updates:
Ordering thing has been resolved by https://github.com/scala/scala/pull/8721
Things are moving along.
Does that mean the warning on Seq.fill(4)(math.random()).sorted will go away? That would be great!
Yes:
Welcome to Scala 2.13.2-20200221-161119-b6850a0 (OpenJDK 64-Bit Server VM, Java 1.8.0_242).
Type in expressions for evaluation. Or try :help.
scala> Seq.fill(4)(math.random()).sorted
val res0: Seq[Double] = List(0.5648754081376393, 0.5713598328482244, 0.7388626006594553, 0.8350097176800951)
scala> :replay -Xmigration
replay> Seq.fill(4)(math.random()).sorted
^
warning: object DeprecatedDoubleOrdering in object Ordering has changed semantics in version 2.13.0:
The default implicit ordering for doubles now maintains consistency
between its `compare` method and its `lt`, `min`, `equiv`, etc., methods,
which means nonconforming to IEEE 754's behavior for -0.0 and NaN.
The sort order of doubles remains the same, however, with NaN at the end.
Import Ordering.Double.IeeeOrdering to recover the previous behavior.
See also https://www.scala-lang.org/api/current/scala/math/Ordering$$Double$.html.
val res0: Seq[Double] = List(0.023228215388040097, 0.061945732108565355, 0.41556056320286316, 0.8010680874673899)
In Scala 2.13.2 that plan is for the REPL to switch to “class-based wrappers” which resolves a source of deadlocks in the REPL (aka scala/bug#9076).
In Scala 2.12.11 this will only be true if you opt-in to -Yrepl-class-based.
For more details see my and @retronym’s PR description: https://github.com/scala/scala/pull/8712.
The PR queue and bug list for Scala 2.12.11 are down to zero, which means that the current build, 2.12.11-bin-f139b612.12.11-bin-cd8410d), is our release candidate.
To test the candidate in your project, add a resolver for scala-integration and update the scala version, in sbt:
resolvers += "scala-integration" at "https://scala-ci.typesafe.com/artifactory/scala-integration/"
scalaVersion := "2.12.11-bin-cd8410d"
2.12.11 will ship with improvements to -Yrepl-class-based, a flag that changes the encoding in the REPL, and -Yrepl-use-magic-imports, a lightweight encoding for import priorities. Bot of these flags will be enabled by default in the upcoming 2.13.2 release, therefore testing the REPL is especially appreciated.
An easy way to run the REPL is by using courser:
$> java -cp $(cs fetch -p -r https://scala-ci.typesafe.com/artifactory/scala-integration org.scala-lang:scala-compiler:2.12.11-bin-cd8410d) scala.tools.nsc.MainGenericRunner -usejavacp -Yrepl-class-based -Yrepl-use-magic-imports
Welcome to Scala 2.12.11-bin-cd8410d (Java HotSpot(TM) 64-Bit GraalVM EE 19.2.1, Java 1.8.0_231).
Type in expressions for evaluation. Or try :help.
scala> for (i <- (1 to 10).par) yield i // no deadlock, https://github.com/scala/bug/issues/9076
res0: scala.collection.parallel.immutable.ParSeq[Int] = ParVector(1, 2, 3, 4, 5, 6, 7, 8, 9, 10)
scala> class Meter(val x: Int) extends AnyVal { override def toString = s"${x}m" }
defined class Meter
scala> new Meter(42)
res1: Meter = 42m
Other than the REPL changes, 2.12.11 ships bug fixes and performance improvements in the compiler and the collections library.
(Added some improvements to my scala-runners wrappers so now you can run that with just
scala --scala-version 2.12.11-bin-cd8410d -Yrepl-class-based -Yrepl-use-magic-imports
brew install --HEAD dwijnand/formulas/scala-runners! 
)
Could you please update https://raw.githubusercontent.com/scala/community-builds/2.12.x/nightly.properties so that it points to that release candidate, then?
This will allow https://github.com/scala-js/scala-js-test-scala-nightly to automatically test Scala.js, as well as derivatives of that script (e.g., Shapeless uses that too: https://github.com/milessabin/shapeless-test-scala-nightly).
I didn’t realize other projects are using this reference 
It’s lagging because the community build for f139b61 is shaking out a few more issues
So there will be another “RC”, hopefully soon.
The two collections regressions (https://github.com/scala/scala-dev/issues/672, https://github.com/scala/scala-dev/issues/673) are now fixed.
The community build is again green, so https://raw.githubusercontent.com/scala/community-builds/2.12.x/nightly.properties now points to the new “RC”, which is 2.12.11-bin-d1e9ac0.
Latest 2.12.11 milestone is 2.12.11-bin-e1e2bfe. It includes one more collection fix (quite minor, only affecting serialization compatibility).
At present the only open 2.12.11 ticket is https://github.com/scala/scala-dev/issues/675 , but it looks like we’ll just close that one and release-note it.
some 2.13.2 updates:
No further 2.12.11 problems have turned up, but we’re waiting a bit longer while some users test it for possible performance regressions. Rough first-draft release notes: https://gist.github.com/SethTisue/5754a63fa0e3561349367ba6f0224f40
In the end, no performance problems turned up.
We merged one final PR with a tiny, safe change that avoids some annoying warnings in the REPL.
https://raw.githubusercontent.com/scala/community-builds/2.12.x/nightly.properties now points to 2.12.11-bin-cd8410d .
We’ll go ahead and re-release that version as 2.12.11 soon — we’re a bit busy with the SIP retreat in Lausanne, so maybe this week, maybe first thing next week.
Scala 2.12.11 is now on maven central. The official announcement will follow soon, but the release notes are already on https://github.com/scala/scala/releases/tag/v2.12.11 (feedback welcome).
Support for 2.12.11 for Scala.js 0.6.32, 1.0.0 and 1.0.1 is on its way to Maven Central.
Macro Paradise 2.1.1 is also available, I hope I did everything right when publishing that release.
https://repo1.maven.org/maven2/org/scalamacros/paradise_2.12.11/
2.12.11: The official announcement went out. No reports of regressions have come in.
2.13.2:
The new-Vector PR (https://github.com/scala/scala/pull/8534) and the configurable-warnings PR (https://github.com/scala/scala/pull/8373) have both landed. As of a few moments ago, https://raw.githubusercontent.com/scala/community-builds/2.13.x/nightly.properties points to 2.13.2-bin-b4428c8.
The replacement of Vector is a big change, so that’s one that we hope the community will give some additional testing (of both correctness and performance) before release.
The new Vector did not manage to break Scala.js 