https://jsfiddle.net/3apqnhmw/

```jsx
class Foo extends React.Component {
  render() {
     return <div>Foo</div>
  }
}

class App extends React.Component {
  render() {
    return Foo
  }
}
```

When `App` returns `Foo` instead of `<Foo />` accidentally, Fiber does not catch this.
getObject = () => {
        return this.props.object;
      };
      render() {
        return <div>{this.props.children}</div>;
      }
    }
    class Component extends React.Component {
      render() {
        var inner = <Wrapper object={innerObj} ref="inner" />;
        var outer = <Wrapper object={outerObj} ref="outer">{inner}</Wrapper>;
        return outer;
      }
      componentDidMount() {
        expect(this.refs.inner.getObject()).toEqual(innerObj);
        expect(this.refs.outer.getObject()).toEqual(outerObj);
      }
    }
    ReactTestUtils.renderIntoDocument(<Component />);
  });
  it('should not have refs on unmounted components', () => {
    class Parent extends React.Component {