From 7f4cf08516c04a9f48f18cc2ca193c022cb32dfd Mon Sep 17 00:00:00 2001
From: yuyi <yuyi98@163.com>
Date: Sun, 17 May 2020 19:51:18 +0800
Subject: [PATCH] parser: check `(mut f Foo)` syntax

---
 cmd/tools/gen_vc.v                            | 20 ++---
 cmd/tools/modules/testing/common.v            |  8 +-
 cmd/tools/modules/vgit/vgit.v                 |  2 +-
 cmd/tools/oldv.v                              |  2 +-
 cmd/tools/preludes/tests_with_stats.v         |  6 +-
 cmd/tools/vrepl.v                             |  2 +-
 examples/json.v                               |  3 +-
 examples/tetris/tetris.v                      | 22 ++---
 examples/vweb/vweb_assets/main.v              | 10 +--
 examples/vweb/vweb_example.v                  | 12 +--
 tutorials/code/blog/blog.v                    | 14 +--
 vlib/benchmark/benchmark.v                    | 20 ++---
 vlib/bitfield/bitfield.v                      | 14 +--
 vlib/builtin/array.v                          | 22 ++---
 vlib/builtin/bare/array_bare.v                |  2 +-
 vlib/builtin/js/array.v                       | 10 +--
 vlib/builtin/js/map.v                         |  6 +-
 vlib/builtin/js/string.v                      | 12 +--
 vlib/builtin/map.v                            | 24 +++---
 vlib/builtin/map_test.v                       |  2 +-
 vlib/builtin/sorted_map.v                     | 24 +++---
 vlib/builtin/string.v                         |  8 +-
 vlib/cli/command.v                            | 14 +--
 vlib/cli/flag.v                               |  6 +-
 vlib/clipboard/clipboard.v                    |  8 +-
 vlib/clipboard/clipboard_darwin.c.v           |  8 +-
 vlib/clipboard/clipboard_linux.c.v            | 14 +--
 vlib/clipboard/clipboard_solaris.c.v          | 10 +--
 vlib/crypto/aes/aes_cbc.v                     |  2 +-
 vlib/crypto/md5/md5.v                         |  6 +-
 vlib/crypto/rc4/rc4.v                         |  4 +-
 vlib/crypto/sha1/sha1.v                       |  6 +-
 vlib/crypto/sha256/sha256.v                   |  6 +-
 vlib/crypto/sha512/sha512.v                   |  6 +-
 vlib/encoding/csv/reader.v                    |  8 +-
 vlib/encoding/csv/writer.v                    |  4 +-
 vlib/eventbus/eventbus.v                      | 12 +--
 vlib/flag/flag.v                              | 44 +++++-----
 vlib/gg/gg.v                                  |  6 +-
 vlib/gg2/gg.v                                 |  2 +-
 vlib/glfw/glfw.v                              | 12 +--
 vlib/hash/crc32/crc32.v                       |  2 +-
 vlib/log/log.v                                | 26 +++---
 vlib/math/big/big.v                           |  4 +-
 vlib/mysql/mysql.v                            |  2 +-
 vlib/net/http/chunked/dechunk.v               |  7 +-
 vlib/net/urllib/urllib.v                      |  2 +-
 vlib/net/urllib/values.v                      |  7 +-
 vlib/net/websocket/handshake.v                |  8 +-
 vlib/net/websocket/io.v                       |  4 +-
 vlib/net/websocket/ssl.v                      |  2 +-
 vlib/net/websocket/utf8.v                     |  6 +-
 vlib/net/websocket/ws.v                       | 12 +--
 vlib/os/os.v                                  |  4 +-
 vlib/os/os_nix.c.v                            | 10 +--
 vlib/os/os_windows.c.v                        |  8 +-
 vlib/picohttpparser/request.v                 |  6 +-
 vlib/picohttpparser/response.v                | 26 +++---
 vlib/rand/pcg32.v                             |  5 +-
 vlib/rand/splitmix64.v                        |  5 +-
 vlib/readline/readline.js.v                   |  4 +-
 vlib/readline/readline_darwin.c.v             |  4 +-
 vlib/readline/readline_linux.c.v              | 46 +++++-----
 vlib/readline/readline_solaris.c.v            |  4 +-
 vlib/readline/readline_windows.c.v            |  4 +-
 vlib/regex/regex.v                            | 22 ++---
 vlib/sokol/gfx/gfx_structs.v                  | 24 +++---
 vlib/strings/builder.c.v                      | 16 ++--
 vlib/strings/builder.js.v                     | 10 +--
 vlib/sync/pool.v                              | 14 +--
 vlib/sync/sync_nix.c.v                        |  5 +-
 vlib/sync/sync_windows.c.v                    |  6 +-
 vlib/sync/waitgroup.v                         |  5 +-
 vlib/szip/szip.v                              | 38 ++++----
 vlib/time/stopwatch.v                         |  9 +-
 vlib/v/ast/scope.v                            |  4 +-
 vlib/v/checker/tests/mut_receiver_warning.out |  7 ++
 vlib/v/checker/tests/mut_receiver_warning.vv  | 10 +++
 vlib/v/gen/js/js.v                            | 86 +++++++++----------
 vlib/v/parser/fn.v                            |  3 +
 vlib/v/parser/module.v                        |  2 +-
 vlib/v/scanner/scanner.v                      | 32 +++----
 vlib/v/tests/generic_test.v                   |  2 +-
 vlib/v/tests/interfaces_map_test.v            |  2 +-
 vlib/v/vmod/vmod.v                            | 12 +--
 vlib/vweb/assets/assets.v                     |  8 +-
 vlib/vweb/vweb.v                              | 24 +++---
 87 files changed, 492 insertions(+), 480 deletions(-)
 create mode 100644 vlib/v/checker/tests/mut_receiver_warning.out
 create mode 100644 vlib/v/checker/tests/mut_receiver_warning.vv

diff --git a/cmd/tools/gen_vc.v b/cmd/tools/gen_vc.v
index 1eeca0d308..f8350d1c2b 100644
--- a/cmd/tools/gen_vc.v
+++ b/cmd/tools/gen_vc.v
@@ -152,7 +152,7 @@ fn new_gen_vc(flag_options FlagOptions) &GenVC {
 }
 
 // WebhookServer init
-pub fn (ws mut WebhookServer) init() {
+pub fn (mut ws WebhookServer) init() {
 
 	mut fp := flag.new_flag_parser(os.args.clone())
 	flag_options := parse_flags(mut fp)
@@ -162,7 +162,7 @@ pub fn (ws mut WebhookServer) init() {
 }
 
 // gen webhook
-pub fn (ws mut WebhookServer) genhook() {
+pub fn (mut ws WebhookServer) genhook() {
 	ws.gen_vc.generate()
 	// error in generate
 	if ws.gen_vc.gen_error {
@@ -191,7 +191,7 @@ fn parse_flags(fp mut flag.FlagParser) FlagOptions {
 }
 
 // init
-fn (gen_vc mut GenVC) init() {
+fn (mut gen_vc GenVC) init() {
 	// purge repos if flag is passed
 	if gen_vc.options.purge {
 		gen_vc.purge_repos()
@@ -199,7 +199,7 @@ fn (gen_vc mut GenVC) init() {
 }
 
 // regenerate
-fn (gen_vc mut GenVC) generate() {
+fn (mut gen_vc GenVC) generate() {
 	// set errors to false
 	gen_vc.gen_error = false
 
@@ -316,17 +316,17 @@ fn (gen_vc mut GenVC) generate() {
 }
 
 // only execute when dry_run option is false, otherwise just log
-fn (gen_vc mut GenVC) cmd_exec_safe(cmd string) string {
+fn (mut gen_vc GenVC) cmd_exec_safe(cmd string) string {
 	return gen_vc.command_execute(cmd, gen_vc.options.dry_run)
 }
 
 // always execute command
-fn (gen_vc mut GenVC) cmd_exec(cmd string) string {
+fn (mut gen_vc GenVC) cmd_exec(cmd string) string {
 	return gen_vc.command_execute(cmd, false)
 }
 
 // execute command
-fn (gen_vc mut GenVC) command_execute(cmd string, dry bool) string {
+fn (mut gen_vc GenVC) command_execute(cmd string, dry bool) string {
 	// if dry is true then dont execute, just log
 	if dry {
 		return gen_vc.command_execute_dry(cmd)
@@ -352,13 +352,13 @@ fn (gen_vc mut GenVC) command_execute(cmd string, dry bool) string {
 }
 
 // just log cmd, dont execute
-fn (gen_vc mut GenVC) command_execute_dry(cmd string) string {
+fn (mut gen_vc GenVC) command_execute_dry(cmd string) string {
 	gen_vc.logger.info('cmd (dry): "$cmd"')
 	return ''
 }
 
 // delete repo directories
-fn (gen_vc mut GenVC) purge_repos() {
+fn (mut gen_vc GenVC) purge_repos() {
 	// delete old repos (better to be fully explicit here, since these are destructive operations)
 	mut repo_dir := '$gen_vc.options.work_dir/$git_repo_dir_v'
 	if os.is_dir(repo_dir) {
@@ -373,7 +373,7 @@ fn (gen_vc mut GenVC) purge_repos() {
 }
 
 // check if file size is too short
-fn (gen_vc mut GenVC) assert_file_exists_and_is_not_too_short(f string, emsg string){
+fn (mut gen_vc GenVC) assert_file_exists_and_is_not_too_short(f string, emsg string){
 	if !os.exists(f) {
 		gen_vc.logger.error('$err_msg_build: $emsg .')
 		gen_vc.gen_error = true
diff --git a/cmd/tools/modules/testing/common.v b/cmd/tools/modules/testing/common.v
index 3bb36d2615..1398663f71 100644
--- a/cmd/tools/modules/testing/common.v
+++ b/cmd/tools/modules/testing/common.v
@@ -27,7 +27,7 @@ pub mut:
 	message_handler &TestMessageHandler
 }
 
-pub fn (mh mut TestMessageHandler) append_message(msg string) {
+pub fn (mut mh TestMessageHandler) append_message(msg string) {
 	mh.mtx.lock()
 	mh.messages << msg
 	mh.mtx.unlock()
@@ -54,11 +54,11 @@ pub fn new_test_session(_vargs string) TestSession {
 	}
 }
 
-pub fn (ts mut TestSession) init() {
+pub fn (mut ts TestSession) init() {
 	ts.benchmark = benchmark.new_benchmark_no_cstep()
 }
 
-pub fn (ts mut TestSession) test() {
+pub fn (mut ts TestSession) test() {
 	ts.init()
 	mut remaining_files := []string{}
 	for dot_relative_file in ts.files {
@@ -111,7 +111,7 @@ pub fn (ts mut TestSession) test() {
 	eprintln(term.h_divider('-'))
 }
 
-pub fn (m mut TestMessageHandler) display_message() {
+pub fn (mut m TestMessageHandler) display_message() {
 	m.mtx.lock()
 	defer {
 		m.messages.clear()
diff --git a/cmd/tools/modules/vgit/vgit.v b/cmd/tools/modules/vgit/vgit.v
index b4005ac2c7..30c1f85dd7 100644
--- a/cmd/tools/modules/vgit/vgit.v
+++ b/cmd/tools/modules/vgit/vgit.v
@@ -92,7 +92,7 @@ pub mut:
 	vvlocation string // v.v or compiler/ or cmd/v, depending on v version
 }
 
-pub fn (vgit_context mut VGitContext) compile_oldv_if_needed() {
+pub fn (mut vgit_context VGitContext) compile_oldv_if_needed() {
 	vgit_context.vexename = if os.user_os() == 'windows' { 'v.exe' } else { 'v' }
 	vgit_context.vexepath = os.real_path(os.join_path(vgit_context.path_v, vgit_context.vexename))
 	mut command_for_building_v_from_c_source := ''
diff --git a/cmd/tools/oldv.v b/cmd/tools/oldv.v
index 1a3d3252dc..2617b7d87b 100644
--- a/cmd/tools/oldv.v
+++ b/cmd/tools/oldv.v
@@ -40,7 +40,7 @@ mut:
 	cleanup       bool // should the tool run a cleanup first
 }
 
-fn (c mut Context) compile_oldv_if_needed() {
+fn (mut c Context) compile_oldv_if_needed() {
 	mut vgit_context := vgit.VGitContext{
 		workdir:     c.vgo.workdir
 		v_repo_url:  c.vgo.v_repo_url
diff --git a/cmd/tools/preludes/tests_with_stats.v b/cmd/tools/preludes/tests_with_stats.v
index 485777a048..36ad06a5da 100644
--- a/cmd/tools/preludes/tests_with_stats.v
+++ b/cmd/tools/preludes/tests_with_stats.v
@@ -36,7 +36,7 @@ fn start_testing(total_number_of_tests int, vfilename string) BenchedTests {
 }
 
 // Called before each test_ function, defined in file_test.v
-fn (b mut BenchedTests) testing_step_start(stepfunc string) {
+fn (mut b BenchedTests) testing_step_start(stepfunc string) {
 	b.step_func_name = stepfunc.replace('main__', '').replace('__', '.')
 	b.oks = C.g_test_oks
 	b.fails = C.g_test_fails
@@ -44,7 +44,7 @@ fn (b mut BenchedTests) testing_step_start(stepfunc string) {
 }
 
 // Called after each test_ function, defined in file_test.v
-fn (b mut BenchedTests) testing_step_end() {
+fn (mut b BenchedTests) testing_step_end() {
 	ok_diff := C.g_test_oks - b.oks
 	fail_diff := C.g_test_fails - b.fails
 	// ////////////////////////////////////////////////////////////////
@@ -76,7 +76,7 @@ fn (b &BenchedTests) fn_name() string {
 }
 
 // Called at the end of the test program produced by `v -stats file_test.v`
-fn (b mut BenchedTests) end_testing() {
+fn (mut b BenchedTests) end_testing() {
 	b.bench.stop()
 	println(INNER_INDENT + b.bench.total_message('running V tests in "' + os.file_name(b.test_suit_file) + '"'))
 }
diff --git a/cmd/tools/vrepl.v b/cmd/tools/vrepl.v
index 81906bd941..c4a42a8df4 100644
--- a/cmd/tools/vrepl.v
+++ b/cmd/tools/vrepl.v
@@ -23,7 +23,7 @@ mut:
 	temp_lines     []string // all the temporary expressions/printlns
 }
 
-fn (r mut Repl) checks() bool {
+fn (mut r Repl) checks() bool {
 	mut in_string := false
 	was_indent := r.indent > 0
 
diff --git a/examples/json.v b/examples/json.v
index ea6c2bdb6b..6c1a6e45b1 100644
--- a/examples/json.v
+++ b/examples/json.v
@@ -35,7 +35,6 @@ fn (u User) can_register() bool {
 	return u.age >= 16
 }
 
-fn (u mut User) register() {
+fn (mut u User) register() {
 	u.is_registered = true
 }
-
diff --git a/examples/tetris/tetris.v b/examples/tetris/tetris.v
index a23f2d9cc0..3015fcb0fa 100644
--- a/examples/tetris/tetris.v
+++ b/examples/tetris/tetris.v
@@ -183,7 +183,7 @@ fn main() {
 	}
 }
 
-fn (g mut Game) init_game() {
+fn (mut g Game) init_game() {
 	g.parse_tetros()
 	rand.seed(time.now().unix)
 	g.generate_tetro()
@@ -205,7 +205,7 @@ fn (g mut Game) init_game() {
 	g.state = .running
 }
 
-fn (g mut Game) parse_tetros() {
+fn (mut g Game) parse_tetros() {
 	for b_tetros0 in b_tetros {
 		for b_tetro in b_tetros0 {
 			for t in parse_binary_tetro(b_tetro) {
@@ -215,7 +215,7 @@ fn (g mut Game) parse_tetros() {
 	}
 }
 
-fn (g mut Game) run() {
+fn (mut g Game) run() {
 	for {
 		if g.state == .running {
 			g.move_tetro()
@@ -226,7 +226,7 @@ fn (g mut Game) run() {
 	}
 }
 
-fn (g mut Game) move_tetro() {
+fn (mut g Game) move_tetro() {
 	// Check each block in current tetro
 	for block in g.tetro {
 		y := block.y + g.pos_y + 1
@@ -250,7 +250,7 @@ fn (g mut Game) move_tetro() {
 	g.pos_y++
 }
 
-fn (g mut Game) move_right(dx int) bool {
+fn (mut g Game) move_right(dx int) bool {
 	// Reached left/right edge or another tetro?
 	for i in 0..tetro_size {
 		tetro := g.tetro[i]
@@ -266,13 +266,13 @@ fn (g mut Game) move_right(dx int) bool {
 	return true
 }
 
-fn (g mut Game) delete_completed_lines() {
+fn (mut g Game) delete_completed_lines() {
 	for y := FieldHeight; y >= 1; y-- {
 		g.delete_completed_line(y)
 	}
 }
 
-fn (g mut Game) delete_completed_line(y int) {
+fn (mut g Game) delete_completed_line(y int) {
 	for x := 1; x <= FieldWidth; x++ {
 		f := g.field[y]
 		if f[x] == 0 {
@@ -291,7 +291,7 @@ fn (g mut Game) delete_completed_line(y int) {
 }
 
 // Place a new tetro on top
-fn (g mut Game) generate_tetro() {
+fn (mut g Game) generate_tetro() {
 	g.pos_y = 0
 	g.pos_x = FieldWidth / 2 - tetro_size / 2
 	g.tetro_idx = rand.next(b_tetros.len)
@@ -300,7 +300,7 @@ fn (g mut Game) generate_tetro() {
 }
 
 // Get the right tetro from cache
-fn (g mut Game) get_tetro() {
+fn (mut g Game) get_tetro() {
 	idx := g.tetro_idx * tetro_size * tetro_size + g.rotation_idx * tetro_size
 	g.tetro = g.tetros_cache[idx..idx+tetro_size]
 }
@@ -342,7 +342,7 @@ fn (g &Game) draw_field() {
 	}
 }
 
-fn (g mut Game) draw_ui() {
+fn (mut g Game) draw_ui() {
 	if g.font_loaded {
 		g.ft.draw_text(1, 3, g.score.str(), text_cfg)
 		if g.state == .gameover {
@@ -360,7 +360,7 @@ fn (g mut Game) draw_ui() {
 	//g.gg.draw_rect(0, BlockSize, WinWidth, LimitThickness, UIColor)
 }
 
-fn (g mut Game) draw_scene() {
+fn (mut g Game) draw_scene() {
 	g.draw_tetro()
 	g.draw_field()
 	g.draw_ui()
diff --git a/examples/vweb/vweb_assets/main.v b/examples/vweb/vweb_assets/main.v
index bd6d05b254..70aad5581a 100644
--- a/examples/vweb/vweb_assets/main.v
+++ b/examples/vweb/vweb_assets/main.v
@@ -17,7 +17,7 @@ fn main() {
 	vweb.run<App>(port)
 }
 
-pub fn (app mut App) init() {
+pub fn (mut app App) init() {
 	// Arbitary mime type.
 	app.vweb.serve_static('/favicon.ico', 'favicon.ico', 'img/x-icon')
 	// Automatically make available known static mime types found in given directory.
@@ -27,9 +27,9 @@ pub fn (app mut App) init() {
 	//app.vweb.handle_static('.')
 }
 
