scala - How to resolve this ambiguity while mapping my Either type? -


suppose i've got 2 types intresult , stringresult:

import cats._ import cats.data._ import cats.implicits._  scala> case class myerror(msg: string) defined class myerror  scala> type result[a] = either[nonemptylist[myerror], a] defined type alias result  scala> type stringresult = result[string] defined type alias stringresult  scala> type intresult = result[int] defined type alias intresult

now convert intresult stringresult using map:

scala> val good1: intresult = 10.asright good1: intresult = right(10)  scala> good1 map (_.tostring) <console>:26: error: type mismatch; found   : good1.type (with underlying type intresult) required: ?{def map: ?} note implicit conversions not applicable because ambiguous: both method catssyntaxeither in trait eithersyntax of type [a, b](eab:either[a,b]) cats.syntax.eitherops[a,b] , method tofunctorops in trait tofunctorops of type [f[_], a](target: f[a])(implicit tc: cats.functor[f])cats.functor.ops[f,a] possible conversion functions good1.type ?{def map: ?}    good1 map (_.tostring)

how resolve ambiguity ?

the simple approach use projections, do:

good1.right.map(_.tostring)

it's not awesome, works. don't know way import functor not conflicting either enrichment (if need both).

of course, import cats.syntax.either._ won't functor.


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