> If it was simple, there'd be an answer to this question: how do I setup Vim/Emacs as a fully feature complete IDE for C, C++, Rust, Go, Java, JavaScript (Node or Web), C#?

That's the promise of Spacemacs:

- clone their git repository into your .emacs.d directory

- run emacs once, answer three basic questions about your preferences

- add your list of languages to the "dotspacemacs-configuration-layers" list in your .spacemacs

  - I even looked up the syntax for you: "c-c++ rust go java javascript csharp"

- make it reload the config

You're done. All this should take less time than it took me to look up those "layer" names in the docs.

> By feature complete I mean autocomplete, error detection, built in one-button-runs, automatic config/sane defaults.

Yes, all that is the promise of Spacemacs.

If anything, I found it to be too much of a kitchen sink (it tries too hard to be "smart" about balancing parentheses for me etc.). Still, you might want to give it a whirl if you have 15 minutes. I ended up going back to vim for almost everything, and I'm on the line on whether to use Proof General from plain Emacs or from Spacemacs. But the time to check it out is not wasted.