Scala 3.8.4 is now available!

Release highlights

Security audit fixes

Scala 3.8.4 includes improvements and fixes for issues discovered during the Scala codebase security audit carried out in collaboration with the Open Source Technology Improvement Fund and Quarkslab. Notable fixes in this release include:

• Hardened TASTy parsing to prevent infinite loops on maliciously crafted files (#25676)
• Fixed a stored XSS vulnerability in Scaladoc (#25681)
• Improved error handling in scala.sys.process.Parser.tokenize (#25675)
• Fixed TastyPrinter’s JAR-walking logic to include subdirectories (#25678)

:help syntax for all compiler settings (#26052)

You can now append :help to any compiler setting to see its documentation — not just a fixed subset as before. This works wherever you pass compiler options, making it easier to discover available flags without leaving your workflow.

With the Scala runner, add :help to a flag on the command line when running a script or project:

> scala test.scala -Xkind-projector:help
-Xkind-projector  Allow `*` as type lambda placeholder to be compatible with
                  kind projector. When invoked as -Xkind-projector:underscores
                  will repurpose `_` to be a type parameter placeholder, this
                  will disable usage of underscore as a wildcard.
                  Default disable
                  Choices: disable, , underscores

In the REPL, pass the same flag through :settings:

scala> :settings -Wunused:help
-Wunused  Enable or disable specific `unused` warnings
          Choices:
          - nowarn,
          - all,
          - imports :
                Warn if an import selector is not referenced.,
          - privates :
                Warn if a private member is unused,
          - locals :
                Warn if a local definition is unused,
          - explicits :
                Warn if an explicit parameter is unused,
          - implicits :
                Warn if an implicit parameter is unused,
          - params :
                Enable -Wunused:explicits,implicits,
          - patvars :
                Warn if a variable bound in a pattern is unused,
          - linted :
                Enable -Wunused:imports,privates,locals,implicits

Upgrade to Scala CLI 1.14.0

The bundled Scala CLI has been upgraded from 1.11.x through 1.12.5, 1.13.0, to 1.14.0. Notable additions across these versions include:

• v1.12.5: experimental --cross support for run, package, and doc; global --offline config key; experimental local .m2 in publish local
• v1.13.0: Scala.js 1.21.0 support; Ammonite REPL deprecated and scheduled for removal; java-test-runner for pure Java tests; GraalVM native-image packaging via packaging.graalvmJvmId and packaging.graalvmArgs
• v1.14.0: support for .test.java files; a toggle to turn auto-IDE-setup off

See the Scala CLI release notes for full details.

For the complete list of changes and contributor credits, see the release notes on GitHub.