Scala、cats、http4s - 无法识别来自 Http4s 的 <+> 符号

Question

我创建了两个 Http4s路线:

class FirstRoutes[F[_] : Async](service: FirstService[F]) extends Http4sDsl[F] {        
  def routes: HttpRoutes[F] = HttpRoutes.of[F] {
        //... some code
  }
}   

class SecondRoutes[F[_] : Async] extends Http4sDsl[F] {            
    def routes: HttpRoutes[F] = HttpRoutes.of[F] {
    //... some code
    }
}

现在在我的 main方法我想这样称呼这条路线:

override def run(args: List[String]): IO[ExitCode] =
    for {
      _ <- {
        val app = {
          //...
          val firstRoutes = new FirstRoutes[F](someService)
          val secondRoutes = new SecondRoutes[F]
          (firstRoutes.routes <+> secondRoutes.routes).orNotFound
        }

但是当我编译这段代码时，我得到了一个错误:

Error:(26, 33) value <+> is not a member of org.http4s.HttpRoutes[Server.F]
          (firstRoutes.routes <+> secondRoutes.routes).orNotFound

对我来说很奇怪，因为我可以正常使用这个 <+>当我在路由类上使用 ctrl+space 并且我有很好的导入时的符号:

import cats.effect._
import cats.data._
import org.http4s.server.blaze.BlazeServerBuilder
import cats.effect._
import cats.implicits._

无法找到如何解决此问题并使用 <+>调用路由类。也许这是intellij问题？有人能帮我吗？

Answer 1

为 build.sbt 添加此 scala 选项

scalacOptions += "-Ypartial-unification"