diff --git a/lua/go.lua b/lua/go.lua
index 7f46985..92d93c4 100644
--- a/lua/go.lua
+++ b/lua/go.lua
@@ -121,7 +121,6 @@ function go.setup(cfg)
   vim.cmd([[command! -nargs=* GoStop lua require("go.asyncmake").stopjob(<f-args>)]])
   -- if you want to output to quickfix
 
-  local sep = require("go.utils").sep()
   -- example to running test in split buffer
   -- vim.cmd(
   --     [[command! -nargs=* -complete=custom,v:lua.package.loaded.go.package_complete GoTest  :setl makeprg=go\ test\ -v\ | lua require'go.runner'.make(<f-args>)]])
@@ -145,7 +144,9 @@ function go.setup(cfg)
   vim.cmd([[command! -nargs=* GoTestFunc   lua require('go.gotest').test_func(<f-args>)]])
 
   -- e.g. GoTestFile unit
-  vim.cmd([[command! -nargs=* -complete=custom,v:lua.package.loaded.go.package_complete GoTestFile lua require('go.gotest').test_file(<f-args>)]])
+  vim.cmd(
+    [[command! -nargs=* -complete=custom,v:lua.package.loaded.go.package_complete GoTestFile lua require('go.gotest').test_file(<f-args>)]]
+  )
   vim.cmd(
     [[command! -nargs=* -complete=custom,v:lua.package.loaded.go.package_complete GoTestPkg lua require('go.gotest').test_package(<f-args>)]]
   )
@@ -159,6 +160,9 @@ function go.setup(cfg)
   vim.cmd([[command! GoCodeLenAct   lua require("go.codelens").run_action()]])
   vim.cmd([[command! GoCodeAction   lua require("go.codeaction").run_action()]])
 
+  vim.cmd(
+    [[command! -nargs=*  -complete=custom,v:lua.package.loaded.go.modify_tags_complete GoModifyTag lua require("go.tags").modify(<f-args>)]]
+  )
   vim.cmd([[command! -nargs=* GoAddTag lua require("go.tags").add(<f-args>)]])
   vim.cmd([[command! -nargs=* GoRmTag lua require("go.tags").rm(<f-args>)]])
   vim.cmd(
@@ -182,7 +186,7 @@ function go.setup(cfg)
 
   vim.cmd([[command!          GoClearTag lua require("go.tags").clear()]])
   vim.cmd([[command!          GoCmt lua require("go.comment").gen()]])
-  vim.cmd([[command!          GoRename lua require("go.rename").run()]])
+  vim.cmd([[command!          GoRename lua require("go.rename").lsprename()]])
   vim.cmd([[command!          GoIfErr lua require("go.iferr").run()]])
   vim.cmd([[command!          GoFillStruct lua require("go.reftool").fillstruct()]])
   vim.cmd([[command!          GoFillSwitch lua require("go.reftool").fillswitch()]])
@@ -260,13 +264,14 @@ go.set_test_runner = function(runner)
   vim.notify("runner not supported " .. runner, vim.lsp.log_levels.ERROR)
 end
 
-go.dbg_complete = function(arglead, cmdline, cursorpos)
+-- go.dbg_complete = function(arglead, cmdline, cursorpos)
+go.dbg_complete = function(_, _, _)
   --  richgo, go test, richgo, dlv, ginkgo
   local testopts = { "--test", "--nearest", "--file", "--package", "--attach", "--stop", "--restart" }
   return table.concat(testopts, "\n")
 end
 
-go.tools_complete = function(arglead, cmdline, cursorpos)
+go.tools_complete = function(_, _, _)
   local gotools = require("go.install").gotools
   table.sort(gotools)
   return table.concat(gotools, "\n")
@@ -280,4 +285,16 @@ go.impl_complete = function(arglead, cmdline, cursorpos)
   -- return table.concat(testopts, "\n")
 end
 
+go.modify_tags_complete = function(_, _, _)
+  local opts = {
+    "-add-tags",
+    "-add-options",
+    "-remove-tags",
+    "-remove-options",
+    "-clear-tags",
+    "-clear-options",
+  }
+  return table.concat(opts, "\n")
+end
+
 return go
diff --git a/lua/go/alternate.lua b/lua/go/alternate.lua
index 1d5f355..2506701 100644
--- a/lua/go/alternate.lua
+++ b/lua/go/alternate.lua
@@ -6,8 +6,8 @@ function M.alternate()
     vim.notify("no buffer name", vim.lsp.log_levels.ERROR)
     return
   end
-  local s, e = string.find(file, "_test%.go$")
-  local s2, e2 = string.find(file, "%.go$")
+  local s  = string.find(file, "_test%.go$")
+  local s2 = string.find(file, "%.go$")
   if s ~= nil then
     alt_file = string.gsub(file, "_test.go", ".go")
   elseif s2 ~= nil then
diff --git a/lua/go/asyncmake.lua b/lua/go/asyncmake.lua
index 3629b0c..0ff950e 100644
--- a/lua/go/asyncmake.lua
+++ b/lua/go/asyncmake.lua
@@ -66,9 +66,9 @@ function M.make(...)
   local bufnr = vim.api.nvim_win_get_buf(winnr)
   local makeprg = vim.api.nvim_buf_get_option(bufnr, "makeprg")
 
-  local optarg, optind, reminder = getopt.get_opts(args, short_opts, long_opts)
+  local optarg, _, reminder = getopt.get_opts(args, short_opts, long_opts)
   log(makeprg, args, optarg, reminder)
-  local indent = "%\\%(    %\\)"
+  -- local indent = "%\\%(    %\\)"
   if not makeprg then
     log("makeprog not setup")
     return
@@ -242,7 +242,7 @@ function M.make(...)
           efm = efm,
         })
         failed = true
-        log(errorlines[1])
+        log(errorlines[1], job_id)
         vim.cmd([[echo v:shell_error]])
       elseif #lines > 0 then
         vim.fn.setqflist({}, " ", {
diff --git a/lua/go/codeaction.lua b/lua/go/codeaction.lua
index b0aab08..2a4f7fa 100644
--- a/lua/go/codeaction.lua
+++ b/lua/go/codeaction.lua
@@ -1,6 +1,5 @@
 local utils = require("go.utils")
 local log = utils.log
-local api = vim.api
 
 -- ONLY SUPPORT GOPLS
 
diff --git a/lua/go/codelens.lua b/lua/go/codelens.lua
index 8cbbb2b..d2c2d0f 100644
--- a/lua/go/codelens.lua
+++ b/lua/go/codelens.lua
@@ -1,7 +1,5 @@
 local utils = require("go.utils")
-local log = utils.log
 local codelens = require("vim.lsp.codelens")
-local api = vim.api
 
 local M = {}
 
diff --git a/lua/go/coverage.lua b/lua/go/coverage.lua
index 2f32512..78c0774 100644
--- a/lua/go/coverage.lua
+++ b/lua/go/coverage.lua
@@ -2,10 +2,11 @@ local utils = require("go.utils")
 local log = utils.log
 local coverage = {}
 local api = vim.api
+local vfn = vim.fn
 local empty = utils.empty
 local M = {}
 local visable = false
-_GO_NVIM_CFG = _GO_NVIM_CFG
+-- _GO_NVIM_CFG = _GO_NVIM_CFG or {}
 local sign_define_cache = {}
 
 M.sign_map = { covered = "goCoverageCovered", uncover = "goCoverageUncover" }
@@ -20,7 +21,7 @@ local function sign_get(bufnr, name)
     sign_define_cache[bufnr] = {}
   end
   if not sign_define_cache[bufnr][name] then
-    local s = vim.fn.sign_getdefined(name)
+    local s = vfn.sign_getdefined(name)
     if not vim.tbl_isempty(s) then
       sign_define_cache[bufnr][name] = s
     end
@@ -31,10 +32,10 @@ end
 -- all windows and buffers
 local function all_bufnr()
   local bufnrl = {}
-  local buffers = vim.fn.getbufinfo({ bufloaded = 1, buflisted = 1 })
+  local buffers = vfn.getbufinfo({ bufloaded = 1, buflisted = 1 })
 
   for _, b in pairs(buffers) do
-    if not (vim.fn.empty(b.name) == 1 or b.hidden == 1) then
+    if not (vfn.empty(b.name) == 1 or b.hidden == 1) then
       local name = b.name
 
       local ext = string.sub(name, #name - 2)
@@ -53,20 +54,20 @@ function M.define(bufnr, name, opts, redefine)
   -- vim.notify(bufnr .. name .. opts .. redefine, vim.lsp.log_levels.DEBUG)
   if redefine then
     sign_define_cache[bufnr][name] = nil
-    vim.fn.sign_undefine(name)
-    vim.fn.sign_define(name, opts)
+    vfn.sign_undefine(name)
+    vfn.sign_define(name, opts)
   elseif not sign_get(name) then
     -- log("define sign", name, vim.inspect(opts))
-    vim.fn.sign_define(name, opts)
+    vfn.sign_define(name, opts)
   end
   -- vim.cmd([[sign list]])
 end
 
 function M.remove(bufnr, lnum)
   if bufnr == nil then
-    bufnr = vim.fn.bufnr("$")
+    bufnr = vfn.bufnr("$")
   end
-  vim.fn.sign_unplace(ns, { buffer = bufnr, id = lnum })
+  vfn.sign_unplace(ns, { buffer = bufnr, id = lnum })
 end
 
 local function remove_all()
@@ -100,7 +101,7 @@ function M.add(bufnr, signs)
   end
 
