playframework/Play20 — pull request #154 by julienrf (2012-03-02 21:12:38+00:00)
Title: Provides a json.Writes[T] for any T <: JsValue (Lighthouse #181 issue)

See the related [issue](https://play.lighthouseapp.com/projects/82401-play-20/tickets/181-add-json-writesjsarray)

Another way to solve the problem would have been to make `Writes[T]` covariant on `T` but I think that’s a bad idea (users may by mistake serialize a specific type using some super type’s serializer).