Can Scala select a concrete implicit when mapping a list of concrete objects inheriting a common trait? -

^{expanding on bit further on previous similar question posted yesterday}

employee , manager both extend person. i've defined implicit "converter" objects both subclasses.

i created list of type list[product serializable person] contains 1 of each concrete class.

import scala.reflect.classtag  object example {   trait person { def age: int }    case class employee(age: int) extends person   case class manager(age: int) extends person    class converter[t] { def convert(t: t) = (t,t) }    def convert[t <: person:classtag](p: t)(implicit converter: converter[t]) =     converter.convert(p)    def main(args: array[string]): unit = {     implicit val employeeconverter = new converter[employee]()     implicit val managerconverter = new converter[manager]()      convert(employee(1)) // works     convert(manager(2)) // works      list(employee(3),manager(4)) map(e => convert(e)) // compile error   } } 

converting employee , manager separately works fine, when try convert list, scala compiler complains because can't find converter person:

$ scalac example.scala && scala example example.scala:21: error: not find implicit value parameter converter: example.converter[product serializable example.person]     list(employee(3),manager(4)) map(e => convert(e)) 

how can guarantee scala compiler have defined implicit conversion concrete implementations of person?

no, cannot. have @ scala documentation http://scala-lang.org/files/archive/spec/2.11/07-implicits.html

however, if there conflicts implicits caused class hierarchy / inheritance specific 1 chosen. if manager inherited employee, should resolve fine.

similar post here, what scala's rules resolving conflicting implicit values