1 files changed, 20 insertions, 0 deletions
diff --git a/test/files/neg/unchecked-knowable.scala b/test/files/neg/unchecked-knowable.scala
new file mode 100644
index 0000000000..667b47f504
--- /dev/null
+++ b/test/files/neg/unchecked-knowable.scala
@@ -0,0 +1,20 @@
+/** Knowable - only final leaves */
+sealed abstract class A1
+sealed abstract class A2 extends A1
+final class A3 extends A1
+final class A4 extends A2
+
+/** Unknowable */
+sealed abstract class B1
+sealed abstract class B2 extends B1
+final class B3 extends B1
+trait B4 extends B2
+
+class Bippy
+trait Dingus
+
+class A {
+  /*   warn */ (new Bippy).isInstanceOf[A1]
+  /* nowarn */ (new Bippy).isInstanceOf[B1]
+  /* nowarn */ ((new Bippy): Any).isInstanceOf[A1]
+}