Fix #941 by adding an ability to derive codecs for Scala 3 enum value…

…s with mixed traits
plokhotnyuk · Sep 9, 2022 · 9d254c6 · 9d254c6
1 parent f66afd9
commit 9d254c6
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diff --git a/...shared/src/main/scala-3/com/github/plokhotnyuk/jsoniter_scala/macros/JsonCodecMaker.scala b/...shared/src/main/scala-3/com/github/plokhotnyuk/jsoniter_scala/macros/JsonCodecMaker.scala
@@ -608,8 +608,9 @@ object JsonCodecMaker {
         case ConstantType(_) => true
         case _ => false
 
-      def isEnumOrModuleValue(tpe: TypeRepr): Boolean =
-        tpe.isSingleton && (tpe.typeSymbol.flags.is(Flags.Enum) || tpe.typeSymbol.flags.is(Flags.Module))
+      def isEnumOrModuleValue(tpe: TypeRepr): Boolean = tpe.isSingleton &&
+        (tpe.typeSymbol.flags.is(Flags.Enum) || tpe.typeSymbol.flags.is(Flags.Module) ||
+          tpe.typeSymbol.flags.is(Flags.EmptyFlags) && !isConstType(tpe)) // FIXME: Remove after fix in Dotty: https://github.com/lampepfl/dotty/issues/16008
 
       def getEnclosingClass(sym: Symbol): Symbol =
         if (sym.isClassDef) sym

diff --git a/.../test/scala-3/com/github/plokhotnyuk/jsoniter_scala/macros/JsonCodeMakerNewEnumSpec.scala b/.../test/scala-3/com/github/plokhotnyuk/jsoniter_scala/macros/JsonCodeMakerNewEnumSpec.scala
@@ -61,6 +61,15 @@ enum FooEnum[A[_]]:
   case Bar[A[_]](a: A[Int]) extends FooEnum[A]
   case Baz[A[_]](a: A[String]) extends FooEnum[A]
 
+trait MyMarker
+
+enum MyEnum(val value: String):
+  case Marked extends MyEnum("item1") with MyMarker
+  case Simple extends MyEnum("item2")
+
+object MyEnum:
+  implicit val codec: JsonValueCodec[MyEnum] = JsonCodecMaker.make // FIXME: Remove after fix in Dotty: https://github.com/lampepfl/dotty/issues/16008
+
 class JsonCodecMakerNewEnumSpec extends VerifyingSpec {
   "JsonCodecMaker.make generate codecs which" should {
     "serialize and deserialize Scala3 enums" in {