Migrating from v3.x branch

I will assume you are using Neovim v0.10 or greater.

Here you will find how to re-enable most of the features that were in the v3.x branch. If you just want to see a complete config, go to example config.

Configure nvim-lspconfig

This is all the configuration that was done automatically in the v2.x branch (plus keymaps).

-- Reserve a space in the gutter
-- This will avoid an annoying layout shift in the screen
vim.opt.signcolumn = 'yes'

-- Add borders to floating windows
vim.lsp.handlers['textDocument/hover'] = vim.lsp.with(
  vim.lsp.handlers.hover,
  {border = 'rounded'}
)
vim.lsp.handlers['textDocument/signatureHelp'] = vim.lsp.with(
  vim.lsp.handlers.signature_help,
  {border = 'rounded'}
)

-- Add cmp_nvim_lsp capabilities settings to lspconfig
-- This should be executed before you configure any language server
local lspconfig_defaults = require('lspconfig').util.default_config
lspconfig_defaults.capabilities = vim.tbl_deep_extend(
  'force',
  lspconfig_defaults.capabilities,
  require('cmp_nvim_lsp').default_capabilities()
)

-- This is where you enable features that only work
-- if there is a language server active in the file
vim.api.nvim_create_autocmd('LspAttach', {
  callback = function(event)
    local opts = {buffer = event.buf}

    vim.keymap.set('n', 'K', '<cmd>lua vim.lsp.buf.hover()<cr>', opts)
    vim.keymap.set('n', 'gd', '<cmd>lua vim.lsp.buf.definition()<cr>', opts)
    vim.keymap.set('n', 'gD', '<cmd>lua vim.lsp.buf.declaration()<cr>', opts)
    vim.keymap.set('n', 'gi', '<cmd>lua vim.lsp.buf.implementation()<cr>', opts)
    vim.keymap.set('n', 'go', '<cmd>lua vim.lsp.buf.type_definition()<cr>', opts)
    vim.keymap.set('n', 'gr', '<cmd>lua vim.lsp.buf.references()<cr>', opts)
    vim.keymap.set('n', 'gs', '<cmd>lua vim.lsp.buf.signature_help()<cr>', opts)
    vim.keymap.set('n', '<F2>', '<cmd>lua vim.lsp.buf.rename()<cr>', opts)
    vim.keymap.set({'n', 'x'}, '<F3>', '<cmd>lua vim.lsp.buf.format({async = true})<cr>', opts)
    vim.keymap.set('n', '<F4>', '<cmd>lua vim.lsp.buf.code_action()<cr>', opts)
  end,
})

Configure nvim-cmp

This is a minimal configuration to make autocompletion work.

local cmp = require('cmp')

cmp.setup({
  sources = {
    {name = 'nvim_lsp'},
  },
  snippet = {
    expand = function(args)
      require('luasnip').lsp_expand(args.body)
    end,
  },
  mapping = cmp.mapping.preset.insert({}),
})

Example Config

--[[
  Make sure you have these plugins installed:
  * neovim/nvim-lspconfig
  * hrsh7th/nvim-cmp
  * hrsh7th/cmp-nvim-lsp
  * L3MON4D3/LuaSnip
]]

local cmp = require('cmp')

cmp.setup({
  sources = {
    {name = 'nvim_lsp'},
  },
  snippet = {
    expand = function(args)
      require('luasnip').lsp_expand(args.body)
    end,
  },
  mapping = cmp.mapping.preset.insert({}),
})

-- Reserve a space in the gutter
-- This will avoid an annoying layout shift in the screen
vim.opt.signcolumn = 'yes'

-- Add borders to floating windows
vim.lsp.handlers['textDocument/hover'] = vim.lsp.with(
  vim.lsp.handlers.hover,
  {border = 'rounded'}
)
vim.lsp.handlers['textDocument/signatureHelp'] = vim.lsp.with(
  vim.lsp.handlers.signature_help,
  {border = 'rounded'}
)

-- Add cmp_nvim_lsp capabilities settings to lspconfig
-- This should be executed before you configure any language server
local lspconfig_defaults = require('lspconfig').util.default_config
lspconfig_defaults.capabilities = vim.tbl_deep_extend(
  'force',
  lspconfig_defaults.capabilities,
  require('cmp_nvim_lsp').default_capabilities()
)

-- This is where you enable features that only work
-- if there is a language server active in the file
vim.api.nvim_create_autocmd('LspAttach', {
  callback = function(event)
    local opts = {buffer = event.buf}

    vim.keymap.set('n', 'K', '<cmd>lua vim.lsp.buf.hover()<cr>', opts)
    vim.keymap.set('n', 'gd', '<cmd>lua vim.lsp.buf.definition()<cr>', opts)
    vim.keymap.set('n', 'gD', '<cmd>lua vim.lsp.buf.declaration()<cr>', opts)
    vim.keymap.set('n', 'gi', '<cmd>lua vim.lsp.buf.implementation()<cr>', opts)
    vim.keymap.set('n', 'go', '<cmd>lua vim.lsp.buf.type_definition()<cr>', opts)
    vim.keymap.set('n', 'gr', '<cmd>lua vim.lsp.buf.references()<cr>', opts)
    vim.keymap.set('n', 'gs', '<cmd>lua vim.lsp.buf.signature_help()<cr>', opts)
    vim.keymap.set('n', '<F2>', '<cmd>lua vim.lsp.buf.rename()<cr>', opts)
    vim.keymap.set({'n', 'x'}, '<F3>', '<cmd>lua vim.lsp.buf.format({async = true})<cr>', opts)
    vim.keymap.set('n', '<F4>', '<cmd>lua vim.lsp.buf.code_action()<cr>', opts)
  end,
})

-- These are just examples. Replace them with the language
-- servers you have installed in your system
require('lspconfig').gleam.setup({})
require('lspconfig').ocamllsp.setup({})