Merge pull request #398 from buildo/scalac-options-scala3

Add Scala 3 support for sbt-buildo

Author: gabro

sbt-buildo/src/main/scala/buildo/ScalaSettingPlugin.scala

@@ -14,39 +14,56 @@ object ScalaSettingPlugin extends AutoPlugin {
     organization := "io.buildo",
   )
 
-  def crossFlags(scalaVersion: String): Seq[String] =
+  val baseScalaOptions = Seq(
+    "-encoding",
+    "utf8",
+    "-feature",
+    "-deprecation",
+    "-language:higherKinds",
+    "-language:implicitConversions",
+  )
+
+  val baseScala2Options = baseScalaOptions ++ Seq(
+    "-unchecked",
+    "-Xlint",
+    "-Ywarn-dead-code",
+    "-Ywarn-numeric-widen",
+    "-Ywarn-value-discard",
+    "-Ywarn-unused",
+    "-Yrangepos",
+  )
+
+  val baseScala3Options = baseScalaOptions ++ Seq(
+    "-Ykind-projector",
+  )
+
+  def crossScalacOptions(scalaVersion: String): Seq[String] =
     CrossVersion.partialVersion(scalaVersion) match {
       case Some((2, 12)) =>
-        Seq("-opt-warnings", "-Ypartial-unification", "-Xfuture", "-Ywarn-unused-import")
-      case Some((2, 13)) => Seq("-Ymacro-annotations", "-Ywarn-unused:imports")
+        baseScala2Options ++
+          Seq("-opt-warnings", "-Ypartial-unification", "-Xfuture", "-Ywarn-unused-import")
+      case Some((2, 13)) => baseScala2Options ++ Seq("-Ymacro-annotations", "-Ywarn-unused:imports")
+      case Some((3, _))  => baseScala3Options
       case _             => Nil
     }
 
   lazy val baseSettings: Seq[Def.Setting[_]] = Seq(
     cancelable in Global := true,
-    scalacOptions ++= Seq(
-      "-encoding",
-      "utf8",
-      "-deprecation",
-      "-feature",
-      "-unchecked",
-      "-Xlint",
-      "-language:higherKinds",
-      "-language:implicitConversions",
-      "-Ywarn-dead-code",
-      "-Ywarn-numeric-widen",
-      "-Ywarn-value-discard",
-      "-Ywarn-unused",
-      "-Yrangepos",
-    ) ++ crossFlags(scalaVersion.value),
+    scalacOptions ++= crossScalacOptions(scalaVersion.value),
     resolvers += Resolver.jcenterRepo,
     libraryDependencies ++= {
       CrossVersion.partialVersion(scalaVersion.value) match {
-        case Some((2, n)) if n >= 13 => Nil
-        case _ =>
+        case Some((2, n)) if n < 13 =>
           compilerPlugin(("org.scalamacros" % "paradise" % "2.1.1").cross(CrossVersion.full)) :: Nil
+        case _ => Nil
+      }
+    },
+    libraryDependencies ++= {
+      CrossVersion.partialVersion(scalaVersion.value) match {
+        case Some((2, _)) =>
+          compilerPlugin(("org.typelevel" % "kind-projector" % "0.11.3").cross(CrossVersion.full)) :: Nil
+        case _ => Nil
       }
     },
-    addCompilerPlugin(("org.typelevel" % "kind-projector" % "0.11.3").cross(CrossVersion.full)),
   )
 }