Rust is in an interesting stage as a programming language. It’s gotten a lot of mindshare, and a decent amount of adoption. It’s not at the point where people are learning Rust by the droves, but there are a respectable amount of people who write Rust. As for jobs, Rust positions are not ubiquitous, though they are increasing in number. Basically, Rust is past the threshold of only being used by programming language nerds, and onto the stage of being a language that real companies depend on, i.e. an up and coming mainstream language.

Which begs the question, where is Rust going? It could level out in growth, and end up a respectable, albeit niche language. Perhaps on the order of Ruby; used in various companies, but not actively growing.

It could keep growing and end up a somewhat popular language, maybe on par with PHP or C#. Both of which are languages with massive communities, however they’re not truly ubiquitous

Or it could end up at the top, with the languages that are so popular they’re almost impossible to avoid. The A-listers of Java, Python, JavaScript, C++. Rust could become so common that people learn it in college, that companies hire Rust developers by the thousands, that entire ecosystems are built with Rust.

This may sound absurd. I don’t think it is.

What Is Rust Replacing?

If you’re like me and get most of your programming news from Hacker News, Twitter and reddit, you’d be forgiven for thinking most people are writing JavaScript and Python. And yes, a lot are. But they’re just the tip of the iceberg. Underneath is a massive, hidden undercurrent of C and C++. Almost everything you use is supported by this code. It’s device drivers, browsers, text editors, network protocol parsers, compilers, and so on. Heck, a lot of the foundational Python libraries rely on tightly optimized C and C++ code. It’s not code that’s tweeted about or posted on Hacker News. But it’s out there.

In 10 years, a significant portion of this code will be in Rust. Not all of it; Zig, Go, and other languages will certainly take a portion. Nonetheless I anticipate Rust will take a very large slice.

Why not C/C++? Well, there’s the standard answer of security issues, memory bugs, etc. Those should not be underlooked. Bugs cost money, as do security issues. Microsoft and Google have both published studies indicating that memory safety bugs cause a significant percentage of their security issues.

Furthermore, there’s the issue of hiring. Before Rust became popular, the general sentiment was that it would attract ex-C++ users and ex-functional programming users, since those were the two main lineages behind Rust. And indeed both groups were attracted. But a third group emerged of ex-scripting language users, people who wrote Ruby and JavaScript.

What people didn’t realize was that there were a large contingent of people who wanted to write systems level code but for whatever reason did not want to write C or C++. You can create all sorts of uncharitable interpretations for this phenomenon, but the reality still stands. Personally, I fall into this camp. I had dabbled with C and C++, but I never wanted to commit to writing it full time. Rust made tackling low level problems a lot more palatable.

From a hiring perspective, this opens up jobs to a wider group than before. Heck, you might not need to even hire, as you can retrain your existing JavaScript or Python developers to use Rust. This is not apparent currently, because Rust is still relatively niche, but as the language gains in popularity due to the previous factors, there will be an additional advantage to using Rust.

To recap, Rust lets you avoid memory bugs and security issues, while being palatable to a wide group of developers.

Why Not Rust?

Indeed, that is a question worth asking. And in some cases there are quite reasonable answers. Rust doesn’t support all of the same targets that C or C++ does. It doesn’t quite have the ultra-low level, super performant capabilities of C or C++. The tooling story is good, but incomplete. The borrow checker does limit some common programming patterns. These issues can all be solved with time, but as of today they are still very much concerns with Rust.

Otherwise, there’s the issue of inertia and ideology. A lot of people are sticking with C/C++ because that is what is taught and therefore that is what they know. Moreover, once they have learned C/C++, they have become accustomed to its mental model, and see Rust as an affront to that model. Much like the programmers of yore who balked at writing compiled languages instead of assembly, they have become used to a certain degree of freedom in their programming. Rust fundamentally challenges the ideology of C++, and that can create discomfort.

But as time passes, as generations come and go, more and more programmers will come of age with Rust as their initial context for systems level programming. They won’t see it as restrictive because it’ll be natural to them. As the old adage goes, science moves forward one death at a time. In a more optimistic tone, software development moves forward with every new developer.

