This is the new flag in Scala 3.1.2-RC1 that enables targeting Scala 3.0 from the Scala 3.1 compiler. One of the exciting things about sbt-typelevel is that we can remotely roll out this feature to several projects :)

I've been thinking about this, and I propose we add a tlScala3Release setting to the typelevel-settings plugin that defaults to 3.0.

@smarter some projects such as fs2 are already being published against Scala 3.1. Is it okay to target them to Scala 3.0 going forward? Otherwise those projects will have to overwrite this setting.

It also seems there's some fiddling required with POM files. @smarter could you clarify what exactly this is? Thanks!

Seems related to:

dependencyOverrides ++= Seq(
  scalaOrganization.value %% "scala3-library" % scalaVersion.value,
  scalaOrganization.value %% "scala3-library_sjs1" % scalaVersion.value // for Scala.js projects
)

https://docs.scala-lang.org/scala3/reference/language-versions/binary-compatibility.html