transform.Pickler.run$$anonfun$1(Pickler.scala:279)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.immutable.List.foreach(List.scala:334)
        at dotty.tools.dotc.transform.Pickler.run(Pickler.scala:278)
        at dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:380)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.immutable.List.foreach(List.scala:334)
        at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:373)
        at dotty.tools.dotc.transform.Pickler.runPhase$1(Pickler.scala:392)
        at dotty.tools.dotc.transform.Pickler.runOn(Pickler.scala:398)
        at dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:343)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1323)
        at dotty.tools.dotc.Run.runPhases$1(Run.scala:336)
        at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:384)
        at dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:396)
        at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:69)
        at dotty.tools.dotc.Run.compileUnits(Run.scala:396)
        at dotty.tools.dotc.Run.compileSources(Run.scala:282)
        at dotty.tools.dotc.Run.compile(Run.scala:267)
        at dotty.tools.dotc.Driver.doCompile(Driver.scala:37)
        at dotty.tools.dotc.Driver.process(Driver.scala:201)
        at dotty.tools.dotc.Driver.process(Driver.scala:169)
        at dotty.tools.dotc.Driver.process(Driver.scala:181)
        at dotty.tools.dotc.Driver.main(Driver.scala:211)
        at dotty.tools.dotc.Main.main(Main.scala)

[Gedochao]

cc @odersky

[odersky]

Looks like a duplicate of #21755?

[Gedochao]

Seems like it... got confused, the bisect points to a different commit (c830ad2 in #21755 and 8d65f19 here)...
But the repro is the same, and they're both from the same PR...

My bad, missed it.
Closing as duplicate.