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".
props.type,
          );
          didWarnDefaultChecked = true;
        }
        if (
          props.value !== undefined &&
          props.defaultValue !== undefined &&
          !didWarnDefaultInputValue
        ) {
          warning(
            false,
            '%s contains an input of type %s with both value and defaultValue props. ' +
              'Input elements must be either controlled or uncontrolled ' +
              '(specify either the value prop, or the defaultValue prop, but not ' +
              'both). Decide between using a controlled or uncontrolled input ' +
              'element and remove one of these props. More info: ' +
              'https://fb.me/react-controlled-components',
            'A component',
            props.type,
          );
          didWarnDefaultInputValue = true;
        }
      }
      props = Object.assign(
        {
          type: undefined,
        },
        props,
        {
          defaultChecked: undefined,