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ZLayer.wire macro fails on compile time

See original GitHub issue

I found an interesting case and extracted it from real project:

object Example {
  import zio._
  import zio.magic._

  type A = Has[A.Service]
  object A {
    trait Service {}
    val live: ULayer[A] = ZLayer.succeed(new Service {})

  type B = Has[B.Service]
  object B {
    trait Service {}
    val live: ULayer[B] =
      ZLayer.succeed(new Service {})

  type C = Has[C.Service]
  object C {
    trait Service {}
    val live: URLayer[A with B, C] =
      ZLayer.succeed(new Service {})

  // Success
  val layer1: ULayer[A with B] = >+> >+>

  // Failure
  val layer2: ULayer[A with B] = ZLayer.wire[A with B](,,

type mismatch;
 found   : zio.ZLayer[Example.A with Example.B with Any with Any,Nothing,Example.C with Example.A with Example.B]
    (which expands to)  zio.ZLayer[zio.Has[Example.A.Service] with zio.Has[Example.B.Service] with Any with Any,Nothing,zio.Has[Example.C.Service] with zio.Has[Example.A.Service] with zio.Has[Example.B.Service]]
 required: zio.ZLayer[Any,Nothing,zio.Has[Example.A.Service] with zio.Has[Example.B.Service]]
  val layer2: ULayer[A with B] = ZLayer.wire[A with B](,,

Issue Analytics

  • State:closed
  • Created 2 years ago
  • Reactions:2
  • Comments:7 (4 by maintainers)

github_iconTop GitHub Comments

vladimirklcommented, Apr 13, 2021

Also works for me, thank you!

hmemcpycommented, Apr 13, 2021

I confirm the latest fix is MAGICAL! It solves my issue (which is very similar to @vladimirkl’s). So thank you 😃)

BTW, this should be fixed for ZIO 2.0, right? image (the package string, it should be

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