this compiles; didn't realize package b would see implicit from package a without an explicit import

implicits.scala

package implicits {

  package a {

    case class Foo(i: Int)

    object FooApp extends App {
      Foo(1).rich
    }

  }

  package object a {

    implicit class RichFoo(f: Foo) {
      def rich = f.i
    }

  }

  package b {

    object FooApp extends App {
      import a.Foo
      Foo(1).rich
    }

  }

}