Add test

liufengyun · liufengyun · commit 6f370fd997df · 2023-05-01T14:03:59.000+02:00
diff --git a/tests/pos-special/isInstanceOf/i16899.scala b/tests/pos-special/isInstanceOf/i16899.scala
@@ -0,0 +1,5 @@
+sealed trait Unset
+
+def foo(v: Unset|Option[Int]): Unit = v match
+  case v: Unset => ()
+  case v: Option[Int] => ()