   -- log("placing", to_place)
-  vim.fn.sign_placelist(to_place)
+  vfn.sign_placelist(to_place)
   return to_place -- for testing
 end
 
@@ -115,7 +116,7 @@ M.highlight = function()
 end
 
 local function augroup()
-  vim.cmd([[ augroup gopher.vim-coverage                                         ]])
+  vim.cmd([[ augroup gopher_vim_coverage                                         ]])
   vim.cmd([[   au!                                                               ]])
   vim.cmd([[   au ColorScheme *    lua require'go.coverage'.highlight()          ]])
   vim.cmd([[   au BufWinLeave *.go lua require'go.coverage'remove()              ]])
@@ -126,11 +127,7 @@ end
 local function enable_all()
   local bufnrs = all_bufnr()
   for _, bufnr in pairs(bufnrs) do
-    -- enable
-    -- local bufnr = vim.fn.winbufnr(id)
-    local fn = vim.fn.bufname(bufnr)
-
-    local filename = vim.fn.fnamemodify(fn, ":t")
+    local fn = vfn.bufname(bufnr)
     if coverage[fn] ~= nil then
       M.add(bufnr, coverage[fn])
     end
@@ -151,13 +148,13 @@ M.toggle = function(show)
 end
 
 local function parse_line(line)
-  local m = vim.fn.matchlist(line, [[\v([^:]+):(\d+)\.(\d+),(\d+)\.(\d+) (\d+) (\d+)]])
+  local m = vfn.matchlist(line, [[\v([^:]+):(\d+)\.(\d+),(\d+)\.(\d+) (\d+) (\d+)]])
 
   if empty(m) then
     return {}
   end
   local path = m[2]
-  local filename = vim.fn.fnamemodify(m[2], ":t")
+  local filename = vfn.fnamemodify(m[2], ":t")
   return {
     file = path,
     filename = filename,
@@ -170,26 +167,26 @@ local function parse_line(line)
   }
 end
 
-if vim.tbl_isempty(vim.fn.sign_getdefined(sign_covered)) then
-  vim.fn.sign_define(sign_covered, {
+if vim.tbl_isempty(vfn.sign_getdefined(sign_covered)) then
+  vfn.sign_define(sign_covered, {
     text = _GO_NVIM_CFG.gocoverage_sign,
     texthl = "goCoverageCovered",
   })
 end
 
-if vim.tbl_isempty(vim.fn.sign_getdefined(sign_uncover)) then
-  vim.fn.sign_define(sign_uncover, {
+if vim.tbl_isempty(vfn.sign_getdefined(sign_uncover)) then
+  vfn.sign_define(sign_uncover, {
     text = _GO_NVIM_CFG.gocoverage_sign,
     texthl = "goCoverageUncover",
   })
 end
 
 M.read_cov = function(covfn)
-  if vim.fn.filereadable(covfn) == 0 then
+  if vfn.filereadable(covfn) == 0 then
     vim.notify(string.format("cov file not exist: %s", covfn), vim.lsp.log_levels.WARN)
     return
   end
-  local cov = vim.fn.readfile(covfn)
+  local cov = vfn.readfile(covfn)
   -- log(vim.inspect(cov))
   for _, line in pairs(cov) do
     local cl = parse_line(line)
@@ -207,8 +204,8 @@ M.read_cov = function(covfn)
   local added = {}
   for _, bid in pairs(bufnrs) do
     -- if added[bid] == nil then
-    local fn = vim.fn.bufname(bid)
-    fn = vim.fn.fnamemodify(fn, ":t")
+    local fn = vfn.bufname(bid)
+    fn = vfn.fnamemodify(fn, ":t")
     log(bid, fn)
     M.add(bid, coverage[fn])
     visable = true
@@ -220,8 +217,8 @@ end
 
 M.run = function(...)
   local get_build_tags = require("go.gotest").get_build_tags
-  -- local cov = vim.fn.tempname()
-  local pwd = vim.fn.getcwd()
+  -- local cov = vfn.tempname()
+  local pwd = vfn.getcwd()
   local cov = pwd .. utils.sep() .. "cover.cov"
 
   local args = { ... }
@@ -256,7 +253,6 @@ M.run = function(...)
 
   log("run coverage", cmd)
 
-  local argsstr = ""
   if _GO_NVIM_CFG.run_in_floaterm then
     cmd = table.concat(cmd, " ")
     if empty(args2) then
@@ -268,9 +264,9 @@ M.run = function(...)
     return
   end
 
-  local j = vim.fn.jobstart(cmd, {
+  vfn.jobstart(cmd, {
     on_stdout = function(jobid, data, event)
-      log("go coverage " .. vim.inspect(data))
+      log("go coverage " .. vim.inspect(data),  jobid, event)
       vim.list_extend(lines, data)
     end,
     on_stderr = function(job_id, data, event)
@@ -298,13 +294,13 @@ M.run = function(...)
       local lp = table.concat(lines, "\n")
       vim.notify(string.format("test finished:\n %s", lp), vim.lsp.log_levels.INFO)
       coverage = M.read_cov(cov)
-      vim.fn.setqflist({}, " ", {
+      vfn.setqflist({}, " ", {
         title = cmd,
         lines = lines,
         efm = vim.o.efm .. [[,]] .. require("go.gotest").efm(),
       })
-      vim.api.nvim_command("doautocmd QuickFixCmdPost")
-      vim.fn.delete(cov)
+      api.nvim_command("doautocmd QuickFixCmdPost")
+      vfn.delete(cov)
     end,
   })
 end
diff --git a/lua/go/dap.lua b/lua/go/dap.lua
index a446bef..fde1092 100644
--- a/lua/go/dap.lua
+++ b/lua/go/dap.lua
@@ -128,7 +128,7 @@ M.save_brks = function()
   local bks = require("dap.breakpoints").get()
   local all_bks = {}
   if bks and next(bks) then
-    local cfg, fld = require("go.project").setup()
+    local _, fld = require("go.project").setup()
     for bufnr, bk in pairs(bks) do
       local uri = vim.uri_from_bufnr(bufnr)
       local _bk = {}
@@ -181,7 +181,7 @@ M.clear_bks = function()
     if not vim.api.nvim_buf_is_loaded(bufnr) then
       vim.fn.bufload(bufnr)
     end
-    for index, lnum in ipairs(brk) do
+    for _, lnum in ipairs(brk) do
       require("dap.breakpoints").set({}, bufnr, lnum.line)
     end
   end
diff --git a/lua/go/format.lua b/lua/go/format.lua
index 0946208..bd53caa 100644
--- a/lua/go/format.lua
+++ b/lua/go/format.lua
@@ -6,6 +6,7 @@ local log = utils.log
 local max_len = _GO_NVIM_CFG.max_line_len or 120
 local goimport = _GO_NVIM_CFG.goimport or "goimports"
 local gofmt = _GO_NVIM_CFG.gofmt or "gofumpt"
+local vfn = vim.fn
 local gofmt_args = _GO_NVIM_CFG.gofmt_args or {
   "--max-len=" .. tostring(max_len),
   "--base-formatter=" .. gofmt,
@@ -22,7 +23,7 @@ local run = function(fmtargs, bufnr, cmd)
   bufnr = bufnr or 0
   if _GO_NVIM_CFG.gofmt == "gopls" then
     if not vim.api.nvim_buf_is_loaded(bufnr) then
-      vim.fn.bufload(bufnr)
+      vfn.bufload(bufnr)
     end
 
     vim.cmd("write")
@@ -35,7 +36,7 @@ local run = function(fmtargs, bufnr, cmd)
   log("formatting buffer... " .. vim.inspect(args), vim.lsp.log_levels.DEBUG)
 
   if bufnr == 0 then
-    if vim.fn.getbufinfo("%")[1].changed == 1 then
+    if vfn.getbufinfo("%")[1].changed == 1 then
       vim.cmd("write")
     end
   end
@@ -48,8 +49,8 @@ local run = function(fmtargs, bufnr, cmd)
   end
   log("fmt cmd:", args)
 
