**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
if (ReactCurrentOwner.current) {
    var name = getComponentName(ReactCurrentOwner.current);
    if (name) {
      return '\n\nCheck the render method of `' + name + '`.';
    }
  }
  return '';
}
function getSourceInfoErrorAddendum(elementProps) {
  if (
    elementProps !== null &&
    elementProps !== undefined &&
    elementProps.__source !== undefined
  ) {
    var source = elementProps.__source;
    var fileName = source.fileName.replace(/^.*[\\\/]/, '');
    var lineNumber = source.lineNumber;
    return '\n\nCheck your code at ' + fileName + ':' + lineNumber + '.';
  }
  return '';
}
/**
 * Warn if there's no key explicitly set on dynamic arrays of children or
 * object keys are not valid. This allows us to keep track of children between
 * updates.
 */
var ownerHasKeyUseWarning = {};
function getCurrentComponentErrorInfo(parentType) {