Actually, saying "MyComponent shouldComponentUpdate() method" sounds a little awkward to me in terms of wording. Maybe just match this format?

```
      invariant(
        typeof this.state === 'object' && !Array.isArray(this.state),
        '%s.getInitialState(): must return an object or null',
        this.constructor.displayName || 'ReactCompositeComponent'
      );
```