-pub fn (app mut App) reset() {}
+pub fn (mut app App) reset() {}
 
-fn (app mut App) index() {
+fn (mut app App) index() {
 	// We can dynamically specify which assets are to be used in template.
 	mut am := assets.new_manager()
 	am.add_css('assets/index.css')
@@ -42,10 +42,10 @@ fn (app mut App) index() {
 	$vweb.html()
 }
 
-fn (app mut App) text() {
+fn (mut app App) text() {
 	app.vweb.text('Hello, world from vweb!')
 }
 
-fn (app mut App) time() {
+fn (mut app App) time() {
 	app.vweb.text(time.now().format())
 }
diff --git a/examples/vweb/vweb_example.v b/examples/vweb/vweb_example.v
index 50fe1bb625..3d07c7b51c 100644
--- a/examples/vweb/vweb_example.v
+++ b/examples/vweb/vweb_example.v
@@ -17,27 +17,27 @@ fn main() {
 	vweb.run<App>(port)
 }
 
-pub fn (app mut App) init() {
+pub fn (mut app App) init() {
 	app.vweb.handle_static('.')
 }
 
-pub fn (app mut App) json_endpoint() {
+pub fn (mut app App) json_endpoint() {
 	app.vweb.json('{"a": 3}')
 }
 
-pub fn (app mut App) index() {
+pub fn (mut app App) index() {
 	app.cnt++
 	$vweb.html()
 }
 
-pub fn (app mut App) reset() {
+pub fn (mut app App) reset() {
 }
 
-pub fn (app mut App) text() {
+pub fn (mut app App) text() {
 	app.vweb.text('Hello world')
 }
 
-pub fn (app mut App) cookie() {
+pub fn (mut app App) cookie() {
 	app.vweb.set_cookie('cookie', 'test')
 	app.vweb.text('Headers: $app.vweb.headers')
 }
diff --git a/tutorials/code/blog/blog.v b/tutorials/code/blog/blog.v
index b843bfac0a..2fdb1e72f7 100644
--- a/tutorials/code/blog/blog.v
+++ b/tutorials/code/blog/blog.v
@@ -15,7 +15,7 @@ fn main() {
 	vweb.run<App>(8080)
 }
 
-fn (app mut App) index_text() {
+fn (mut app App) index_text() {
 	app.vweb.text('Hello, world from vweb!')
 }
 
@@ -31,7 +31,7 @@ fn (app &App) index() {
 	$vweb.html()
 }
 
-pub fn (app mut App) init() {
+pub fn (mut app App) init() {
 	db := pg.connect(pg.Config{
 		host:   '127.0.0.1'
 		dbname: 'blog'
@@ -40,14 +40,14 @@ pub fn (app mut App) init() {
 	app.db = db
 }
 
-pub fn (app mut App) new() {
+pub fn (mut app App) new() {
 	$vweb.html()
 }
 
-pub fn (app mut App) reset() {
+pub fn (mut app App) reset() {
 }
 
-pub fn (app mut App) new_article() {
+pub fn (mut app App) new_article() {
 	title := app.vweb.form['title']
 	text := app.vweb.form['text']
 	if title == '' || text == ''  {
@@ -64,11 +64,11 @@ pub fn (app mut App) new_article() {
 	app.vweb.redirect('/article/')
 }
 
-pub fn (app mut App) articles() {
+pub fn (mut app App) articles() {
 	articles := app.find_all_articles()
 	app.vweb.json(json.encode(articles))
 }
 
-fn (app mut App) time() {
+fn (mut app App) time() {
 	app.vweb.text(time.now().format())
 }
diff --git a/vlib/benchmark/benchmark.v b/vlib/benchmark/benchmark.v
index 112db9d7fb..650d236ec0 100644
--- a/vlib/benchmark/benchmark.v
+++ b/vlib/benchmark/benchmark.v
@@ -90,52 +90,52 @@ pub fn new_benchmark_pointer() &Benchmark {
 	}
 }
 
-pub fn (b mut Benchmark) set_total_expected_steps(n int) {
+pub fn (mut b Benchmark) set_total_expected_steps(n int) {
 	b.nexpected_steps = n
 }
 
-pub fn (b mut Benchmark) stop() {
+pub fn (mut b Benchmark) stop() {
 	b.bench_timer.stop()
 }
 
-pub fn (b mut Benchmark) step() {
+pub fn (mut b Benchmark) step() {
 	b.step_timer.restart()
 	if !b.no_cstep {
 		b.cstep++
 	}
 }
 
-pub fn (b mut Benchmark) fail() {
+pub fn (mut b Benchmark) fail() {
 	b.step_timer.stop()
 	b.ntotal++
 	b.nfail++
 }
 
-pub fn (b mut Benchmark) ok() {
+pub fn (mut b Benchmark) ok() {
 	b.step_timer.stop()
 	b.ntotal++
 	b.nok++
 }
 
-pub fn (b mut Benchmark) skip() {
+pub fn (mut b Benchmark) skip() {
 	b.step_timer.stop()
 	b.ntotal++
 	b.nskip++
 }
 
-pub fn (b mut Benchmark) fail_many(n int) {
+pub fn (mut b Benchmark) fail_many(n int) {
 	b.step_timer.stop()
 	b.ntotal += n
 	b.nfail += n
 }
 
-pub fn (b mut Benchmark) ok_many(n int) {
+pub fn (mut b Benchmark) ok_many(n int) {
 	b.step_timer.stop()
 	b.ntotal += n
 	b.nok += n
 }
 
-pub fn (b mut Benchmark) neither_fail_nor_ok() {
+pub fn (mut b Benchmark) neither_fail_nor_ok() {
 	b.step_timer.stop()
 }
 
@@ -145,7 +145,7 @@ pub fn start() Benchmark {
 	return b
 }
 
-pub fn (b mut Benchmark) measure(label string) i64 {
+pub fn (mut b Benchmark) measure(label string) i64 {
 	b.ok()
 	res := b.step_timer.elapsed().microseconds()
 	println(b.step_message_with_label(BSPENT, 'in $label'))
diff --git a/vlib/bitfield/bitfield.v b/vlib/bitfield/bitfield.v
index e9632f366d..69a9dd7a00 100644
--- a/vlib/bitfield/bitfield.v
+++ b/vlib/bitfield/bitfield.v
@@ -88,7 +88,7 @@ pub fn (instance BitField) get_bit(bitnr int) int {
 }
 
 // set_bit sets bit number 'bit_nr' to 1 (count from 0).
-pub fn (instance mut BitField) set_bit(bitnr int) {
+pub fn (mut instance BitField) set_bit(bitnr int) {
 	if bitnr >= instance.size {
 		return
 	}
@@ -96,7 +96,7 @@ pub fn (instance mut BitField) set_bit(bitnr int) {
 }
 
 // clear_bit clears (sets to zero) bit number 'bit_nr' (count from 0).
-pub fn (instance mut BitField) clear_bit(bitnr int) {
+pub fn (mut instance BitField) clear_bit(bitnr int) {
 	if bitnr >= instance.size {
 		return
 	}
@@ -104,7 +104,7 @@ pub fn (instance mut BitField) clear_bit(bitnr int) {
 }
 
 // set_all sets all bits in the array to 1.
-pub fn (instance mut BitField) set_all() {
+pub fn (mut instance BitField) set_all() {
 	for i in 0..bitnslots(instance.size) {
 		instance.field[i] = u32(-1)
 	}
@@ -112,7 +112,7 @@ pub fn (instance mut BitField) set_all() {
 }
 
 // clear_all clears (sets to zero) all bits in the array.
-pub fn (instance mut BitField) clear_all() {
+pub fn (mut instance BitField) clear_all() {
 	for i in 0..bitnslots(instance.size) {
 		instance.field[i] = u32(0)
 	}
@@ -120,7 +120,7 @@ pub fn (instance mut BitField) clear_all() {
 
 // toggle_bit changes the value (from 0 to 1 or from 1 to 0) of bit
 // number 'bit_nr'.
-pub fn (instance mut BitField) toggle_bit(bitnr int) {
+pub fn (mut instance BitField) toggle_bit(bitnr int) {
 	if bitnr >= instance.size {
 		return
 	}
@@ -390,7 +390,7 @@ pub fn (instance BitField) reverse() BitField {
 }
 
 // resize changes the size of the bit array to 'new_size'.
-pub fn (instance mut BitField) resize(new_size int) {
+pub fn (mut instance BitField) resize(new_size int) {
 	new_bitnslots := bitnslots(new_size)
 	old_size := instance.size
 	old_bitnslots := bitnslots(old_size)
@@ -433,7 +433,7 @@ pub fn (instance BitField) rotate(offset int) BitField {
 
 // Internal functions
 
-fn (instance mut BitField) clear_tail() {
+fn (mut instance BitField) clear_tail() {
 	tail := instance.size % SLOT_SIZE
 	if tail != 0 {
 		// create a mask for the tail
diff --git a/vlib/builtin/array.v b/vlib/builtin/array.v
index 969fa38bc3..c7419431eb 100644
--- a/vlib/builtin/array.v
+++ b/vlib/builtin/array.v
@@ -71,7 +71,7 @@ fn new_array_from_c_array_no_alloc(len, cap, elm_size int, c_array voidptr) arra
 
 // Private function. Doubles array capacity if needed
 [inline]
-fn (a mut array) ensure_cap(required int) {
+fn (mut a array) ensure_cap(required int) {
 	if required <= a.cap {
 		return
 	}
@@ -110,7 +110,7 @@ pub fn (a array) repeat(count int) array {
 }
 
 // array.sort sorts array in-place using given `compare` function as comparator
-pub fn (a mut array) sort_with_compare(compare voidptr) {
+pub fn (mut a array) sort_with_compare(compare voidptr) {
 	C.qsort(a.data, a.len, a.element_size, compare)
 }
 
@@ -120,7 +120,7 @@ pub fn (a mut array) sort_with_compare(compare voidptr) {
 // i := 3
 // a.insert(0, &i)
 // ----------------------------
-pub fn (a mut array) insert(i int, val voidptr) {
+pub fn (mut a array) insert(i int, val voidptr) {
 	$if !no_bounds_checking? {
 		if i < 0 || i > a.len {
 			panic('array.insert: index out of range (i == $i, a.len == $a.len)')
@@ -136,12 +136,12 @@ pub fn (a mut array) insert(i int, val voidptr) {
 // TODO array.prepend is broken
 // It depends on array.insert
 // -----------------------------
-pub fn (a mut array) prepend(val voidptr) {
+pub fn (mut a array) prepend(val voidptr) {
 	a.insert(0, val)
 }
 
 // array.delete deletes array element at the given index
-pub fn (a mut array) delete(i int) {
+pub fn (mut a array) delete(i int) {
 	$if !no_bounds_checking? {
 		if i < 0 || i >= a.len {
 			panic('array.delete: index out of range (i == $i, a.len == $a.len)')
@@ -153,13 +153,13 @@ pub fn (a mut array) delete(i int) {
 }
 
 // clears the array without deallocating the allocated data
-pub fn (a mut array) clear() {
+pub fn (mut a array) clear() {
 	a.len = 0
 }
 
 // trims the array length to "index" without modifying the allocated data. If "index" is greater
 // than len nothing will be changed
-pub fn (a mut array) trim(index int) {
+pub fn (mut a array) trim(index int) {
 	if index < a.len {
 		a.len = index
 	}
@@ -274,7 +274,7 @@ fn (a &array) slice_clone(start, _end int) array {
 }
 
 // Private function. Used to implement assigment to the array element.
-fn (a mut array) set(i int, val voidptr) {
+fn (mut a array) set(i int, val voidptr) {
 	$if !no_bounds_checking? {
 		if i < 0 || i >= a.len {
 			panic('array.set: index out of range (i == $i, a.len == $a.len)')
@@ -283,7 +283,7 @@ fn (a mut array) set(i int, val voidptr) {
 	C.memcpy(byteptr(a.data) + a.element_size * i, val, a.element_size)
 }
 
-fn (a mut array) push(val voidptr) {
+fn (mut a array) push(val voidptr) {
 	a.ensure_cap(a.len + 1)
 	C.memcpy(byteptr(a.data) + a.element_size * a.len, val, a.element_size)
 	a.len++
@@ -291,7 +291,7 @@ fn (a mut array) push(val voidptr) {
 
 // `val` is array.data
 // TODO make private, right now it's used by strings.Builder
-pub fn (a3 mut array) push_many(val voidptr, size int) {
+pub fn (mut a3 array) push_many(val voidptr, size int) {
 	if a3.data == val {
 		// handle `arr << arr`
 		copy := a3.clone()
@@ -392,7 +392,7 @@ fn compare_ints(a, b &int) int {
 }
 
 // []int.sort sorts array of int in place in ascending order.
-pub fn (a mut []int) sort() {
+pub fn (mut a []int) sort() {
 	a.sort_with_compare(compare_ints)
 }
 
diff --git a/vlib/builtin/bare/array_bare.v b/vlib/builtin/bare/array_bare.v
index a2f8c0c181..3c39d1164e 100644
--- a/vlib/builtin/bare/array_bare.v
+++ b/vlib/builtin/bare/array_bare.v
@@ -28,7 +28,7 @@ fn (a array) get(i int) voidptr {
 }
 
 // Private function. Used to implement assigment to the array element.
-fn (a mut array) set(i int, val voidptr) {
+fn (mut a array) set(i int, val voidptr) {
 	if i < 0 || i >= a.len {
 		panic('array.set: index out of range') //FIXME: (i == $i, a.len == $a.len)')
 	}
diff --git a/vlib/builtin/js/array.v b/vlib/builtin/js/array.v
index 56e6cef8ab..6c9afda12d 100644
--- a/vlib/builtin/js/array.v
+++ b/vlib/builtin/js/array.v
@@ -47,17 +47,17 @@ pub fn (a array) repeat(nr_repeats int) array {
 	return a
 }
 
-pub fn (a mut array) sort_with_compare(compare voidptr) {
+pub fn (mut a array) sort_with_compare(compare voidptr) {
 }
 
-pub fn (a mut array) insert(i int, val voidptr) {
+pub fn (mut a array) insert(i int, val voidptr) {
 }
 
-pub fn (a mut array) prepend(val voidptr) {
+pub fn (mut a array) prepend(val voidptr) {
 	a.insert(0, val)
 }
 
-pub fn (a mut array) delete_elm(idx int) {
+pub fn (mut a array) delete_elm(idx int) {
 }
 
 /*
@@ -132,7 +132,7 @@ pub fn (b []byte) hex() string {
 	return 'sdf'
 }
 
-pub fn (arr mut array) push_many(val voidptr, size int) {
+pub fn (mut arr array) push_many(val voidptr, size int) {
 }
 
 pub fn free(voidptr) {
diff --git a/vlib/builtin/js/map.v b/vlib/builtin/js/map.v
index 516fb5ae4a..6ea2979870 100644
--- a/vlib/builtin/js/map.v
+++ b/vlib/builtin/js/map.v
@@ -10,7 +10,7 @@ pub struct map {
 	obj voidptr
 }
 
-//fn (m mut map) insert(n mut mapnode, key string, val voidptr) {
+//fn (mut m map) insert(n mut mapnode, key string, val voidptr) {
 //}
 
 //////fn (n & mapnode) find(key string, out voidptr, element_size int) bool{
@@ -26,7 +26,7 @@ pub struct map {
 	//return 0
 //}
 
-pub fn (m mut map) keys() []string {
+pub fn (mut m map) keys() []string {
 	return ['']
 }
 
@@ -34,7 +34,7 @@ fn (m map) get(key string, out voidptr) bool {
 	return false
 }
 
-pub fn (m mut map) delete(key string) {
+pub fn (mut m map) delete(key string) {
 }
 
 fn (m map) exists(key string) bool {
diff --git a/vlib/builtin/js/string.v b/vlib/builtin/js/string.v
index a64818e3ee..01306a2173 100644
--- a/vlib/builtin/js/string.v
+++ b/vlib/builtin/js/string.v
@@ -23,8 +23,8 @@ pub fn tos(s byteptr) string {
 	return string{
 		str: s
 		len: len
-	}	
-}	
+	}
+}
 
 // string.clone_static returns an independent copy of a given array
 // It should be used only in -autofree generated code.
@@ -209,14 +209,14 @@ pub fn (s string) trim_right(cutset string) string {
 // fn print_cur_thread() {
 // //C.printf("tid = %08x \n", pthread_self());
 // }
-pub fn (s mut []string) sort() {
-	
+pub fn (mut s []string) sort() {
+
 }
 
-pub fn (s mut []string) sort_ignore_case() {
+pub fn (mut s []string) sort_ignore_case() {
 }
 
-pub fn (s mut []string) sort_by_len() {
+pub fn (mut s []string) sort_by_len() {
 }
 
 fn (s string) at(idx int) byte {
diff --git a/vlib/builtin/map.v b/vlib/builtin/map.v
index 4752ac3a2c..15b2a9c1de 100644
--- a/vlib/builtin/map.v
+++ b/vlib/builtin/map.v
@@ -9,7 +9,7 @@ import hash.wyhash
 fn C.memcmp(byteptr, byteptr, int) int
 
 /*
-This is a highly optimized hashmap implementation. It has several traits that 
+This is a highly optimized hashmap implementation. It has several traits that
 in combination makes it very fast and memory efficient. Here is a short expl-
 anation of each trait. After reading this you should have a basic understand-
 ing of how it functions:
@@ -22,7 +22,7 @@ resolved by probing. As opposed to linear probing, Robin Hood hashing has a
 simple but clever twist: As new keys are inserted, old keys are shifted arou-
 nd in a way such that all keys stay reasonably close to the slot they origin-
 ally hash to. A new key may displace a key already inserted if its probe cou-
-nt is larger than that of the key at the current position. 
+nt is larger than that of the key at the current position.
 
 3. Memory layout: key-value pairs are stored in a `DenseArray`. This is a dy-
 namic array with a very low volume of unused memory, at the cost of more rea-
@@ -49,7 +49,7 @@ using a well-dispersed hash-function.
 
 5. The hashmap keeps track of the highest probe_count. The trick is to alloc-
 ate `extra_metas` > max(probe_count), so you never have to do any bounds-che-
-cking since the extra meta memory ensures that a meta will never go beyond 
+cking since the extra meta memory ensures that a meta will never go beyond
 the last index.
 
