Thanks for the video @vilmibm, it was great to hear your thoughts while seeing the prototype in action. This works better than I expected it to! Below are some thoughts I had while watching this:

• What would view diff do. Since I'm already looking at a diff I was confused
• I like how you can see the diff in the discarded section while you are commenting.
• I would feel some hesitation to use this because it isn't easy to toggle between the different diff hunks. Most of the time I move up and down the code a bunch before leaving a review. Making this easy and obvious would make this feel less like I have one shot to do it correctly.

Loved the video demo! 💯

I can see that this was modelled after git add --patch, one of my most often-used tools. So naturally, I would also be biased towards supporting this style of interaction.

What I find missing from this concept is a fleshed-out way for commenting on a specific line (or a set of lines). Furthermore, I think that a code review tool should allow adding comments specifically on either added lines (right side of split diff) or removed lines (left side of split diff). From your prototype, it looks like it's only possible to comment on whole chunks of diff. Did you have a vision on how to enable more precise targeting for comments?

I second all @probablycorey's points; I think you did explain what is the use-case for v: view diff in your narration, but without that explanation it was also not clear to me what would "view diff" do.

Overall, I feel that this style of interaction is promising and I'd be interested in adding it to our roadmap.