Currently, if you define `shouldComponentUpdate` on `React.PureComponent` nothing bad happens and it acts like `React.Component` https://jsfiddle.net/jekmdfva/

We should probably warn in dev since it defaults the point of `PureComponent`
});
      } else {
        transaction.getReactMountReady().enqueue(inst.componentDidMount, inst);
      }
    }
    
    const callbacks = this._pendingCallbacks;
    if (callbacks) {
      this._pendingCallbacks = null;
      for (let i = 0; i < callbacks.length; i++) {
        transaction.getReactMountReady().enqueue(callbacks[i], inst);
      }
    }
    return markup;
  },
  _constructComponent: function(
    doConstruct,
    publicProps,
    publicContext,
    updateQueue,
  ) {
    if (__DEV__) {
      ReactCurrentOwner.current = this;
      try {
        return this._constructComponentWithoutOwner(
          doConstruct,
          publicProps,
          publicContext,
          updateQueue,
        );