 6. Cached rehashing. When the `load_factor` of the map exceeds the `max_load_
@@ -81,7 +81,7 @@ const (
 	probe_inc           = u32(0x01000000)
 )
 
-// This function is intended to be fast when 
+// This function is intended to be fast when
 // the strings are very likely to be equal
 // TODO: add branch prediction hints
 [inline]
@@ -119,7 +119,7 @@ fn new_dense_array(value_bytes int) DenseArray {
 // Push element to array and return index
 // The growth-factor is roughly 1.125 `(x + (x >> 3))`
 [inline]
-fn (d mut DenseArray) push(key string, value voidptr) u32 {
+fn (mut d DenseArray) push(key string, value voidptr) u32 {
 	if d.cap == d.size {
 		d.cap += d.cap >> 3
 		d.keys = &string(C.realloc(d.keys, sizeof(string) * d.cap))
@@ -144,7 +144,7 @@ fn (d DenseArray) get(i int) voidptr {
 
 // Move all zeros to the end of the array
 // and resize array
-fn (d mut DenseArray) zeros_to_end() {
+fn (mut d DenseArray) zeros_to_end() {
 	mut tmp_value := malloc(d.value_bytes)
 	mut count := u32(0)
 	for i in 0 .. d.size {
@@ -233,7 +233,7 @@ fn (m &map) meta_less(_index u32, _metas u32) (u32,u32) {
 }
 
 [inline]
-fn (m mut map) meta_greater(_index u32, _metas u32, kvi u32) {
+fn (mut m map) meta_greater(_index u32, _metas u32, kvi u32) {
 	mut meta := _metas
 	mut index := _index
 	mut kv_index := kvi
@@ -264,7 +264,7 @@ fn (m mut map) meta_greater(_index u32, _metas u32, kvi u32) {
 	}
 }
 
-fn (m mut map) set(key string, value voidptr) {
+fn (mut m map) set(key string, value voidptr) {
 	load_factor := f32(m.size << 1) / f32(m.cap)
 	if load_factor > max_load_factor {
 		m.expand()
@@ -287,7 +287,7 @@ fn (m mut map) set(key string, value voidptr) {
 }
 
 // Doubles the size of the hashmap
-fn (m mut map) expand() {
+fn (mut m map) expand() {
 	old_cap := m.cap
 	m.cap = ((m.cap + 2) << 1) - 2
 	// Check if any hashbits are left
@@ -302,7 +302,7 @@ fn (m mut map) expand() {
 	}
 }
 
-fn (m mut map) rehash() {
+fn (mut m map) rehash() {
 	meta_bytes := sizeof(u32) * (m.cap + 2 + m.extra_metas)
 	m.metas = &u32(C.realloc(m.metas, meta_bytes))
 	C.memset(m.metas, 0, meta_bytes)
@@ -316,7 +316,7 @@ fn (m mut map) rehash() {
 	}
 }
 
-fn (m mut map) cached_rehash(old_cap u32) {
+fn (mut m map) cached_rehash(old_cap u32) {
 	old_metas := m.metas
 	m.metas = &u32(vcalloc(sizeof(u32) * (m.cap + 2 + m.extra_metas)))
 	old_extra_metas := m.extra_metas
@@ -370,7 +370,7 @@ fn (m map) exists(key string) bool {
 	return false
 }
 
-pub fn (m mut map) delete(key string) {
+pub fn (mut m map) delete(key string) {
 	mut index,mut meta := m.key_to_index(key)
 	index,meta = m.meta_less(index, meta)
 	// Perform backwards shifting
diff --git a/vlib/builtin/map_test.v b/vlib/builtin/map_test.v
index 1474248a5a..223266516a 100644
--- a/vlib/builtin/map_test.v
+++ b/vlib/builtin/map_test.v
@@ -10,7 +10,7 @@ mut:
 	users map[string]User
 }
 
-fn (a mut A) set(key string, val int) {
+fn (mut a A) set(key string, val int) {
 	a.m[key] = val
 }
 
diff --git a/vlib/builtin/sorted_map.v b/vlib/builtin/sorted_map.v
index 0ece0177f7..ddae014271 100644
--- a/vlib/builtin/sorted_map.v
+++ b/vlib/builtin/sorted_map.v
@@ -65,7 +65,7 @@ fn new_node() &mapnode {
 
 // This implementation does proactive insertion, meaning
 // that splits are done top-down and not bottom-up.
-fn (m mut SortedMap) set(key string, value voidptr) {
+fn (mut m SortedMap) set(key string, value voidptr) {
 	mut node := m.root
 	mut child_index := 0
 	mut parent := &mapnode(0)
@@ -112,7 +112,7 @@ fn (m mut SortedMap) set(key string, value voidptr) {
 	}
 }
 
-fn (n mut mapnode) split_child(child_index int, y mut mapnode) {
+fn (mut n mapnode) split_child(child_index int, y mut mapnode) {
 	mut z := new_node()
 	z.size = mid_index
 	y.size = mid_index
@@ -186,7 +186,7 @@ fn (n &mapnode) find_key(k string) int {
 	return idx
 }
 
-fn (n mut mapnode) remove_key(k string) bool {
+fn (mut n mapnode) remove_key(k string) bool {
 	idx := n.find_key(k)
 	if idx < n.size && n.keys[idx] == k {
 		if isnil(n.children) {
@@ -212,7 +212,7 @@ fn (n mut mapnode) remove_key(k string) bool {
 	}
 }
 
-fn (n mut mapnode) remove_from_leaf(idx int) {
+fn (mut n mapnode) remove_from_leaf(idx int) {
 	for i := idx + 1; i < n.size; i++ {
 		n.keys[i - 1] = n.keys[i]
 		n.values[i - 1] = n.values[i]
@@ -220,7 +220,7 @@ fn (n mut mapnode) remove_from_leaf(idx int) {
 	n.size--
 }
 
-fn (n mut mapnode) remove_from_non_leaf(idx int) {
+fn (mut n mapnode) remove_from_non_leaf(idx int) {
 	k := n.keys[idx]
 	if &mapnode(n.children[idx]).size >= degree {
 		mut current := &mapnode(n.children[idx])
@@ -246,7 +246,7 @@ fn (n mut mapnode) remove_from_non_leaf(idx int) {
 	}
 }
 
-fn (n mut mapnode) fill(idx int) {
+fn (mut n mapnode) fill(idx int) {
 	if idx != 0 && &mapnode(n.children[idx - 1]).size >= degree {
 		n.borrow_from_prev(idx)
 	} else if idx != n.size && &mapnode(n.children[idx + 1]).size >= degree {
@@ -258,7 +258,7 @@ fn (n mut mapnode) fill(idx int) {
 	}
 }
 
-fn (n mut mapnode) borrow_from_prev(idx int) {
+fn (mut n mapnode) borrow_from_prev(idx int) {
 	mut child := &mapnode(n.children[idx])
 	mut sibling := &mapnode(n.children[idx - 1])
 	for i := child.size - 1; i >= 0; i-- {
@@ -281,7 +281,7 @@ fn (n mut mapnode) borrow_from_prev(idx int) {
 	sibling.size--
 }
 
-fn (n mut mapnode) borrow_from_next(idx int) {
+fn (mut n mapnode) borrow_from_next(idx int) {
 	mut child := &mapnode(n.children[idx])
 	mut sibling := &mapnode(n.children[idx + 1])
 	child.keys[child.size] = n.keys[idx]
@@ -304,7 +304,7 @@ fn (n mut mapnode) borrow_from_next(idx int) {
 	sibling.size--
 }
 
-fn (n mut mapnode) merge(idx int) {
+fn (mut n mapnode) merge(idx int) {
 	mut child := &mapnode(n.children[idx])
 	sibling := &mapnode(n.children[idx + 1])
 	child.keys[mid_index] = n.keys[idx]
@@ -330,7 +330,7 @@ fn (n mut mapnode) merge(idx int) {
 	// free(sibling)
 }
 
-pub fn (m mut SortedMap) delete(key string) {
+pub fn (mut m SortedMap) delete(key string) {
 	if m.root.size == 0 {
 		return
 	}
@@ -387,11 +387,11 @@ pub fn (m &SortedMap) keys() []string {
 	return keys
 }
 
-fn (n mut mapnode) free() {
+fn (mut n mapnode) free() {
 	println('TODO')
 }
 
-pub fn (m mut SortedMap) free() {
+pub fn (mut m SortedMap) free() {
 	if isnil(m.root) {
 		return
 	}
diff --git a/vlib/builtin/string.v b/vlib/builtin/string.v
index 9e6ee8198a..35ec0eea6c 100644
--- a/vlib/builtin/string.v
+++ b/vlib/builtin/string.v
@@ -222,7 +222,7 @@ fn compare_rep_index(a, b &RepIndex) int {
 }
 
 
-fn (a mut []RepIndex) sort() {
+fn (mut a []RepIndex) sort() {
 	a.sort_with_compare(compare_rep_index)
 }
 
@@ -969,15 +969,15 @@ fn compare_lower_strings(a, b &string) int {
 	return compare_strings(aa, bb)
 }
 
-pub fn (s mut []string) sort() {
+pub fn (mut s []string) sort() {
 	s.sort_with_compare(compare_strings)
 }
 
-pub fn (s mut []string) sort_ignore_case() {
+pub fn (mut s []string) sort_ignore_case() {
 	s.sort_with_compare(compare_lower_strings)
 }
 
-pub fn (s mut []string) sort_by_len() {
+pub fn (mut s []string) sort_by_len() {
 	s.sort_with_compare(compare_strings_by_len)
 }
 
diff --git a/vlib/cli/command.v b/vlib/cli/command.v
index 55099a7382..f8e6c9da9f 100644
--- a/vlib/cli/command.v
+++ b/vlib/cli/command.v
@@ -34,15 +34,15 @@ pub fn (cmd Command) root() Command {
 	return cmd.parent.root()
 }
 
-pub fn (cmd mut Command) add_command(command Command) {
+pub fn (mut cmd Command) add_command(command Command) {
 	cmd.commands << command
 }
 
-pub fn (cmd mut Command) add_flag(flag Flag) {
+pub fn (mut cmd Command) add_flag(flag Flag) {
 	cmd.flags << flag
 }
 
-pub fn (cmd mut Command) parse(args []string) {
+pub fn (mut cmd Command) parse(args []string) {
 	cmd.add_default_flags()
 	cmd.add_default_commands()
 
@@ -55,7 +55,7 @@ pub fn (cmd mut Command) parse(args []string) {
 	cmd.parse_commands()
 }
 
-fn (cmd mut Command) add_default_flags() {
+fn (mut cmd Command) add_default_flags() {
 	if !cmd.disable_help && !cmd.flags.contains('help') && !cmd.flags.contains('h') {
 		cmd.add_flag(help_flag())
 	}
@@ -64,7 +64,7 @@ fn (cmd mut Command) add_default_flags() {
 	}
 }
 
-fn (cmd mut Command) add_default_commands() {
+fn (mut cmd Command) add_default_commands() {
 	if !cmd.disable_help && !cmd.commands.contains('help') {
 		cmd.add_command(help_cmd())
 	}
@@ -73,7 +73,7 @@ fn (cmd mut Command) add_default_commands() {
 	}
 }
 
-fn (cmd mut Command) parse_flags() {
+fn (mut cmd Command) parse_flags() {
 	for {
 		if cmd.args.len < 1 || !cmd.args[0].starts_with('-') {
 			break
@@ -137,7 +137,7 @@ fn (cmd &Command) parse_commands() {
 
 		execute := cmd.execute
 		execute(cmd) // TODO: fix once higher order function can be execute on struct variable
-		
+
 		if int(cmd.post_execute) > 0 {
 			post_execute := cmd.post_execute
 			post_execute(cmd)
diff --git a/vlib/cli/flag.v b/vlib/cli/flag.v
index 3c9eb6b198..362806cb80 100644
--- a/vlib/cli/flag.v
+++ b/vlib/cli/flag.v
@@ -64,7 +64,7 @@ pub fn (flags []Flag) get_string_or(name string, or_value string) string {
 }
 
 // parse flag value from arguments and return arguments with all consumed element removed
-fn (flag mut Flag) parse(args []string) ?[]string {
+fn (mut flag Flag) parse(args []string) ?[]string {
 	if flag.matches(args) {
 		if flag.flag == .bool {
 			new_args := flag.parse_bool(args) or { return error(err) }
@@ -85,7 +85,7 @@ fn (flag &Flag) matches(args []string) bool {
 		(flag.abbrev != '' && args[0].starts_with('-${flag.abbrev}'))
 }
 
-fn (flag mut Flag) parse_raw(args []string) ?[]string {
+fn (mut flag Flag) parse_raw(args []string) ?[]string {
 	if args[0].len > flag.name.len && args[0].contains('=') {
 		flag.value = args[0].split('=')[1]
 		return args[1..]
@@ -96,7 +96,7 @@ fn (flag mut Flag) parse_raw(args []string) ?[]string {
 	return error('missing argument for ${flag.name}')
 }
 
-fn (flag mut Flag) parse_bool(args []string) ?[]string {
+fn (mut flag Flag) parse_bool(args []string) ?[]string {
 	if args[0].len > flag.name.len && args[0].contains('=') {
 		flag.value = args[0].split('=')[1]
 		return args[1..]
diff --git a/vlib/clipboard/clipboard.v b/vlib/clipboard/clipboard.v
index d8cc82adb9..6d4ebffac4 100644
--- a/vlib/clipboard/clipboard.v
+++ b/vlib/clipboard/clipboard.v
@@ -6,22 +6,22 @@ pub fn new() &Clipboard {
 }
 
 // copy some text into the clipboard
-pub fn (cb mut Clipboard) copy(text string) bool {
+pub fn (mut cb Clipboard) copy(text string) bool {
 	return cb.set_text(text)
 }
 
 // get the text from the clipboard
-pub fn (cb mut Clipboard) paste() string {
+pub fn (mut cb Clipboard) paste() string {
 	return cb.get_text()
 }
 
 // clear the clipboard
-pub fn (cb mut Clipboard) clear_all() {
+pub fn (mut cb Clipboard) clear_all() {
 	cb.clear()
 }
 
 // destroy the clipboard
-pub fn (cb mut Clipboard) destroy() {
+pub fn (mut cb Clipboard) destroy() {
 	cb.free()
 }
 
diff --git a/vlib/clipboard/clipboard_darwin.c.v b/vlib/clipboard/clipboard_darwin.c.v
index 3209b40ba1..e4b383ea3a 100644
--- a/vlib/clipboard/clipboard_darwin.c.v
+++ b/vlib/clipboard/clipboard_darwin.c.v
@@ -25,12 +25,12 @@ fn (cb &Clipboard) check_availability() bool {
 	return cb.pb != C.NULL
 }
 
-fn (cb mut Clipboard) clear(){
+fn (mut cb Clipboard) clear(){
 	cb.foo = 0
 	#[cb->pb clearContents];
 }
 
-fn (cb mut Clipboard) free(){
+fn (mut cb Clipboard) free(){
 	cb.foo = 0
 	//nothing to free
 }
@@ -43,7 +43,7 @@ fn (cb &Clipboard) has_ownership() bool {
 
 fn C.OSAtomicCompareAndSwapLong()
 
-fn (cb mut Clipboard) set_text(text string) bool {
+fn (mut cb Clipboard) set_text(text string) bool {
 	cb.foo = 0
 	#NSString *ns_clip;
 	ret := false
@@ -59,7 +59,7 @@ fn (cb mut Clipboard) set_text(text string) bool {
 	return ret
 }
 
-fn (cb mut Clipboard) get_text() string {
+fn (mut cb Clipboard) get_text() string {
 	cb.foo = 0
 	#NSString *ns_clip;
 	utf8_clip := byteptr(0)
diff --git a/vlib/clipboard/clipboard_linux.c.v b/vlib/clipboard/clipboard_linux.c.v
index 96028ff332..e933a4df8f 100644
--- a/vlib/clipboard/clipboard_linux.c.v
+++ b/vlib/clipboard/clipboard_linux.c.v
@@ -172,14 +172,14 @@ fn (cb &Clipboard) check_availability() bool {
 	return cb.display != C.NULL
 }
 
-fn (cb mut Clipboard) free() {
+fn (mut cb Clipboard) free() {
 	C.XDestroyWindow(cb.display, cb.window)
 	cb.window = C.Window(C.None)
 	//FIX ME: program hangs when closing display
 	//XCloseDisplay(cb.display)
 }
 
-fn (cb mut Clipboard) clear(){
+fn (mut cb Clipboard) clear(){
 	cb.mutex.lock()
 	C.XSetSelectionOwner(cb.display, cb.selection, C.Window(C.None), C.CurrentTime)
 	C.XFlush(cb.display)
@@ -197,7 +197,7 @@ fn (cb &Clipboard) take_ownership(){
 	C.XFlush(cb.display)
 }
 
-fn (cb mut Clipboard) set_text(text string) bool {
+fn (mut cb Clipboard) set_text(text string) bool {
 	if cb.window == C.Window(C.None) {return false}
 	cb.mutex.lock()
 	cb.text = text
@@ -210,7 +210,7 @@ fn (cb mut Clipboard) set_text(text string) bool {
 	return cb.is_owner
 }
 
-fn (cb mut Clipboard) get_text() string {
+fn (mut cb Clipboard) get_text() string {
 	if cb.window == C.Window(C.None) {return ""}
 	if cb.is_owner {
 		return cb.text
@@ -232,7 +232,7 @@ fn (cb mut Clipboard) get_text() string {
 
 // this function is crucial to handling all the different data types
 // if we ever support other mimetypes they should be handled here
-fn (cb mut Clipboard) transmit_selection(xse &C.XSelectionEvent) bool {
+fn (mut cb Clipboard) transmit_selection(xse &C.XSelectionEvent) bool {
 	if xse.target == cb.get_atom(.targets) {
 		targets := cb.get_supported_targets()
 		C.XChangeProperty(xse.display, xse.requestor, xse.property, cb.get_atom(.xa_atom), 32, C.PropModeReplace, targets.data, targets.len)
@@ -246,7 +246,7 @@ fn (cb mut Clipboard) transmit_selection(xse &C.XSelectionEvent) bool {
 	return true
 }
 
-fn (cb mut Clipboard) start_listener(){
+fn (mut cb Clipboard) start_listener(){
 	event := C.XEvent{}
 	mut sent_request := false
 	mut to_be_requested := C.Atom(0)
@@ -325,7 +325,7 @@ fn (cb mut Clipboard) start_listener(){
 // Helpers
 
 // Initialize all the atoms we need
-fn (cb mut Clipboard) intern_atoms(){
+fn (mut cb Clipboard) intern_atoms(){
 	cb.atoms << C.Atom(4) //XA_ATOM
 	cb.atoms << C.Atom(31) //XA_STRING
 	for i, name in atom_names{
diff --git a/vlib/clipboard/clipboard_solaris.c.v b/vlib/clipboard/clipboard_solaris.c.v
index 4a023207c6..56905b4a44 100644
--- a/vlib/clipboard/clipboard_solaris.c.v
+++ b/vlib/clipboard/clipboard_solaris.c.v
@@ -17,23 +17,23 @@ pub fn new_primary() &Clipboard {
    return &Clipboard{}
 }
 
-fn (cb mut Clipboard) set_text(text string) bool {
+fn (mut cb Clipboard) set_text(text string) bool {
    cb.text = text
    cb.is_owner = true
    cb.got_text = true
    return true
 }
 
-fn (cb mut Clipboard) get_text() string {
+fn (mut cb Clipboard) get_text() string {
    return cb.text
 }
 
-fn (cb mut Clipboard) clear(){
+fn (mut cb Clipboard) clear(){
    cb.text = ''
    cb.is_owner = false
 }
 
-fn (cb mut Clipboard) free(){   
+fn (mut cb Clipboard) free(){
 }
 
 fn (cb &Clipboard) has_ownership() bool {
@@ -41,7 +41,7 @@ fn (cb &Clipboard) has_ownership() bool {
 }
 
 fn (cb &Clipboard) check_availability() bool {
-   // This is a dummy clipboard implementation, 
+   // This is a dummy clipboard implementation,
    // which can be always used, although it does not do much...
    return true
 }
diff --git a/vlib/crypto/aes/aes_cbc.v b/vlib/crypto/aes/aes_cbc.v
index c270694112..99ef4e8418 100644
--- a/vlib/crypto/aes/aes_cbc.v
+++ b/vlib/crypto/aes/aes_cbc.v
@@ -79,7 +79,7 @@ pub fn (x &AesCbc) encrypt_blocks(dst mut []byte, src_ []byte) {
 	copy(x.iv, iv)
 }
 
