**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
nextProps.hasOwnProperty(propKey) ||
        !lastProps.hasOwnProperty(propKey) ||
        lastProps[propKey] == null
      ) {
        continue;
      }
      if (propKey === STYLE) {
        var lastStyle = lastProps[propKey];
        for (styleName in lastStyle) {
          if (lastStyle.hasOwnProperty(styleName)) {
            if (!styleUpdates) {
              styleUpdates = {};
            }
            styleUpdates[styleName] = '';
          }
        }
      } else if (
        propKey === DANGEROUSLY_SET_INNER_HTML ||
        propKey === CHILDREN
      ) {
        
      } else if (propKey === SUPPRESS_CONTENT_EDITABLE_WARNING) {
        
      } else if (registrationNameModules.hasOwnProperty(propKey)) {
        
        
        
        if (!updatePayload) {