Merge pull request #1343 from dotty-staging/change-hk-direct2

Direct representation of higher-kinded types 

1 files changed, 61 insertions, 0 deletions

diff --git a/tests/neg/existentials.scala b/tests/neg/existentials.scala
new file mode 100644
index 000000000..4798504d9
--- /dev/null
+++ b/tests/neg/existentials.scala
@@ -0,0 +1,61 @@
+object TestList {
+
+  var x: ([X] -> List[List[X]])[_] = List(List(1)) // error: unreducible
+  var y: ([X] -> List[Seq[X]])[_] = List(List(1)) // error: unreducible
+
+  x = x
+  y = y
+  y = x
+
+  val h = x.head
+  val x1: List[_] = h
+
+  var z: List[_] = x
+
+}
+object TestSet {
+
+  var x: ([Y] -> Set[Set[Y]])[_] = Set(Set("a")) // error: unreducible
+  var y: ([Y] -> Set[Iterable[Y]])[_] = Set(Set("a")) // error: unreducible
+
+  x = x
+  y = y
+
+  val h = x.head
+  val h1: Set[_] = h
+
+  // val p = x.+ // infinite loop in implicit search
+
+  var z: Set[_] = x
+
+}
+class TestX {
+
+  class C[T](x: T) {
+    def get: T = x
+    def cmp: T => Boolean = (x == _)
+  }
+
+  val x: ([Y] -> C[C[Y]])[_] = new C(new C("a")) // error: unreducible
+
+  type CC[X] = C[C[X]]
+  val y: CC[_] = ??? // error: unreducible
+
+  type D[X] <: C[X]
+
+  type DD = [X] -> D[D[X]]
+  val z: DD[_] = ??? // error: unreducible
+
+  val g = x.get
+
+  val c = x.cmp
+}
+
+object Test6014 {
+  case class CC[T](key: T)
+  type Alias[T] = Seq[CC[T]]
+
+  def f(xs: Seq[CC[_]]) = xs map { case CC(x) => CC(x) }    // ok
+  def g(xs: Alias[_])   = xs map { case CC(x) => CC(x) }    // error: unreducible application
+}
+