-pub fn (x mut AesCbc) decrypt_blocks(dst mut []byte, src []byte) {
+pub fn (mut x AesCbc) decrypt_blocks(dst mut []byte, src []byte) {
 	if src.len%x.block_size != 0 {
 		panic('crypto.cipher: input not full blocks')
 	}
diff --git a/vlib/crypto/md5/md5.v b/vlib/crypto/md5/md5.v
index 63e7b32366..c7e003d6f3 100644
--- a/vlib/crypto/md5/md5.v
+++ b/vlib/crypto/md5/md5.v
@@ -37,7 +37,7 @@ mut:
 	len u64
 }
 
-fn (d mut Digest) reset() {
+fn (mut d Digest) reset() {
 	d.s = [u32(0)].repeat(4)
 	d.x = [byte(0)].repeat(block_size)
     d.s[0] = u32(init0)
@@ -55,7 +55,7 @@ pub fn new() &Digest {
 	return d
 }
 
-pub fn (d mut Digest) write(p_ []byte) int {
+pub fn (mut d Digest) write(p_ []byte) int {
 	mut p := p_
 	nn := p.len
 	d.len += u64(nn)
@@ -98,7 +98,7 @@ pub fn (d &Digest) sum(b_in []byte) []byte {
 	return b_out
 }
 
-pub fn (d mut Digest) checksum() []byte {
+pub fn (mut d Digest) checksum() []byte {
 	// Append 0x80 to the end of the message and then append zeros
 	// until the length is a multiple of 56 bytes. Finally append
 	// 8 bytes representing the message length in bits.
diff --git a/vlib/crypto/rc4/rc4.v b/vlib/crypto/rc4/rc4.v
index e818889f41..4c7d2f3d63 100644
--- a/vlib/crypto/rc4/rc4.v
+++ b/vlib/crypto/rc4/rc4.v
@@ -49,7 +49,7 @@ pub fn new_cipher(key []byte) ?Cipher {
 //
 // Deprecated: Reset can't guarantee that the key will be entirely removed from
 // the process's memory.
-pub fn (c mut Cipher) reset() {
+pub fn (mut c Cipher) reset() {
 	for i in c.s {
 		c.s[i] = 0
 	}
@@ -59,7 +59,7 @@ pub fn (c mut Cipher) reset() {
 
 // xor_key_stream sets dst to the result of XORing src with the key stream.
 // Dst and src must overlap entirely or not at all.
-pub fn (c mut Cipher) xor_key_stream(dst mut []byte, src []byte) {
+pub fn (mut c Cipher) xor_key_stream(dst mut []byte, src []byte) {
 	if src.len == 0 {
 		return
 	}
diff --git a/vlib/crypto/sha1/sha1.v b/vlib/crypto/sha1/sha1.v
index 3c1fab064a..e7fbbe6884 100644
--- a/vlib/crypto/sha1/sha1.v
+++ b/vlib/crypto/sha1/sha1.v
@@ -39,7 +39,7 @@ mut:
 	len u64
 }
 
-fn (d mut Digest) reset() {
+fn (mut d Digest) reset() {
 	d.x = [byte(0)].repeat(chunk)
 	d.h = [u32(0)].repeat(5)
 	d.h[0] = u32(init0)
@@ -58,7 +58,7 @@ pub fn new() &Digest {
 	return d
 }
 
-pub fn (d mut Digest) write(p_ []byte) int {
+pub fn (mut d Digest) write(p_ []byte) int {
 	mut p := p_
 	nn := p.len
 	d.len += u64(nn)
@@ -102,7 +102,7 @@ pub fn (d &Digest) sum(b_in []byte) []byte {
 	return b_out
 }
 
-fn (d mut Digest) checksum() []byte {
+fn (mut d Digest) checksum() []byte {
 	mut len := d.len
 	// Padding.  Add a 1 bit and 0 bits until 56 bytes mod 64.
 	mut tmp := [byte(0)].repeat(64)
diff --git a/vlib/crypto/sha256/sha256.v b/vlib/crypto/sha256/sha256.v
index 66b31b60b3..f39dbacba8 100644
--- a/vlib/crypto/sha256/sha256.v
+++ b/vlib/crypto/sha256/sha256.v
@@ -51,7 +51,7 @@ mut:
 	is224 bool // mark if this digest is SHA-224
 }
 
-fn (d mut Digest) reset() {
+fn (mut d Digest) reset() {
 	d.h = [u32(0)].repeat(8)
 	d.x = [byte(0)].repeat(chunk)
 	if !d.is224 {
@@ -92,7 +92,7 @@ pub fn new224() &Digest {
 	return d
 }
 
-fn (d mut Digest) write(p_ []byte) int {
+fn (mut d Digest) write(p_ []byte) int {
 	mut p := p_
 	nn := p.len
 	d.len += u64(nn)
@@ -141,7 +141,7 @@ fn (d &Digest) sum(b_in []byte) []byte {
 	return b_out
 }
 
-fn (d mut Digest) checksum() []byte {
+fn (mut d Digest) checksum() []byte {
 	mut len := d.len
 	// Padding. Add a 1 bit and 0 bits until 56 bytes mod 64.
 	mut tmp := [byte(0)].repeat(64)
diff --git a/vlib/crypto/sha512/sha512.v b/vlib/crypto/sha512/sha512.v
index 0f6e290737..377481ad68 100644
--- a/vlib/crypto/sha512/sha512.v
+++ b/vlib/crypto/sha512/sha512.v
@@ -69,7 +69,7 @@ mut:
 	function crypto.Hash
 }
 
-fn (d mut Digest) reset() {
+fn (mut d Digest) reset() {
 	d.h = [u64(0)].repeat(8)
 	d.x = [byte(0)].repeat(chunk)
 	match d.function {
@@ -146,7 +146,7 @@ fn new384() &Digest {
 	return new_digest(.sha384)
 }
 
-fn (d mut Digest) write(p_ []byte) int {
+fn (mut d Digest) write(p_ []byte) int {
 	mut p := p_
 	nn := p.len
 	d.len += u64(nn)
@@ -209,7 +209,7 @@ fn (d &Digest) sum(b_in []byte) []byte {
 	return b_out
 }
 
-fn (d mut Digest) checksum() []byte {
+fn (mut d Digest) checksum() []byte {
 	// Padding. Add a 1 bit and 0 bits until 112 bytes mod 128.
 	mut len := d.len
 	mut tmp := [byte(0)].repeat(128)
diff --git a/vlib/encoding/csv/reader.v b/vlib/encoding/csv/reader.v
index a434fb8277..5bf012221b 100644
--- a/vlib/encoding/csv/reader.v
+++ b/vlib/encoding/csv/reader.v
@@ -37,7 +37,7 @@ pub fn new_reader(data string) &Reader {
 }
 
 // read() reads one row from the csv file
-pub fn (r mut Reader) read() ?[]string {
+pub fn (mut r Reader) read() ?[]string {
 	l := r.read_record() or {
 		return error(err)
 	}
@@ -45,7 +45,7 @@ pub fn (r mut Reader) read() ?[]string {
 }
 
 // Once we have multi dimensional array
-// pub fn (r mut Reader) read_all() ?[][]string {
+// pub fn (mut r Reader) read_all() ?[][]string {
 // 	mut records := []string{}
 // 	for {
 // 		record := r.read_record() or {
@@ -60,7 +60,7 @@ pub fn (r mut Reader) read() ?[]string {
 // 	return records
 // }
 
-fn (r mut Reader) read_line() ?string {
+fn (mut r Reader) read_line() ?string {
 	// last record
 	if r.row_pos == r.data.len {
 		return err_eof
@@ -91,7 +91,7 @@ fn (r mut Reader) read_line() ?string {
 	return line
 }
 
-fn (r mut Reader) read_record() ?[]string {
+fn (mut r Reader) read_record() ?[]string {
 	if r.delimiter == r.comment {
 		return err_comment_is_delim
 	}
diff --git a/vlib/encoding/csv/writer.v b/vlib/encoding/csv/writer.v
index 08b5040cd5..5aba0cffbd 100644
--- a/vlib/encoding/csv/writer.v
+++ b/vlib/encoding/csv/writer.v
@@ -21,7 +21,7 @@ pub fn new_writer() &Writer {
 }
 
 // write writes a single record
-pub fn (w mut Writer) write(record []string) ?bool {
+pub fn (mut w Writer) write(record []string) ?bool {
 	if !valid_delim(w.delimiter) {
 		return err_invalid_delim
 	}
@@ -86,6 +86,6 @@ fn (w &Writer) field_needs_quotes(field string) bool {
 	return false
 }
 
-pub fn (w mut Writer) str() string {
+pub fn (mut w Writer) str() string {
 	return w.sb.str()
 }
diff --git a/vlib/eventbus/eventbus.v b/vlib/eventbus/eventbus.v
index 0daf83dd06..66dbc6588e 100644
--- a/vlib/eventbus/eventbus.v
+++ b/vlib/eventbus/eventbus.v
@@ -59,7 +59,7 @@ pub fn (eb &EventBus) has_subscriber(name string) bool {
 }
 
 // Publisher Methods
-fn (pb mut Publisher) publish(name string, sender voidptr, args voidptr) {
+fn (mut pb Publisher) publish(name string, sender voidptr, args voidptr) {
 	for i, event in pb.registry.events {
 		if event.name == name {
 			if event.once {
@@ -74,7 +74,7 @@ fn (pb mut Publisher) publish(name string, sender voidptr, args voidptr) {
 	}
 }
 
-fn (p mut Publisher) clear_all() {
+fn (mut p Publisher) clear_all() {
 	if p.registry.events.len == 0 {
 		return
 	}
@@ -84,7 +84,7 @@ fn (p mut Publisher) clear_all() {
 }
 
 // Subscriber Methods
-pub fn (s mut Subscriber) subscribe(name string, handler EventHandlerFn) {
+pub fn (mut s Subscriber) subscribe(name string, handler EventHandlerFn) {
 	s.registry.events << EventHandler {
 		name: name
 		handler: handler
@@ -92,7 +92,7 @@ pub fn (s mut Subscriber) subscribe(name string, handler EventHandlerFn) {
 	}
 }
 
-pub fn (s mut Subscriber) subscribe_method(name string, handler EventHandlerFn, receiver voidptr) {
+pub fn (mut s Subscriber) subscribe_method(name string, handler EventHandlerFn, receiver voidptr) {
 	s.registry.events << EventHandler {
 		name: name
 		handler: handler
@@ -100,7 +100,7 @@ pub fn (s mut Subscriber) subscribe_method(name string, handler EventHandlerFn,
 	}
 }
 
-pub fn (s mut Subscriber) subscribe_once(name string, handler EventHandlerFn) {
+pub fn (mut s Subscriber) subscribe_once(name string, handler EventHandlerFn) {
 	s.registry.events << EventHandler {
 		name: name
 		handler: handler
@@ -113,7 +113,7 @@ pub fn (s &Subscriber) is_subscribed(name string) bool {
 	return s.registry.check_subscriber(name)
 }
 
-pub fn (s mut Subscriber) unsubscribe(name string, handler EventHandlerFn) {
+pub fn (mut s Subscriber) unsubscribe(name string, handler EventHandlerFn) {
 	// v := voidptr(handler)
 	for i, event in s.registry.events {
 		if event.name == name {
diff --git a/vlib/flag/flag.v b/vlib/flag/flag.v
index a92d7ee993..678137477e 100644
--- a/vlib/flag/flag.v
+++ b/vlib/flag/flag.v
@@ -100,27 +100,27 @@ pub fn new_flag_parser(args []string) &FlagParser {
 }
 
 // change the application name to be used in 'usage' output
-pub fn (fs mut FlagParser) application(name string) {
+pub fn (mut fs FlagParser) application(name string) {
 	fs.application_name = name
 }
 
 // change the application version to be used in 'usage' output
-pub fn (fs mut FlagParser) version(vers string) {
+pub fn (mut fs FlagParser) version(vers string) {
 	fs.application_version = vers
 }
 
 // change the application version to be used in 'usage' output
-pub fn (fs mut FlagParser) description(desc string) {
+pub fn (mut fs FlagParser) description(desc string) {
 	fs.application_description = desc
 }
 
 // in most cases you do not need the first argv for flag parsing
-pub fn (fs mut FlagParser) skip_executable() {
+pub fn (mut fs FlagParser) skip_executable() {
 	fs.args.delete(0)
 }
 
 // private helper to register a flag
-fn (fs mut FlagParser) add_flag(name string, abbr byte, usage string, desc string) {
+fn (mut fs FlagParser) add_flag(name string, abbr byte, usage string, desc string) {
 	fs.flags << Flag{
 		name: name,
 		abbr: abbr,
@@ -138,7 +138,7 @@ fn (fs mut FlagParser) add_flag(name string, abbr byte, usage string, desc strin
 //
 //  - the name, usage are registered
 //  - found arguments and corresponding values are removed from args list
-fn (fs mut FlagParser) parse_value(longhand string, shorthand byte) []string {
+fn (mut fs FlagParser) parse_value(longhand string, shorthand byte) []string {
 	full := '--$longhand'
 	mut found_entries := []string{}
 	mut to_delete := []int{}
@@ -190,7 +190,7 @@ fn (fs mut FlagParser) parse_value(longhand string, shorthand byte) []string {
 // special: it is allowed to define bool flags without value
 // -> '--flag' is parsed as true
 // -> '--flag' is equal to '--flag=true'
-fn (fs mut FlagParser) parse_bool_value(longhand string, shorthand byte) ?string {
+fn (mut fs FlagParser) parse_bool_value(longhand string, shorthand byte) ?string {
 	full := '--$longhand'
 	for i, arg in fs.args {
 		if arg == '--' {
@@ -230,7 +230,7 @@ fn (fs mut FlagParser) parse_bool_value(longhand string, shorthand byte) ?string
 
 // bool_opt returns an optional that returns the value associated with the flag.
 // In the situation that the flag was not provided, it returns null.
-pub fn (fs mut FlagParser) bool_opt(name string, abbr byte, usage string) ?bool {
+pub fn (mut fs FlagParser) bool_opt(name string, abbr byte, usage string) ?bool {
 	fs.add_flag(name, abbr, usage, '<bool>')
 	parsed := fs.parse_bool_value(name, abbr) or {
 		return error("parameter '$name' not provided")
@@ -245,7 +245,7 @@ pub fn (fs mut FlagParser) bool_opt(name string, abbr byte, usage string) ?bool
 //      the default value is returned
 // version with abbr
 //TODO error handling for invalid string to bool conversion
-pub fn (fs mut FlagParser) bool(name string, abbr byte, bdefault bool, usage string) bool {
+pub fn (mut fs FlagParser) bool(name string, abbr byte, bdefault bool, usage string) bool {
 	value := fs.bool_opt(name, abbr, usage) or {
 		return bdefault
 	}
@@ -254,7 +254,7 @@ pub fn (fs mut FlagParser) bool(name string, abbr byte, bdefault bool, usage str
 
 // int_multi returns all instances of values associated with the flags provided
 // In the case that none were found, it returns an empty array.
-pub fn (fs mut FlagParser) int_multi(name string, abbr byte, usage string) []int {
+pub fn (mut fs FlagParser) int_multi(name string, abbr byte, usage string) []int {
 	fs.add_flag(name, abbr, usage, '<multiple ints>')
 	parsed := fs.parse_value(name, abbr)
 	mut value := []int{}
@@ -266,7 +266,7 @@ pub fn (fs mut FlagParser) int_multi(name string, abbr byte, usage string) []int
 
 // int_opt returns an optional that returns the value associated with the flag.
 // In the situation that the flag was not provided, it returns null.
-pub fn (fs mut FlagParser) int_opt(name string, abbr byte, usage string) ?int {
+pub fn (mut fs FlagParser) int_opt(name string, abbr byte, usage string) ?int {
 	fs.add_flag(name, abbr, usage, '<int>')
 	parsed := fs.parse_value(name, abbr)
 	if parsed.len == 0 {
@@ -282,7 +282,7 @@ pub fn (fs mut FlagParser) int_opt(name string, abbr byte, usage string) ?int {
 //      the default value is returned
 // version with abbr
 //TODO error handling for invalid string to int conversion
-pub fn (fs mut FlagParser) int(name string, abbr byte, idefault int, usage string) int {
+pub fn (mut fs FlagParser) int(name string, abbr byte, idefault int, usage string) int {
 	value := fs.int_opt(name, abbr, usage) or {
 		return idefault
 	}
@@ -291,7 +291,7 @@ pub fn (fs mut FlagParser) int(name string, abbr byte, idefault int, usage strin
 
 // float_multi returns all instances of values associated with the flags provided
 // In the case that none were found, it returns an empty array.
-pub fn (fs mut FlagParser) float_multi(name string, abbr byte, usage string) []f64 {
+pub fn (mut fs FlagParser) float_multi(name string, abbr byte, usage string) []f64 {
 	fs.add_flag(name, abbr, usage, '<multiple floats>')
 	parsed := fs.parse_value(name, abbr)
 	mut value := []f64{}
@@ -303,7 +303,7 @@ pub fn (fs mut FlagParser) float_multi(name string, abbr byte, usage string) []f
 
 // float_opt returns an optional that returns the value associated with the flag.
 // In the situation that the flag was not provided, it returns null.
-pub fn (fs mut FlagParser) float_opt(name string, abbr byte, usage string) ?f64 {
+pub fn (mut fs FlagParser) float_opt(name string, abbr byte, usage string) ?f64 {
 	fs.add_flag(name, abbr, usage, '<float>')
 	parsed := fs.parse_value(name, abbr)
 	if parsed.len == 0 {
@@ -319,7 +319,7 @@ pub fn (fs mut FlagParser) float_opt(name string, abbr byte, usage string) ?f64
 //      the default value is returned
 // version with abbr
 //TODO error handling for invalid string to float conversion
-pub fn (fs mut FlagParser) float(name string, abbr byte, fdefault f64, usage string) f64 {
+pub fn (mut fs FlagParser) float(name string, abbr byte, fdefault f64, usage string) f64 {
 	value := fs.float_opt(name, abbr, usage) or {
 		return fdefault
 	}
@@ -328,14 +328,14 @@ pub fn (fs mut FlagParser) float(name string, abbr byte, fdefault f64, usage str
 
 // string_multi returns all instances of values associated with the flags provided
 // In the case that none were found, it returns an empty array.
-pub fn (fs mut FlagParser) string_multi(name string, abbr byte, usage string) []string {
+pub fn (mut fs FlagParser) string_multi(name string, abbr byte, usage string) []string {
 	fs.add_flag(name, abbr, usage, '<multiple floats>')
 	return fs.parse_value(name, abbr)
 }
 
 // string_opt returns an optional that returns the value associated with the flag.
 // In the situation that the flag was not provided, it returns null.
-pub fn (fs mut FlagParser) string_opt(name string, abbr byte, usage string) ?string {
+pub fn (mut fs FlagParser) string_opt(name string, abbr byte, usage string) ?string {
 	fs.add_flag(name, abbr, usage, '<string>')
 	parsed := fs.parse_value(name, abbr)
 	if parsed.len == 0 {
@@ -350,14 +350,14 @@ pub fn (fs mut FlagParser) string_opt(name string, abbr byte, usage string) ?str
 //  else
 //      the default value is returned
 // version with abbr
-pub fn (fs mut FlagParser) string(name string, abbr byte, sdefault string, usage string) string {
+pub fn (mut fs FlagParser) string(name string, abbr byte, sdefault string, usage string) string {
 	value := fs.string_opt(name, abbr, usage) or {
 		return sdefault
 	}
 	return value
 }
 
