gistfile1.scala

// Where the hell does B come from? Looks like a type variable is escaping.

scala> Left(1).disjunction
res14: scalaz.\/[Int,B] = -\/(1)

// It's not Nothing

scala> Left(1).disjunction : (Int \/ Nothing)
<console>:17: error: type mismatch;
 found   : scalaz.\/[Int,B]
 required: scalaz.\/[Int,Nothing]
              Left(1).disjunction : (Int \/ Nothing)
                      ^

// If we get the syntax explicitly it infers Nothing, as expected

scala> ToEitherOpsFromEither(Left(1)).disjunction
res0: scalaz.\/[Int,Nothing] = -\/(1)

// Also, um

scala> reflect.runtime.universe.reify { Left(1).disjunction }
<console>:17: error: macro has not been expanded
              reflect.runtime.universe.reify { Left(1).disjunction }