Follow up from https://github.com/facebook/react/pull/11616.

Here's one I found. These two invariants:

https://github.com/facebook/react/blob/7e7127387ba64f57299eaff8656542cea6fb3a2d/packages/react-reconciler/src/ReactFiberClassComponent.js#L330-L343

are in a function that's behind a DEV block:

https://github.com/facebook/react/blob/7e7127387ba64f57299eaff8656542cea6fb3a2d/packages/react-reconciler/src/ReactFiberClassComponent.js#L447-L449

I don't think this is intentional, but need to verify.

There may be more. I'll use this issue to track while https://github.com/facebook/react/pull/11616 preserves existing behavior.
context: Object,
  footer: string,
};
type FrameDev = Frame & {
  debugElementStack: Array<ReactElement>,
};
class ReactDOMServerRenderer {
  stack: Array<Frame>;
  exhausted: boolean;
  // TODO: type this more strictly:
  currentSelectValue: any;
  previousWasTextNode: boolean;
  makeStaticMarkup: boolean;
  constructor(children: mixed, makeStaticMarkup: boolean) {
    const flatChildren = flattenTopLevelChildren(children);
    var topFrame: Frame = {
      
      
      domNamespace: Namespaces.html,
      children: flatChildren,
      childIndex: 0,
      context: emptyObject,
      footer: '',
    };
    if (__DEV__) {
      ((topFrame: any): FrameDev).debugElementStack = [];
    }
    this.stack = [topFrame];
    this.exhausted = false;
    this.currentSelectValue = null;