-pub fn (fs mut FlagParser) limit_free_args_to_at_least(n int) {
+pub fn (mut fs FlagParser) limit_free_args_to_at_least(n int) {
 	if n > MAX_ARGS_NUMBER {
 		panic('flag.limit_free_args_to_at_least expect n to be smaller than $MAX_ARGS_NUMBER')
 	}
@@ -367,7 +367,7 @@ pub fn (fs mut FlagParser) limit_free_args_to_at_least(n int) {
 	fs.min_free_args = n
 }
 
-pub fn (fs mut FlagParser) limit_free_args_to_exactly(n int) {
+pub fn (mut fs FlagParser) limit_free_args_to_exactly(n int) {
 	if n > MAX_ARGS_NUMBER {
 		panic('flag.limit_free_args_to_exactly expect n to be smaller than $MAX_ARGS_NUMBER')
 	}
@@ -380,7 +380,7 @@ pub fn (fs mut FlagParser) limit_free_args_to_exactly(n int) {
 
 // this will cause an error in finalize() if free args are out of range
 // (min, ..., max)
-pub fn (fs mut FlagParser) limit_free_args(min, max int) {
+pub fn (mut fs FlagParser) limit_free_args(min, max int) {
 	if min > max {
 		panic('flag.limit_free_args expect min < max, got $min >= $max')
 	}
@@ -388,7 +388,7 @@ pub fn (fs mut FlagParser) limit_free_args(min, max int) {
 	fs.max_free_args = max
 }
 
-pub fn (fs mut FlagParser) arguments_description(description string){
+pub fn (mut fs FlagParser) arguments_description(description string){
 	fs.args_description = description
 }
 
diff --git a/vlib/gg/gg.v b/vlib/gg/gg.v
index 251e30636d..0fd181b42d 100644
--- a/vlib/gg/gg.v
+++ b/vlib/gg/gg.v
@@ -236,7 +236,7 @@ pub fn set_mode_fill() {
 }
 
 /*
-fn (ctx mut GG) init_rect_vao() {
+fn (mut ctx GG) init_rect_vao() {
 
 	ctx.rect_vao = gl.gen_vertex_array()
 	ctx.rect_vbo = gl.gen_buffer()
@@ -421,7 +421,7 @@ pub fn (ctx &GG) draw_line(x, y, x2, y2 f32, color gx.Color) {
 }
 
 pub fn (ctx &GG) draw_arc(x, y, r, start_angle, end_angle f32, segments int, color gx.Color) {
-	ctx.use_color_shader(color)	
+	ctx.use_color_shader(color)
 	vertices := arc_vertices(x, y, r, start_angle, end_angle, segments)
 	ctx.bind_vertices(vertices)
 	gl.draw_arrays(C.GL_LINE_STRIP, 0, segments + 1)
@@ -431,7 +431,7 @@ pub fn (ctx &GG) draw_arc(x, y, r, start_angle, end_angle f32, segments int, col
 pub fn (ctx &GG) draw_filled_arc(x, y, r, start_angle, end_angle f32, segments int, color gx.Color) {
 	ctx.use_color_shader(color)
 
-	
+
 	mut vertices := []f32{}
 	vertices << [x, y] !
 	vertices << arc_vertices(x, y, r, start_angle, end_angle, segments)
diff --git a/vlib/gg2/gg.v b/vlib/gg2/gg.v
index 3b755c7a07..a2ff04d90f 100644
--- a/vlib/gg2/gg.v
+++ b/vlib/gg2/gg.v
@@ -124,7 +124,7 @@ pub fn (ctx &GG) draw_text_def(x, y int, text string) {
 	ctx.draw_text(x, y, text, cfg)
 }
 
-pub fn (gg mut GG) init_font() {
+pub fn (mut gg GG) init_font() {
 	// TODO
 	gg.fons =g_fons
 	gg.font_normal=g_font_normal
diff --git a/vlib/glfw/glfw.v b/vlib/glfw/glfw.v
index c68eeb66ec..c95102b307 100644
--- a/vlib/glfw/glfw.v
+++ b/vlib/glfw/glfw.v
@@ -233,19 +233,19 @@ pub fn (w &Window) swap_buffers() {
 	C.glfwSwapBuffers(w.data)
 }
 
-pub fn (w mut Window) onmousemove(cb voidptr) {
+pub fn (mut w Window) onmousemove(cb voidptr) {
 	C.glfwSetCursorPosCallback(w.data, cb)
 }
 
-pub fn (w mut Window) set_mouse_button_callback(cb voidptr) {
+pub fn (mut w Window) set_mouse_button_callback(cb voidptr) {
 	C.glfwSetMouseButtonCallback(w.data, cb)
 }
 
-pub fn (w mut Window) on_resize(cb voidptr) {
+pub fn (mut w Window) on_resize(cb voidptr) {
 	C.glfwSetWindowSizeCallback(w.data, cb)
 }
 
-pub fn (w mut Window) on_click(cb voidptr) {
+pub fn (mut w Window) on_click(cb voidptr) {
 	C.glfwSetMouseButtonCallback(w.data, cb)
 }
 
@@ -261,11 +261,11 @@ pub fn post_empty_event() {
 	C.glfwPostEmptyEvent()
 }
 
-pub fn (w mut Window) onkeydown(cb voidptr) {
+pub fn (mut w Window) onkeydown(cb voidptr) {
 	C.glfwSetKeyCallback(w.data, cb)
 }
 
-pub fn (w mut Window) onchar(cb voidptr) {
+pub fn (mut w Window) onchar(cb voidptr) {
 	C.glfwSetCharModsCallback(w.data, cb)
 }
 
diff --git a/vlib/hash/crc32/crc32.v b/vlib/hash/crc32/crc32.v
index 5ddd796452..5ab8ef2353 100644
--- a/vlib/hash/crc32/crc32.v
+++ b/vlib/hash/crc32/crc32.v
@@ -23,7 +23,7 @@ mut:
 	table []u32
 }
 
-fn(c mut Crc32) generate_table(poly int) {
+fn(mut c Crc32) generate_table(poly int) {
 	for i in 0..256 {
 		mut crc := u32(i)
 		for _ in 0..8 {
diff --git a/vlib/log/log.v b/vlib/log/log.v
index 4df86e2126..1472293bb7 100644
--- a/vlib/log/log.v
+++ b/vlib/log/log.v
@@ -40,25 +40,25 @@ pub mut:
 	output_file_name string
 }
 
-pub fn (l mut Log) set_level(level Level) {
+pub fn (mut l Log) set_level(level Level) {
 	l.level = level
 }
 
-pub fn (l mut Log) set_output_level(level Level) {
+pub fn (mut l Log) set_output_level(level Level) {
 	l.level = level
 }
 
-pub fn (l mut Log) set_full_logpath(full_log_path string) {
+pub fn (mut l Log) set_full_logpath(full_log_path string) {
 	rlog_file := os.real_path( full_log_path )
 	l.set_output_label( os.file_name( rlog_file ) )
 	l.set_output_path( os.base_dir( rlog_file ) )
 }
 
-pub fn (l mut Log) set_output_label(label string){
+pub fn (mut l Log) set_output_label(label string){
 	l.output_label = label
 }
 
-pub fn (l mut Log) set_output_path(output_file_path string) {
+pub fn (mut l Log) set_output_path(output_file_path string) {
 	if l.ofile.is_opened() { l.ofile.close() }
 	l.output_to_file = true
 	l.output_file_name = os.join_path( os.real_path( output_file_path ) , l.output_label )
@@ -68,11 +68,11 @@ pub fn (l mut Log) set_output_path(output_file_path string) {
 	l.ofile = ofile
 }
 
-pub fn (l mut Log) close() {
+pub fn (mut l Log) close() {
   l.ofile.close()
 }
 
-fn (l mut Log) log_file(s string, level Level) {
+fn (mut l Log) log_file(s string, level Level) {
 	timestamp := time.now().format_ss()
 	e := tag(level)
 	l.ofile.writeln('$timestamp [$e] $s')
@@ -84,7 +84,7 @@ fn (l &Log) log_cli(s string, level Level) {
 	println('[$f ${t.format_ss()}] $s')
 }
 
-fn (l mut Log) send_output(s &string, level Level) {
+fn (mut l Log) send_output(s &string, level Level) {
 	if l.output_to_file {
 		l.log_file(s, level)
 	} else {
@@ -92,29 +92,29 @@ fn (l mut Log) send_output(s &string, level Level) {
 	}
 }
 
-pub fn (l mut Log) fatal(s string){
+pub fn (mut l Log) fatal(s string){
 	if l.level < .fatal { return }
 	l.send_output(s, .fatal)
 	l.ofile.close()
 	panic('$l.output_label: $s')
 }
 
-pub fn (l mut Log) error(s string) {
+pub fn (mut l Log) error(s string) {
 	if l.level < .error { return }
 	l.send_output(s, .error)
 }
 
-pub fn (l mut Log) warn(s string) {
+pub fn (mut l Log) warn(s string) {
 	if l.level < .warn { return }
 	l.send_output(s, .warn)
 }
 
-pub fn (l mut Log) info(s string) {
+pub fn (mut l Log) info(s string) {
 	if l.level < .info { return }
 	l.send_output(s, .info)
 }
 
-pub fn (l mut Log) debug(s string) {
+pub fn (mut l Log) debug(s string) {
 	if l.level < .debug { return }
 	l.send_output(s, .debug)
 }
diff --git a/vlib/math/big/big.v b/vlib/math/big/big.v
index 3c16a22ad3..25b1906c5f 100644
--- a/vlib/math/big/big.v
+++ b/vlib/math/big/big.v
@@ -124,10 +124,10 @@ pub fn cmp(a Number, b Number) int {
 pub fn (a Number) is_zero() bool {
 	return C.bignum_is_zero(&a) != 0
 }
-pub fn (a mut Number) inc() {
+pub fn (mut a Number) inc() {
 	C.bignum_inc(a)
 }
-pub fn (a mut Number) dec() {
+pub fn (mut a Number) dec() {
 	C.bignum_dec(a)
 }
 pub fn pow(a Number, b Number) Number {
diff --git a/vlib/mysql/mysql.v b/vlib/mysql/mysql.v
index b19ae99466..e9461677a4 100644
--- a/vlib/mysql/mysql.v
+++ b/vlib/mysql/mysql.v
@@ -23,7 +23,7 @@ pub fn new_connection(host, username, password, dbname string) ?Connection {
 	return Connection{ host, 0, username, password, dbname, 0, instance }
 }
 
-pub fn (conn mut Connection) connect() ?bool {
+pub fn (mut conn Connection) connect() ?bool {
 	mut instance := C.mysql_init(0)
 	if !isnil(conn.conn) {
 		instance = conn.conn
diff --git a/vlib/net/http/chunked/dechunk.v b/vlib/net/http/chunked/dechunk.v
index b51f956a55..ad1197d2aa 100644
--- a/vlib/net/http/chunked/dechunk.v
+++ b/vlib/net/http/chunked/dechunk.v
@@ -13,7 +13,7 @@ mut:
 	text string
 }
 
-fn (s mut ChunkScanner) read_chunk_size() int {
+fn (mut s ChunkScanner) read_chunk_size() int {
 	mut n := 0
 	for {
 		if s.pos >= s.text.len {
@@ -43,11 +43,11 @@ fn unhex(c byte) byte {
 	return 0
 }
 
-fn (s mut ChunkScanner) skip_crlf() {
+fn (mut s ChunkScanner) skip_crlf() {
 	s.pos += 2
 }
 
-fn (s mut ChunkScanner) read_chunk(chunksize int) string {
+fn (mut s ChunkScanner) read_chunk(chunksize int) string {
 	startpos := s.pos
 	s.pos += chunksize
 	return s.text[startpos..s.pos]
@@ -71,4 +71,3 @@ pub fn decode(text string) string {
 	cscanner.skip_crlf()
 	return sb.str()
 }
-
diff --git a/vlib/net/urllib/urllib.v b/vlib/net/urllib/urllib.v
index 6ef5d277f0..cef458ebfe 100644
--- a/vlib/net/urllib/urllib.v
+++ b/vlib/net/urllib/urllib.v
@@ -651,7 +651,7 @@ fn parse_host(host string) ?string {
 // - set_path('/foo%2fbar') will set path='/foo/bar' and raw_path='/foo%2fbar'
 // set_path will return an error only if the provided path contains an invalid
 // escaping.
-pub fn (u mut URL) set_path(p string) ?bool {
+pub fn (mut u URL) set_path(p string) ?bool {
 	path := unescape(p, .encode_path) or {
 		return error(err)
 	}
diff --git a/vlib/net/urllib/values.v b/vlib/net/urllib/values.v
index 506df5a850..c05187a4b1 100644
--- a/vlib/net/urllib/values.v
+++ b/vlib/net/urllib/values.v
@@ -61,7 +61,7 @@ pub fn (v &Values) get_all(key string) []string {
 
 // set sets the key to value. It replaces any existing
 // values.
-pub fn (v mut Values) set(key, value string) {
+pub fn (mut v Values) set(key, value string) {
 	mut a := v.data[key]
 	a.data = [value]
 	v.data[key] = a
@@ -70,7 +70,7 @@ pub fn (v mut Values) set(key, value string) {
 
 // add adds the value to key. It appends to any existing
 // values associated with key.
-pub fn (v mut Values) add(key, value string) {
+pub fn (mut v Values) add(key, value string) {
 	mut a := v.data[key]
 	if a.data.len == 0 {
 		a.data = []
@@ -81,8 +81,7 @@ pub fn (v mut Values) add(key, value string) {
 }
 
 // del deletes the values associated with key.
-pub fn (v mut Values) del(key string) {
+pub fn (mut v Values) del(key string) {
 	v.data.delete(key)
 	v.size = v.data.size
 }
-
diff --git a/vlib/net/websocket/handshake.v b/vlib/net/websocket/handshake.v
index 8fe3beb0b3..9335f2b096 100644
--- a/vlib/net/websocket/handshake.v
+++ b/vlib/net/websocket/handshake.v
@@ -1,6 +1,6 @@
 module websocket
 
-fn (ws mut Client) read_handshake(seckey string){
+fn (mut ws Client) read_handshake(seckey string){
 	l.d("reading handshake...")
 	mut bytes_read := 0
 	max_buffer := 1024
@@ -9,7 +9,7 @@ fn (ws mut Client) read_handshake(seckey string){
 
 	for bytes_read <= max_buffer {
 		res := ws.read_from_server(buffer + bytes_read, buffer_size)
-		if res == 0 || res == -1 { 
+		if res == 0 || res == -1 {
 			l.f("read_handshake: Failed to read handshake.")
 		}
 		if buffer[bytes_read] == `\n` && buffer[bytes_read-1] == `\r` && buffer[bytes_read-2] == `\n` && buffer[bytes_read-3] == `\r` {
@@ -21,10 +21,10 @@ fn (ws mut Client) read_handshake(seckey string){
 	ws.handshake_handler(string(byteptr(buffer)), seckey)
 }
 
-fn (ws mut Client) handshake_handler(handshake_response, seckey string){
+fn (mut ws Client) handshake_handler(handshake_response, seckey string){
 	l.d("handshake_handler:\r\n${handshake_response}")
 	lines := handshake_response.split_into_lines()
-	
+
 	header := lines[0]
 	if !header.starts_with("HTTP/1.1 101") && !header.starts_with("HTTP/1.0 101") {
 		l.f("handshake_handler: invalid HTTP status response code")
diff --git a/vlib/net/websocket/io.v b/vlib/net/websocket/io.v
index 4f67a10af4..7e1f20095b 100644
--- a/vlib/net/websocket/io.v
+++ b/vlib/net/websocket/io.v
@@ -2,13 +2,13 @@ module websocket
 
 fn C.write() int
 
-fn (ws mut Client) write_to_server(buf voidptr, len int) int {
+fn (mut ws Client) write_to_server(buf voidptr, len int) int {
 	mut bytes_written := 0
 	ws.write_lock.lock()
 	bytes_written = if ws.is_ssl {
 		C.SSL_write(ws.ssl, buf, len)
 	} else {
-		C.write(ws.socket.sockfd, buf, len) 
+		C.write(ws.socket.sockfd, buf, len)
 	}
 	ws.write_lock.unlock()
 	return bytes_written
diff --git a/vlib/net/websocket/ssl.v b/vlib/net/websocket/ssl.v
index 09036efa41..9c6b8dc856 100644
--- a/vlib/net/websocket/ssl.v
+++ b/vlib/net/websocket/ssl.v
@@ -21,7 +21,7 @@ fn C.SSL_CTX_free()
 fn C.SSL_write() int
 fn C.SSL_read() int
 
-fn (ws mut Client) connect_ssl(){
+fn (mut ws Client) connect_ssl(){
 	l.i("Using secure SSL connection")
 	C.SSL_load_error_strings()
 	C.SSL_library_init()
diff --git a/vlib/net/websocket/utf8.v b/vlib/net/websocket/utf8.v
index 0aee273285..468f7e264b 100644
--- a/vlib/net/websocket/utf8.v
+++ b/vlib/net/websocket/utf8.v
@@ -23,7 +23,7 @@ pub fn utf8_validate(data byteptr, len int) bool {
 	return !state.failed && state.subindex <= 0
 }
 
-fn (s mut Utf8State) seq(r0 bool, r1 bool, is_tail bool) bool {
+fn (mut s Utf8State) seq(r0 bool, r1 bool, is_tail bool) bool {
 	if s.subindex == 0 || (s.index > 1 && s.subindex == 1) || (s.index >= 6 && s.subindex == 2) {
 		if (s.subindex == 0 && r0) || (s.subindex == 1 && r1) || (s.subindex == 2 && is_tail) {
 			s.subindex++
@@ -46,7 +46,7 @@ fn (s mut Utf8State) seq(r0 bool, r1 bool, is_tail bool) bool {
 	return false
 }
 
-fn (s mut Utf8State) next_state (c byte) {
+fn (mut s Utf8State) next_state (c byte) {
 	//sequence 1
 	if s.index == 0 {
 		if (c >= 0x00 + 1 && c <= 0x7F) || c == 0x00 {
@@ -58,7 +58,7 @@ fn (s mut Utf8State) next_state (c byte) {
 	is_tail := c >= 0x80 && c <= 0xBF
 	//sequence 2
 	if s.index == 1 && s.seq(c >= 0xC2 && c <= 0xDF, false, is_tail) {return}
-	
+
 	//sequence 3
 	if s.index == 2 && s.seq(c == 0xE0, c >= 0xA0 && c <= 0xBF, is_tail) {return}
 	if s.index == 3 && s.seq(c >= 0xE1 && c <= 0xEC, c >= 0x80 && c <= 0xBF, is_tail) {return}
diff --git a/vlib/net/websocket/ws.v b/vlib/net/websocket/ws.v
index 18854800bd..f68d2e2639 100644
--- a/vlib/net/websocket/ws.v
+++ b/vlib/net/websocket/ws.v
@@ -115,7 +115,7 @@ fn (ws &Client) parse_uri() &Uri {
 	}
 }
 
