And one of the absolute dog's-breakfast worst to refactor regardless of editing environment. No statically typed language should be this hard to do basic changes in, and yet it exists.
Being writable in a "simple text editor" isn't a plus when the "simple text editors" in 2020 are IDEs with the name filed off.
As long as you never refactor anything.
> Rust is among the hardest due to its complexity and demanding static analysis
I have never wanted or needed to offload Rust's "demanding static analysis" to my text editor. Rust's linearity/lifetime type system is really quite simple - it's not like you have to keep track of long-distance lifetime relationships in your head.
Even a reasonably powerful type system with e.g. HKTs, arithmetic, etc. like Haskell's rarely benefits from external tooling, and any interactivity can often be just as easily done via a polling build tool like ghcid rather than integrating it into a text editor.
The one place where it strikes me as sane to have a "smart" text editor is if you're using a proof assistant-style language like Coq/Idris/Isabelle/Liquid Haskell/etc. where there's actually a non-trivial amount of interactivity required while writing the code.
The demanding static analysis and clear compiler errors actually make it easier and more robust to write unaided for me. Especially when it comes to refactoring -- it's essentially a process of resolving the compiler errors and you can be pretty confident you've arrived at a correct result.
Source: I write Rust everyday in a plain text editor without syntax highlighting.