diff --git a/tests/patmat/i12808.scala b/tests/patmat/i12808.scala
new file mode 100644
index 000000000000..b0c5aad78a64
--- /dev/null
+++ b/tests/patmat/i12808.scala
@@ -0,0 +1,10 @@
+import scala.reflect.Typeable
+
+case class Err1()
+case class Err2()
+
+def handleError[A: Typeable, B: Typeable](x: Either[A | B, Nothing]): Unit =
+  x match // false alarm warning: It would fail on pattern case: Left(_)
+  case Left(e: A)  => println("A")
+  case Left(_: B) => println("B")
+  case Right(_)    => println("Nothing")