Fix issue 545 causing case class default values to fail to resolve in Scala 3.x

.mill-version

@@ -1,2 +1,2 @@
-0.11.2
+0.11.6
 

upickle/implicits/src-3/upickle/implicits/macros.scala

@@ -7,7 +7,8 @@ type IsInt[A <: Int] = A
 
 def getDefaultParamsImpl0[T](using Quotes, Type[T]): Map[String, Expr[AnyRef]] =
   import quotes.reflect._
-  val sym = TypeTree.of[T].symbol
+  val unwrapped = TypeRepr.of[T] match{case AppliedType(p, v) => p case t => t}
+  val sym = unwrapped.typeSymbol
 
   if (!sym.isClassDef) Map.empty
   else
@@ -23,14 +24,16 @@ def getDefaultParamsImpl0[T](using Quotes, Type[T]): Map[String, Expr[AnyRef]] =
 
     val body = comp.tree.asInstanceOf[ClassDef].body
 
-    val idents: List[Ref] =
+    val idents: List[Term] =
       for case deff @ DefDef(name, _, _, _) <- body
       if name.startsWith("$lessinit$greater$default")
-      yield Ref(deff.symbol)
+      yield TypeRepr.of[T] match{ // Fix copied from https://github.com/circe/circe/issues/2093
+        case AppliedType(p, v) => Ref(deff.symbol).appliedToTypes(TypeRepr.of[T].typeArgs)
+        case t => Ref(deff.symbol)
+      }
 
     names.zip(idents.map(_.asExpr).map(e => '{$e.asInstanceOf[AnyRef]})).toMap
 
-
 def extractKey[A](using Quotes)(sym: quotes.reflect.Symbol): Option[String] =
   import quotes.reflect._
   sym

upickle/test/src/upickle/MacroTests.scala

@@ -68,6 +68,16 @@ object SpecialChars{
   implicit def rw: RW[SpecialChars] = default.macroRW
 }
 
+object GenericIssue545{
+  case class Person(id: Int, name: String = "test")
+
+  implicit val personRw: upickle.default.ReadWriter[Person] = upickle.default.macroRW[Person]
+
+  case class ApiResult[T](data: Option[T] = None, @upickle.implicits.key("total_count") totalCount: Int)
+
+  implicit def apiResultRw[T: upickle.default.ReadWriter]: upickle.default.ReadWriter[ApiResult[T]] = upickle.default.macroRW[ApiResult[T]]
+}
+
 object MacroTests extends TestSuite {
 
   // Doesn't work :(
@@ -564,5 +574,17 @@ object MacroTests extends TestSuite {
       rw(SpecialChars.`-1`(), """{"$type": "upickle.SpecialChars.-1"}""")
       rw(SpecialChars.`-1`(1), """{"$type": "upickle.SpecialChars.-1", "-1": 1}""")
     }
+
+    test("genericIssue545"){
+      // Make sure case class default values are properly picked up for
+      // generic case classes in Scala 3
+      import upickle.implicits.key
+
+      upickle.default.read[GenericIssue545.Person]("{\"id\":1}") ==>
+        GenericIssue545.Person(1)
+
+      upickle.default.read[GenericIssue545.ApiResult[GenericIssue545.Person]]("{\"total_count\": 10}") ==>
+        GenericIssue545.ApiResult[GenericIssue545.Person](None, 10)
+    }
   }
 }