neovim/lua/lsp.lua

local on_attach = function(client, bufnr)
    local utils = require('utils')

    utils.opt("o", "omnifunc", "v:lua.vim.lsp.omnifunc")

    -- Mappings.
    utils.map("n", "K", "<Cmd>lua vim.lsp.buf.hover()<CR>")
    utils.map("n", "<C-k>", "<cmd>lua vim.lsp.buf.signature_help()<CR>")
    utils.map("n", "<M-k>", "<cmd>lua vim.lsp.buf.type_definition()<CR>")
    utils.map("n", "<M-r>", "<cmd>lua vim.lsp.buf.rename()()<CR>")

    utils.map("n", "<leader>ca", "<cmd>lua vim.lsp.buf.code_action()<CR>")

    -- list/add/remove workspace folders, not that I use them often
    utils.map("n", "<leader>wl", "<cmd>lua print(vim.inspect(vim.lsp.buf.list_workspace_folders()))<CR>")
    utils.map("n", "<leader>wa", "<cmd>lua vim.lsp.buf.add_workspace_folder()<CR>")
    utils.map("n", "<leader>wr", "<cmd>lua vim.lsp.buf.remove_workspace_folder()<CR>")

    -- Set formatting keybinds conditional on server capabilities
    if client.server_capabilities.document_formatting then
        utils.map('n', '<leader>lf', '<cmd>lua vim.lsp.buf.formatting()<CR>')
    elseif client.server_capabilities.document_range_formatting then
        utils.map('n', '<leader>lf', '<cmd>lua vim.lsp.buf.range_formatting()<CR>')
    end

    client.server_capabilities.semanticTokensProvider = nil

    -- Set autocommands conditional on server_capabilities
    if client.server_capabilities.document_highlight then
        vim.api.nvim_exec([[
        hi LspReferenceRead cterm=bold ctermbg=red guibg=LightYellow
        hi LspReferenceText cterm=bold ctermbg=red guibg=LightYellow
        hi LspReferenceWrite cterm=bold ctermbg=red guibg=LightYellow
        augroup lsp_document_highlight
        autocmd! * <buffer>
        autocmd CursorHold <buffer> lua vim.lsp.buf.document_highlight()
        autocmd CursorMoved <buffer> lua vim.lsp.buf.clear_references()
        augroup END
        ]], false)
    end
end

local nvim_lsp = require('lspconfig')
local capabilities = vim.lsp.protocol.make_client_capabilities()

-- show snippets in code completion popup
capabilities.textDocument.completion.completionItem.snippetSupport = true;

-- LSPs
local servers = {
  "lua_ls",
  "ocamllsp",
  "vimls",
  "clangd",
  "rnix",
  "pyright",
  "ruff_lsp",
}
for _, lsp in ipairs(servers) do
    nvim_lsp[lsp].setup {capabilities = capabilities, on_attach = on_attach}
end

nvim_lsp.rust_analyzer.setup({
    on_attach = on_attach,
    capabilities = capabilities,
    settings = {
        ["rust-analyzer"] = {
            imports = {
                granularity = {
                    group = "module",
                },
                prefix = "self",
            },
            cargo = {
                buildScripts = {
                    enable = true,
                },
            },
            procMacro = {
                enable = true
            },
            checkOnSave = {
                command = "clippy",
            },
        }
    }
})

vim.g.code_action_menu_window_border = 'single'

-- symbols-outline.nvim
vim.g.symbols_outline = {
    highlight_hovered_item = true,
    show_guides = true,
    auto_preview = false, -- experimental
    position = 'right',
    keymaps = {
        close = "<Esc>",
        goto_location = "<Cr>",
        focus_location = "o",
        hover_symbol = "<C-space>",
        rename_symbol = "r",
        code_actions = "a"
    },
    lsp_blacklist = {}
}

-- LSP Enable diagnostics
vim.lsp.handlers["textDocument/publishDiagnostics"] =
    vim.lsp.with(vim.lsp.diagnostic.on_publish_diagnostics, {
        virtual_text = false,
        underline = true,
        signs = true,
        update_in_insert = false
    })

-- Send diagnostics to quickfix list
do
    local method = "textDocument/publishDiagnostics"
    local default_handler = vim.lsp.handlers[method]
    vim.lsp.handlers[method] = function(err, method, result, client_id, bufnr,
                                        config)
        default_handler(err, method, result, client_id, bufnr, config)
        local diagnostics = vim.diagnostic.get()
        local qflist = {}
        for bufnr, diagnostic in pairs(diagnostics) do
            for _, d in ipairs(diagnostic) do
                d.bufnr = bufnr
                d.lnum = d.range.start.line + 1
                d.col = d.range.start.character + 1
                d.text = d.message
                table.insert(qflist, d)
            end
        end
    end
end