Add test for SI-9795

Author: felixmulder

tests/pos/t9795.scala

@@ -0,0 +1,7 @@
+case class A(v: Int)
+class B(v: Int) extends A(v)
+
+object Test {
+  val a = new B(1)
+  a match { case A(_) => 1 }
+}