Can't export all members of mutable.TreeMap (tried with List as well)

[mpskowron]

dottyVersion = "0.27.0-RC1"
Please find 3 different verions and 2 different outputs here:

Minimized code

1:

class MaxSizeMap[K, V](maxSize: Int)(using o: Ordering[K]):
  private val sortedMap: mutable.TreeMap[K, V] = mutable.TreeMap.empty[K, V](o)
  
  export sortedMap._

2:

class MaxSizeMap[K, V](maxSize: Int)(using o: Ordering[K]):
  val sortedMap: mutable.TreeMap[K, V] = mutable.TreeMap.empty[K, V](o)
  
  export sortedMap._

3:
notice that all the methods I had to exclude to get rid of error messages from 1 return this.type

class MaxSizeMap[K, V](maxSize: Int)(using o: Ordering[K]):
  private val sortedMap: mutable.TreeMap[K, V] = mutable.TreeMap.empty[K, V](o)
  
  export sortedMap.{mapValuesInPlace => _, toIterable => _, seq => _, --= => _, ++= => _, += => _, addAll => _, subtractAll => _, 
    lazyZip => _, filterInPlace => _, -= => _, addOne => _, subtractOne => _, transform => _, retain => _, _}

Output

1:

[error] 8 |  export sortedMap._
[error]   |                   ^
[error]   |non-private method += in class MaxSizeMap refers to private value sortedMap
[error]   |in its type signature (elem1: (K, V), elem2: (K, V), elems: (K, V)*): 
[error]   |  (MaxSizeMap.this.sortedMap : collection.mutable.TreeMap[K, V])

2 and 3 (same stack trace):
truncated stack trace:

[error] ## Exception when compiling 6 sources to /home/michal/programming/scala/crypto-db/target/scala-0.27/classes
[error] java.lang.AssertionError: assertion failed
[error] dotty.DottyPredef$.assertFail(DottyPredef.scala:16)
[error] dotty.tools.dotc.transform.ResolveSuper.transformDefDef(ResolveSuper.scala:63)
[error] dotty.tools.dotc.transform.MegaPhase.goDefDef(MegaPhase.scala:973)
[error] dotty.tools.dotc.transform.MegaPhase.goDefDef(MegaPhase.scala:974)
[error] dotty.tools.dotc.transform.MegaPhase.transformNamed$1(MegaPhase.scala:251)
[error] dotty.tools.dotc.transform.MegaPhase.transformTree(MegaPhase.scala:426)
[error] dotty.tools.dotc.transform.MegaPhase.transformStat$2(MegaPhase.scala:436)
[error] dotty.tools.dotc.transform.MegaPhase.recur$3$$anonfun$1(MegaPhase.scala:441)
[error] dotty.tools.dotc.transform.MegaPhase$$Lambda$6255/00000000480AB540.apply(Unknown Source)
[error] scala.collection.immutable.List.mapConserve(List.scala:472)

Expectation

It compiles

[bishabosha]

Thank you for opening this issue.

For 1. It is not clear to me why you should want to export += from sortedMap, What would you expect to happen in this situation?

but the crash in 2 and 3 is troubling

[mpskowron]

Thank you for a quick answer.
For 1. I didn't think about it - you're right, methods like += shouldn't be exported. Anyway, I think it should compile and export all methods that can be exported (maybe with a warning or maybe without). My main motivation to use it in this case is to avoid boilerplate, so exporting anything exportable seems like desired behavior.