I'm honestly no expert on the subject. I have virtually zero experience with Erlang language. And I don't know a thing about Rust. However, if that counts I have read large parts of Joe Armstrong's PhD thesis about distributed systems and written plenty of Elixir.
It may be wrong to say we need a better Erlang, but for modern web development we certainly could use a fair bit more compiler enforced type safety for writing more correct programs. Mostly due to the lack of a proper type system, Erlang is not particularly expressive as a language, although its primitives (processes & message passing) are well geared exactly for what it focuses on.
Erlang focuses strongly on fault-tolerance and subsequently on high availability, but I'm not sure this perk is so significant benefit anymore compared to various other runtimes spinning the wheels of your typical web server in a cloud setup. We rarely need to write servers anymore that keep running for many years straight without a restart, only patching code via hot reloads.
Just my take but since you asked, trading some fault tolerance for more correct programs would therefore probably be a fair trade-off for a new kind of Erlang.
Yeah; I always added type annotations to my code and ran Dialyzer...I wish there was a stricter compilation mode for that. That said, I really liked the 'optimistic' part of it, so I didn't spend a large amount of time correcting my type specs when proper testing proved it work.
I can agree with bfrog's comment too; Rust's typing can definitely help eliminate a bunch of classes of bugs...but honestly I'm not sure I ever ran into them using Erlang in production anyway. Immutable data + message passing tends to make it easy to implement things correctly, whereas some of Rust's more standout features seem designed to solve problems caused by the language itself picking a different set of tradeoffs (i.e., borrow checking as part of what is necessary to manage memory without risking it going out of scope prematurely, or being unable to be reclaimed at a deterministic time by the compiler). I'm not familiar enough with Rust myself to really comment though; I just know that in two and a half years of production Erlang, the only bug we ever encountered was caused by a C driver (and our own bad design in not circuit breaking calls to it, leading to restarts that trickled up the supervisor chain under heavier load than we'd tested for. None of which would Rust have been able to help us with. In fact, even the driver, the issue was an unnecessary network call that sometimes hit an empty cache, causing a huge network hiccup that led to an unhandled timeout). It got 'correctness' as well as 'fault tolerance'. At least as much as a language can (i.e., we could still implement the wrong things, such as when we implemented an O(N^2), but correct, algorithm, that we had to fix to an O(N) when we noticed certain calls being too slow)
It may be wrong to say we need a better Erlang, but for modern web development we certainly could use a fair bit more compiler enforced type safety for writing more correct programs. Mostly due to the lack of a proper type system, Erlang is not particularly expressive as a language, although its primitives (processes & message passing) are well geared exactly for what it focuses on.
Erlang focuses strongly on fault-tolerance and subsequently on high availability, but I'm not sure this perk is so significant benefit anymore compared to various other runtimes spinning the wheels of your typical web server in a cloud setup. We rarely need to write servers anymore that keep running for many years straight without a restart, only patching code via hot reloads.
Just my take but since you asked, trading some fault tolerance for more correct programs would therefore probably be a fair trade-off for a new kind of Erlang.