This is a config file for NeoVim.

1. Make sure NeoVim is installed with python3 support by running

pip2 install --user neovim
pip3 install --user neovim

2. Open .profile and add the line export NVIM=$HOME/.config/nvim, then log out and in of Ubuntu.
3. Go to config folder cd $HOME/.config/.
4. Run git clone https://github.com/holwech/nvim/.
5. cd nvim and delete the repo folder by calling rm -rf repos.
6. Make backup folder

mkdir temp
cd temp
mkdir swp backup

6. Run the install script for Dein sh ./installer.sh $NVIM.
7. Open Neovim to install the addons.
8. That's all!

Install xsel sudo apt-get install xsel.

Run the following commands

pip2 install --upgrade neovim
pip3 install --upgrade neovim
go get -u github.com/nsf/gocode

See more here here

This is probably a problem with the path variable to the go bin folder

The deoplete-clang plugin for C++ autocompletion requires clang >3.9. Make sure to have this version or higher installed, also make sure that the relevant config lines for the deoplete-clang plugin in the nvim file are pointing to the right folders.