How can collections use implicit conversions on element types?

Question

While working on this question, I came up with the following issue. Consider two method definitions:

def foo[T <: Ordered[T]](s : Seq[T]) = s.sorted

def          


        

Answer 1

scala> implicit def ordering[T <% Ordered[T]] = new Ordering[T]{def compare(x: T, y: T) = x compare y}
ordering: [T](implicit evidence$1: (T) => Ordered[T])java.lang.Object with Ordering[T]

scala> def foo[T <% Ordered[T]](s : Seq[T]) = s.sorted
foo: [T](s: Seq[T])(implicit evidence$1: (T) => Ordered[T])Seq[T]

Answer 2

% scala29
Welcome to Scala version 2.9.0.r24168-b20110202012927 (Java HotSpot(TM) 64-Bit Server VM, Java 1.6.0_22).
Type in expressions to have them evaluated.
Type :help for more information.

scala> def foo[T <% Ordered[T]](s : Seq[T]) = s.sorted
foo: [T](s: Seq[T])(implicit evidence$1: (T) => Ordered[T])Seq[T]

scala>

By the way, re "here it seems easy", it wasn't. Implicits like these enjoy diverging and they were pretty determined.