//> using scala 3.7.3 package example import scala.deriving.Mirror class MyTypeClass[T](value: T) { def map[S](f: T => S): MyTypeClass[S] = new MyTypeClass[S](f(value)) def flatMap[S](f: T => MyTypeClass[S]): MyTypeClass[S] = f(value) } object MyTypeClass { given MyTypeClass[EmptyTuple] = new MyTypeClass[EmptyTuple](EmptyTuple) given [H, T <: Tuple](using H: => MyTypeClass[H], T: => MyTypeClass[T]): MyTypeClass[H *: T] = for { h <- H t <- T } yield h *: t given [P <: Product, A]( using m: Mirror.ProductOf[P], i: A =:= m.MirroredElemTypes, w: MyTypeClass[A] ): MyTypeClass[P] = w.map(a => m.fromProduct(i(a))) given MyTypeClass[Int] = MyTypeClass(3) } case class A( x: Int, y: C ) sealed trait C object C { case object C1 extends C } object Main { def main(args: Array[String]): Unit = { println(summon[MyTypeClass[A]]) } }

 val x$proxy1: example.MyTypeClass[example.A] = { final class $_lazy_implicit_$2() extends Object(), Serializable { val $_lazy_implicit_$1: example.MyTypeClass[example.C *: EmptyTuple.type] = example.MyTypeClass.given_MyTypeClass_P[ example.C *: EmptyTuple.type, example.C *: EmptyTuple.type ]( new scala.runtime.TupleMirror(1).$asInstanceOf[ scala.deriving.Mirror.Product{ type MirroredMonoType = example.C *: EmptyTuple.type ; type MirroredType = example.C *: EmptyTuple.type; type MirroredLabel = ("Tuple1" : String); type MirroredElemTypes = example.C *: EmptyTuple.type; type MirroredElemLabels = ("_1" : String) *: EmptyTuple.type } ], <:<.refl[example.C *: EmptyTuple.type], this.$_lazy_implicit_$1) } val $_lazy_implicit_$3: $_lazy_implicit_$2 = new $_lazy_implicit_$2() example.MyTypeClass.given_MyTypeClass_P[example.A, (Int, example.C)]( example.A.$asInstanceOf[ scala.deriving.Mirror.Product{ type MirroredMonoType = example.A; type MirroredType = example.A; type MirroredLabel = ("A" : String); type MirroredElemTypes = (Int, example.C); type MirroredElemLabels = (("x" : String), ("y" : String)) } ], <:<.refl[(Int, example.C)], example.MyTypeClass.given_MyTypeClass_*:[Int, example.C *: EmptyTuple.type]( example.MyTypeClass.given_MyTypeClass_Int, $_lazy_implicit_$3.$_lazy_implicit_$1) ) } x$proxy1