https://codesandbox.io/s/elastic-mayer-rzz4h2?file=/package.json

This is supposed to `console.error` but it doesn't.

17 warns: https://codesandbox.io/s/admiring-minsky-sze07m?file=/src/App.js
cancelCallback(existingCallbackNode);
    }
    root.callbackNode = null;
    root.callbackPriority = NoLane;
    return;
  }
   
  const newCallbackPriority = getHighestPriorityLane(nextLanes);
   
  const existingCallbackPriority = root.callbackPriority;
  if (
    existingCallbackPriority === newCallbackPriority &&
     
     
     
    !(
      __DEV__ &&
      ReactCurrentActQueue.current !== null &&
      existingCallbackNode !== fakeActCallbackNode
    )
  ) {
    if (__DEV__) {