Crash on inferred escaping singleton type followed by transparent inline

[prolativ]

Compiler version

3.3.1-RC1-bin-20230425-c9ca7ce-NIGHTLY-git-c9ca7ce and before

Minimized code

def foo[A](bar: Bar[A]): Foo = new Foo

class Foo:
  transparent inline def qux: Int = 0

class Bar[A]

val x = foo {
  val y: Any = ???
  Bar[y.type]
}.qux

Output (click arrow to expand)

Exception in thread "main" java.lang.AssertionError: assertion failed: unresolved symbols: value y (line 8) #4917 when pickling Bug.scala
        at scala.runtime.Scala3RunTime$.assertFailed(Scala3RunTime.scala:8)
        at dotty.tools.dotc.core.tasty.TreePickler.pickle(TreePickler.scala:809)
        at dotty.tools.dotc.transform.Pickler.run$$anonfun$1$$anonfun$1(Pickler.scala:90)
        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:333)
        at dotty.tools.dotc.transform.Pickler.run$$anonfun$1(Pickler.scala:142)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.immutable.List.foreach(List.scala:333)
        at dotty.tools.dotc.transform.Pickler.run(Pickler.scala:142)
        at dotty.tools.dotc.core.Phases$Phase.runOn$$anonfun$1(Phases.scala:324)
        at scala.collection.immutable.List.map(List.scala:246)
        at dotty.tools.dotc.core.Phases$Phase.runOn(Phases.scala:328)
        at dotty.tools.dotc.transform.Pickler.runOn(Pickler.scala:150)
        at dotty.tools.dotc.Run.runPhases$1$$anonfun$1(Run.scala:246)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:15)
        at scala.runtime.function.JProcedure1.apply(JProcedure1.java:10)
        at scala.collection.ArrayOps$.foreach$extension(ArrayOps.scala:1321)
        at dotty.tools.dotc.Run.runPhases$1(Run.scala:262)
        at dotty.tools.dotc.Run.compileUnits$$anonfun$1(Run.scala:270)
        at dotty.tools.dotc.Run.compileUnits$$anonfun$adapted$1(Run.scala:279)
        at dotty.tools.dotc.util.Stats$.maybeMonitored(Stats.scala:67)
        at dotty.tools.dotc.Run.compileUnits(Run.scala:279)
        at dotty.tools.dotc.Run.compileSources(Run.scala:194)
        at dotty.tools.dotc.Run.compile(Run.scala:179)
        at dotty.tools.dotc.Driver.doCompile(Driver.scala:37)
        at dotty.tools.dotc.Driver.process(Driver.scala:197)
        at dotty.tools.dotc.Driver.process(Driver.scala:165)
        at dotty.tools.dotc.Driver.process(Driver.scala:177)
        at dotty.tools.dotc.Driver.main(Driver.scala:207)
        at dotty.tools.dotc.Main.main(Main.scala)

There's no crash if transparent gets removed

[nicolasstucki]

It seems that the cause is the y.type in the inferred type of A. Not sure if this is an avoidance issue.

foo[(y : Any)](
  {
    val y: Any = ???
    new Bar[y.type]():Bar[(y : Any)]
  }
)

[nicolasstucki]

It also fails with inline and -Ycheck:all.

[nicolasstucki]

I assume that the issue is that when we inline we update the references to y within the block but not the ones outside.