Better type inference for Scala: send us your problematic cases!

Language Design
118

This was working prior to 0.24:

trait P[M: Ordering, C] {
  def apply(s: (M, C)*): Seq[(M, C)]
  def sort(x: Seq[(M, C)]) = apply(x.sortBy((s, _) => s): _*)
                                             ^
                 cannot infer type; expected type <?> is not fully defined
}