-  local j = vim.fn.jobstart(args, {
-    on_stdout = function(job_id, data, event)
+  local j = vfn.jobstart(args, {
+    on_stdout = function(_, data, _)
       data = utils.handle_job_data(data)
       if not data then
         return
@@ -64,19 +65,18 @@ local run = function(fmtargs, bufnr, cmd)
       -- log("stdout" .. vim.inspect(data))
       old_lines = nil
     end,
-    on_stderr = function(job_id, data, event)
+    on_stderr = function(_, data, _)
       data = utils.handle_job_data(data)
       log(vim.inspect(data) .. "from stderr")
     end,
-    on_exit = function(id, data, event)
+    on_exit = function(_, data, _)  -- id, data, event
       -- log(vim.inspect(data) .. "exit")
-      -- log("current data " .. vim.inspect(new_lines))
       if data.code ~= 0 then
         return vim.notify("golines failed " .. tostring(data), vim.lsp.log_levels.ERROR)
       end
       old_lines = nil
       vim.defer_fn(function()
-        if vim.fn.getbufinfo("%")[1].changed == 1 then
+        if vfn.getbufinfo("%")[1].changed == 1 then
           vim.cmd("write")
         end
       end, 300)
@@ -84,8 +84,8 @@ local run = function(fmtargs, bufnr, cmd)
     stdout_buffered = true,
     stderr_buffered = true,
   })
-  vim.fn.chansend(j, old_lines)
-  vim.fn.chanclose(j, "stdin")
+  vfn.chansend(j, old_lines)
+  vfn.chanclose(j, "stdin")
 end
 
 local M = {}
@@ -98,7 +98,7 @@ M.gofmt = function(...)
   local args = ... or {}
 
   local getopt = require("go.alt_getopt")
-  local optarg, optind, reminder = getopt.get_opts(args, short_opts, long_opts)
+  local optarg = getopt.get_opts(args, short_opts, long_opts)
   log(optarg)
 
   vim.env.GO_FMT = "gofumpt"
@@ -121,7 +121,7 @@ M.gofmt = function(...)
       run(a, b.bufnr)
     end
   else
-    if vim.fn.getbufinfo("%")[1].changed == 1 then
+    if vfn.getbufinfo("%")[1].changed == 1 then
       vim.cmd("write")
     end
     run(a, 0)
@@ -139,7 +139,7 @@ end
 M.goimport = function(...)
   local args = { ... }
   if _GO_NVIM_CFG.goimport == "gopls" then
-    if vim.fn.empty(args) == 1 then
+    if vfn.empty(args) == 1 then
       return M.org_imports(1000)
     else
       local path = select(1, ...)
@@ -147,7 +147,6 @@ M.goimport = function(...)
       return gopls.import(path)
     end
   end
-  local a1 = select(1, args)
   local buf = vim.api.nvim_get_current_buf()
   require("go.install").install(goimport)
   -- specified the pkg name
diff --git a/lua/go/ginkgo.lua b/lua/go/ginkgo.lua
index 6065c15..aeeb644 100644
--- a/lua/go/ginkgo.lua
+++ b/lua/go/ginkgo.lua
@@ -2,6 +2,7 @@
 local M = {}
 local utils = require("go.utils")
 local log = utils.log
+local vfn = vim.fn
 local long_opts = {
   verbose = "v",
   compile = "c",
@@ -17,7 +18,7 @@ local short_opts = "vct:bsF"
 local function get_build_tags(args)
   local tags = {}
 
-  local optarg, optind, reminder = getopt.get_opts(args, short_opts, long_opts)
+  local optarg = getopt.get_opts(args, short_opts, long_opts)
   if optarg['t'] then
     table.insert(tags, optarg['t'])
   end
@@ -63,8 +64,8 @@ end
 M.test_func = function(...)
   local args = { ... }
   log(args)
-  local optarg, optind, reminder = getopt.get_opts(args, short_opts, long_opts)
-  local fpath = vim.fn.expand("%:p:h")
+  local optarg = getopt.get_opts(args, short_opts, long_opts)
+  local fpath = vfn.expand("%:p:h")
 
   local row, col = unpack(vim.api.nvim_win_get_cursor(0))
   row, col = row, col + 1
@@ -104,8 +105,8 @@ M.test_file = function(...)
   local args = { ... }
   log(args)
   -- require sed
-  local fpath = vim.fn.expand("%:p:h")
-  local fname = vim.fn.expand("%:p")
+  local fpath = vfn.expand("%:p:h")
+  local fname = vfn.expand("%:p")
 
   log(fpath, fname)
 
diff --git a/lua/go/godoc.lua b/lua/go/godoc.lua
index 1ffbf15..f35c1b1 100644
--- a/lua/go/godoc.lua
+++ b/lua/go/godoc.lua
@@ -2,19 +2,20 @@ local utils = require("go.utils")
 local log = utils.log
 local gopls = require("go.gopls")
 local help_items = {}
+local vfn = vim.fn
 local m = {}
-function m.help_complete(arglead, cmdline, cursorpos)
+function m.help_complete(_, _, _)
   if #help_items < 1 then
-    local doc = vim.fn.systemlist("go help")
+    local doc = vfn.systemlist("go help")
     if vim.v.shell_error ~= 0 then
       vim.notify(string.format("failed to run go help %d", vim.v.shell_error), vim.lsp.log_levels.ERROR)
       return
     end
 
     for _, line in ipairs(doc) do
-      local m = string.match(line, "^%s+([%w-]+)")
-      if m ~= nil and m ~= "go" then
-        table.insert(help_items, m)
+      local m1 = string.match(line, "^%s+([%w-]+)")
+      if m1 ~= nil and m1 ~= "go" then
+        table.insert(help_items, m1)
       end
     end
     table.sort(help_items)
@@ -42,7 +43,7 @@ end
 
 local function match_partial_item_name(pkg, pattern)
   local cmd = string.format("go doc %s", pkg)
-  local doc = vim.fn.systemlist(cmd)
+  local doc = vfn.systemlist(cmd)
   if vim.v.shell_error ~= 0 then
     return
   end
@@ -71,7 +72,7 @@ local function match_partial_item_name(pkg, pattern)
   return items
 end
 
-function m.doc_complete(arglead, cmdline, cursorpos)
+function m.doc_complete(_, cmdline, _)
   local words = vim.split(cmdline, "%s+")
   if string.match(words[#words], "^-") then
     log(words)
@@ -113,7 +114,7 @@ function m.doc_complete(arglead, cmdline, cursorpos)
   return ""
 end
 
-m.run = function(kind, func, ...)
+m.run = function(kind, func)
   log(func)
 
   if func == nil or next(func) == nil then
@@ -123,8 +124,8 @@ m.run = function(kind, func, ...)
 
   local setup = { "go", kind, unpack(func) }
   --
-  local j = vim.fn.jobstart(setup, {
-    on_stdout = function(jobid, data, event)
+  vfn.jobstart(setup, {
+    on_stdout = function(_, data, _)
       data = utils.handle_job_data(data)
       if not data then
         return
diff --git a/lua/go/golint.lua b/lua/go/golint.lua
new file mode 100644
index 0000000..b1c510f
--- /dev/null
+++ b/lua/go/golint.lua
@@ -0,0 +1,26 @@
+-- local ts_utils = require 'nvim-treesitter.ts_utils'
+local utils = require("go.utils")
+
+local golangci_lint = "golangci-lint"
+local run = function(...)
+  require("go.install").install(golangci_lint)
+  local fname = vim.fn.expand("%:p") -- %:p:h ? %:p
+
+  local cmd = string.format("golangci-lint -pos %d", byte_offset)
+
+  local data = vim.fn.systemlist(cmd, vim.fn.bufnr("%"))
+
+  data = utils.handle_job_data(data)
+  if not data then
+    return
+  end
+
+  local pos = vim.fn.getcurpos()[2]
+  vim.fn.append(pos, data)
+
+  vim.cmd("silent normal! j=2j")
+  vim.fn.setpos(".", pos)
+  vim.cmd("silent normal! 4j")
+  --
+end
+return { run = run }
diff --git a/lua/go/gopls.lua b/lua/go/gopls.lua
index f777581..63e58ca 100644
--- a/lua/go/gopls.lua
+++ b/lua/go/gopls.lua
@@ -1,5 +1,6 @@
 local utils = require("go.utils")
 local log = utils.log
+local vfn = vim.fn
 
 local M = {}
 local cmds = {}
@@ -108,17 +109,17 @@ end
 
 -- check_for_upgrades({Modules = {'package'}})
 function M.version()
-  local cache_dir = vim.fn.stdpath("cache")
+  local cache_dir = vfn.stdpath("cache")
   local path = string.format("%s%sversion.txt", cache_dir, utils.sep())
   local cfg = _GO_NVIM_CFG or {}
   local gopls = cfg.gopls_cmd or { "gopls" }
 
