Add test

Author: odersky

tests/run/implicit-functors.check

@@ -0,0 +1,2 @@
+functorId
+funcorConst

tests/run/implicit-functors.scala

@@ -0,0 +1,25 @@
+object Utils {
+  type Id[t] = t
+  type Const[c] = [t] => c
+}
+
+import Utils._
+
+class Instances[F[_[_]], T[_]]
+
+trait Functor[F[_]]
+
+object Functor {
+  implicit val functorId: Functor[Id] = { println("functorId"); null }
+  implicit def functorGen[F[_]](implicit inst: Instances[Functor, F]): Functor[F] = { println("funcorGen"); null }
+  implicit def functorConst[T]: Functor[Const[T]] =  { println("funcorConst"); null }
+}
+
+case class Sm[A](value: A)
+object Sm {
+  implicit def smInstances[F[_[_]]]: Instances[F, Sm] = { println("smInstances"); null }
+}
+
+object Test extends App {
+  implicitly[Functor[Sm]]
+}