Indeed the biggest challenge to Rust is not C, C++, Go or any established language. It’s the next language—the language that leapfrogs Rust by being a better version of it. Maybe it has a better, easier borrow checker. Maybe it’s faster to compile. Maybe it solves the orphan rule. That is the main obstacle towards Rust becoming a true A-list language. And even then, it’s quite unlikely that a new language will suddenly leapfrog Rust, given that Rust has a 15 year head start.

Beginner Friendly

This belief that Rust will win the long-term game stems from a key observation: Rust is really really beginner friendly. This may seem counterintuitive, since the borrow checker is frustrating and there are a lot of things to learn, but language complexity is only part of the story. Rust comes with simple, excellent tooling. You can jump into almost any project and build it with cargo build. There’s a built in formatter and linter that helps steer your code in the right direction. You don’t have to fiddle with compiler flags or Makefiles. This makes Rust a very compelling language to learn. The incidental complexity of setting up a tool is much more frustrating than the inherent complexity of a language.

And the error messages! Rust has fantastic error messages. They’re often so good that you can solve your issue simply by reading the message and applying the recommended solution. You can learn the borrow checker simply by writing Rust and fighting through the compiler messages. The difference between a good error message and a bad one is a long detour through StackOverflow and GitHub Issues versus a quick fix that keeps your flow state.

Packages are also massively helpful for beginners. Instead of rolling my own implementation, I can use a package written by a more qualified developer. Suddenly something like creating a SQL linter is within reach of a novice Rust developer. You can import a SQL parser, import an error printing library, and you’re off to the races! C++ has some packaging options, but nothing on this level.

Rust’s strong culture of documentation means you can jump into almost any library and figure it out. I still remember trying to learn Haskell and having to discern documentation from a function type signature. Or being really confused about where to find the damn documentation for a JavaScript library. There’s still some rough edges here, but the ecosystem is by and large excellent at documenting libraries.

One other undersung aspect is syntax. I know it’s gauche to discuss syntax as meaningful in programming language circles, but it truly is crucal for adoption. That is how beginners first interact with your language and interpret its meaning. Rust, by staying relatively close to C/C++ syntax, made it much more familiar to users than other languages with more esoteric syntax. I know that I’ve encountered OCaml or Haskell code that is so syntactically foreign that I struggle to understand it.

Other Languages

Rust can and will replace other languages too. We’re seeing a trend of JavaScript developer tools written in Rust, such as linters, compilers, build tools, etc. This is partially for performance, yes, but also because Rust is a fantastic cross-platform language. Turns out, when you’re building for 6 different targets (x86/aarch64 * macOS/Linux/Windows), you want a language that has proper abstractions around operating system APIs, file systems, encodings, etc.

Likewise, Rust could replace a lot of functional programming languages. It offers a similarly sophisticated type system, and similar safety guarantees, but with better ecosystem, better escape hatches and better performance.

Some critics have cited the complexity of borrow checking and lifetimes as a reason for OCaml or Haskell over Rust. And those are valid critiques in many cases. However, the better tooling story still makes Rust a more compelling option for many developers. OCaml is starting to improve its tooling—I’m quite excited actually to see it go through a renaissance—so if it reaches a point where it’s comparable to Rust, I could see it siphoning back some users from Rust. But until then, Rust still has the advantage.

And really, it’s not that Rust is per se better than these other languages. That’s completely subjective and there are certainly arguments against Rust. But Rust is good enough for a lot of people. It has the performance and low level capabilities that the C/C++ community desires, the type system and mutability control for the functional programming community, the ease of use for the scripting language community. By choosing Rust, there is something for everyone.

Conclusion

Rust will likely become a massively popular language in the next 10 years. It will eat into a significant chunk of the C/C++ market, as well as other languages. It will do so because of advantages in safety, hiring, beginner friendliness, tooling, cross-platform support and so on.

If you came away from this post thinking it’s just the ramblings of a Rust fanboy, then I don’t blame you. The goal of this post wasn’t to provide an even-handed perspective on Rust. Rust has plenty of flaws like slow compilation, borrow checking limitations, the orphan rule, and so on. But the benefits of Rust, especially compared to the flaws of existing languages, outweight these limitations.