-  if vim.fn.executable(gopls[1]) == 0 then
+  if vfn.executable(gopls[1]) == 0 then
     vim.notify("gopls not found", vim.log.levels.WARN)
     return
   end
-  vim.fn.jobstart({ gopls[1], "version" }, {
-    on_stdout = function(c, data, name)
+  vfn.jobstart({ gopls[1], "version" }, {
+    on_stdout = function(_, data, _)
       local msg = ""
       if type(data) == "table" and #data > 0 then
         data = table.concat(data, " ")
@@ -147,7 +148,7 @@ function M.version()
   local f = io.open(path, "r")
   if f == nil then
     local version_cmd = gopls[1] .. " version"
-    return vim.fn.system(version_cmd):match("%s+v([%d%.]+)%s+")
+    return vfn.system(version_cmd):match("%s+v([%d%.]+)%s+")
   end
   local version = f:read("*l")
   f:close()
diff --git a/lua/go/gotest.lua b/lua/go/gotest.lua
index dc15f16..a2be26b 100644
--- a/lua/go/gotest.lua
+++ b/lua/go/gotest.lua
@@ -5,6 +5,7 @@ local log = utils.log
 local empty = utils.empty
 local ginkgo = require("go.ginkgo")
 local getopt = require("go.alt_getopt")
+local vfn = vim.fn
 
 local long_opts = {
   verbose = "v",
@@ -20,7 +21,7 @@ local short_opts = "vct:bsF"
 local bench_opts = { "-benchmem", "-cpuprofile", "profile.out" }
 
 M.efm = function()
-  local indent = [[%\\%(    %\\)]]
+  -- local indent = [[%\\%(    %\\)]]
   local efm = [[%-G=== RUN   %.%#]]
   efm = efm .. [[,%-G" .. indent .. "%#--- PASS: %.%#]]
   efm = efm .. [[,%G--- FAIL: %\\%(Example%\\)%\\@=%m (%.%#)]]
@@ -55,7 +56,7 @@ M.get_build_tags = function(args)
     tags = { _GO_NVIM_CFG.build_tags }
   end
 
-  local optarg, optind, reminder = getopt.get_opts(args, short_opts, long_opts)
+  local optarg, _, reminder = getopt.get_opts(args, short_opts, long_opts)
   if optarg["t"] then
     table.insert(tags, optarg["t"])
   end
@@ -65,25 +66,25 @@ M.get_build_tags = function(args)
 end
 
 local function richgo(cmd)
-  if cmd[1] == "go" and vim.fn.executable("richgo") then
+  if cmd[1] == "go" and vfn.executable("richgo") then
     cmd[1] = "richgo"
   end
   return cmd
 end
 
 local function get_test_filebufnr()
-  local fn = vim.fn.expand("%")
+  local fn = vfn.expand("%")
   log(fn)
 
   local bufnr = vim.api.nvim_get_current_buf()
   if not fn:find("test%.go$") then
     fn = require("go.alternate").alternate()
-    fn = vim.fn.fnamemodify(fn, ":p") -- expand to full path
+    fn = vfn.fnamemodify(fn, ":p") -- expand to full path
     local uri = vim.uri_from_fname(fn)
     bufnr = vim.uri_to_bufnr(uri)
     log(fn, bufnr, uri)
     if not vim.api.nvim_buf_is_loaded(bufnr) then
-      vim.fn.bufload(bufnr)
+      vfn.bufload(bufnr)
     end
   end
   return bufnr
@@ -94,9 +95,9 @@ local function run_test(path, args)
   log(args)
   local compile = false
   local bench = false
-  local optarg, optind, reminder = getopt.get_opts(args, short_opts, long_opts)
+  local optarg, _, reminder = getopt.get_opts(args, short_opts, long_opts)
   if optarg["c"] then
-    path = utils.rel_path(true) -- vim.fn.expand("%:p:h") can not resolve releative path
+    path = utils.rel_path(true) -- vfn.expand("%:p:h") can not resolve releative path
     compile = true
   end
   if optarg["b"] then
@@ -183,9 +184,9 @@ M.test = function(...)
   }
 
   local test_short_opts = "vct:bsfnpF"
-  local optarg, optind, reminder = getopt.get_opts(args, test_short_opts, test_opts)
+  local optarg, _, reminder = getopt.get_opts(args, test_short_opts, test_opts)
 
-  vim.fn.setqflist({})
+  vfn.setqflist({})
 
   if optarg["n"] then --nearest
     optarg["n"] = nil
@@ -234,7 +235,7 @@ end
 M.test_package = function(...)
   local args = { ... }
   log(args)
-  local fpath = "." .. sep .. vim.fn.fnamemodify(vim.fn.expand("%:h"), ":.") .. sep .. "..."
+  local fpath = "." .. sep .. vfn.fnamemodify(vfn.expand("%:h"), ":.") .. sep .. "..."
   utils.log("fpath: " .. fpath)
   return run_test(fpath, args)
 end
@@ -246,6 +247,9 @@ M.get_test_func_name = function()
   if empty(ns) then
     return nil
   end
+  if ns == nil or ns.name == nil then
+    return nil
+  end
   if not string.find(ns.name, "[T|t]est") then
     -- not in a test function
     local fns = M.get_testfunc()
@@ -265,11 +269,11 @@ M.test_func = function(...)
   local args = { ... }
   log(args)
 
-  ns = M.get_test_func_name()
+  local ns = M.get_test_func_name()
   if empty(ns) then
     return M.select_tests()
   end
-  local optarg, optind, reminder = getopt.get_opts(args, short_opts, long_opts)
+  local optarg, _, reminder = getopt.get_opts(args, short_opts, long_opts)
   local tags = M.get_build_tags(args)
   utils.log("parnode" .. vim.inspect(ns))
 
@@ -302,6 +306,9 @@ M.test_func = function(...)
   if tags and tags ~= "" then
     table.insert(cmd, tags)
   end
+  if ns == nil or ns.name == nil then
+    return
+  end
 
   if ns.name:find("Bench") then
     local bench = "-bench=" .. ns.name
@@ -312,7 +319,7 @@ M.test_func = function(...)
     table.insert(cmd, [[^]] .. ns.name)
   end
 
-  local fpath = "." .. sep .. vim.fn.fnamemodify(vim.fn.expand("%:h"), ":.")
+  local fpath = "." .. sep .. vfn.fnamemodify(vfn.expand("%:h"), ":.")
   table.insert(cmd, fpath)
 
   if test_runner == "dlv" then
@@ -344,24 +351,24 @@ M.test_file = function(...)
 
