7 public static void Main ()
13 x?.Contains (y?.ToLowerInvariant ());
14 x?.Contains (y?.Length.ToString ());
16 var res = x?[y?.Length ?? 0];
18 var res2 = z?[x?.Length ?? 0];
20 x?.Foo (y?.ToLowerInvariant ());
23 xx?.a (y?.ToLowerInvariant ());
29 public static string Foo (this string arg, string value)