Error

[error] /private/var/greplin/src/widmore/src/main/scala/com/greplin/widmore/util/RichResource.scala:11: Parameter type in structural refinement may not refer to an abstract type defined outside that refinement
[error]     def returnResource(loaner: T)

gistfile1.scala

object RichResource {
  type Resource[T] = {
    def getResource: T
    def returnResource(loaner: T) // Line 11 is right here
  }

  implicit
  def resourceToRichResource[T](res: Resource[T]) = new RichResource[T](res)
}

class RichResource[T](resource: RichResource.Resource[T]) {
  def loan[R](block: T => R): R = {
    val loaner: T = resource.getResource

    try {
      block(loaner)
    } finally {
      resource.returnResource(loaner)
    }
  }
}