I'm trying to learn Haskell. I have configured Emacs for Haskell development, I followed this blog post:

<http://tim.dysinger.net/posts/2014-02-18-haskell-with-emacs.html>

The system works but I always get this error:

> 
> Error (el-get): while initializing haskell-mode: Symbol's value as variable is void: haskell-mode-map
> 
> 
> 

I looked up the files and the variable is defined, I do not know why this is happening.