1 files changed, 3 insertions, 1 deletions
diff --git a/test/files/neg/unchecked-knowable.scala b/test/files/neg/unchecked-knowable.scala
index 667b47f504..21624c4fb4 100644
--- a/test/files/neg/unchecked-knowable.scala
+++ b/test/files/neg/unchecked-knowable.scala
@@ -7,6 +7,7 @@ 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
 
@@ -15,6 +16,7 @@ trait Dingus
 
 class A {
   /*   warn */ (new Bippy).isInstanceOf[A1]
-  /* nowarn */ (new Bippy).isInstanceOf[B1]
+  /*   warn */ (new Bippy).isInstanceOf[B1]
+  /* nowarn */ (null: Dingus).isInstanceOf[B1]
   /* nowarn */ ((new Bippy): Any).isInstanceOf[A1]
 }