I’m a Rust user rather than a Rust developer. I have been writing Rust code since just before the 1.0 release, and have followed the development of the language since then. I believe the future of systems programming is likely to be in Rust. I am certainly invested in the Rust language. Last month I resigned from my job writing embedded C, so I could start my own company, producing IP Networking software in Rust.
The “Rust 2018” theme was Productivity, and there is still work to be done there. In my day to day programming the much mentioned “long compile times” and “RLS performance” have the most immediate impact. But the trend on both of these looks good.
I feel having frequent (3 yearly) releases is beneficial as it makes the upgrade between releases a moderate piece of work. I moved from 2015 to 2018 when I had a spare couple of hours. I did not plan the upgrade, I just had some time free so decided to do it. (The upgrade was flawless, thanks to all involved). If releases are infrequent, then the task becomes > 1 day, and its never going to be the highest priority work.
If there is to be a “Rust 2021” then I think the theme should be along the lines of “scoping”. That is, what is part of the Rust language now, what might become part of it, and what will never be part of it. A similar exercise could cover the Rust standard libraries.
I have spent many years programming in C and (despite carrying around the loaded gun) I’ve enjoyed it. I like C as a language, it is fast, compact, portable. You can look at C code and have some idea what Assembly will be produced (as long as optimizations are off!). You can predict roughly how it will perform. For me Rust 2018 is already a drop in replacement for C, and at the moment I can reason about Rust programs in roughly the same way.
As languages mature there is a tendency to add more and more features as each users needs are unique. Often it is easier to just say yes to a new feature to keep everyone happy, and well why not ? But the language gets bloated, the language loses a coherent style, and the subset of the language used starts to vary greatly between projects.
So could “Rust 2021” draw a periphery around the Rust language ? If an RFC wants to add a feature outside of this area then it should be held to a higher standard.
One thing that I hope won’t change in Rust going forward is the open constructive technical discussions that take place. The Rust core teams seem to be full of highly skilled engineers who are also humble and genuinely want to find the best technical solution, regardless of where it originated. This is a very productive and healthy culture, but easily lost, so long may it continue. Hopefully new members to the core teams will share similar traits. Sorry couldn’t resist finishing on a pun.