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

**What is the current behavior?**
App doesn't render in IE11 and below.

**If the current behavior is a bug, please provide the steps to reproduce and if possible a minimal demo of the problem via https://jsfiddle.net or similar (template: https://jsfiddle.net/reactjs/69z2wepo/).**
- Build React app with Webpack
- Launch IE11 or below (not an emulator)
- You will see a blank screen or half-compiled React app with the following error:
![24f8f6e8-afde-11e6-9a6f-a3cc6355f55c](https://cloud.githubusercontent.com/assets/1647596/20527736/7b9075a8-b097-11e6-8ccb-d205b1908f31.png)

**What is the expected behavior?**
- To render as it does in Chrome, Firefox, etc.

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
We've temporarily shrink-wrapped our dependencies so that we can continue to serve our app. We're starting to believe that it's coming from a dependency that `react`, `apollo`  or `webpack` may be relying on...

Shrink-wrapped versions of our dependencies (left is the new one that's broken and the right one is the old one that continues to work across all browsers) https://www.diffchecker.com/SyaJUcsk
createMarkupForProperty,
  createMarkupForRoot,
} from './DOMMarkupOperations';
import {
  Namespaces,
  getIntrinsicNamespace,
  getChildNamespace,
} from '../shared/DOMNamespaces';
import ReactControlledValuePropTypes from '../shared/ReactControlledValuePropTypes';
import assertValidProps from '../shared/assertValidProps';
import dangerousStyleValue from '../shared/dangerousStyleValue';
import escapeTextContentForBrowser from '../shared/escapeTextContentForBrowser';
import isCustomComponent from '../shared/isCustomComponent';
import omittedCloseTags from '../shared/omittedCloseTags';
import warnValidStyle from '../shared/warnValidStyle';
import {validateProperties as validateARIAProperties} from '../shared/ReactDOMInvalidARIAHook';
import {validateProperties as validateInputProperties} from '../shared/ReactDOMNullInputValuePropHook';
import {validateProperties as validateUnknownProperties} from '../shared/ReactDOMUnknownPropertyHook';
var REACT_FRAGMENT_TYPE =
  (typeof Symbol === 'function' &&
    Symbol.for &&
    Symbol.for('react.fragment')) ||
  0xeacb;
type ReactNode = string | number | ReactElement;
type FlatReactChildren = Array<null | ReactNode>;
type toArrayType = (children: mixed) => FlatReactChildren;
var toArray = ((React.Children.toArray: any): toArrayType);
var getStackAddendum = emptyFunction.thatReturns('');
if (__DEV__) {
  var validatePropertiesInDevelopment = function(type, props) {