Autocomplete in neovim with built-in LSP client

In the last blog post, we saw how to setup the built-in lsp client in neovim for diagnostics and such. Now we’ll see how to setup autocomplete.

First, install completion-nvim. Add this to your vimrc and run PlugInstall.

Plug 'nvim-lua/completion-nvim'

Now, in the lsp_config.lua file, you need to make some changes. The file should look like this:

lspconfig = require'lspconfig'
completion_callback = require'completion'.on_attach

lspconfig.pyls.setup{on_attach=completion_callback}
lspconfig.tsserver.setup{on_attach=completion_callback}
lspconfig.rust_analyzer.setup{on_attach=completion_callback}

This should give you completion. Now, we need a trigger to activate completion. I like the tab key. The config for this is available in the repo.

" Use <Tab> and <S-Tab> to navigate through popup menu
inoremap <expr> <Tab>   pumvisible() ? "\<C-n>" : "\<Tab>"
inoremap <expr> <S-Tab> pumvisible() ? "\<C-p>" : "\<S-Tab>"

" Set completeopt to have a better completion experience
set completeopt=menuone,noinsert,noselect

" Avoid showing message extra message when using completion
set shortmess+=c

let g:completion_enable_auto_popup = 0
imap <tab> <Plug>(completion_smart_tab)
imap <s-tab> <Plug>(completion_smart_s_tab)

Now, you can use tab and shift + tab to navigate through suggestions.