scala/scala v2.13.12

Scala 2.13.12

on GitHub

The Scala team at Lightbend is pleased to announce Scala 2.13.12.

The following changes are highlights of this release:

Feature: Quickfixes

For some errors and warnings, the compiler now suggests an edit that could fix the issue. Tooling such as IDEs can then offer the edits, or the compiler itself will make the change if run again with -quickfix.

• Implement quickfixes, aka actionable diagnostics (via CodeAction) (#10406 by @eed3si9n)
• Add -quickfix compiler option to apply quickfixes to source files (#10482 by @lrytz)
• Add quickfixes to some warnings and errors (#10484 by @lrytz)

Align with Scala 3

• Emit migration warnings under -Xsource:3 as fatal warnings, not errors; -Xmigration disables fatality (#10439 by @som-snytt, #10511)
• Warn about @elidable under -Xsource:3 (#10377 by @som-snytt)

Collections

• IndexedSeq#head now throws NoSuchElementException (not IndexOutOfBoundsException) (#10392 by @som-snytt)

Regression fixes

• Deduplicate JavaDeprecatedAttr in ClassfileParser (#10422 by @som-snytt)
• Avoid brittle flags encoding for Java enums (#10424 by @som-snytt)

Tooling

The following change is mainly of concern to tooling maintainers.

• In-source sbt compiler bridge (#10472 by @lrytz)

Other notable changes

For the complete 2.13.12 change lists, see all merged PRs and all closed bugs.

Compatibility

As usual for our minor releases, Scala 2.13.12 is binary-compatible with the whole Scala 2.13 series.

Upgrading from 2.12? Enable -Xmigration while upgrading to request migration advice from the compiler.

Contributors

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.

We especially acknowledge and thank A. P. Marki, also known as Som Snytt, who is responsible for a large share of the improvements in this release.

This release was brought to you by 12 contributors, according to git shortlog -sn --no-merges @ ^v2.13.11 ^2.12.x ^366ba2f. Thank you A. P. Marki, Lukas Rytz, Seth Tisue, Scala Steward, Michel Davit, Nicolas Stucki, Alex Leigh, Eugene Yokota, Georgi Krastev, Jamie Willis, Julien Richard-Foy, NthPortal.

Thanks to Lightbend for their continued sponsorship of the Scala 2 team’s efforts. Lightbend offers commercial support for Scala.

Scala 2.13 notes

The release notes for Scala 2.13.0 have important information applicable to the whole 2.13 series.

Obtaining Scala

Scala releases are available through a variety of channels, including (but not limited to):

• Bump the using scala setting in your Scala CLI project
• Bump the scalaVersion setting in your sbt or Mill project
• Download a distribution from scala-lang.org
• Obtain JARs via Maven Central