gr.scala

scala> object Foo {
     |   implicit def foo(i: Int) = i.toString
     | }
warning: there was one feature warning; re-run with -feature for details
defined object Foo

scala> object Bar {
     |   implicit def foo(s: Symbol) = s.toString
     | }
warning: there was one feature warning; re-run with -feature for details
defined object Bar

scala> import Foo._
import Foo._

scala> 3: String
res0: String = 3

scala> import Bar._
import Bar._

scala> 3: String
<console>:16: error: type mismatch;
 found   : Int(3)
 required: String
              3: String
              ^