diff --git a/tests/warn/i15661.scala b/tests/warn/i15661.scala
new file mode 100644
index 000000000000..f641222efe4b
--- /dev/null
+++ b/tests/warn/i15661.scala
@@ -0,0 +1,7 @@
+case class Composite[T](l: List[T], v: T)
+
+def m(composite: Composite[?]): Unit =
+  composite match {
+    case Composite(l: List[Int], v: Int) => println(v) // warn: type test for List[Int] cannot be checked at runtime
+    case _ => println("This is not Int") // was: warn: Unreachable case except for null
+  }