Scala 2.13 is almost here! We present the third 2.13 release candidate. The changes since RC2 are minor.
We hope library maintainers will test and publish their libraries for RC3, to validate the release candidate and enable 2.13.0 to go forward.
About these notes
These are the detailed technical release notes for RC3 only, documenting changes since RC2 only.
As usual for Scala pre-releases, RC3 is not binary compatible with any other Scala version, including previous 2.13 milestones and release candidates.
We will not break binary compatibility between RC3 and 2.13.0 unless really necessary.
Libraries for RC3
As libraries are published for RC3, they're added to https://github.com/scala/make-release-notes/blob/2.13.x/projects-2.13.md .
Changes in RC3
We merged 16 pull requests for RC3. The highlights are:
- Remove unnecessary type parameter on
- Add default
option2Iterableimplicit conversion (#8106)
Compiler performance in 2.13 is 5-10% better than 2.12. The integration of the new collections library shows up in the performance graph as a nice improvement.
To learn about the collections changes since 2.12 and how to adapt your code, take a look at these documents:
- Scala 2.13's Collections
- The Architecture of Scala 2.13 Collections
- Implementing Custom Collections (Scala 2.13)
- Adding Custom Collection Operations (Scala 2.13)
- Migrating a Project to 2.13's Collections. This document describes the main changes for collection users that migrate to Scala 2.13 and shows how to cross-build projects with Scala 2.11 / 2.12 and 2.13.
- scala-collection-compat provides shims for cross-building code that uses collections across Scala 2.11, 2.12, and 2.13. It also provides two sets of Scalafix rewrites, one for cross-building, one for moving to 2.13 only.
These documents are still being expanded and improved.
A big thank you to everyone who's helped improve Scala by reporting bugs, improving our documentation, spreading kindness in discussions around Scala, and submitting and reviewing pull requests! You are all magnificent.
This release was brought to you by 10 contributors, according to
git shortlog -sn --no-merges v2.13.0-RC2..v2.13.0-RC3. Thank you Lukas Rytz, NthPortal, Josh Lemer, Philippus Baalman, Stefan Zeiger, Aaron S. Hawley, mcintdan, Adriaan Moors, Anatolii, Eugene Yokota.
Scala releases are available through a variety of channels, including (but not limited to):