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object ImplicitProblem {
class M[T]
def nullval[T] = null.asInstanceOf[T];
trait Rep[T] {
def eval: Int
}
implicit def toRep0(n: Int) = new Rep[Int] {
def eval = 0
}
implicit def toRepN[T](n: M[T])(implicit f: T => Rep[T]) = new Rep[M[T]] {
def eval = f(nullval[T]).eval + 1
}
def depth[T <% Rep[T]](n: T) = n.eval
def main(args: Array[String]) {
println(depth(nullval[M[Int]])) // (1) this works
println(nullval[M[Int]].eval) // (2) this works
type m = M[Int]
println(depth(nullval[m])) // (3) this doesn't compile on 2.7.RC1
println(nullval[m].eval) // (4) this works
}
}
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