[This example](https://codesandbox.io/s/1zn2o513pq) presents a huge performance drop between React 16.2 and React 16.3.

In investigated it and noticed several things:

- Perfomance drop is only visible using development bundle
- This is not related to styled-components (a simple div presents the same problem)
- I tried to investigate in performance tab of Chrome dev tools and I noticed that I get React measures even without "?react_perf"
- React Tree Reconciliation seems very long, do not know why

It is not a big problem for me, but it looks weird, so I decided to [share it on Twitter](https://twitter.com/neoziro/status/979756579296817154),  then @gaearon [invited me to submit an issue about it](https://twitter.com/dan_abramov/status/980036013518139398).


return next;
        }
        if (
          returnFiber !== null &&
          
          (returnFiber.effectTag & Incomplete) === NoEffect
        ) {
          
          
          
          if (returnFiber.firstEffect === null) {
            returnFiber.firstEffect = workInProgress.firstEffect;
          }
          if (workInProgress.lastEffect !== null) {
            if (returnFiber.lastEffect !== null) {
              returnFiber.lastEffect.nextEffect = workInProgress.firstEffect;
            }
            returnFiber.lastEffect = workInProgress.lastEffect;
          }
          
          
          
          
          
          
          const effectTag = workInProgress.effectTag;
          
          
          if (effectTag > PerformedWork) {