Canon has stated that their new full-frame mirrorless line will sit alongside their existing systems in their product lineup. That an APS-C format mirrorless in the EOS R is essentially not possible, and that EOS M will continue to live on and see development.
True to their word, a new patent has just surfaced for a potential 10mm f/2.8 Fisheye lens design. The short backfocus distance suggests that it is for a mirrorless camera with an APS-C projection size. Given that it’s APS-C, it won’t be for the EOS R, but for the EOS M line.