**Do you want to request a *feature* or report a *bug*?**

Feature

**What is the current behavior?**

While server rendering React DOM and then hydrating with a different structure, React rightly warns that there are inconsistencies. But when I first saw these warnings I was not sure exactly what was going wrong.

Here are a few of the warnings I have been receiving:

```
Warning: Did not find a matching <button> in <div>.

Warning: Did not find a matching <img> in <div>.

Warning: Did not expect server HTML to contain a <div> in <div>.
```

Only on that last error did I catch on that this was a problem with server-rendering and the inconsistencies between that and my client render (intentional at the moment while testing some things in unpure render functions).

**What is the expected behavior?**

Being more explicit that this was a rendering inconsistency between server and client.

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**

React v16-beta.1
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      case 'textarea':
        lastProps = ReactDOMFiberTextarea.getHostProps(
          domElement,
          lastRawProps,
        );
        nextProps = ReactDOMFiberTextarea.getHostProps(
          domElement,
          nextRawProps,
        );
        updatePayload = [];
        break;
      default:
        lastProps = lastRawProps;
        nextProps = nextRawProps;
        if (
          typeof lastProps.onClick !== 'function' &&
          typeof nextProps.onClick === 'function'
        ) {
          
          trapClickOnNonInteractiveElement(((domElement: any): HTMLElement));
        }
        break;
    }
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    var styleName;
    var styleUpdates = null;
    for (propKey in lastProps) {
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