How can I use callermembername in tostring()?

See more:

C#5.0

attributes

The (relatively) new CallerMemberName attribute is useful, but I would like to use it in some overrides like ToString(). The problem is that when I add it to my method, the signature changes sufficiently so that the override is no longer seen as such.

In Visual Studio 2015, it shows a red squiggly under it indicating:
Item.ToString(string): no suitable method found to override

Which sort of makes sense, since we have added a string argument, but on the other hand it doesn't, because it's an optional parameter. Is there a way to make this work short of creating a MyToString() and changing all references in my code to that?

What I have tried:

class Item
    {
        public override string ToString([CallerMemberName] string caller = null)
        {
            return base.ToString();
        }
    }