Avoid classtype checking for refinements.

In a refinement type T { R } we do not need T to be a class. But analyzing the refeinement
type will create a temporary class type. This refinement class has to be treated specially in
what concerns parent types.

1 files changed, 22 insertions, 0 deletions

diff --git a/tests/pos/tycons.scala b/tests/pos/tycons.scala
new file mode 100644
index 000000000..f138c78be
--- /dev/null
+++ b/tests/pos/tycons.scala
@@ -0,0 +1,22 @@
+class TypeConstructor {
+  type TypeArg
+}
+
+trait List[+T] extends TypeConstructor { type TypeArg <: T }
+
+trait Set[T] extends TypeConstructor { type TypeArg <: T }
+
+object obj extends List[Number] with Set[Exception] {
+  val x: TypeArg = ???
+  val n: Number = x
+  val e: Exception = x
+}
+
+class Functor[F <: TypeConstructor] {
+  def map[A, B](f: F { type TypeArg <: A }): F { type TypeArg <: B }
+}
+
+implicit object ListFunctor extends Functor[List] {
+  def map[A, B](f: List[A]): List[B] = ???
+}
+