What kind of features? With Elixir, I use the ‘click in stack trace to go to error’ feature, do some debugging, use code completion, test running - and not much else.

I’d be interested to know what other kinds of features there could or should be, as I’d like to be as productive as possible and I don’t feel like I really am.

I'm just starting to learn Elixir, but for other languages as you type in the code editor in an IDE it will auto-suggest method names and method arguments based on the libraries/modules you have included in your project.

Eclipse got this right, but the JetBrains IDEs (such as IntelliJ and CLion) are a bit heavy-handed.

The Elixir add-ons for VS Code provide this too.