import scalaz._
import Scalaz._

import scala.concurrent._, duration._

import scala.concurrent.ExecutionContext.Implicits.global

object FooBar {

  def main(args: Array[String]): Unit = {

    def webServiceCall: Future[String / String] = Future(/-("Some data"))

    def foo : String / String = /-("foo")

    def getData(): EitherT[Future, String, String] = EitherT(webServiceCall)

    def auth() = for {
      e1 <- getData()
      e2 <- EitherT.fromDisjunction(foo)
    } yield e1

    println(Await.result(auth.run, 5.second))
  }

}

diverging implicit expansion for type scalaz.Monoid[A]
[error] starting with value bigIntegerMultiplication in trait BigIntegerInstances
[error]       e2 <- EitherT.fromDisjunction(foo)
[error]                                    ^
[error] one error found
[error] (Compile / compileIncremental) Compilation failed