Release 3.0.0-RC2

• Finalize release
  • Look at the milestone of the version being released. Move all the open issues from it to the next milestone.
  • Merge branch of the previous release into master to guarantee that all of the commits are propagated to master
• Publish artifacts to Maven via CI
  • Create branch 3.0.0-RC2 from master
  • On that branch, set baseVersion and tag it as 3.0.0-RC2
  • On master, set baseVersion to the next version to be released
• Update scalaVersion (and, if applicable, the sbt-dotty version) in the Dotty ecosystem projects
  • https://github.com/scala/scala3-example-project
  • https://github.com/scala/scala3-example-project/tree/mill
  • https://github.com/scala/scala3.g8
  • https://github.com/scala/scala3-cross.g8
  • https://github.com/lampepfl/scala3-staging.g8
  • https://github.com/scala/scala3-tasty-inspector.g8
  • https://github.com/lampepfl/homebrew-brew
  • https://github.com/lampepfl/packtest
  • https://github.com/lampepfl/xml-interpolator
  • https://github.com/scalacenter/scastie
    • PR submitted
    • PR merged
    • https://scastie.scala-lang.org/ -> Build Settings -> Dotty mentions <rc-version>
  • Dotty reference compiler
    • PR submitted
    • PR merged
  • Scalac
    • PR submitted
    • PR merged
  • Update the dotty-repl Coursier app definition
    • PR submitted: coursier/apps#90
• Announce the release
  • Publish releases for the RC and stable versions on GitHub Releases
  • Publish Blog Post on dotty.epfl.ch
  • Make an announcement thread on https://contributors.scala-lang.org
  • Tweet the announcement blog post on https://twitter.com/scala_lang

Instructions on how to release

[SethTisue]

I strongly support this change. But I would like to add:

Historically, it has been rather difficult to use Scala 2 nightlies on some codebases, namely if there are dependencies, perhaps transitive ones, that are fully cross-versioned (as opposed to only by major version): so e.g. kind-projector, Scalameta. I’ve struggled with this myself, even though I’m pretty well versed in sbt. In simple cases I’m sometimes able to resolve it adding an override or by publishing a dependency locally, but sometimes it gets tricky. (In other cases I use dbuild, but I’m almost the only person for whom that’s a reasonable solution.)

I assume users might run into comparable difficulties in testing Scala 3 nightlies with their codebases. If so, it remains a build tool issue and not a language issue, but: I believe this change will put some pressure on build tool maintainers to make nightlies convenient to use on more projects. Whether it’s through documentation, or actual changes to the tool, or both. (Typically sbt leads on these sorts of issues and then the other tools try to catch up.)

/cc @eed3si9n

[smarter]

When upgrading the scalaVersion in the example projects, I suggest also upgrading to sbt 1.5.0-RC2 and removing sbt-dotty: this way we’ll get more people to test that sbt 1.5 works well with scala 3 by default.