Update scala 3 macro to support a hierarchy of sealed traits

lloydmeta · Jul 19, 2023 · 9792830 · 9792830
1 parent 74a7b36
commit 9792830
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Showing 2 changed files with 32 additions and 2 deletions.
diff --git a/enumeratum-core/src/test/scala/enumeratum/values/ValueEnumSpec.scala b/enumeratum-core/src/test/scala/enumeratum/values/ValueEnumSpec.scala
@@ -135,6 +135,22 @@ class ValueEnumSpec extends AnyFunSpec with Matchers with ValueEnumHelpers {
        """ should (compile)
       }
 
+      it("should compile when there is a hierarchy of sealed traits") {
+        """
+        sealed abstract class Top(val value: Int) extends IntEnumEntry
+        sealed trait Middle extends Top
+
+        case object Top extends IntEnum[Top] {
+          case object One extends Top(1)
+          case object Two extends Top(2)
+          case object Three extends Top(3) with Middle
+          case object Four extends Top(4) with Middle
+
+          val values = findValues
+        }
+        """ should compile
+      }
+
       it("should fail to compile when there are non literal values") {
         """
         sealed abstract class ContentTypeRepeated(val value: Long, name: String) extends LongEnumEntry

diff --git a/macros/src/main/scala-3/enumeratum/ValueEnumMacros.scala b/macros/src/main/scala-3/enumeratum/ValueEnumMacros.scala
@@ -109,7 +109,8 @@ object ValueEnumMacros {
       tpe: Type[A],
       valueTpe: Type[ValueType]
   )(using cls: ClassTag[ValueType]): Expr[IndexedSeq[A]] = {
-    type TakeHead[Head <: A & Singleton, Tail <: Tuple] = Head *: Tail
+    type SingletonHead[Head <: A & Singleton, Tail <: Tuple] = Head *: Tail
+    type OtherHead[Head <: A, Tail <: Tuple]                 = Head *: Tail
 
     type SumOf[X <: A, T <: Tuple] = Mirror.SumOf[X] {
       type MirroredElemTypes = T
@@ -186,7 +187,7 @@ In SBT settings:
         values: Map[TypeRepr, ValueType]
     )(using tupleTpe: Type[T]): Either[String, Expr[List[A]]] =
       tupleTpe match {
-        case '[TakeHead[h, tail]] => {
+        case '[SingletonHead[h, tail]] => {
           val htpr = TypeRepr.of[h]
 
           (for {
@@ -224,6 +225,19 @@ In SBT settings:
           }
         }
 
+        case '[OtherHead[h, tail]] =>
+          Expr.summon[Mirror.SumOf[h]] match {
+            case Some(sum) =>
+              sum.asTerm.tpe.asType match {
+                case '[SumOf[a, t]] => collect[Tuple.Concat[t, tail]](instances, values)
+
+                case _ => Left(s"Invalid `Mirror.SumOf[${TypeRepr.of[h].show}]")
+              }
+
+            case None =>
+              Left(s"Missing `Mirror.SumOf[${TypeRepr.of[h].show}]`")
+          }
+
         case '[EmptyTuple] => {
           val allowAlias = repr <:< TypeRepr.of[AllowAlias]