error: recursive value needs type

I have a multi-project build where I have three projects defined: interface, client and service (root project):

lazy val interface = (project in file("interface"))
  .settings(...)

lazy val client = (project in file("client"))
  .dependsOn(interface, service % "test->test")
  .settings(...)

lazy val service = (project in file("."))
  .dependsOn(interface)
  .settings(...)

As you can see, client and service both depend on interface, and client test scope also depends on service test scope. This works fine. However, I would like service, as the root project, to also aggregate the client project – however, if I add this line to the service config:

.aggregate(client)

I get the following error in the client project definition:

/Users/kflorence/dev/mosaic/utility-service/build.sbt:42: error: recursive value service needs type
  .dependsOn(interface, service % "test->test")

Is there any way to make this work?

[eed3si9n]

Related #2104 and #2183. This is because aggregate doesn’t take the by-name parameter. You could try working around this issue by creating a Ref value:

lazy val interface = (project in file("interface"))

lazy val client = (project in file("client"))
  .dependsOn(interface, service % "test->test")
lazy val clientRef = LocalProject("client")

lazy val service = (project in file("."))
  .aggregate(clientRef)
  .dependsOn(interface)

[dwijnand]

Yeah you need to either provide the type or use a project reference like LocalProject.