   -- require sed
   -- local testcases = [[sed -n 's/func.*\(Test.*\)(.*/\1/p' | xargs | sed 's/ /\\\|/g']]
-  -- local fpath = vim.fn.expand("%:p")
+  -- local fpath = vfn.expand("%:p")
 
-  local fpath = "." .. sep .. vim.fn.fnamemodify(vim.fn.expand("%:p"), ":.")
+  local fpath = "." .. sep .. vfn.fnamemodify(vfn.expand("%:p"), ":.")
   -- utils.log(args)
   local cmd = [[cat ]] .. fpath .. [[| sed -n 's/func.*\(Test.*\)(.*/\1/p' | xargs | sed 's/ /\|/g']]
   -- TODO maybe with treesitter or lsp list all functions in current file and regex with Test
-  if vim.fn.executable("sed") == 0 then
+  if vfn.executable("sed") == 0 then
     M.test_package(...)
     return
   end
 
-  local optarg, optind, reminder = getopt.get_opts(args, short_opts, long_opts)
+  local optarg, _, reminder = getopt.get_opts(args, short_opts, long_opts)
 
   local run_in_floaterm = optarg["F"] or _GO_NVIM_CFG.run_in_floaterm
-  local tests = vim.fn.systemlist(cmd)
+  local tests = vfn.systemlist(cmd)
   utils.log(cmd, tests)
   tests = tests[1]
-  if vim.fn.empty(tests) == 1 then
+  if vfn.empty(tests) == 1 then
     vim.notify("no test found fallback to package test", vim.lsp.log_levels.DEBUG)
     M.test_package(...)
     return
@@ -434,7 +441,7 @@ M.run_file = function()
   local query = vim.treesitter.parse_query("go", require("go.ts.textobjects").query_test_func)
 
   local test_names = {}
-  for id, node, metadata in query:iter_captures(tree:root(), bufnr, 0, -1) do
+  for id, node  in query:iter_captures(tree:root(), bufnr, 0, -1) do
     local name = query.captures[id] -- name of the capture in the query
     if name == "test_name" then
       table.insert(test_names, vim.treesitter.query.get_node_text(node, bufnr))
@@ -457,7 +464,7 @@ M.get_testfunc = function()
   local query = vim.treesitter.parse_query("go", require("go.ts.go").query_test_func)
 
   local test_names = {}
-  for id, node, metadata in query:iter_captures(tree:root(), bufnr, 0, -1) do
+  for id, node in query:iter_captures(tree:root(), bufnr, 0, -1) do
     local name = query.captures[id] -- name of the capture in the query
     if name == "test_name" then
       table.insert(test_names, vim.treesitter.query.get_node_text(node, bufnr))
diff --git a/lua/go/gotests.lua b/lua/go/gotests.lua
index b37783a..25df994 100644
--- a/lua/go/gotests.lua
+++ b/lua/go/gotests.lua
@@ -47,7 +47,9 @@ ut.fun_test = function(parallel)
   if empty(ns) then
     return
   end
-
+  if ns == nil or ns.name == nil then
+    return
+  end
   -- utils.log("parnode" .. vim.inspect(ns))
   local funame = ns.name
   -- local rs, re = ns.dim.s.r, ns.dim.e.r
diff --git a/lua/go/health.lua b/lua/go/health.lua
index 8dcdd32..469e2db 100644
--- a/lua/go/health.lua
+++ b/lua/go/health.lua
@@ -10,12 +10,13 @@ local ok = health.report_ok
 local error = health.report_error
 local warn = health.report_warn
 local info = health.report_info
+local vfn = vim.fn
 
 local function binary_check()
   health.report_start("Binaries")
   local no_err = true
   local go_bin = _GO_NVIM_CFG.go or "go"
-  if vim.fn.executable(go_bin) == 1 then
+  if vfn.executable(go_bin) == 1 then
     info(go_bin .. " installed.")
   else
     error(go_bin .. " is not installed.")
@@ -23,7 +24,7 @@ local function binary_check()
   end
   for _, val in ipairs(tools) do
     log(val)
-    if vim.fn.executable(val) == 1 then
+    if vfn.executable(val) == 1 then
       info("Tool installed: " .. val)
     else
       warn("Missing tool: " .. val)
@@ -33,19 +34,19 @@ local function binary_check()
     ok("All binaries installed")
   end
 
-  if vim.fn.executable('sed') == 1 then
+  if vfn.executable('sed') == 1 then
     info("sed installed.")
   else
     warn("sed is not installed.")
   end
 
-  if vim.fn.executable('sed') == 1 then
+  if vfn.executable('sed') == 1 then
     info("sed installed.")
   else
     warn("sed is not installed.")
   end
 
-  if vim.fn.executable('curl') == 1 then
+  if vfn.executable('curl') == 1 then
     info("curl installed.")
   else
     warn("curl is not installed.")
@@ -77,8 +78,8 @@ local function plugin_check()
     end
   end
   if ts_installed then
-  local info = require("nvim-treesitter.info").installed_parsers()
-  if vim.tbl_contains(info, "go") then
+  local _info = require("nvim-treesitter.info").installed_parsers()
+  if vim.tbl_contains(_info, "go") then
     ok("nvim-treesitter-go is installed")
   else
     warn("nvim-treesitter-go is not installed, Please run TSInstall go to install")
diff --git a/lua/go/iferr.lua b/lua/go/iferr.lua
index 8bfb2e4..c75d9c2 100644
--- a/lua/go/iferr.lua
+++ b/lua/go/iferr.lua
@@ -1,27 +1,27 @@
 -- local ts_utils = require 'nvim-treesitter.ts_utils'
 local utils = require("go.utils")
+local vfn = vim.fn
 
 local iferr = "iferr"
-local run = function(...)
+local run = function()
   require("go.install").install(iferr)
-  local fname = vim.fn.expand("%:p") -- %:p:h ? %:p
 
-  local byte_offset = vim.fn.wordcount().cursor_bytes
+  local byte_offset = vfn.wordcount().cursor_bytes
 
   local cmd = string.format('iferr -pos %d', byte_offset)
 
-  local data = vim.fn.systemlist(cmd, vim.fn.bufnr('%'))
+  local data = vfn.systemlist(cmd, vfn.bufnr('%'))
 
   data = utils.handle_job_data(data)
   if not data then
     return
   end
 
-  local pos = vim.fn.getcurpos()[2]
-  vim.fn.append(pos, data)
+  local pos = vfn.getcurpos()[2]
+  vfn.append(pos, data)
 
   vim.cmd('silent normal! j=2j')
-  vim.fn.setpos('.', pos)
+  vfn.setpos('.', pos)
   vim.cmd('silent normal! 4j')
   --
 
diff --git a/lua/go/impl.lua b/lua/go/impl.lua
index f02b35f..7a0a94e 100644
--- a/lua/go/impl.lua
+++ b/lua/go/impl.lua
@@ -1,6 +1,6 @@
 -- local ts_utils = require 'nvim-treesitter.ts_utils'
 local utils = require("go.utils")
-
+local vfn = vim.fn
 local impl = "impl" -- GoImpl f *Foo io.Writer
 -- use ts to get name
 local function get_struct_name()
@@ -33,7 +33,7 @@ local run = function(...)
 
   local recv = get_struct_name()
   if #arg == 0 then
-    iface = vim.fn.input("Impl: generating method stubs for interface: ")
+    iface = vfn.input("Impl: generating method stubs for interface: ")
     vim.cmd("redraw!")
     if iface == "" then
       print("Impl: please input interface name e.g. io.Reader")
@@ -61,23 +61,23 @@ local run = function(...)
   end
 
   utils.log(#arg, recv_name, recv, iface)
-  local dir = vim.fn.fnameescape(vim.fn.expand("%:p:h"))
+  local dir = vfn.fnameescape(vfn.expand("%:p:h"))
 
   setup = { setup, "-dir", dir, recv, iface }
   utils.log(setup)
   -- vim.cmd("normal! $%") -- do a bracket match. changed to treesitter
-  local data = vim.fn.systemlist(setup)
+  local data = vfn.systemlist(setup)
   data = utils.handle_job_data(data)
   if not data then
     return
   end
   --
-  local pos = vim.fn.getcurpos()[2]
+  local pos = vfn.getcurpos()[2]
   table.insert(data, 1, "")
-  vim.fn.append(pos, data)
+  vfn.append(pos, data)
 
   -- vim.cmd("silent normal! j=2j")
-  -- vim.fn.setpos(".", pos)
+  -- vfn.setpos(".", pos)
   -- vim.cmd("silent normal! 4j")
   --
 end
@@ -87,7 +87,7 @@ local function match_iface_name(part)
 
   utils.log(pkg, iface)
   local cmd = string.format("go doc %s", pkg)
-  local doc = vim.fn.systemlist(cmd)
+  local doc = vfn.systemlist(cmd)
   if vim.v.shell_error ~= 0 then
     return
   end
@@ -103,7 +103,8 @@ local function match_iface_name(part)
   return ifaces
 end
 
-function complete(arglead, cmdline, cursorpos)
+-- function complete(arglead, cmdline, cursorpos)
+local function complete(_, cmdline, _)
   local words = vim.split(cmdline, [[%s+]])
   local gopls = require("go.gopls")
   local last = words[#words]
@@ -115,8 +116,7 @@ function complete(arglead, cmdline, cursorpos)
     end
   end
 
