Emacs front-end, which is consistent with binaries on Hackage, is available *stable* MELPA whose URL is http://melpa-stable.milkbox.net/packages/. So, your "~/.emacs" should be:
With this configuration you can install the stable Emacs front end indicated by "ghc" from MELPA while you can install `ghc-mod`/`ghc-modi` binaries by:
You should install both Emacs front-end and binaries from this git repo. If you use the snapshot MELPA to install Emacs front-end, you would suffer from inconsistency between Emacs front-end and binaries.