Add isSingletonCasesEnum flag

build.sbt

@@ -2,7 +2,7 @@ import com.softwaremill.UpdateVersionInDocs
 import com.softwaremill.SbtSoftwareMillCommon.commonSmlBuildSettings
 import com.softwaremill.Publish.{updateDocs, ossPublishSettings}
 
-val scala3 = "3.2.1"
+val scala3 = "3.2.2"
 
 ThisBuild / dynverTagPrefix := "scala3-v" // a custom prefix is needed to differentiate tags between scala2 & scala3 versions
 

project/build.properties

@@ -1 +1 @@
-sbt.version=1.8.0
+sbt.version=1.8.2

project/plugins.sbt

@@ -8,6 +8,6 @@ addSbtPlugin(
   "com.softwaremill.sbt-softwaremill" % "sbt-softwaremill-publish" % sbtSoftwareMillVersion
 )
 
-addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.12.0")
-addSbtPlugin("org.scala-native" % "sbt-scala-native" % "0.4.9")
+addSbtPlugin("org.scala-js" % "sbt-scalajs" % "1.13.0")
+addSbtPlugin("org.scala-native" % "sbt-scala-native" % "0.4.10")
 addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "1.1.1")

src/core/impl.scala

@@ -167,6 +167,7 @@ trait SealedTraitDerivation:
       IArray.from(anns[A]),
       IArray(paramTypeAnns[A]*),
       isEnum[A],
+      isSingletonCasesEnum[A],
       IArray.from(inheritedAnns[A])
     )
 

src/core/interface.scala

@@ -144,6 +144,7 @@ case class SealedTrait[Typeclass[_], Type](
     annotations: IArray[Any],
     typeAnnotations: IArray[Any],
     isEnum: Boolean,
+    isSingletonCasesEnum: Boolean,
     inheritedAnnotations: IArray[Any]
 ) extends Serializable:
 

src/core/macro.scala

@@ -14,6 +14,9 @@ object Macro:
 
   inline def isEnum[T]: Boolean =
     ${ isEnum[T] }
+
+  inline def isSingletonCasesEnum[T]: Boolean =
+    ${ isSingletonCasesEnum[T] }
 
   inline def anns[T]: List[Any] =
     ${ anns[T] }
@@ -57,6 +60,12 @@ object Macro:
     import quotes.reflect.*
 
     Expr(TypeRepr.of[T].typeSymbol.flags.is(Flags.Enum))
+
+  def isSingletonCasesEnum[T: Type](using Quotes): Expr[Boolean] =
+    import quotes.reflect.*
+
+    val ts = TypeRepr.of[T].typeSymbol
+    Expr(ts.flags.is(Flags.Enum) && ts.companionClass.methodMember("values").nonEmpty)
 
   def paramTypeAnns[T: Type](using
       q: Quotes

src/examples/SubtypeInfo.scala

@@ -7,6 +7,7 @@ trait SubtypeInfo[T] {
   def traitAnnotations: Seq[Any]
   def subtypeAnnotations: Seq[Seq[Any]]
   def isEnum: Boolean
+  def isSingletonCasesEnum: Boolean
 }
 
 object SubtypeInfo extends Derivation[SubtypeInfo]:
@@ -16,6 +17,7 @@ object SubtypeInfo extends Derivation[SubtypeInfo]:
       def traitAnnotations: List[Any] = Nil
       def subtypeAnnotations: List[List[Any]] = Nil
       def isEnum: Boolean = false
+      def isSingletonCasesEnum: Boolean = false
 
   override def split[T](ctx: SealedTrait[SubtypeInfo, T]): SubtypeInfo[T] =
     new SubtypeInfo[T]:
@@ -24,10 +26,12 @@ object SubtypeInfo extends Derivation[SubtypeInfo]:
       def subtypeAnnotations: Seq[Seq[Any]] =
         ctx.subtypes.map(_.annotations.toList).toList
       def isEnum: Boolean = ctx.isEnum
+      def isSingletonCasesEnum: Boolean = ctx.isSingletonCasesEnum
 
   given fallback[T]: SubtypeInfo[T] =
     new SubtypeInfo[T]:
       def subtypeIsObject: Seq[Boolean] = Nil
       def traitAnnotations: Seq[Any] = Nil
       def subtypeAnnotations: Seq[Seq[Any]] = Nil
       def isEnum: Boolean = false
+      def isSingletonCasesEnum: Boolean = false

src/test/SumsTests.scala

@@ -50,6 +50,17 @@ class SumsTests extends munit.FunSuite:
     assertEquals(derivedSubtypeInfo.isEnum, false)
   }
 
+  test("isSingletonCasesEnum field in SubtypeInfo should be true for singleton cases only enum") {
+    assertEquals(SubtypeInfo.derived[Size].isSingletonCasesEnum, true)
+    assertEquals(SubtypeInfo.derived[Planet].isSingletonCasesEnum, true)
+    assertEquals(SubtypeInfo.derived[ExtendingTraits].isSingletonCasesEnum, true)
+  }
+
+  test("isSingletonCasesEnum field in SubtypeInfo should be false for enum with non-singleton cases") {
+    assertEquals(SubtypeInfo.derived[Sport].isSingletonCasesEnum, false)
+    assertEquals(SubtypeInfo.derived[OptInt].isSingletonCasesEnum, false)
+  }
+
   test("construct a Show instance for an enum") {
     val res = Show.derived[Size].show(Size.S)
     assertEquals(res, "S()")
@@ -178,7 +189,15 @@ object SumsTests:
 
   enum Size:
     case S, M, L
-
+
+  enum Planet(mass: Double, radius: Double):
+    case Earth extends Planet(5.976e+24, 6.37814e6)
+    case Mars extends Planet(6.421e+23, 3.3972e6)
+
+  enum OptInt:
+    case Some(x: Int)
+    case None
+
   sealed trait Sport
   case object Boxing extends Sport
   case class Soccer(players: Int) extends Sport