Upgrades to handle subtyping between parameterized and higher-kinded types.

1 files changed, 35 insertions, 0 deletions

diff --git a/tests/pos/hk.scala b/tests/pos/hk.scala
new file mode 100644
index 000000000..f2f10bbfb
--- /dev/null
+++ b/tests/pos/hk.scala
@@ -0,0 +1,35 @@
+import language.higherKinds
+
+object higherKinded {
+  
+  type Untyped = Null
+
+  class Tree[-T >: Untyped] {
+    type ThisType[-U >: Untyped] <: Tree[U]
+    def withString(s: String): ThisType[String] = withString(s)
+  }
+  
+  class Ident[-T >: Untyped] extends Tree[T] {
+    type ThisType[-U] = Ident[U]
+  }
+  
+  val id = new Ident[Integer]
+  
+  val y = id.withString("abc")
+  
+  val z: Ident[String] = y
+  
+  val zz: tpd.Tree = y
+  
+  abstract class Instance[T >: Untyped] {
+    type Tree = higherKinded.Tree[T]
+  }
+  
+  object tpd extends Instance[String]
+  
+  def transform(tree: Tree[String]) = {
+    val tree1 = tree.withString("") 
+    tree1: Tree[String]
+  }
+
+}
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