.to(mutable.PriorityQueue) not compiling on 2.12

[fdietze]

I'm porting Scala.rx to 2.13 (lihaoyi/scala.rx#138). It now compiles for 2.13, but not for 2.12 anymore (https://travis-ci.org/lihaoyi/scala.rx/builds/579881994?utm_source=github_status&utm_medium=notification):

[error]      type mismatch;
[error]       found   : scala.collection.mutable.PriorityQueue.type
[error]       required: scala.collection.generic.CanBuildFrom[Nothing,rx.Rx.Dynamic[_],scala.collection.mutable.PriorityQueue[rx.Rx.Dynamic[_]]]
[error]      L44:       args.iterator.flatMap(_.v.downStream).to(mutable.PriorityQueue),

Am I doing something wrong?

[julienrf]

That’s our fault: https://scastie.scala-lang.org/wuOulN8JS2WQTIcveEtgLQ

We should add an implicit conversion to CanBuildFrom for companion objects extending GenericOrderedCompanion (we currently support GenericCompanion and SortedSetFactory only).