Rust + Neovim

This assumes you have Neovim installed already.

Install Rust. Make sure to add export PATH="$HOME/.cargo/bin:$PATH" to end of ~/.bashrc. Note: you can uninstall at anytime with rustup self uninstall.
Install rustfmt and its Vim counterpart, rust.vim
Install Rust Clippy

Getting Autocomplete in Neovim with Deoplete

You may first be required to install some Python stuff. You may want to get your pyenv setup working first. However, in a pinch, these commands have worked for me in the past:
- Install pip3 with sudo apt-get install python3-pip
- and then pip3 install neovim

Then make sure you've got all this (or something similar) in your init.vim file:

" Auto-complete
if has('nvim')
  Plug 'Shougo/deoplete.nvim', { 'do': ':UpdateRemotePlugins' }
else
  Plug 'Shougo/deoplete.nvim'
  Plug 'roxma/nvim-yarp'
  Plug 'roxma/vim-hug-neovim-rpc'
endif

" then further down
let g:deoplete#enable_at_startup = 1

rust-analyzer and LanguageServer

To get some nice Rust-specific, IDE-esque goodies in Neovim, we're going to install rust-analyzer. Below, I outline the relatively simple installation option that uses LanguageClient-neovim, though do check documentation for latest instructions.

1. Install rust-analyzer Language Server Binary

Install rust-analyzer Language Server Binary by running the following:

git clone https://github.com/rust-analyzer/rust-analyzer.git && cd rust-analyzer
cargo xtask install --server

Think this installs the project's code to ~/.config/nvim/rust-analyzer/. Executable is rust-analyzer, so can check that it's in your PATH by running rust-analyzer --version. Assume you'd upgrade by running git pull && cargo xtask install --force --server?

2. Configure by adding this to your vim/neovim config file...

...replacing the existing Rust-specific line if it exists:

let g:LanguageClient_serverCommands = {
\ 'rust': ['rust-analyzer'],
\ }

3. Get the neovim LanguageClient installed

Plug 'autozimu/LanguageClient-neovim', {
\ 'branch': 'next',
\ 'do': 'bash install.sh',
\ }

" (Optional) Multi-entry selection UI.
Plug 'junegunn/fzf'

Then down below the g:LanguageClient_serverCommands bit, let's add some mappings. The plugin's readme provides some ideas, but as a minimum:

nmap <F5> <Plug>(lcn-menu)

4. Install plugins

Back in the terminal, run nvim +PlugInstall +UpdateRemotePlugins +qa

Think you should now be good-to go? F5 will give you some options for analysis.

Notes on alternative approaches to making Neovim more of a Rust IDE

Alternative methods of installing rust-analyzer

For rust-analyzer, there is an alternative installation process described where it's integrated with coc.nvim, which you might be using anyway, or like for its other features. To me, right now, it seems a bit intense, and requires Node to be installed.

Racer

There also seems to be another way to "teach" Neovim about the Rust language using Racer ("code completion for Rust") and its associated Vim plugin, but I think I tried it before and it through halting errors as I was typing code.

Schlink's Docs