**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
validateARIAProperties(type, props);
    validateInputProperties(type, props);
    validateUnknownProperties(type, props);
  };
  var describeStackFrame = function(element): string {
    var source = element._source;
    var type = element.type;
    var name = getComponentName(type);
    var ownerName = null;
    return describeComponentFrame(name, source, ownerName);
  };
  var currentDebugStack = null;
  var currentDebugElementStack = null;
  var setCurrentDebugStack = function(stack: Array<Frame>) {
    var frame: Frame = stack[stack.length - 1];
    currentDebugElementStack = ((frame: any): FrameDev).debugElementStack;
    
    currentDebugElementStack.length = 0;
    currentDebugStack = stack;
    ReactDebugCurrentFrame.getCurrentStack = getStackAddendum;
  };
  var pushElementToDebugStack = function(element: ReactElement) {
    if (currentDebugElementStack !== null) {
      currentDebugElementStack.push(element);
    }
  };
  var resetCurrentDebugStack = function() {
    currentDebugElementStack = null;
    currentDebugStack = null;
    ReactDebugCurrentFrame.getCurrentStack = null;