-  local bnum = vim.api.nvim_get_current_buf()
-  return vim.fn.uniq(vim.fn.sort(gopls.list_pkgs(bnum)))
+  return vfn.uniq(vfn.sort(gopls.list_pkgs()))
 end
 
 return { run = run, complete = complete }
diff --git a/lua/go/install.lua b/lua/go/install.lua
index d09854e..8a45ae4 100644
--- a/lua/go/install.lua
+++ b/lua/go/install.lua
@@ -1,5 +1,5 @@
 local uv = vim.loop
-local DIR_SEP = package.config:sub(1, 1)
+local DIR_SEP = package.config[1]
 local log = require("go.utils").log
 
 local url = {
@@ -28,7 +28,7 @@ local function is_installed(bin)
   local env_path = os.getenv("PATH")
   local base_paths = vim.split(env_path, ":", true)
 
-  for key, value in pairs(base_paths) do
+  for _, value in pairs(base_paths) do
     if uv.fs_stat(value .. DIR_SEP .. bin) then
       return true
     end
@@ -50,7 +50,7 @@ local function go_install(pkg)
   local setup = { "go", "install", u }
 
   vim.fn.jobstart(setup, {
-    on_stdout = function(c, data, name)
+    on_stdout = function(_, data, _)
       log(setup)
       if type(data) == "table" and #data > 0 then
         data = table.concat(data, " ")
@@ -84,13 +84,13 @@ local function update(bin)
 end
 
 local function install_all()
-  for key, value in pairs(url) do
+  for key, _ in pairs(url) do
     install(key)
   end
 end
 
 local function update_all()
-  for key, value in pairs(url) do
+  for key, _ in pairs(url) do
     update(key)
   end
 end
diff --git a/lua/go/launch.lua b/lua/go/launch.lua
index bfb8537..cf0a971 100644
--- a/lua/go/launch.lua
+++ b/lua/go/launch.lua
@@ -84,13 +84,13 @@ local util = require("go.utils")
 local log = util.log
 local M = {}
 local sep = require("go.utils").sep()
-
+local vfn = vim.fn
 function M.vs_launch()
-  local workfolder = vim.lsp.buf.list_workspace_folders()[1] or vim.fn.getcwd()
+  local workfolder = vim.lsp.buf.list_workspace_folders()[1] or vfn.getcwd()
 
   local launch_json = _GO_NVIM_CFG.launch_json or (workfolder .. sep .. ".vscode" .. sep .. "launch.json")
   log(launch_json)
-  if vim.fn.filereadable(launch_json) == 1 then
+  if vfn.filereadable(launch_json) == 1 then
     return true, launch_json
   else
     return false, launch_json
@@ -98,23 +98,23 @@ function M.vs_launch()
 end
 
 function M.config()
-  local workfolder = vim.lsp.buf.list_workspace_folders()[1] or vim.fn.getcwd()
+  local workfolder = vim.lsp.buf.list_workspace_folders()[1] or vfn.getcwd()
   local launch_json = _GO_NVIM_CFG.launch_json or (workfolder .. sep .. ".vscode" .. sep .. "launch.json")
   local launch_dir = string.match(launch_json, ".*" .. sep)
 
   local cmd = "e " .. launch_json
 
-  if vim.fn.isdirectory(launch_dir) == 0 then
-    vim.fn.mkdir(launch_dir)
+  if vfn.isdirectory(launch_dir) == 0 then
+    vfn.mkdir(launch_dir)
   end
 
-  if vim.fn.filereadable(launch_json) == 1 then
+  if vfn.filereadable(launch_json) == 1 then
     return vim.cmd(cmd)
   end
 
-  -- vim.fn.writefile(launch_json_content, launch_json)
-  local contents = vim.fn.split(launch_json_content, "\n")
-  vim.fn.writefile(contents, launch_json)
+  -- vfn.writefile(launch_json_content, launch_json)
+  local contents = vfn.split(launch_json_content, "\n")
+  vfn.writefile(contents, launch_json)
   vim.cmd(cmd)
 end
 
diff --git a/lua/go/lsp.lua b/lua/go/lsp.lua
index 47890e8..2d04d3b 100644
--- a/lua/go/lsp.lua
+++ b/lua/go/lsp.lua
@@ -50,7 +50,7 @@ local on_attach = function(client, bufnr)
     buf_set_keymap("n", "<space>wr", "<cmd>lua vim.lsp.buf.remove_workspace_folder()<CR>", opts)
     buf_set_keymap("n", "<space>wl", "<cmd>lua print(vim.inspect(vim.lsp.buf.list_workspace_folders()))<CR>", opts)
     buf_set_keymap("n", "<space>D", "<cmd>lua vim.lsp.buf.type_definition()<CR>", opts)
-    buf_set_keymap("n", "<space>rn", "<cmd>lua require('go.rename').lsprename()<CR>", opts)
+    buf_set_keymap("n", "<space>rn", "<cmd>lua require('go.rename').run()<CR>", opts)
     buf_set_keymap("n", "<space>ca", "<cmd>lua require('go.codeaction').run_action()<CR>", opts)
     buf_set_keymap("n", "gr", "<cmd>lua vim.lsp.buf.references()<CR>", opts)
     buf_set_keymap("n", "<space>e", "<cmd>lua vim.lsp.diagnostic.show_line_diagnostics()<CR>", opts)
diff --git a/lua/go/lsp_diag.lua b/lua/go/lsp_diag.lua
index f98489c..204e075 100644
--- a/lua/go/lsp_diag.lua
+++ b/lua/go/lsp_diag.lua
@@ -4,6 +4,7 @@
 -- New signature on_publish_diagnostics({_}, {result}, {ctx}, {config})
 debug = debug or nil
 local nvim_0_6 = false
+local vfn = vim.fn
 if debug.getinfo(vim.lsp.handlers["textDocument/publishDiagnostics"]).nparams == 4 then
   nvim_0_6 = true
 end
@@ -14,7 +15,7 @@ local function hdlr(result)
     local s = result.uri
     local fname = s
     for _, v in ipairs(result.diagnostics) do
-      local i, j = string.find(s, "file://")
+      local _, j = string.find(s, "file://")
       if j then
         fname = string.sub(s, j + 1)
       end
@@ -25,23 +26,23 @@ local function hdlr(result)
         text = v.message,
       })
     end
-    local old_items = vim.fn.getqflist()
+    local old_items = vfn.getqflist()
     for _, old_item in ipairs(old_items) do
       if vim.uri_from_bufnr(old_item.bufnr) ~= result.uri then
         table.insert(item_list, old_item)
       end
     end
-    vim.fn.setqflist({}, " ", { title = "LSP", items = item_list })
+    vfn.setqflist({}, " ", { title = "LSP", items = item_list })
   end
 end
 local diag_hdlr_0_5 = function(err, result, ctx, config)
-  -- vim.lsp.diagnostic.clear(vim.fn.bufnr(), client.id, nil, nil)
+  -- vim.lsp.diagnostic.clear(vfn.bufnr(), client.id, nil, nil)
   vim.lsp.diagnostic.on_publish_diagnostics(err, result, ctx, config)
   hdlr(result)
 end
 
 local diag_hdlr_0_6 = function(err, result, ctx, config)
-  -- vim.lsp.diagnostic.clear(vim.fn.bufnr(), client.id, nil, nil)
+  -- vim.lsp.diagnostic.clear(vfn.bufnr(), client.id, nil, nil)
   vim.lsp.diagnostic.on_publish_diagnostics(err, result, ctx, config)
   hdlr(result)
 end
diff --git a/lua/go/package.lua b/lua/go/package.lua
index c3956ec..5a10270 100644
--- a/lua/go/package.lua
+++ b/lua/go/package.lua
@@ -1,6 +1,7 @@
 local golist = require'go.list'.list
 local util = require 'go.utils'
 local log = util.log
+local vfn = vim.fn
 return {
   complete = function()
     local ok, l = golist(false, {util.all_pkgs()})
@@ -8,12 +9,12 @@ return {
       log('Failed to find all packages for current module/project.')
     end
     local curpkgmatch = false
-    local curpkg = vim.fn.fnamemodify(vim.fn.expand('%'), ':h:.')
+    local curpkg = vfn.fnamemodify(vfn.expand('%'), ':h:.')
     local pkgs = {}
     for _, p in ipairs(l) do
-      local d = vim.fn.fnamemodify(p.Dir, ':.')
+      local d = vfn.fnamemodify(p.Dir, ':.')
       if curpkg ~= d then
-        if d ~= vim.fn.getcwd() then
+        if d ~= vfn.getcwd() then
           table.insert(pkgs, util.relative_to_cwd(d))
         end
       else
diff --git a/lua/go/project.lua b/lua/go/project.lua
index 0fbff53..587b9c9 100644
--- a/lua/go/project.lua
+++ b/lua/go/project.lua
@@ -11,7 +11,7 @@ return  {
   test_dir = "",
   gocoverage_sign_priority = 5,
   launch_json = nil, -- the launch.json file path, default to .vscode/launch.json
-  -- launch_json = vim.fn.getcwd() .. "/.vscode/launch.json",
+  -- launch_json = vfn.getcwd() .. "/.vscode/launch.json",
 
   build_tags = "", --- you can provide extra build tags for tests or debugger
 
@@ -20,32 +20,32 @@ return  {
 ]]
 
