gistfile1.txt

scala> val x = implicitly[Monoid[Promise]]
<console>:7: error: not found: type Monoid
       val x = implicitly[Monoid[Promise]]
                          ^
<console>:7: error: ambiguous implicit values:
 both method stringCanBuildFrom in object Predef of type => scala.collection.generic.CanBuildFrom[String,Char,String]
 and method conforms in object Predef of type [A]=> <:<[A,A]
 match expected type <error>
       val x = implicitly[Monoid[Promise]]
                         ^

scala> import scalaz._
import scalaz._

scala> import Scalaz._
import Scalaz._

scala> val x = implicitly[Monoid[Promise]]
<console>:13: error: not found: type Promise
       val x = implicitly[Monoid[Promise]]
                                 ^
<console>:13: error: ambiguous implicit values:
 both value unitInstance in trait AnyValInstances of type => scalaz.Group[Unit] with scalaz.Enum[Unit] with scalaz.Show[Unit]
 and value booleanDisjunctionNewTypeInstance in trait AnyValInstances of type => scalaz.Monoid[scalaz.package.@@[Boolean,scalaz.Tags.Disjunction]] with scalaz.Enum[scalaz.package.@@[Boolean,scalaz.Tags.Disjunction]]
 match expected type scalaz.Monoid[<error>]
       val x = implicitly[Monoid[Promise]]
                         ^

scala> 

scala> 

scala> import scalaz.concurrent._
import scalaz.concurrent._

scala> val x = implicitly[Monoid[Promise]]
<console>:16: error: trait Promise takes type parameters
       val x = implicitly[Monoid[Promise]]
                                 ^
<console>:16: error: ambiguous implicit values:
 both value unitInstance in trait AnyValInstances of type => scalaz.Group[Unit] with scalaz.Enum[Unit] with scalaz.Show[Unit]
 and value booleanDisjunctionNewTypeInstance in trait AnyValInstances of type => scalaz.Monoid[scalaz.package.@@[Boolean,scalaz.Tags.Disjunction]] with scalaz.Enum[scalaz.package.@@[Boolean,scalaz.Tags.Disjunction]]
 match expected type scalaz.Monoid[<error>]
       val x = implicitly[Monoid[Promise]]

scala> val x = implicitly[Monoid[Promise[Int]]]
<console>:16: error: could not find implicit value for parameter e: scalaz.Monoid[scalaz.concurrent.Promise[Int]]
       val x = implicitly[Monoid[Promise[Int]]]