**Do you want to request a _feature_ or report a _bug_?**

Report a bug.

**What is the current behavior?**

When testing components, `Warning: ReactComponentTreeDevtool: Missing React element for debugID 1 when building stack` is shown when calling `TestUtils.renderIntoDocument`.

**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/).**

https://github.com/angusfretwell/reproduce-debugid-warning (`npm install && npm test`).

**What is the expected behavior?**

According to #7187 this is an internal warning and shouldn't be displayed.

**Which versions of React, and which browser / OS are affected by this issue? Did this work in previous versions of React?**
- react@15.2.1
- react-addons-test-utils@15.2.1
- react-dom@15.2.1

I didn't receive this warning on 15.2.0.

render: function() {
    return (
      <div>
        <div ref="resetDiv" onClick={this.doReset}>
          Reset Me By Clicking This.
        </div>
        <GeneralContainerComponent ref="myContainer">
          <ClickCounter ref="myCounter" initialCount={1}/>
        </GeneralContainerComponent>
      </div>
    );
  },
});
/**
 * Render a TestRefsComponent and ensure that the main refs are wired up.
 */
var renderTestRefsComponent = function() {
  var testRefsComponent =
      ReactTestUtils.renderIntoDocument(<TestRefsComponent />);
  reactComponentExpect(testRefsComponent)
      .toBeCompositeComponentWithType(TestRefsComponent);
  var generalContainer = testRefsComponent.refs.myContainer;
  var counter = testRefsComponent.refs.myCounter;
  reactComponentExpect(generalContainer)
      .toBeCompositeComponentWithType(GeneralContainerComponent);
  reactComponentExpect(counter)
      .toBeCompositeComponentWithType(ClickCounter);
  return testRefsComponent;
};
var expectClickLogsLengthToBe = function(instance, length) {