 -- if the file existed, load it into config
-
+local vfn = vim.fn
 local util = require("go.utils")
 local log = util.log
 local M = {}
 local sep = require("go.utils").sep()
 
 function M.project_existed()
-  local workfolder = vim.lsp.buf.list_workspace_folders()[1] or vim.fn.getcwd()
+  local workfolder = vim.lsp.buf.list_workspace_folders()[1] or vfn.getcwd()
   local gocfgfd = workfolder .. sep .. ".gonvim"
   local gocfgbrks = gocfgfd .. sep .. "breakpoints.lua"
   local gocfg = gocfgfd .. sep .. "init.lua"
-  if vim.fn.filereadable(gocfg) == 1 or  vim.fn.filereadable(gocfgbrks) == 1 then
+  if vfn.filereadable(gocfg) == 1 or  vfn.filereadable(gocfgbrks) == 1 then
     log("projects existed", gocfg, gocfgbrks)
     return gocfg, gocfgbrks
   end
 end
 
 function M.setup()
-  local workfolder = vim.lsp.buf.list_workspace_folders()[1] or vim.fn.getcwd()
+  local workfolder = vim.lsp.buf.list_workspace_folders()[1] or vfn.getcwd()
   local gocfgfd = workfolder .. sep .. ".gonvim"
   local gocfg = gocfgfd .. sep .. "init.lua"
 
-  if vim.fn.isdirectory(gocfgfd) == 0 then
-    vim.fn.mkdir(gocfgfd)
+  if vfn.isdirectory(gocfgfd) == 0 then
+    vfn.mkdir(gocfgfd)
   end
-  if vim.fn.filereadable(gocfg) == 0 then
+  if vfn.filereadable(gocfg) == 0 then
     local f = io.open(gocfg, "w")
     f:write("return {}")
     f:close()
@@ -54,9 +54,9 @@ function M.setup()
 end
 
 function M.load_project()
-  local workfolder = vim.lsp.buf.list_workspace_folders()[1] or vim.fn.getcwd()
+  local workfolder = vim.lsp.buf.list_workspace_folders()[1] or vfn.getcwd()
   local gocfg = workfolder .. sep .. ".gonvim" .. sep .. "init.lua"
-  if vim.fn.filereadable(gocfg) == 1 then
+  if vfn.filereadable(gocfg) == 1 then
     local f = assert(loadfile(gocfg))
     log(f())
     _GO_NVIM_CFG = vim.tbl_deep_extend("force", _GO_NVIM_CFG, f())
diff --git a/lua/go/reftool.lua b/lua/go/reftool.lua
index 8d1c28f..5c420ba 100644
--- a/lua/go/reftool.lua
+++ b/lua/go/reftool.lua
@@ -2,10 +2,10 @@ local reftool = {}
 
 local utils = require("go.utils")
 local log = utils.log
-local fn = vim.fn
+local vfn = vim.fn
 
 local function insert_result(result)
-  local curpos = fn.getcurpos()
+  local curpos = vfn.getcurpos()
   local goto_l = string.format("goto %d", result["start"] + 1)
   vim.cmd(goto_l)
   local inserts = result.code
@@ -17,14 +17,14 @@ local function insert_result(result)
   local curline = curpos[2]
   for i = 2, #inserts do
     log("append ", curline, inserts[i])
-    vim.fn.append(curline, inserts[i])
+    vfn.append(curline, inserts[i])
     curline = curline + 1
   end
 
   vim.cmd("stopinsert!")
   vim.cmd("write")
   -- format(#inserts, curpos)
-  fn.setpos(".", curpos)
+  vfn.setpos(".", curpos)
   vim.defer_fn(function()
     vim.lsp.buf.format({ async = _GO_NVIM_CFG.lsp_fmt_async })
   end, 300)
@@ -39,21 +39,21 @@ local function fill(cmd)
   require("go.install").install(cmd)
 
   log(cmd)
-  local file = fn.expand("%:p")
-  local line = fn.line(".")
-  local run = string.format("%s -file=%s -line=%d 2>/dev/null", cmd, file, line)
+  local file = vfn.expand("%:p")
+  local line = vfn.line(".")
+  -- local run = string.format("%s -file=%s -line=%d 2>/dev/null", cmd, file, line)
   local farg = string.format("-file=%s", file)
   local larg = string.format("-line=%d", line)
   local args = { cmd, farg, larg, "2>/dev/null" }
   log(args)
-  vim.fn.jobstart(args, {
-    on_stdout = function(jobid, str, event)
+  vfn.jobstart(args, {
+    on_stdout = function(_, str, _)
       log(str)
       if #str < 2 then
         log("reftools", cmd, "finished with no result")
         return
       end
-      local json = fn.json_decode(str)
+      local json = vfn.json_decode(str)
       if #json == 0 then
         vim.notify("reftools " .. cmd .. " finished with no result", vim.lsp.log_levels.DEBUG)
       end
diff --git a/lua/go/rename.lua b/lua/go/rename.lua
index 439e50c..553c636 100644
--- a/lua/go/rename.lua
+++ b/lua/go/rename.lua
@@ -2,6 +2,7 @@
 local utils = require("go.utils")
 
 local gorename = "gorename"
+local vfn = vim.fn
 
 local lsprename = function()
 
@@ -20,39 +21,31 @@ end
 
 local run = function(to_identifier, ...)
   require("go.install").install(gorename)
-  local fname = vim.fn.expand("%:p") -- %:p:h ? %:p
+  local fname = vfn.expand("%:p") -- %:p:h ? %:p
 
-  local old_identifier = vim.fn.expand("<cword>")
+  local old_identifier = vfn.expand("<cword>")
 
-  local prompt = vim.fn.printf("GoRename '%s' to (may take a while) :", old_identifier)
-  to_identifier = to_identifier or vim.fn.input(prompt, old_identifier)
-  local byte_offset = vim.fn.wordcount().cursor_bytes
+  local prompt = vfn.printf("GoRename '%s' to (may take a while) :", old_identifier)
+  to_identifier = to_identifier or vfn.input(prompt, old_identifier)
+  local byte_offset = vfn.wordcount().cursor_bytes
 
   local clients = vim.lsp.get_active_clients() or {}
   if #clients > 0 then
     -- TODO check gopls?
-    return lsprename(to_identifier)
+    return lsprename()
   end
 
   local offset = string.format("%s:#%i", fname, byte_offset)
 
   local setup = { gorename, "-offset", offset, "-to", to_identifier }
 
-  -- vim.notify("setup: " .. vim.inspect(setup), vim.lsp.log_levels.DEBUG)
-  --
-  -- local arg = {...}
-  -- for i, v in ipairs(arg) do
-  --   table.insert(setup, v)
-  -- end
-  --
-  -- vim.notify(vim.inspect(setup), vim.lsp.log_levels.DEBUG)
-  local j = vim.fn.jobstart(setup, {
-    on_stdout = function(jobid, data, event)
+  vfn.jobstart(setup, {
+    on_stdout = function(_, data, _)
       data = utils.handle_job_data(data)
       if not data then
         return
       end
-      -- local result = vim.fn.json_decode(data)
+      -- local result = vfn.json_decode(data)
       local result = vim.json.decode(data)
       if result.errors ~= nil or result.lines == nil or result["start"] == nil or result["start"] == 0 then
         vim.notify("failed to rename" .. vim.inspect(result), vim.lsp.log_levels.ERROR)
diff --git a/lua/go/runner.lua b/lua/go/runner.lua
index 817b4ab..3492798 100644
--- a/lua/go/runner.lua
+++ b/lua/go/runner.lua
@@ -1,21 +1,9 @@
 local uv, api = vim.loop, vim.api
 local util = require("go.utils")
 local log = require("go.utils").log
-local check_same = function(tbl1, tbl2)
-  if #tbl1 ~= #tbl2 then
-    return
-  end
-  for k, v in ipairs(tbl1) do
-    if v ~= tbl2[k] then
-      return true
-    end
-  end
-  return false
-end
 
