Xcode 8 does the same thing:
  https://screenshot.googleplex.com/DeTgSfbnW7b

Just tap the <!> filter button on the bottom right to ignore warnings.

Or we can upgrade the hybrid wrapper to try and fix these errors.

Ah, it looks like Xcode 8 only show this for the app you are running while Xcode 9 shows it for all apps. It never bothered me when it was just a single app since the errors were not lost in the warnings, and that's why I never noticed earlier.

I guess filtering will work for me, but fixing it (and the other warning about upgrading to recommended settings) could be worth doing it on a cold winter day when there is nothing else to do.

This issue has been Available for over a year. If it's no longer important or seems unlikely to be fixed, please consider closing it out. If it is important, please re-triage the issue.

Sorry for the inconvenience if the bug really should have been left as Available.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot