If the fs detects a bit error does it flag the file as entirely unreadable? Move it to lost+found? Force me to restore the file from a backup? For files stored

If the fs detects a bit error does it flag the file as entirely unreadable? Move it to lost+found? Force me to restore the file from a backup? For files stored in iCloud Drive, if that version of the file exists in the cloud, the OS could automatically re-fetch the file. But, yeah, for lots of circumstances there's not going to be a "good" option to give the user. EDIT: Same applies to Time Machine (or whatever Apple's backup solution will be called in the APFS era).