无法将类从一个模块导入到另一个模块 - Scala

Question

我创建了一个包含3个不同模块的项目。第一个被称为http和第二个algebra。我在sbt文件中将它们连接成一个，但是当我想在algebra中使用来自http的类时，我无法导入它们，因为它们没有看到对方。这是我的sbt文件：

lazy val commonSettings = Seq(
  libraryDependencies ++= Seq(
    "org.typelevel" %% "cats-core" % CatsVersion,
    "org.typelevel" %% "cats-effect" % "1.2.0",
    "org.typelevel" %% "cats-tagless-macros" % "0.2.0",
    "org.typelevel" %% "cats-mtl-core" % "0.5.0",
  )
)

lazy val root = project.in(file(".")).aggregate(http, domain, algebra)
  .settings(commonSettings)
  .settings(libraryDependencies ++= Seq(
    "org.tpolecat" %% "doobie-core" % DoobieVersion,
    "org.tpolecat" %% "doobie-h2" % DoobieVersion,
    "org.tpolecat" %% "doobie-scalatest" % DoobieVersion,
    "org.tpolecat" %% "doobie-hikari" % DoobieVersion,
  ))

lazy val http = (project in file("http"))
  .dependsOn(algebra)
  .settings(commonSettings)
  .settings(
    name := "my-http",
    libraryDependencies ++= Seq(
      "io.circe" %% "circe-generic" % CirceVersion,
      "io.circe" %% "circe-literal" % CirceVersion,
      "io.circe" %% "circe-generic-extras" % CirceVersion,
      "io.circe" %% "circe-parser" % CirceVersion,
      "io.circe" %% "circe-java8" % CirceVersion,
      "io.circe" %% "circe-config" % CirceConfigVersion,

      "org.http4s" %% "http4s-blaze-server" % Http4sVersion,
      "org.http4s" %% "http4s-circe" % Http4sVersion,
      "org.http4s" %% "http4s-dsl" % Http4sVersion,
    ))

lazy val domain = project.in(file("domain"))

lazy val algebra = (project in file("algebra"))
  .settings(commonSettings)
  .settings(
    name := "my-algebra",
  )

我试图刷新所有项目，但它没有用。

class MyRoutes[F[_]: Effect](services: MyService[F]) extends Http4sDsl[F]{...}

类MyRoutes在http模块中，MyService在代数模块中。错误是Cannot find declaration to go to上的MyService。我该如何解决？