circe + refined

test.scala

import $ivy.`io.circe::circe-generic:0.8.0`
import $ivy.`io.circe::circe-parser:0.8.0`
import $ivy.`io.circe::circe-refined:0.8.0`
import $ivy.`org.scalaz::scalaz-core:7.2.16`

import eu.timepit.refined._
import eu.timepit.refined.api.Refined
import eu.timepit.refined.auto._
import eu.timepit.refined.boolean._
import eu.timepit.refined.collection._
import eu.timepit.refined.generic._

import io.circe._
import io.circe.generic.auto._
import io.circe.parser._
import io.circe.refined._
import io.circe.syntax._

import scalaz._
import Scalaz._

object Test {
  type ShortStringSpec = NonEmpty And MaxSize[W.`10`.T]
  type ShortString = String Refined ShortStringSpec
}

implicit def toScalazEither[T](e: Either[Error, T]): Error \/ T = e.disjunction

import Test._

case class Doc(i: Int, s: ShortString)

val str: ShortString = "lala"
val d = Doc(42, str)

val t = d.asJson.noSpaces

val good: Error \/ Doc = decode[Doc](t)

val bad: Error \/ Doc = decode[Doc]("""{"i":21,"s":"abcdefghijk"}""")