Function which generically takes a type and returns the same type

Question

I am having a tough time understanding why the Scala compiler is unhappy about this function definition:

def trimNonWordCharacters[T <: Iterable[String]](         


        

Answer 1

[Entering as an answer rather than a comment because code in comments doesn't format properly]

@Daniel, thanks for the explanation, I also found it useful. As Iterable derives from IterableLike, the following also seems to work, and is slightly more compact:

import scala.collection.IterableLike
import scala.collection.generic.CanBuildFrom
def trimNonWordCharacters[T <: IterableLike[String, T]]
 (items: T)
 (implicit cbf: CanBuildFrom[T, String, T]): T =
 items map { _.replaceAll("\\W", "") }