-pub fn (ws mut Client) connect() int {
+pub fn (mut ws Client) connect() int {
 	match ws.state {
 		.connected {
 			l.f("connect: websocket already connected")
@@ -191,7 +191,7 @@ pub fn (ws mut Client) connect() int {
 	return 0
 }
 
-pub fn (ws mut Client) close(code int, message string){
+pub fn (mut ws Client) close(code int, message string){
 	if ws.state != .closed && ws.socket.sockfd > 1 {
 
 		ws.lock.lock()
@@ -248,7 +248,7 @@ pub fn (ws mut Client) close(code int, message string){
 	}
 }
 
-pub fn (ws mut Client) write(payload byteptr, payload_len int, code OPCode) int {
+pub fn (mut ws Client) write(payload byteptr, payload_len int, code OPCode) int {
 	if ws.state != .open {
 		ws.send_error_event("WebSocket closed. Cannot write.")
 		goto free_data
@@ -319,7 +319,7 @@ pub fn (ws mut Client) write(payload byteptr, payload_len int, code OPCode) int
 	return bytes_written
 }
 
-pub fn (ws mut Client) listen() {
+pub fn (mut ws Client) listen() {
 	l.i("Starting listener...")
 	for ws.state == .open {
 		ws.read()
@@ -327,7 +327,7 @@ pub fn (ws mut Client) listen() {
 	l.i("Listener stopped as websocket was closed.")
 }
 
-pub fn (ws mut Client) read() int {
+pub fn (mut ws Client) read() int {
 	mut bytes_read := u64(0)
 
 	initial_buffer := u64(256)
@@ -601,7 +601,7 @@ pub fn (ws mut Client) read() int {
 	return -1
 }
 
-fn (ws mut Client) send_control_frame(code OPCode, frame_typ string, payload []byte) int {
+fn (mut ws Client) send_control_frame(code OPCode, frame_typ string, payload []byte) int {
 	if ws.socket.sockfd <= 0 {
 		l.e("No socket opened.")
 		goto free_data
diff --git a/vlib/os/os.v b/vlib/os/os.v
index 44d79ed9fb..807514e28e 100644
--- a/vlib/os/os.v
+++ b/vlib/os/os.v
@@ -325,7 +325,7 @@ pub fn open_file(path string, mode string, options ...int) ?File {
 	}
 }
 
-pub fn (f mut File) write_bytes_at(data voidptr, size, pos int) {
+pub fn (mut f File) write_bytes_at(data voidptr, size, pos int) {
 	//$if linux {
 	//}
 	//$else {
@@ -335,7 +335,7 @@ pub fn (f mut File) write_bytes_at(data voidptr, size, pos int) {
 	//}
 }
 
-pub fn (f mut File) flush() {
+pub fn (mut f File) flush() {
 	if !f.opened {
 		return
 	}
diff --git a/vlib/os/os_nix.c.v b/vlib/os/os_nix.c.v
index 1bdccd3ed6..c4b91e6139 100644
--- a/vlib/os/os_nix.c.v
+++ b/vlib/os/os_nix.c.v
@@ -128,12 +128,12 @@ pub fn create(path string) ?File {
 }
 
 /*
-pub fn (f mut File) fseek(pos, mode int) {
+pub fn (mut f File) fseek(pos, mode int) {
 }
 */
 
 
-pub fn (f mut File) write(s string) {
+pub fn (mut f File) write(s string) {
 	if !f.opened {
 		return
 	}
@@ -149,7 +149,7 @@ pub fn (f mut File) write(s string) {
 	// C.fwrite(s.str, 1, s.len, f.cfile)
 }
 
-pub fn (f mut File) writeln(s string) {
+pub fn (mut f File) writeln(s string) {
 	if !f.opened {
 		return
 	}
@@ -237,7 +237,7 @@ pub fn get_error_msg(code int) string {
 // convert any value to []byte (LittleEndian) and write it
 // for example if we have write(7, 4), "07 00 00 00" gets written
 // write(0x1234, 2) => "34 12"
-pub fn (f mut File) write_bytes(data voidptr, size int) {
+pub fn (mut f File) write_bytes(data voidptr, size int) {
 /*
 	$if linux {
 		$if !android {
@@ -249,7 +249,7 @@ pub fn (f mut File) write_bytes(data voidptr, size int) {
 	C.fwrite(data, 1, size, f.cfile)
 }
 
-pub fn (f mut File) close() {
+pub fn (mut f File) close() {
 	if !f.opened {
 		return
 	}
diff --git a/vlib/os/os_windows.c.v b/vlib/os/os_windows.c.v
index 48ba63e11d..73167bf25b 100644
--- a/vlib/os/os_windows.c.v
+++ b/vlib/os/os_windows.c.v
@@ -155,14 +155,14 @@ pub fn create(path string) ?File {
 	return file
 }
 
-pub fn (f mut File) write(s string) {
+pub fn (mut f File) write(s string) {
 	if !f.opened {
 		return
 	}
 	C.fputs(s.str, f.cfile)
 }
 
-pub fn (f mut File) writeln(s string) {
+pub fn (mut f File) writeln(s string) {
 	if !f.opened {
 		return
 	}
@@ -344,11 +344,11 @@ pub fn symlink(origin, target string) ?bool {
 	return error(get_error_msg(int(C.GetLastError())))
 }
 
-pub fn (f mut File) write_bytes(data voidptr, size int) {
+pub fn (mut f File) write_bytes(data voidptr, size int) {
 	C.fwrite(data, 1, size, f.cfile)
 }
 
-pub fn (f mut File) close() {
+pub fn (mut f File) close() {
 	if !f.opened {
 		return
 	}
diff --git a/vlib/picohttpparser/request.v b/vlib/picohttpparser/request.v
index 8addc232b4..eec3c33a00 100644
--- a/vlib/picohttpparser/request.v
+++ b/vlib/picohttpparser/request.v
@@ -9,7 +9,7 @@ mut:
 }
 
 [inline]
-pub fn (r mut Request) parse_request(s string, headers *C.phr_header_t, max_headers int) int {
+pub fn (mut r Request) parse_request(s string, headers *C.phr_header_t, max_headers int) int {
 	method_len := u64(0)
 	path_len := u64(0)
 	minor_version := 0
@@ -33,7 +33,7 @@ pub fn (r mut Request) parse_request(s string, headers *C.phr_header_t, max_head
 }
 
 [inline]
-pub fn (r mut Request) parse_request_path(s string) int {
+pub fn (mut r Request) parse_request_path(s string) int {
 	method_len := u64(0)
 	path_len := u64(0)
 
@@ -50,7 +50,7 @@ pub fn (r mut Request) parse_request_path(s string) int {
 }
 
 [inline]
-pub fn (r mut Request) parse_request_path_pipeline(s string) int {
+pub fn (mut r Request) parse_request_path_pipeline(s string) int {
 	method_len := u64(0)
 	path_len := u64(0)
 
diff --git a/vlib/picohttpparser/response.v b/vlib/picohttpparser/response.v
index 2540fb7943..a7b914124e 100644
--- a/vlib/picohttpparser/response.v
+++ b/vlib/picohttpparser/response.v
@@ -10,13 +10,13 @@ mut:
 }
 
 [inline]
-pub fn (r mut Response) http_ok() &Response {
+pub fn (mut r Response) http_ok() &Response {
 	r.buf += cpy_str(r.buf, "HTTP/1.1 200 OK\r\n")
 	return r
 }
 
 [inline]
-pub fn (r mut Response) header(k, v string) &Response {
+pub fn (mut r Response) header(k, v string) &Response {
 	r.buf += cpy_str(r.buf, k)
 	r.buf += cpy_str(r.buf, ": ")
 	r.buf += cpy_str(r.buf, v)
@@ -25,7 +25,7 @@ pub fn (r mut Response) header(k, v string) &Response {
 }
 
 [inline]
-pub fn (r mut Response) header_date() &Response {
+pub fn (mut r Response) header_date() &Response {
 	r.buf += cpy_str(r.buf, "Date: ")
 	r.buf += cpy(r.buf, r.date, 29)
 	r.buf += cpy_str(r.buf, "\r\n")
@@ -33,13 +33,13 @@ pub fn (r mut Response) header_date() &Response {
 }
 
 [inline]
-pub fn (r mut Response) header_server() &Response {
+pub fn (mut r Response) header_server() &Response {
 	r.buf += cpy_str(r.buf, "Server: V\r\n")
 	return r
 }
 
 [inline]
-pub fn (r mut Response) content_type(s string) &Response {
+pub fn (mut r Response) content_type(s string) &Response {
 	r.buf += cpy_str(r.buf, "Content-Type: ")
 	r.buf += cpy_str(r.buf, s)
 	r.buf += cpy_str(r.buf, "\r\n")
@@ -47,19 +47,19 @@ pub fn (r mut Response) content_type(s string) &Response {
 }
 
 [inline]
-pub fn (r mut Response) plain() &Response {
+pub fn (mut r Response) plain() &Response {
 	r.buf += cpy_str(r.buf, "Content-Type: text/plain\r\n")
 	return r
 }
 
 [inline]
-pub fn (r mut Response) json() &Response {
+pub fn (mut r Response) json() &Response {
 	r.buf += cpy_str(r.buf, "Content-Type: application/json\r\n")
 	return r
 }
 
 [inline]
-pub fn (r mut Response) body(body string) {
+pub fn (mut r Response) body(body string) {
 	r.buf += cpy_str(r.buf, "Content-Length: ")
 	r.buf += C.u64toa(r.buf, body.len)
 	r.buf += cpy_str(r.buf, "\r\n\r\n")
@@ -67,27 +67,27 @@ pub fn (r mut Response) body(body string) {
 }
 
 [inline]
-pub fn (r mut Response) http_404() {
+pub fn (mut r Response) http_404() {
 	r.buf += cpy_str(r.buf, 'HTTP/1.1 404 Not Found\r\nContent-Length: 0\r\n\r\n')
 }
 
 [inline]
-pub fn (r mut Response) http_405() {
+pub fn (mut r Response) http_405() {
 	r.buf += cpy_str(r.buf, 'HTTP/1.1 405 Method Not Allowed\r\nContent-Length: 0\r\n\r\n')
 }
 
 [inline]
-pub fn (r mut Response) http_500() {
+pub fn (mut r Response) http_500() {
 	r.buf += cpy_str(r.buf, 'HTTP/1.1 500 Internal Server Error\r\nContent-Length: 0\r\n\r\n')
 }
 
 [inline]
-pub fn (r mut Response) raw(response string) {
+pub fn (mut r Response) raw(response string) {
 	r.buf += cpy_str(r.buf, response)
 }
 
 [inline]
-pub fn (r mut Response) end() int {
+pub fn (mut r Response) end() int {
 	n := int(r.buf - r.buf_start)
 	if C.write(r.fd, r.buf_start, n) != n {
 		return -1
diff --git a/vlib/rand/pcg32.v b/vlib/rand/pcg32.v
index d7e008e4cf..84c25c2c69 100644
--- a/vlib/rand/pcg32.v
+++ b/vlib/rand/pcg32.v
@@ -33,7 +33,7 @@ pub fn new_pcg32(initstate u64, initseq u64) Pcg32 {
 
 
 [inline]
-pub fn (rng mut Pcg32) next() u32 {
+pub fn (mut rng Pcg32) next() u32 {
 	oldstate := rng.state
 	rng.state = oldstate * (6364136223846793005) + rng.inc
 	xorshifted := u32(((oldstate>>u64(18)) ^ oldstate)>>u64(27))
@@ -49,7 +49,7 @@ pub fn (rng mut Pcg32) next() u32 {
 
 
 [inline]
-pub fn (rng mut Pcg32) bounded_next(bound u32) u32 {
+pub fn (mut rng Pcg32) bounded_next(bound u32) u32 {
 	// To avoid bias, we need to make the range of the RNG a multiple of
 	// bound, which we do by dropping output less than a threshold.
 	threshold := (-bound % bound)
@@ -66,4 +66,3 @@ pub fn (rng mut Pcg32) bounded_next(bound u32) u32 {
 	}
 	return u32(0)
 }
-
diff --git a/vlib/rand/splitmix64.v b/vlib/rand/splitmix64.v
index f5c8145750..c1c26099a6 100644
--- a/vlib/rand/splitmix64.v
+++ b/vlib/rand/splitmix64.v
@@ -24,7 +24,7 @@ pub fn new_splitmix64(seed u64) Splitmix64 {
 
 
 [inline]
-pub fn (rng mut Splitmix64) next() u64 {
+pub fn (mut rng Splitmix64) next() u64 {
 	rng.state += (0x9e3779b97f4a7c15)
 	mut z := rng.state
 	z = (z ^ ((z>>u64(30)))) * (0xbf58476d1ce4e5b9)
@@ -40,7 +40,7 @@ pub fn (rng mut Splitmix64) next() u64 {
 
 
 [inline]
-pub fn (rng mut Splitmix64) bounded_next(bound u64) u64 {
+pub fn (mut rng Splitmix64) bounded_next(bound u64) u64 {
 	threshold := -bound % bound
 	for {
 		r := rng.next()
@@ -50,4 +50,3 @@ pub fn (rng mut Splitmix64) bounded_next(bound u64) u64 {
 	}
 	return u64(0)
 }
-
diff --git a/vlib/readline/readline.js.v b/vlib/readline/readline.js.v
index 19a2926ef9..cf5a613fbb 100644
--- a/vlib/readline/readline.js.v
+++ b/vlib/readline/readline.js.v
@@ -13,7 +13,7 @@ import os
 
 // Only use standard os.get_line
 // Need implementation for readline capabilities
-pub fn (r mut Readline) read_line_utf8(prompt string) ?ustring {
+pub fn (mut r Readline) read_line_utf8(prompt string) ?ustring {
   r.current = ''.ustring()
   r.cursor = 0
   r.prompt = prompt
@@ -38,7 +38,7 @@ pub fn (r mut Readline) read_line_utf8(prompt string) ?ustring {
 }
 
 // Returns the string from the utf8 ustring
-pub fn (r mut Readline) read_line(prompt string) ?string {
+pub fn (mut r Readline) read_line(prompt string) ?string {
   s := r.read_line_utf8(prompt) or {
     return error(err)
   }
diff --git a/vlib/readline/readline_darwin.c.v b/vlib/readline/readline_darwin.c.v
index 9c0cfeb5b2..e82e4d976d 100644
--- a/vlib/readline/readline_darwin.c.v
+++ b/vlib/readline/readline_darwin.c.v
@@ -15,7 +15,7 @@ import os
 
 // Only use standard os.get_line
 // Need implementation for readline capabilities
-pub fn (r mut Readline) read_line_utf8(prompt string) ?ustring {
+pub fn (mut r Readline) read_line_utf8(prompt string) ?ustring {
   r.current = ''.ustring()
   r.cursor = 0
   r.prompt = prompt
@@ -43,7 +43,7 @@ pub fn (r mut Readline) read_line_utf8(prompt string) ?ustring {
 }
 
 // Returns the string from the utf8 ustring
-pub fn (r mut Readline) read_line(prompt string) ?string {
+pub fn (mut r Readline) read_line(prompt string) ?string {
   s := r.read_line_utf8(prompt) or {
     return error(err)
   }
diff --git a/vlib/readline/readline_linux.c.v b/vlib/readline/readline_linux.c.v
index 4dca991c32..a472c4a800 100644
--- a/vlib/readline/readline_linux.c.v
+++ b/vlib/readline/readline_linux.c.v
@@ -42,7 +42,7 @@ fn C.raise()
 // Enable the raw mode of the terminal
 // In raw mode all keypresses are directly sent to the program and no interpretation is done
 // Catches the SIGUSER (CTRL+C) Signal
-pub fn (r mut Readline) enable_raw_mode() {
+pub fn (mut r Readline) enable_raw_mode() {
   if C.tcgetattr(0, &r.orig_termios) == -1 {
     r.is_tty = false
     r.is_raw = false
@@ -61,7 +61,7 @@ pub fn (r mut Readline) enable_raw_mode() {
 
 // Enable the raw mode of the terminal
 // Does not catch the SIGUSER (CTRL+C) Signal
-pub fn (r mut Readline) enable_raw_mode_nosig() {
+pub fn (mut r Readline) enable_raw_mode_nosig() {
   if C.tcgetattr(0, &r.orig_termios) == -1 {
     r.is_tty = false
     r.is_raw = false
@@ -79,7 +79,7 @@ pub fn (r mut Readline) enable_raw_mode_nosig() {
 }
 
 // Disable the raw mode of the terminal
-pub fn (r mut Readline) disable_raw_mode() {
+pub fn (mut r Readline) disable_raw_mode() {
   if r.is_raw {
     C.tcsetattr(0, C.TCSADRAIN, &r.orig_termios)
     r.is_raw = false
@@ -95,7 +95,7 @@ pub fn (r Readline) read_char() int {
 // Will loop and ingest characters until EOF or Enter
 // Returns the completed line as utf8 ustring
 // Will return an error if line is empty
-pub fn (r mut Readline) read_line_utf8(prompt string) ?ustring {
+pub fn (mut r Readline) read_line_utf8(prompt string) ?ustring {
   r.current = ''.ustring()
   r.cursor = 0
   r.prompt = prompt
@@ -132,7 +132,7 @@ pub fn (r mut Readline) read_line_utf8(prompt string) ?ustring {
 }
 
 // Returns the string from the utf8 ustring
-pub fn (r mut Readline) read_line(prompt string) ?string {
+pub fn (mut r Readline) read_line(prompt string) ?string {
   s := r.read_line_utf8(prompt) or {
     return error(err)
   }
@@ -272,7 +272,7 @@ fn (r Readline) analyse_extended_control_no_eat(last_c byte) Action {
   return .nothing
 }
 
-fn (r mut Readline) execute(a Action, c int) bool {
+fn (mut r Readline) execute(a Action, c int) bool {
   match a {
     .eof                    { return r.eof() }
     .insert_character       { r.insert_character(c) }
@@ -336,7 +336,7 @@ fn calculate_screen_position(x_in int, y_in int, screen_columns int, char_count
 }
 
 // Will redraw the line
-fn (r mut Readline) refresh_line() {
+fn (mut r Readline) refresh_line() {
   mut end_of_input := [0, 0]
   end_of_input = calculate_screen_position(r.prompt.len, 0, get_screen_columns(), r.current.len, end_of_input)
   end_of_input[1] += r.current.count('\n'.ustring())
@@ -355,7 +355,7 @@ fn (r mut Readline) refresh_line() {
 }
 
 // End the line without a newline
-fn (r mut Readline) eof() bool {
+fn (mut r Readline) eof() bool {
   r.previous_lines.insert(1, r.current)
   r.cursor = r.current.len
   if r.is_tty {
@@ -364,7 +364,7 @@ fn (r mut Readline) eof() bool {
   return true
 }
 
-fn (r mut Readline) insert_character(c int) {
+fn (mut r Readline) insert_character(c int) {
   if !r.overwrite || r.cursor == r.current.len {
     r.current = r.current.left(r.cursor).ustring().add( utf32_to_str(u32(c)).ustring() ).add( r.current.right(r.cursor).ustring() )
   } else {
@@ -378,7 +378,7 @@ fn (r mut Readline) insert_character(c int) {
 }
 
 // Removes the character behind cursor.
-fn (r mut Readline) delete_character() {
+fn (mut r Readline) delete_character() {
   if r.cursor <= 0 {
     return
   }
@@ -388,7 +388,7 @@ fn (r mut Readline) delete_character() {
 }
 
