Review

.github/workflows/build-test.yml

@@ -81,7 +81,7 @@ jobs:
     strategy:
       matrix:
         jdk: [ 11, 8 ]
-        scala: [ 2.12.15, 2.13.8, 3.1.2-RC1-bin-20211222-c94b333-NIGHTLY ] # Should be sync with Mergify conditions (.mergify.yml)
+        scala: [ 2.12.15, 2.13.8, 3.1.2-RC2 ] # Should be sync with Mergify conditions (.mergify.yml)
     name: Check / Tests (Scala ${{ matrix.scala }} & JDK ${{ matrix.jdk }})
     steps:
       - name: Checkout

build.sbt

@@ -10,8 +10,6 @@ import com.typesafe.tools.mima.core._
 import sbtcrossproject.CrossPlugin.autoImport.crossProject
 import sbtcrossproject.CrossType
 
-ThisBuild / scalafmtOnCompile := true
-
 resolvers ++= DefaultOptions.resolvers(snapshot = true)
 
 val isScala3 = Def.setting {

docs/manual/working/scalaGuide/main/json/ScalaJsonAutomated.md

@@ -55,7 +55,7 @@ The macros work for classes and traits meeting the following requirements.
 - The return types of the `unapply` must match the argument types of the `apply` method.
 - The parameter names of the `apply` method must be the same as the property names desired in the JSON.
 
-**Class in Scala 3.x:**
+**Class in Scala 3.1.x:** (+3.1.2-RC2)
 
 - It must be provided a [`Conversion`](https://dotty.epfl.ch/api/scala/Conversion.html) to a `_ <: Product`.
 - It must be provided a valid [`ProductOf`](https://dotty.epfl.ch/api/scala/deriving/Mirror$.html#ProductOf-0).

play-json/shared/src/main/scala-3/play/api/libs/json/MacroHelpers.scala

@@ -22,7 +22,12 @@ private[json] trait MacroHelpers { self: OptionSupport =>
 
     def unapply(tpr: TypeRepr): Option[TypeRepr] = {
       if (self.isOptionalType(tpr)) {
-        tpr.typeArgs.headOption
+        // TODO: tpr.typeArgs.headOption
+
+        tpr match {
+          case AppliedType(_, args) => args.headOption
+          case _ => None
+        }
       } else None
     }
   }

play-json/shared/src/test/scala-2/play/api/libs/json/MacroScala2Spec.scala

@@ -7,8 +7,6 @@ package play.api.libs.json
 import org.scalatest.matchers.must.Matchers
 import org.scalatest.wordspec.AnyWordSpec
 
-import org.scalacheck.Gen
-
 class MacroScala2Spec extends AnyWordSpec with Matchers with org.scalatestplus.scalacheck.ScalaCheckPropertyChecks {
   import MacroScala2Spec._
 

project/Dependencies.scala

@@ -4,5 +4,5 @@ object Dependencies {
   //   - Mergify conditions (.mergify.yml)
   val Scala212 = "2.12.15"
   val Scala213 = "2.13.8"
-  val Scala3   = "3.1.2-RC1-bin-20211222-c94b333-NIGHTLY"
+  val Scala3   = "3.1.2-RC2"
 }