Sorry I didn't notice this before...but it looks like this needs to be defined in the subclasses as well: there's `find_matching_method_stub` and `find_matching_expectation`.  Before fixing this, it'd be good to add a failing test first.  Reading the code, I think it would come into play in a case like this:

``` ruby
expect(obj).to receive(:foo)
expect(obj).to receive_message_chain(:foo, :bar, :bazz)
```

I'm not 100% sure on that, though.