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.
out += this.render(child, frame.context, frame.domNamespace);
      if (__DEV__) {
        
        resetCurrentDebugStack();
      }
    }
    return out;
  }
  render(
    child: ReactNode | null,
    context: Object,
    parentNamespace: string,
  ): string {
    if (typeof child === 'string' || typeof child === 'number') {
      var text = '' + child;
      if (text === '') {
        return '';
      }
      if (this.makeStaticMarkup) {
        return escapeTextContentForBrowser(text);
      }
      if (this.previousWasTextNode) {
        return '<!-- -->' + escapeTextContentForBrowser(text);
      }
      this.previousWasTextNode = true;
      return escapeTextContentForBrowser(text);
    } else {
      var nextChild;
      ({child: nextChild, context} = resolve(child, context));
      if (nextChild === null || nextChild === false) {