RBS, Ruby’s new type signature language

I've been using typescript for a few years now and to be honest I almost never rely on the compilation errors. I just use the built in Jetbrains IDE completion, autosuggestion, and navigation to make it work.

Yep. A good IDE to a first approximation doesn't allow compilation errors to occur because you are auto-completing everything, including symbol completion based on the type at cursor, etc.

Jetbrains is a wonderful company.

Since the advent of LSP, I think the value proposition of a full featured IDE has been greatly diminished.

For example, I used to use Intellij for Scala but recently switched to Emacs+Metals and haven't really missed anything. In fact, it's probably an even better editing experience.

Intellij still has better refactoring (though I don't use it much), and the integrated debugger and database viewer are really nice. I've found myself using Emacs and only switching to Intellij for the aforementioned specialized tasks.

5 years ago you would have been crazy not using an IDE for JVM work but this is no longer the case. LSP is such a wonderful technology and has empowered the creation of new programming languages like never before. It's truly remarkable.

If I was Intellij, I would be a little worried about my future market share. They simply can't provide the same value as before, and I'm not sure how they intend to change that.

I wish I had had your luck with language servers. They are fantastic when they work but in my experience configuring them is finicky and difficult, particularly with Emacs. I have also run into problems where the server crashes and does not restart itself, so the IDE functionality in my editor will just silently break and I have to go fix it. JetBrains still dominates the market for IDEs that work out of the box, and I still don't know of any LSPs that can even remotely compete with the sophistication of their static analysis tools and such.

IntelliJ's own checking has had its issues (e.g. this bug https://github.com/intellij-rust/intellij-rust/issues/5807).

However, my experience with rls/rust-analyzer with VSCode hasn't been great either. Red squiggly lines that persist even if the syntax is correct - I have to erase and type the same thing to trigger refreshed checking which is very annoying and counter-productive. Though it is possible that this is more of an integration issue considering I haven't had similar problems with Typescript on VSCode - the checking was flawless (I think typescript checking also uses a language server).

Does Metals have a feature to add parameter names at method callsites? I use that IntelliJ feature of the Scala plugin all the time, it's such a lifesaver.