Imported Upstream version 4.2.0.179

Former-commit-id: 0a113cb3a6feb7873f632839b1307cc6033cd595

mcs/tests/test-null-operator-11.cs

@@ -0,0 +1,28 @@
+class X
+{
+	public static void Main ()
+	{
+		A a = new A ();
+		var x = (a.b?.c?.d as A)?.b;
+	}
+}
+
+class A
+{
+	public B b { get; set; }
+}
+
+class B
+{
+	public C c { get; set; }
+}
+
+class C
+{
+	public D d { get; set; }
+}
+
+class D : A
+{
+
+}