**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.

if (!nextChildren.hasOwnProperty(name)) {
        continue;
      }
      prevChild = prevChildren && prevChildren[name];
      var prevElement = prevChild && prevChild._currentElement;
      var nextElement = nextChildren[name];
      if (prevChild != null &&
          shouldUpdateReactComponent(prevElement, nextElement)) {
        ReactReconciler.receiveComponent(
          prevChild, nextElement, transaction, context
        );
        nextChildren[name] = prevChild;
      } else {
        if (prevChild) {
          removedNodes[name] = ReactReconciler.getHostNode(prevChild);
          ReactReconciler.unmountComponent(prevChild, false);
        }
        
        var nextChildInstance = instantiateReactComponent(nextElement, true);
        nextChildren[name] = nextChildInstance;
        
        
        var nextChildMountImage = ReactReconciler.mountComponent(
          nextChildInstance,
          transaction,
          hostParent,
          hostContainerInfo,
          context
        );
        mountImages.push(nextChildMountImage);