https://github.com/TinkoffCreditSystems/tofu/blob/dfd548636296d0bfb243698140daf9920ecbf1c2/core/src/main/scala/tofu/control/Selective.scala#L42

есть такое определение

Selective[Writer[Chain[Int], *]]

выдаёт

ambiguous implicit values:
[error]  both method selectiveWriterT in trait SelectiveInstances2 of type [F[_], W](implicit evidence$5: tofu.control.Selective[F], implicit evidence$6: cats.Monoid[W])tofu.control.Select
ive[[γ$3$]cats.data.WriterT[F,W,γ$3$]]
[error]  and method selectiveOverMonad in trait SelectiveInstances of type [F[_]](implicit evidence$1: cats.Monad[F])tofu.control.Selective[F]
[error]  match expected type tofu.control.Selective[[β$0$]cats.data.WriterT[[A]A,cats.data.Chain[Int],β$0$]]