C# quiz: 2/?

Continuing on the series of C# and/or .NET Framework short questions:

        private void Foo(List<int> bar) {
          bar = new List<int>();
          // ...
        }

With the method above and the code below:

        List<int> bar = null;
      Foo(bar);
      if (bar != null) {
          Console.WriteLine("populated");
      } else {
          Console.WriteLine("still null");
      }

If or else ?

EDIT: fixed typo in code sample.