 local run = function(cmd, opts)
   opts = opts or {}
-  local shell_cmd
   log(cmd)
   if type(cmd) == "string" then
     local split_pattern = "%s+"
@@ -51,6 +39,9 @@ local run = function(cmd, opts)
 
   local output_buf = ""
   local function update_chunk(err, chunk)
+    if err then
+      vim.notify("error " .. err, vim.lsp.log_levels.INFO)
+    end
     if chunk then
       output_buf = output_buf .. chunk
       local lines = vim.split(output_buf, "\n", true)
@@ -66,7 +57,7 @@ local run = function(cmd, opts)
   update_chunk = vim.schedule_wrap(update_chunk)
 
   log("job:", cmd, job_options)
-  handle, pid = uv.spawn(
+  handle, _ = uv.spawn(
     cmd,
     { stdio = { stdin, stdout, stderr }, args = job_options.args },
     function(code, signal) -- on exit
@@ -111,7 +102,7 @@ local function make(...)
   local args = { ... }
   local setup = {}
   if #args > 0 then
-    for i, v in ipairs(args) do
+    for _, v in ipairs(args) do
       table.insert(setup, v)
     end
   end
diff --git a/lua/go/tags.lua b/lua/go/tags.lua
index e442851..26f6946 100644
--- a/lua/go/tags.lua
+++ b/lua/go/tags.lua
@@ -9,15 +9,6 @@ local tags = {}
 -- gomodifytags -file demo.go -struct Server -add-tags json,xml -transform camelcase
 -- gomodifytags -file demo.go -line 8,11 -clear-tags xml
 
-local opts = {
-  "-add-tags",
-  "-add-options",
-  "-remove-tags",
-  "-remove-options",
-  "-clear-tags",
-  "-clear-options",
-}
-
 local gomodify = "gomodifytags"
 local transform = _GO_NVIM_CFG.tag_transform
 tags.modify = function(...)
@@ -31,7 +22,6 @@ tags.modify = function(...)
 
   -- vim.notify("parnode" .. vim.inspect(ns), vim.lsp.log_levels.DEBUG)
   local struct_name = ns.name
-  local rs, re = ns.dim.s.r, ns.dim.e.r
   local setup = { gomodify, "-format", "json", "-file", fname, "-w" }
 
   if struct_name == nil then
@@ -47,7 +37,7 @@ tags.modify = function(...)
     table.insert(setup, transform)
   end
   local arg = { ... }
-  for i, v in ipairs(arg) do
+  for _, v in ipairs(arg) do
     table.insert(setup, v)
   end
 
@@ -55,8 +45,8 @@ tags.modify = function(...)
     table.insert(setup, "json")
   end
   -- vim.notify(vim.inspect(setup), vim.lsp.log_levels.DEBUG)
-  local j = vim.fn.jobstart(setup, {
-    on_stdout = function(jobid, data, event)
+  vim.fn.jobstart(setup, {
+    on_stdout = function(_, data, _)
       data = utils.handle_job_data(data)
       if not data then
         return
diff --git a/lua/go/utils.lua b/lua/go/utils.lua
index a3ba506..085c3ed 100644
--- a/lua/go/utils.lua
+++ b/lua/go/utils.lua
@@ -4,7 +4,7 @@ local fn = vim.fn
 local os_name = vim.loop.os_uname().sysname
 local is_windows = os_name == "Windows" or os_name == "Windows_NT"
 -- Check whether current buffer contains main function
-local function has_main()
+function util.has_main()
   local output = vim.api.nvim_exec("grep func\\ main\\(\\) %", true)
   local matchCount = vim.split(output, "\n")
 
@@ -99,7 +99,7 @@ function util.interface_list(pkg)
   util.log(p)
   local ifaces = {}
   if p then
-    contents = p -- vim.split(p[1], "\n")
+    local contents = p -- vim.split(p[1], "\n")
     for _, content in pairs(contents) do
       util.log(content)
       if content:find("interface") then
@@ -114,10 +114,9 @@ function util.interface_list(pkg)
   return ifaces
 end
 
-local function smartrun()
+function util.smartrun()
   local cmd
-  if has_main() then
-    -- Found main function in current buffer
+  if util.has_main() then
     cmd = string.format("lcd %:p:h | :set makeprg=%s\\ run\\ . | :make | :lcd -", _GO_NVIM_CFG.go)
     vim.cmd(cmd)
   else
@@ -126,10 +125,9 @@ local function smartrun()
   end
 end
 
-local function smartbuild()
+function util.smartbuild()
   local cmd
-  if has_main() then
-    -- Found main function in current buffer
+  if util.has_main() then
     cmd = string.format("lcd %:p:h | :set makeprg=%s\\ build\\ . | :make | :lcd -", _GO_NVIM_CFG.go)
     vim.cmd(cmd)
   else
@@ -194,7 +192,7 @@ util.handle_job_data = function(data)
     return nil
   end
   -- Because the nvim.stdout's data will have an extra empty line at end on some OS (e.g. maxOS), we should remove it.
-  for i = 1, 3, 1 do
+  for _ = 1, 3, 1 do
     if data[#data] == "" then
       table.remove(data, #data)
     end
@@ -338,7 +336,8 @@ function util.load_plugin(name, modulename)
   if has then
     return plugin
   end
-  if packer_plugins ~= nil then
+  local pkg =  packer_plugins or nil
+  if pkg ~= nil then
     -- packer installed
     local has_packer = pcall(require, "packer")
     if not has_packer then
@@ -346,10 +345,10 @@ function util.load_plugin(name, modulename)
       return nil
     end
     local loader = require("packer").loader
-    if not packer_plugins[name] or not packer_plugins[name].loaded then
+    if not pkg[name] or not pkg[name].loaded then
       util.log("packer loader " .. name)
       vim.cmd("packadd " .. name) -- load with default
-      if packer_plugins[name] ~= nil then
+      if pkg[name] ~= nil then
         loader(name)
       end
     end
@@ -397,7 +396,7 @@ end
 -- end
 
 function util.relative_to_cwd(name)
-  local rel = fn.isdirectory(name) == 0 and vim.fn.fnamemodify(name, ":h:.") or vim.fn.fnamemodify(name, ":.")
+  local rel = fn.isdirectory(name) == 0 and fn.fnamemodify(name, ":h:.") or fn.fnamemodify(name, ":.")
   if rel == "." then
     return "."
   else
@@ -434,7 +433,7 @@ function util.rel_path(folder)
   if workfolders ~= nil and next(workfolders) then
     fpath = "." .. fpath:sub(#workfolders[1] + 1)
   end
-  return "." .. util.sep() .. fn.fnamemodify(vim.fn.expand(mod), ":.")
+  return "." .. util.sep() .. fn.fnamemodify(fn.expand(mod), ":.")
 end
 
 function util.rtrim(s)
@@ -449,16 +448,6 @@ function util.ltrim(s)
   return (s:gsub("^%s*", ""))
 end
 
-function util.file_exists(name)
-  local f = io.open(name, "r")
-  if f ~= nil then
-    io.close(f)
-    return true
-  else
-    return false
-  end
-end
-
 function util.work_path()
   local fpath = fn.expand("%:p:h")
   local workfolders = vim.lsp.buf.list_workspace_folders()
@@ -528,12 +517,13 @@ util.deletedir = function(dir)
   util.log("remove dir", dir)
 end
 
-function util.file_exists(file)
-  local f = io.open(file, "rb")
-  if f then
-    f:close()
+function util.file_exists(name)
+  local f = io.open(name, "r")
+  if f ~= nil then
+    io.close(f)
+    return true
   end
-  return f ~= nil
+  return false
 end
 
 -- get all lines from a file, returns an empty
@@ -550,7 +540,7 @@ function util.lines_from(file)
 end
 
 function util.list_directory()
-  local dirs = fn.map(fn.glob(fn.fnameescape("./") .. "/{,.}*/", 1, 1), 'fnamemodify(v:val, ":h:t")')
+   return fn.map(fn.glob(fn.fnameescape("./") .. "/{,.}*/", 1, 1), 'fnamemodify(v:val, ":h:t")')
 end
 
 function util.get_active_buf()