We missed this because Flow wasn't being run properly on Travis but now that it is, it's clear that #7716 introduced a bunch of new Flow failures. Most of these shouldn't be too bad and I like to say "you break it you buy it" so this one is for you @Aweary :)

There were a couple other pre-existing Flow issues that @vjeux is going to fix, so mostly this should just be the TestRenderer issues.

var element = this._currentElement;
    var options = transaction.getTestOptions();
    return options.createNodeMock(element);
  }
  toJSON(): ReactTestRendererJSON {
    var {children, ...props} = this._currentElement.props;
    var childrenJSON = [];
    for (var key in this._renderedChildren) {
      var inst = this._renderedChildren[key];
      inst = getRenderedHostOrTextFromComponent(inst);
      var json = inst.toJSON();
      if (json !== undefined) {
        childrenJSON.push(json);
      }
    }
    var object = {
      type: this._currentElement.type,
      props: props,
      children: childrenJSON.length ? childrenJSON : null,
    };
    Object.defineProperty(object, '$$typeof', {
      value: Symbol.for('react.test.json'),
    });
    return object;
  }
  getHostNode(): void {}