1 files changed, 39 insertions, 0 deletions
diff --git a/tests/invalid/pos/ticket2251.scala b/tests/invalid/pos/ticket2251.scala
new file mode 100644
index 000000000..006407247
--- /dev/null
+++ b/tests/invalid/pos/ticket2251.scala
@@ -0,0 +1,39 @@
+
+// Martin: I am not sure this is a solvable problem right now. I'll leave it in pending.
+// derived from pos/t1001
+class A
+trait B[T <: B[T]] extends A
+class C extends B[C]
+class D extends B[D]
+
+class Data {
+  // force computing lub of C and D (printLubs enabled:)
+
+/*
+lub of List(D, C) at depth 2
+  lub of List(D, C) at depth 1
+    lub of List(D, C) at depth 0
+    lub of List(D, C) is A
+  lub of List(D, C) is B[_1] forSome { type _1 >: D with C <: A }
+lub of List(D, C) is B[_2] forSome { type _2 >: D with C{} <: B[_1] forSome { type _1 >: D with C{} <: A } }
+*/
+// --> result = WRONG
+
+  // should be: B[X] forSome {type X <: B[X]} -- can this be done automatically? for now, just detect f-bounded polymorphism and fall back to more coarse approximation
+
+  val data: List[A] = List(new C, new D)
+
+  val data2 = List(new C, new D)
+
+  val data3: List[B[_ <: B[_ <: A]]] = List(new C, new D)
+
+  // Not yet --
+  // val data4: List[B[X] forSome { type X <: B[X] }] = List(new C, new D)
+  // <console>:7: error: type mismatch;
+  //  found   : List[B[_ >: D with C <: B[_ >: D with C <: A]]]
+  //  required: List[B[X] forSome { type X <: B[X] }]
+  //        val data4: List[B[X] forSome { type X <: B[X] }] = List(new C, new D)
+
+  // works
+  val data5 = List[B[X] forSome { type X <: B[X] }](new C, new D)
+}