broken.scala

trait Foo[A]

object A {
  implicit val foo: Foo[Int] = new Foo[Int] {}
}
object B {
  implicit val foo: Foo[String] = new Foo[String] {}
}

object C {
  import A._
  import B._
  // Whoops, the implicits have the same name so neither will resolve.
  implicitly[Foo[Int]]
  implicitly[Foo[String]]
}

working.scala

trait Foo[A]

case class A()
object A {
  implicit val foo: Foo[A] = new Foo[A] {}
}
case class B()
object B {
  implicit val foo: Foo[B] = new Foo[B] {}
}

object C {
  implicitly[Foo[A]]
  implicitly[Foo[B]]
}