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
if (fn) {
      return fn();
    } else {
      return undefined;
    }
  } finally {
    setCurrentUpdatePriority(previousPriority);
    ReactCurrentBatchConfig.transition = prevTransition;
    executionContext = prevExecutionContext;
     
     
     
    if ((executionContext & (RenderContext | CommitContext)) === NoContext) {
      flushSyncCallbacks();
    }
  }
}
export function isAlreadyRendering() {
   
   
  return (
    __DEV__ &&
    (executionContext & (RenderContext | CommitContext)) !== NoContext
  );
}
export function flushControlled(fn: () => mixed): void {
  const prevExecutionContext = executionContext;
  executionContext |= BatchedContext;
  const prevTransition = ReactCurrentBatchConfig.transition;
  const previousPriority = getCurrentUpdatePriority();