 // Removes the character in front of cursor.
-fn (r mut Readline) suppr_character() {
+fn (mut r Readline) suppr_character() {
   if r.cursor > r.current.len {
     return
   }
@@ -397,7 +397,7 @@ fn (r mut Readline) suppr_character() {
 }
 
 // Add a line break then stops the main loop
-fn (r mut Readline) commit_line() bool {
+fn (mut r Readline) commit_line() bool {
   r.previous_lines.insert(1, r.current)
   a := '\n'.ustring()
   r.current = r.current.add( a )
@@ -409,26 +409,26 @@ fn (r mut Readline) commit_line() bool {
   return true
 }
 
-fn (r mut Readline) move_cursor_left() {
+fn (mut r Readline) move_cursor_left() {
   if r.cursor > 0 {
     r.cursor--
     r.refresh_line()
   }
 }
 
-fn (r mut Readline) move_cursor_right() {
+fn (mut r Readline) move_cursor_right() {
   if r.cursor < r.current.len {
     r.cursor++
     r.refresh_line()
   }
 }
 
-fn (r mut Readline) move_cursor_begining() {
+fn (mut r Readline) move_cursor_begining() {
   r.cursor = 0
   r.refresh_line()
 }
 
-fn (r mut Readline) move_cursor_end() {
+fn (mut r Readline) move_cursor_end() {
   r.cursor = r.current.len
   r.refresh_line()
 }
@@ -439,7 +439,7 @@ fn (r Readline) is_break_character(c string) bool {
   return break_characters.contains(c)
 }
 
-fn (r mut Readline) move_cursor_word_left() {
+fn (mut r Readline) move_cursor_word_left() {
   if r.cursor > 0 {
     for ; r.cursor > 0 && r.is_break_character(r.current.at(r.cursor - 1)); r.cursor-- {}
     for ; r.cursor > 0 && !r.is_break_character(r.current.at(r.cursor - 1)); r.cursor-- {}
@@ -447,7 +447,7 @@ fn (r mut Readline) move_cursor_word_left() {
   }
 }
 
-fn (r mut Readline) move_cursor_word_right() {
+fn (mut r Readline) move_cursor_word_right() {
   if r.cursor < r.current.len {
     for ; r.cursor < r.current.len && r.is_break_character(r.current.at(r.cursor)); r.cursor++ {}
     for ; r.cursor < r.current.len && !r.is_break_character(r.current.at(r.cursor)); r.cursor++ {}
@@ -455,17 +455,17 @@ fn (r mut Readline) move_cursor_word_right() {
   }
 }
 
-fn (r mut Readline) switch_overwrite() {
+fn (mut r Readline) switch_overwrite() {
   r.overwrite = !r.overwrite
 }
 
-fn (r mut Readline) clear_screen() {
+fn (mut r Readline) clear_screen() {
   term.set_cursor_position(1, 1)
   term.erase_clear()
   r.refresh_line()
 }
 
-fn (r mut Readline) history_previous() {
+fn (mut r Readline) history_previous() {
   if r.search_index + 2 >= r.previous_lines.len {
     return
   }
@@ -478,7 +478,7 @@ fn (r mut Readline) history_previous() {
   r.refresh_line()
 }
 
-fn (r mut Readline) history_next() {
+fn (mut r Readline) history_next() {
   if r.search_index <= 0 {
     return
   }
@@ -488,7 +488,7 @@ fn (r mut Readline) history_next() {
   r.refresh_line()
 }
 
-fn (r mut Readline) suspend() {
+fn (mut r Readline) suspend() {
   C.raise(C.SIGSTOP)
   r.refresh_line()
 }
diff --git a/vlib/readline/readline_solaris.c.v b/vlib/readline/readline_solaris.c.v
index 9c0cfeb5b2..e82e4d976d 100644
--- a/vlib/readline/readline_solaris.c.v
+++ b/vlib/readline/readline_solaris.c.v
@@ -15,7 +15,7 @@ import os
 
 // Only use standard os.get_line
 // Need implementation for readline capabilities
-pub fn (r mut Readline) read_line_utf8(prompt string) ?ustring {
+pub fn (mut r Readline) read_line_utf8(prompt string) ?ustring {
   r.current = ''.ustring()
   r.cursor = 0
   r.prompt = prompt
@@ -43,7 +43,7 @@ pub fn (r mut Readline) read_line_utf8(prompt string) ?ustring {
 }
 
 // Returns the string from the utf8 ustring
-pub fn (r mut Readline) read_line(prompt string) ?string {
+pub fn (mut r Readline) read_line(prompt string) ?string {
   s := r.read_line_utf8(prompt) or {
     return error(err)
   }
diff --git a/vlib/readline/readline_windows.c.v b/vlib/readline/readline_windows.c.v
index 62b679a77b..34f29b9a93 100644
--- a/vlib/readline/readline_windows.c.v
+++ b/vlib/readline/readline_windows.c.v
@@ -13,7 +13,7 @@ import os
 
 // Only use standard os.get_line
 // Need implementation for readline capabilities
-pub fn (r mut Readline) read_line_utf8(prompt string) ?ustring {
+pub fn (mut r Readline) read_line_utf8(prompt string) ?ustring {
   r.current = ''.ustring()
   r.cursor = 0
   r.prompt = prompt
@@ -38,7 +38,7 @@ pub fn (r mut Readline) read_line_utf8(prompt string) ?ustring {
 }
 
 // Returns the string from the utf8 ustring
-pub fn (r mut Readline) read_line(prompt string) ?string {
+pub fn (mut r Readline) read_line(prompt string) ?string {
   s := r.read_line_utf8(prompt) or {
     return error(err)
   }
diff --git a/vlib/regex/regex.v b/vlib/regex/regex.v
index 8805ad51b1..d7ee1af84b 100644
--- a/vlib/regex/regex.v
+++ b/vlib/regex/regex.v
@@ -262,7 +262,7 @@ mut:
 }
 
 [inline]
-fn (tok mut Token) reset() {
+fn (mut tok Token) reset() {
 	tok.rep = 0
 }
 
@@ -330,7 +330,7 @@ pub mut:
 
 // Reset RE object
 //[inline]
-fn (re mut RE) reset(){
+fn (mut re RE) reset(){
 	re.cc_index         = 0
 
 	mut i := 0
@@ -352,7 +352,7 @@ fn (re mut RE) reset(){
 
 // reset for search mode fail
 // gcc bug, dont use [inline] or go 5 time slower
-fn (re mut RE) reset_src(){
+fn (mut re RE) reset_src(){
 	mut i := 0
 	for i < re.prog.len {
 		re.prog[i].group_rep          = 0 // clear repetition of the group
@@ -544,7 +544,7 @@ fn (re RE) check_char_class(pc int, ch u32) bool {
 }
 
 // parse_char_class return (index, str_len, cc_type) of a char class [abcm-p], char class start after the [ char
-fn (re mut RE) parse_char_class(in_txt string, in_i int) (int, int, u32) {
+fn (mut re RE) parse_char_class(in_txt string, in_i int) (int, int, u32) {
 	mut status := CharClass_parse_state.start
 	mut i := in_i
 
@@ -897,7 +897,7 @@ fn (re RE) parse_groups(in_txt string, in_i int) (int, bool, string, int) {
 // main compiler
 //
 // compile return (return code, index) where index is the index of the error in the query string if return code is an error code
-pub fn (re mut RE) compile(in_txt string) (int,int) {
+pub fn (mut re RE) compile(in_txt string) (int,int) {
 	mut i        := 0      // input string index
 	mut pc       := 0      // program counter
 	mut tmp_code := u32(0)
@@ -1467,7 +1467,7 @@ pub mut:
 	match_first int = -1
 }
 
-pub fn (re mut RE) match_base(in_txt byteptr, in_txt_len int ) (int,int) {
+pub fn (mut re RE) match_base(in_txt byteptr, in_txt_len int ) (int,int) {
 	// result status
 	mut result := NO_MATCH_FOUND     // function return
 	mut first_match := -1             //index of the first match
@@ -1595,7 +1595,7 @@ pub fn (re mut RE) match_base(in_txt byteptr, in_txt_len int ) (int,int) {
 					tmp_pc := group_data[group_index]
 					re.prog[tmp_pc].group_rep++
 					//println("Closing group $group_index {${re.prog[tmp_pc].rep_min},${re.prog[tmp_pc].rep_max}}:${re.prog[tmp_pc].group_rep}")
-					
+
 					if re.prog[tmp_pc].group_rep >= re.prog[tmp_pc].rep_min && re.prog[tmp_pc].group_id >= 0{
 						start_i   := group_stack[group_index]
 	 					group_stack[group_index]=-1
@@ -2201,7 +2201,7 @@ pub fn new_regex_by_size(mult int) RE {
 // Matchers
 //
 
-pub fn (re mut RE) match_string(in_txt string) (int,int) {
+pub fn (mut re RE) match_string(in_txt string) (int,int) {
 	start, end := re.match_base(in_txt.str,in_txt.len)
 	if start >= 0 && end > start {
 		if (re.flag & F_MS) != 0 && start > 0 {
@@ -2223,7 +2223,7 @@ pub fn (re mut RE) match_string(in_txt string) (int,int) {
 //
 
 // find try to find the first match in the input string
-pub fn (re mut RE) find(in_txt string) (int,int) {
+pub fn (mut re RE) find(in_txt string) (int,int) {
 	old_flag := re.flag
 	re.flag |= F_SRC  // enable search mode
 	start, end := re.match_base(in_txt.str, in_txt.len)
@@ -2235,7 +2235,7 @@ pub fn (re mut RE) find(in_txt string) (int,int) {
 }
 
 // find all the non overlapping occurrences of the match pattern
-pub fn (re mut RE) find_all(in_txt string) []int {
+pub fn (mut re RE) find_all(in_txt string) []int {
 	mut i := 0
 	mut res := []int{}
 	mut ls := -1
@@ -2257,7 +2257,7 @@ pub fn (re mut RE) find_all(in_txt string) []int {
 }
 
 // replace return a string where the matches are replaced with the replace string
-pub fn (re mut RE) replace(in_txt string, repl string) string {
+pub fn (mut re RE) replace(in_txt string, repl string) string {
 	pos := re.find_all(in_txt)
 	if pos.len > 0 {
 		mut res := ""
diff --git a/vlib/sokol/gfx/gfx_structs.v b/vlib/sokol/gfx/gfx_structs.v
index 04fdb790e8..a729052136 100644
--- a/vlib/sokol/gfx/gfx_structs.v
+++ b/vlib/sokol/gfx/gfx_structs.v
@@ -61,11 +61,11 @@ pub mut:
     _end_canary u32
 }
 
-pub fn (b mut C.sg_bindings) set_vert_image(index int, img C.sg_image) {
+pub fn (mut b C.sg_bindings) set_vert_image(index int, img C.sg_image) {
     b.vs_images[index] = img
 }
 
-pub fn (b mut C.sg_bindings) set_frag_image(index int, img C.sg_image) {
+pub fn (mut b C.sg_bindings) set_frag_image(index int, img C.sg_image) {
     b.fs_images[index] = img
 }
 
@@ -96,45 +96,45 @@ pub mut:
     _end_canary u32
 }
 
-pub fn (desc mut C.sg_shader_desc) set_vert_src(src string) &C.sg_shader_desc {
+pub fn (mut desc C.sg_shader_desc) set_vert_src(src string) &C.sg_shader_desc {
     desc.vs.source = src.str
     return desc
 }
 
-pub fn (desc mut C.sg_shader_desc) set_frag_src(src string) &C.sg_shader_desc {
+pub fn (mut desc C.sg_shader_desc) set_frag_src(src string) &C.sg_shader_desc {
     desc.fs.source = src.str
     return desc
 }
 
-pub fn (desc mut C.sg_shader_desc) set_vert_image(index int, name string) &C.sg_shader_desc {
+pub fn (mut desc C.sg_shader_desc) set_vert_image(index int, name string) &C.sg_shader_desc {
     desc.vs.images[index].name = name.str
     desc.vs.images[index].@type = ._2d
     return desc
 }
 
-pub fn (desc mut C.sg_shader_desc) set_frag_image(index int, name string) &C.sg_shader_desc {
+pub fn (mut desc C.sg_shader_desc) set_frag_image(index int, name string) &C.sg_shader_desc {
     desc.fs.images[index].name = name.str
     desc.fs.images[index].@type = ._2d
     return desc
 }
 
-pub fn (desc mut C.sg_shader_desc) set_vert_uniform_block_size(block_index, size int) &C.sg_shader_desc {
+pub fn (mut desc C.sg_shader_desc) set_vert_uniform_block_size(block_index, size int) &C.sg_shader_desc {
     desc.vs.uniform_blocks[block_index].size = size
     return desc
 }
 
-pub fn (desc mut C.sg_shader_desc) set_frag_uniform_block_size(block_index, size int) &C.sg_shader_desc {
+pub fn (mut desc C.sg_shader_desc) set_frag_uniform_block_size(block_index, size int) &C.sg_shader_desc {
     desc.fs.uniform_blocks[block_index].size = size
     return desc
 }
 
-pub fn (desc mut C.sg_shader_desc) set_vert_uniform(block_index int, uniform_index int, name string, @type UniformType, array_count int) &C.sg_shader_desc {
+pub fn (mut desc C.sg_shader_desc) set_vert_uniform(block_index int, uniform_index int, name string, @type UniformType, array_count int) &C.sg_shader_desc {
     desc.vs.uniform_blocks[block_index].uniforms[uniform_index].name = name.str
 	desc.vs.uniform_blocks[block_index].uniforms[uniform_index].@type = @type
     return desc
 }
 
-pub fn (desc mut C.sg_shader_desc) set_frag_uniform(block_index int, uniform_index int, name string, @type UniformType, array_count int) &C.sg_shader_desc {
+pub fn (mut desc C.sg_shader_desc) set_frag_uniform(block_index int, uniform_index int, name string, @type UniformType, array_count int) &C.sg_shader_desc {
     desc.fs.uniform_blocks[block_index].uniforms[uniform_index].name = name.str
 	desc.fs.uniform_blocks[block_index].uniforms[uniform_index].@type = @type
     return desc
@@ -162,7 +162,7 @@ pub mut:
     images [12]C.sg_shader_image_desc
 }
 
-pub fn (desc mut C.sg_shader_stage_desc) set_image(index int, name string) C.sg_shader_stage_desc {
+pub fn (mut desc C.sg_shader_stage_desc) set_image(index int, name string) C.sg_shader_stage_desc {
     desc.images[index].name = name.str
     desc.images[index].@type = ._2d
     return desc
@@ -416,7 +416,7 @@ pub mut:
 }
 
 /*
-pub fn (action mut C.sg_color_attachment_action) set_color_values(r, g, b, a f32) {
+pub fn (mut action C.sg_color_attachment_action) set_color_values(r, g, b, a f32) {
     action.val[0] = r
     action.val[1] = g
     action.val[2] = b
diff --git a/vlib/strings/builder.c.v b/vlib/strings/builder.c.v
index fbb2211321..108016ff72 100644
--- a/vlib/strings/builder.c.v
+++ b/vlib/strings/builder.c.v
@@ -20,17 +20,17 @@ pub fn new_builder(initial_size int) Builder {
 	}
 }
 
-pub fn (b mut Builder) write_bytes(bytes byteptr, howmany int) {
+pub fn (mut b Builder) write_bytes(bytes byteptr, howmany int) {
 	b.buf.push_many(bytes, howmany)
 	b.len += howmany
 }
 
-pub fn (b mut Builder) write_b(data byte) {
+pub fn (mut b Builder) write_b(data byte) {
 	b.buf << data
 	b.len++
 }
 
-pub fn (b mut Builder) write(s string) {
+pub fn (mut b Builder) write(s string) {
 	if s == '' {
 		return
 	}
@@ -42,17 +42,17 @@ pub fn (b mut Builder) write(s string) {
 	b.len += s.len
 }
 
-pub fn (b mut Builder) go_back(n int) {
+pub fn (mut b Builder) go_back(n int) {
 	b.buf.trim(b.buf.len-n)
 	b.len -= n
 }
 
-pub fn (b mut Builder) go_back_to(pos int) {
+pub fn (mut b Builder) go_back_to(pos int) {
 	b.buf.trim(pos)
 	b.len = pos
 }
 
-pub fn (b mut Builder) writeln(s string) {
+pub fn (mut b Builder) writeln(s string) {
 	// for c in s {
 	// b.buf << c
 	// }
@@ -86,7 +86,7 @@ pub fn (b &Builder) after(n int) string {
 
 // NB: in order to avoid memleaks and additional memory copies, after a call to b.str(),
 // the builder b will be empty. The returned string *owns* the accumulated data so far.
-pub fn (b mut Builder) str() string {
+pub fn (mut b Builder) str() string {
 	b.str_calls++
 	if b.str_calls > 1 {
 		panic('builder.str() should be called just once.\n' +
@@ -100,7 +100,7 @@ pub fn (b mut Builder) str() string {
 	return s
 }
 
-pub fn (b mut Builder) free() {
+pub fn (mut b Builder) free() {
 	unsafe{
 		free(b.buf.data)
 	}
diff --git a/vlib/strings/builder.js.v b/vlib/strings/builder.js.v
index 77dc3cd476..d66483ff80 100644
--- a/vlib/strings/builder.js.v
+++ b/vlib/strings/builder.js.v
@@ -19,18 +19,18 @@ pub fn new_builder(initial_size int) Builder {
 	}
 }
 
-pub fn (b mut Builder) write_b(data byte) {
+pub fn (mut b Builder) write_b(data byte) {
 	b.buf << data
 	b.len++
 }
 
-pub fn (b mut Builder) write(s string) {
+pub fn (mut b Builder) write(s string) {
 	b.buf.push_many(s.str, s.len)
 	//b.buf << []byte(s)  // TODO
 	b.len += s.len
 }
 
-pub fn (b mut Builder) writeln(s string) {
+pub fn (mut b Builder) writeln(s string) {
 	b.buf.push_many(s.str, s.len)
 	//b.buf << []byte(s)  // TODO
 	b.buf << `\n`
@@ -41,11 +41,11 @@ pub fn (b Builder) str() string {
 	return string(b.buf, b.len)
 }
 
-pub fn (b mut Builder) cut(n int) {
+pub fn (mut b Builder) cut(n int) {
 	b.len -= n
 }
 
-pub fn (b mut Builder) free() {
+pub fn (mut b Builder) free() {
 	b.buf = make(0, b.initial_size, 1)
 	b.len = 0
 }
diff --git a/vlib/sync/pool.v b/vlib/sync/pool.v
index e97f41357b..cfe254ad68 100644
--- a/vlib/sync/pool.v
+++ b/vlib/sync/pool.v
@@ -86,7 +86,7 @@ pub fn new_pool_processor(context PoolProcessorConfig) &PoolProcessor {
 
 // set_max_jobs gives you the ability to override the number
 // of jobs *after* the PoolProcessor had been created already.
-pub fn (pool mut PoolProcessor) set_max_jobs(njobs int) {
+pub fn (mut pool PoolProcessor) set_max_jobs(njobs int) {
 	pool.njobs = njobs
 }
 
