They didn't document what version of Rust they used, but our support is still fairly preliminary. For example, it wasn't until very recently that we even passed in flags to optimize the output at all. My understanding is that there's still a lot of low-hanging fruit with the integration generally.
I didn't see a link to the source. It would be really cool to see the source code so that other people could validate the work and help point out better implementation options. It's like a scientific paper not disclosing its methods.
That doesn't answer the question of "which nightly". Is this a new post? I don't see a date anywhere.
But regardless, my ultimate point is mostly "hey this stuff is brand new so some stuff not being great is to be expected." The exact details aren't very important.
