1 files changed, 22 insertions, 0 deletions
diff --git a/tests/untried/neg/unchecked-knowable.scala b/tests/untried/neg/unchecked-knowable.scala
new file mode 100644
index 000000000..21624c4fb
--- /dev/null
+++ b/tests/untried/neg/unchecked-knowable.scala
@@ -0,0 +1,22 @@
+/** 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
+sealed trait B2B extends B1
+final class B3 extends B1
+trait B4 extends B2
+
+class Bippy
+trait Dingus
+
+class A {
+  /*   warn */ (new Bippy).isInstanceOf[A1]
+  /*   warn */ (new Bippy).isInstanceOf[B1]
+  /* nowarn */ (null: Dingus).isInstanceOf[B1]
+  /* nowarn */ ((new Bippy): Any).isInstanceOf[A1]
+}