[erlang-questions] Which IDE do you use for Erlang/OTP core development?

[ami]

Hi all,

I decided to understand how Erlang works from inside.
Probably I’ll even become a contributor(I hope).

I started with forking https://github.com/erlang/otp, then cloning it to my local copy.
And it’s quite big. And not only big, there are both C and Erlang sources:

1s-MacBook-Pro:otp a1$ find . -name '*.erl' | wc -l
    3650
1s-MacBook-Pro:otp a1$ find . -name '*.c' | wc -l
     547

I would say, Erlang sources mostly.

Here’s my question.

Which IDEs do you use to treat all the source tree(both Erlang & C) as a single project?
I might use one IDE for C and another for Erlang. But it’s quite ugly and inconvenient.

Though, I’m not the very first person who decided to contribute to Erlang/OTP :)
So, I think, that somebody already faced with these questions.

If you use some
  * special-designed IDEs(preferably), BTW, do they exist in nature?
  * emacs plugins(less preferably) or
  * vim plugins,

please share links, configs, etc.

The most needed features are:
* go to declaration
* code completion
* easy navigation through the code


Thanks in advance,

Alexander