Get Union types -- generalised

gistfile1.fs

let GetUnionTypes (t:Type) =
  seq { yield t
        if FSharpType.IsUnion t
        then yield! FSharpType.GetUnionCases t
                    // implementation detail leaks here -- nested type name
                    |> Seq.map (fun x -> Type.GetType ((string t) + "+" + x.Name))
                    // except when the case has no data, so there's no such class
                    |> Seq.filter (fun x -> x <> null) }