**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
} else if ((propertyInfo = DOMProperty.properties[propKey])) {
          
          extraAttributeNames.delete(propertyInfo.attributeName);
          serverValue = DOMPropertyOperations.getValueForProperty(
            domElement,
            propKey,
            nextProp,
          );
          if (nextProp !== serverValue) {
            warnForPropDifference(propKey, serverValue, nextProp);
          }
        }
      }
    }
    if (__DEV__) {
      
      if (extraAttributeNames.size > 0) {
        
        warnForExtraAttributes(extraAttributeNames);
      }
    }
    switch (tag) {
      case 'input':
        
        
        inputValueTracking.track((domElement: any));
        ReactDOMFiberInput.postMountWrapper(domElement, rawProps);
        break;
      case 'textarea':