Observed this on react@16.0.0-beta.5

```js
import React from 'react';
import { renderToString } from 'react-dom/server';

const B = () => 'b';

console.log(renderToString(<div>{'a'}<B />{'c'}</div>));
```

This renders as `<div data-reactroot="">a<!-- -->bc</div>`. If you try to hydrate this you'll get the error: Text content did not match. Server: "bc" Client: "b".
return <div id={this.props.id} />;
            }
          };
          PureComponent = props => <div id={props.id} />;
          bareElement = <div id="foobarbaz" />;
        });
        it('should reconnect ES6 Class to ES6 Class', () =>
          expectMarkupMatch(
            <ES6ClassComponent id="foobarbaz" />,
            <ES6ClassComponent id="foobarbaz" />,
          ));
        it('should reconnect Pure Component to ES6 Class', () =>
          expectMarkupMatch(
            <ES6ClassComponent id="foobarbaz" />,
            <PureComponent id="foobarbaz" />,
          ));
        it('should reconnect Bare Element to ES6 Class', () =>
          expectMarkupMatch(<ES6ClassComponent id="foobarbaz" />, bareElement));
        it('should reconnect ES6 Class to Pure Component', () =>
          expectMarkupMatch(
            <PureComponent id="foobarbaz" />,