1 files changed, 20 insertions, 0 deletions
diff --git a/tests/neg/t3683-modified.scala b/tests/neg/t3683-modified.scala
new file mode 100644
index 000000000..19b981e0a
--- /dev/null
+++ b/tests/neg/t3683-modified.scala
@@ -0,0 +1,20 @@
+sealed trait Foo
+sealed trait Bar extends Foo
+sealed trait W[T >: Bar <: Foo]
+case class X() extends W[Foo]
+case class XX() extends W[Bar]
+case class Y() extends W[Bar]
+case class Z[T >: T <: Foo](               // error: cyclic reference
+  z1: W[T]
+) extends W[T]
+
+object Main {
+  // should warn for not including XX()
+  def f1(w: W[Bar]): Int = {
+    w match {
+      // case XX() => 2
+      case Y() => 1
+      case Z(z) => f1(z)
+    }
+  }
+}