1 files changed, 16 insertions, 0 deletions
diff --git a/tests/pos/t4911.scala b/tests/pos/t4911.scala
new file mode 100644
index 000000000..cfb3792ae
--- /dev/null
+++ b/tests/pos/t4911.scala
@@ -0,0 +1,16 @@
+import language._
+
+object Test {
+  class Foo[T](val x: T) ; object Foo { def unapply[T](x: Foo[T]) = Some(x.x) }
+  def f1[T](x: Foo[T]) = x match { case Foo(y) => y }
+  def f2[M[_], T](x: M[T]) = x match { case Foo(y) => y }
+
+  case class Bar[T](x: T)
+  def f3[T](x: Bar[T]) = x match { case Bar(y) => y }
+  def f4[M[_], T](x: M[T]) = x match { case Bar(y) => y }
+}
+//
+// ./b.scala:4: warning: non variable type-argument T in type pattern Test.Foo[T] is unchecked since it is eliminated by erasure
+//   def f2[M[_], T](x: M[T]) = x match { case Foo(y) => y }
+//                                                ^
+// one warning found