SortedSet.collect does not accept a function for which there is no Ordering on the codomain

[MasseGuillaume]

2.12

case class A(v: Int)
collection.immutable.SortedSet(1).collect{ case x => A(x) }
// collection.immutable.Set[A] = Set(A(1))

2.13

[error] /home/gui/scala/test/junit/scala/Playground.scala:12: No implicit Ordering defined for A.
[error]     collection.immutable.SortedSet(1).collect{ case x => A(x) }
[error]                                              ^

[MasseGuillaume]

Hum, this is probably due to the absence of CanBuildFrom.

For map, I think the behavior in 2.13 make sense:

2.12

immutable.SortedSet(1).map(x => x)
// collection.immutable.SortedSet[Int] = TreeSet(1)

immutable.SortedSet(1).map(x => A(x))
// collection.immutable.Set[A] = Set(A(1))

2.13

[error] /home/gui/scala/test/junit/scala/Playground.scala:12: No implicit Ordering defined for A.
[error]     collection.immutable.SortedSet(1).map(x => A(x))
[error]                                          ^

[MasseGuillaume]

This is documented here: https://github.com/scala/collection-strawman/wiki/FAQ#what-are-the-breaking-changes.

workarround:

val temp: Set[Int] = collection.immutable.SortedSet(1).
temp.collect{ case x => A(x) }

[julienrf]

What should we do @MasseGuillaume?

This is a documented change (and I would argue that the new behavior is a feature) and the recommended way to achieve what you want to achieve in the first post is to use the unsorted operation:

case class A(v: Int)
collection.immutable.SortedSet(1).unsorted.collect{ case x => A(x) }
// collection.immutable.Set[A] = Set(A(1))

[MasseGuillaume]

unsorted is only available in 2.13: scala/scala-collection-compat#95