@@ -99,11 +99,11 @@ pub fn (pool mut PoolProcessor) set_max_jobs(njobs int) {
 // work_on_items returns *after* all threads finish.
 // You can optionally call get_results after that.
 // TODO: uncomment, when generics work again
-//pub fn (pool mut PoolProcessor) work_on_items<T>(items []T) {
+//pub fn (mut pool PoolProcessor) work_on_items<T>(items []T) {
 //	pool.work_on_pointers( items.pointers() )
 //}
 
-pub fn (pool mut PoolProcessor) work_on_pointers(items []voidptr) {
+pub fn (mut pool PoolProcessor) work_on_pointers(items []voidptr) {
 	mut njobs := runtime.nr_jobs()
 	if pool.njobs > 0 {
 		njobs = pool.njobs
@@ -186,7 +186,7 @@ pub fn (pool &PoolProcessor) get_int_item(idx int) int {
 // set_shared_context - can be called during the setup so that you can
 // provide a context that is shared between all worker threads, like
 // common options/settings.
-pub fn (pool mut PoolProcessor) set_shared_context(context voidptr) {
+pub fn (mut pool PoolProcessor) set_shared_context(context voidptr) {
 	pool.shared_context = context
 }
 
@@ -201,7 +201,7 @@ pub fn (pool &PoolProcessor) get_shared_context() voidptr {
 // local storage area where it can write/read information that is private
 // to the given thread, without worrying that it will get overwritten by
 // another thread
-pub fn (pool mut PoolProcessor) set_thread_context(idx int, context voidptr) {
+pub fn (mut pool PoolProcessor) set_thread_context(idx int, context voidptr) {
 	pool.thread_contexts[idx] = context
 }
 
@@ -223,11 +223,11 @@ pub:
 
 //
 
-pub fn (pool mut PoolProcessor) work_on_items_s(items []string) {
+pub fn (mut pool PoolProcessor) work_on_items_s(items []string) {
 	pool.work_on_pointers( items.pointers() )
 }
 
-pub fn (pool mut PoolProcessor) work_on_items_i(items []int) {
+pub fn (mut pool PoolProcessor) work_on_items_i(items []int) {
 	pool.work_on_pointers( items.pointers() )
 }
 
diff --git a/vlib/sync/sync_nix.c.v b/vlib/sync/sync_nix.c.v
index cb14de141b..37be8ae997 100644
--- a/vlib/sync/sync_nix.c.v
+++ b/vlib/sync/sync_nix.c.v
@@ -15,11 +15,10 @@ pub fn new_mutex() &Mutex {
 	return m
 }
 
-pub fn (m mut Mutex) lock() {
+pub fn (mut m Mutex) lock() {
 	C.pthread_mutex_lock(&m.mutex)
 }
 
-pub fn (m mut Mutex) unlock() {
+pub fn (mut m Mutex) unlock() {
 	C.pthread_mutex_unlock(&m.mutex)
 }
-
diff --git a/vlib/sync/sync_windows.c.v b/vlib/sync/sync_windows.c.v
index 9c765351b2..09bb7874e7 100644
--- a/vlib/sync/sync_windows.c.v
+++ b/vlib/sync/sync_windows.c.v
@@ -41,7 +41,7 @@ pub fn new_mutex() &Mutex {
 	return sm
 }
 
-pub fn (m mut Mutex) lock() {
+pub fn (mut m Mutex) lock() {
 	// if mutex handle not initalized
 	if isnil(m.mx) {
 		m.mx = C.CreateMutex(0, false, 0)
@@ -68,7 +68,7 @@ pub fn (m mut Mutex) lock() {
 	}
 }
 
-pub fn (m mut Mutex) unlock() {
+pub fn (mut m Mutex) unlock() {
 	if m.state == .waiting {
 		if C.ReleaseMutex(m.mx) {
 			m.state = .broken
@@ -78,7 +78,7 @@ pub fn (m mut Mutex) unlock() {
 	m.state = .released
 }
 
-pub fn (m mut Mutex) destroy() {
+pub fn (mut m Mutex) destroy() {
 	if m.state == .waiting {
 		m.unlock() // unlock mutex before destroying
 	}
diff --git a/vlib/sync/waitgroup.v b/vlib/sync/waitgroup.v
index 78f5ba8794..92fe3b16d7 100644
--- a/vlib/sync/waitgroup.v
+++ b/vlib/sync/waitgroup.v
@@ -15,7 +15,7 @@ pub fn new_waitgroup() &WaitGroup {
 	return &WaitGroup{mu: sync.new_mutex() }
 }
 
-pub fn (wg mut WaitGroup) add(delta int) {
+pub fn (mut wg WaitGroup) add(delta int) {
 	wg.mu.lock()
 	wg.active += delta
 	wg.mu.unlock()
@@ -24,7 +24,7 @@ pub fn (wg mut WaitGroup) add(delta int) {
 	}
 }
 
-pub fn (wg mut WaitGroup) done() {
+pub fn (mut wg WaitGroup) done() {
 	wg.add(-1)
 }
 
@@ -39,4 +39,3 @@ pub fn (wg &WaitGroup) wait() {
 		}
 	}
 }
-
diff --git a/vlib/szip/szip.v b/vlib/szip/szip.v
index 74e81cb5e7..007d4cc1f1 100644
--- a/vlib/szip/szip.v
+++ b/vlib/szip/szip.v
@@ -53,7 +53,7 @@ pub fn open(name string, level int, mode string) ?zip_ptr {
     if mode != M_WRITE && mode != M_RONLY && mode != M_APPEND {
         return error('szip: invalid provided open mode')
     }
-    /* struct zip_t* */_p_zip := zip_ptr(C.zip_open(name.str, 
+    /* struct zip_t* */_p_zip := zip_ptr(C.zip_open(name.str,
                                  _nlevel, mode.str))
     if _p_zip == zip_ptr(0) {
         return error('szip: cannot open/create/append new zip archive')
@@ -66,7 +66,7 @@ pub fn open(name string, level int, mode string) ?zip_ptr {
  *
  * @param zip zip archive handler.
  */
-pub fn (z mut zip_ptr) close() {
+pub fn (mut z zip_ptr) close() {
     C.zip_close(z)
 }
 
@@ -82,7 +82,7 @@ pub fn (z mut zip_ptr) close() {
  *
  * @return the return code - 0 on success, negative number (< 0) on error.
  */
-pub fn (zentry mut zip_ptr) open_entry(name string) /*?*/bool {
+pub fn (mut zentry zip_ptr) open_entry(name string) /*?*/bool {
     res := C.zip_entry_open(zentry, name.str)
     return res != -1
 }
@@ -94,7 +94,7 @@ pub fn (zentry mut zip_ptr) open_entry(name string) /*?*/bool {
  *
  * @return the return code - 0 on success, negative number (< 0) on error.
  */
-pub fn (zentry mut zip_ptr) close_entry() {
+pub fn (mut zentry zip_ptr) close_entry() {
     C.zip_entry_close(zentry)
 }
 
@@ -112,7 +112,7 @@ pub fn (zentry mut zip_ptr) close_entry() {
  *
  * @return the pointer to the current zip entry name, or NULL on error.
  */
-pub fn (zentry mut zip_ptr) name() string {
+pub fn (mut zentry zip_ptr) name() string {
     _name := C.zip_entry_name(zentry)
     if _name == 0 {
         return ''
@@ -127,7 +127,7 @@ pub fn (zentry mut zip_ptr) name() string {
  *
  * @return the index on success, negative number (< 0) on error.
  */
-pub fn (zentry mut zip_ptr) index() ?int {
+pub fn (mut zentry zip_ptr) index() ?int {
     _index := int(C.zip_entry_index(zentry))
     if _index == -1 {
         return error('szip: cannot get current index of zip entry')
@@ -143,7 +143,7 @@ pub fn (zentry mut zip_ptr) index() ?int {
  * @return the return code - 1 (true), 0 (false), negative number (< 0) on
  *         error.
  */
-pub fn (zentry mut zip_ptr) isdir() ?bool {
+pub fn (mut zentry zip_ptr) isdir() ?bool {
     _isdir := C.zip_entry_isdir(zentry)
     if _isdir == -1 {
         return error('szip: cannot check entry type')
@@ -159,7 +159,7 @@ pub fn (zentry mut zip_ptr) isdir() ?bool {
  *
  * @return the uncompressed size in bytes.
  */
-pub fn (zentry mut zip_ptr) size() i64 {
+pub fn (mut zentry zip_ptr) size() i64 {
     _size := i64(C.zip_entry_size(zentry))
     return _size
 }
@@ -171,7 +171,7 @@ pub fn (zentry mut zip_ptr) size() i64 {
  *
  * @return the CRC-32 checksum.
  */
-pub fn (zentry mut zip_ptr) crc32() u32 {
+pub fn (mut zentry zip_ptr) crc32() u32 {
     _checksum := u32(C.zip_entry_crc32(zentry))
     return _checksum // 0
 }
@@ -185,10 +185,10 @@ pub fn (zentry mut zip_ptr) crc32() u32 {
  *
  * @return the return code - 0 on success, negative number (< 0) on error.
  */
-pub fn (zentry mut zip_ptr) write_entry(data []byte) bool {
-    if (data[0] & 0xff) == -1 { 
-        return false 
-    } 
+pub fn (mut zentry zip_ptr) write_entry(data []byte) bool {
+    if (data[0] & 0xff) == -1 {
+        return false
+    }
     buf := data // alias of data
     res := C.zip_entry_write(zentry, buf.data, buf.len)
     return res == 0
@@ -202,7 +202,7 @@ pub fn (zentry mut zip_ptr) write_entry(data []byte) bool {
  *
  * @return the return code - 0 on success, negative number (< 0) on error.
  */
-pub fn (zentry mut zip_ptr) create_entry(name string) bool {
+pub fn (mut zentry zip_ptr) create_entry(name string) bool {
     res := C.zip_entry_fwrite(zentry, name.str)
     return res == 0
 }
@@ -222,7 +222,7 @@ pub fn (zentry mut zip_ptr) create_entry(name string) bool {
  * @return the return code - the number of bytes actually read on success.
  *         Otherwise a -1 on error.
  */
-pub fn (zentry mut zip_ptr) read_entry() ?voidptr {
+pub fn (mut zentry zip_ptr) read_entry() ?voidptr {
     mut _buf := voidptr(0)
     mut _bsize := i64(0)
     res := C.zip_entry_read(zentry, &_buf, &_bsize)
@@ -240,7 +240,7 @@ pub fn (zentry mut zip_ptr) read_entry() ?voidptr {
  *
  * @return the return code - 0 on success, negative number (< 0) on error.
  */
-pub fn (zentry mut zip_ptr) extract_entry(path string) /*?*/bool {
+pub fn (mut zentry zip_ptr) extract_entry(path string) /*?*/bool {
     if C.access(path.str, 0) == -1 {
         return false
         //return error('Cannot open file for extracting, file not exists')
@@ -259,7 +259,7 @@ pub fn (zentry mut zip_ptr) extract_entry(path string) /*?*/bool {
  *
  * @return the return code - 0 on success, negative number (< 0) on error.
  */
-/*fn (zentry mut zip_ptr) extract(path string) bool {
+/*fn (mut zentry zip_ptr) extract(path string) bool {
     if C.access(path.str, 0) == -1 {
         return false
         //return error('Cannot open directory for extracting, directory not exists')
@@ -276,10 +276,10 @@ pub fn (zentry mut zip_ptr) extract_entry(path string) /*?*/bool {
  * @return the return code - the number of entries on success, negative number
  *         (< 0) on error.
  */
-pub fn (zentry mut zip_ptr) total() ?int {
+pub fn (mut zentry zip_ptr) total() ?int {
     _tentry := int(C.zip_total_entries(zentry))
     if _tentry == -1 {
         return error('szip: cannot count total entries')
     }
     return _tentry
-} 
+}
diff --git a/vlib/time/stopwatch.v b/vlib/time/stopwatch.v
index 9d416efa60..d3792068fb 100644
--- a/vlib/time/stopwatch.v
+++ b/vlib/time/stopwatch.v
@@ -16,7 +16,7 @@ pub fn new_stopwatch() StopWatch {
 }
 
 // start Starts the timer. If the timer was paused, restarts counting.
-pub fn (t mut StopWatch) start() {
+pub fn (mut t StopWatch) start() {
 	if t.pause_time == 0 {
 		t.start = time.sys_mono_now()
 	} else {
@@ -26,18 +26,18 @@ pub fn (t mut StopWatch) start() {
 	t.pause_time = 0
 }
 
-pub fn (t mut StopWatch) restart() {
+pub fn (mut t StopWatch) restart() {
 	t.end = 0
 	t.pause_time = 0
 	t.start = time.sys_mono_now()
 }
 
-pub fn (t mut StopWatch) stop() {
+pub fn (mut t StopWatch) stop() {
 	t.end = time.sys_mono_now()
 	t.pause_time = 0
 }
 
-pub fn (t mut StopWatch) pause() {
+pub fn (mut t StopWatch) pause() {
 	t.pause_time = time.sys_mono_now()
 	t.end = t.pause_time // so elapsed keeps track of actual running time
 }
@@ -50,4 +50,3 @@ pub fn (t StopWatch) elapsed() Duration {
 		return Duration(t.end - t.start)
 	}
 }
-
diff --git a/vlib/v/ast/scope.v b/vlib/v/ast/scope.v
index 9c3c3e6c63..bed9db999e 100644
--- a/vlib/v/ast/scope.v
+++ b/vlib/v/ast/scope.v
@@ -88,7 +88,7 @@ pub fn (s &Scope) known_var(name string) bool {
 	return false
 }
 
-pub fn (s mut Scope) update_var_type(name string, typ table.Type) {
+pub fn (mut s Scope) update_var_type(name string, typ table.Type) {
 	match mut s.objects[name] {
 		Var {
 			if it.typ == typ {
@@ -100,7 +100,7 @@ pub fn (s mut Scope) update_var_type(name string, typ table.Type) {
 	}
 }
 
-pub fn (s mut Scope) register(name string, obj ScopeObject) {
+pub fn (mut s Scope) register(name string, obj ScopeObject) {
 	if name == '_' {
 		return
 	}
diff --git a/vlib/v/checker/tests/mut_receiver_warning.out b/vlib/v/checker/tests/mut_receiver_warning.out
new file mode 100644
index 0000000000..533a3465a1
--- /dev/null
+++ b/vlib/v/checker/tests/mut_receiver_warning.out
@@ -0,0 +1,7 @@
+vlib/v/checker/tests/mut_receiver_warning.v:5:7: warning: use `(mut f Foo)` instead of `(f mut Foo)`
+    3 |     name string
+    4 | }
+    5 | fn (f mut Foo) info() {
+      |       ~~~
+    6 |     f.name = 'foo'
+    7 | }
\ No newline at end of file
diff --git a/vlib/v/checker/tests/mut_receiver_warning.vv b/vlib/v/checker/tests/mut_receiver_warning.vv
new file mode 100644
index 0000000000..e01bb499e3
--- /dev/null
+++ b/vlib/v/checker/tests/mut_receiver_warning.vv
@@ -0,0 +1,10 @@
+struct Foo{
+mut:
+	name string
+}
+fn (f mut Foo) info() {
+	f.name = 'foo'
+}
+fn main() {
+	println('hello, world')
+}
diff --git a/vlib/v/gen/js/js.v b/vlib/v/gen/js/js.v
index 3752784e45..9bef52f249 100644
--- a/vlib/v/gen/js/js.v
+++ b/vlib/v/gen/js/js.v
@@ -91,7 +91,7 @@ pub fn gen(files []ast.File, table &table.Table, pref &pref.Preferences) string
 	return out
 }
 
-pub fn (g mut JsGen) enter_namespace(n string) {
+pub fn (mut g JsGen) enter_namespace(n string) {
 	g.namespace = n
 	if g.namespaces[g.namespace].len == 0 {
 		// create a new namespace
@@ -104,16 +104,16 @@ pub fn (g mut JsGen) enter_namespace(n string) {
 	}
 }
 
-pub fn (g mut JsGen) escape_namespace() {
+pub fn (mut g JsGen) escape_namespace() {
 	g.namespaces[g.namespace] = g.out
 	g.namespace = ""
 }
 
-pub fn (g mut JsGen) push_pub_var(s string) {
+pub fn (mut g JsGen) push_pub_var(s string) {
 	g.namespaces_pub[g.namespace] << s
 }
 
-pub fn (g mut JsGen) find_class_methods(stmts []ast.Stmt) {
+pub fn (mut g JsGen) find_class_methods(stmts []ast.Stmt) {
 	for stmt in stmts {
 		match stmt {
 			ast.FnDecl {
@@ -131,13 +131,13 @@ pub fn (g mut JsGen) find_class_methods(stmts []ast.Stmt) {
 	}
 }
 
-pub fn (g mut JsGen) init() {
+pub fn (mut g JsGen) init() {
 	g.definitions.writeln('// Generated by the V compiler')
 	g.definitions.writeln('"use strict";')
 	g.definitions.writeln('')
 }
 
-pub fn (g mut JsGen) finish() {
+pub fn (mut g JsGen) finish() {
 	if g.constants.len > 0 {
 		constants := g.constants.str()
 		g.constants = strings.new_builder(100)
@@ -156,7 +156,7 @@ pub fn (g JsGen) hashes() string {
 
 
 // V type to JS type
-pub fn (g mut JsGen) typ(t table.Type) string {
+pub fn (mut g JsGen) typ(t table.Type) string {
 	sym := g.table.get_type_symbol(t)
 	mut styp := sym.name.replace('.', '__')
 	if styp.starts_with('JS__') {
@@ -165,7 +165,7 @@ pub fn (g mut JsGen) typ(t table.Type) string {
 	return g.to_js_typ(styp)
 }
 
-fn (g mut JsGen) to_js_typ(typ string) string {
+fn (mut g JsGen) to_js_typ(typ string) string {
 	mut styp := ''
 	match typ {
 		'int' {
@@ -199,33 +199,33 @@ fn (g mut JsGen) to_js_typ(typ string) string {
 
 pub fn (g &JsGen) save() {}
 
-pub fn (g mut JsGen) gen_indent() {
+pub fn (mut g JsGen) gen_indent() {
 	if g.indents[g.namespace] > 0 && g.empty_line {
 		g.out.write(tabs[g.indents[g.namespace]])
 	}
 	g.empty_line = false
 }
 
-pub fn (g mut JsGen) inc_indent() {
+pub fn (mut g JsGen) inc_indent() {
 	g.indents[g.namespace]++
 }
 
-pub fn (g mut JsGen) dec_indent() {
+pub fn (mut g JsGen) dec_indent() {
 	g.indents[g.namespace]--
 }
 
-pub fn (g mut JsGen) write(s string) {
+pub fn (mut g JsGen) write(s string) {
 	g.gen_indent()
 	g.out.write(s)
 }
 
-pub fn (g mut JsGen) writeln(s string) {
+pub fn (mut g JsGen) writeln(s string) {
 	g.gen_indent()
 	g.out.writeln(s)
 	g.empty_line = true
 }
 
-pub fn (g mut JsGen) new_tmp_var() string {
+pub fn (mut g JsGen) new_tmp_var() string {
 	g.tmp_count++
 	return '_tmp$g.tmp_count'
 }
@@ -239,7 +239,7 @@ fn js_name(name string) string {
 	return name
 }
 
-fn (g mut JsGen) stmts(stmts []ast.Stmt) {
+fn (mut g JsGen) stmts(stmts []ast.Stmt) {
 	g.inc_indent()
 	for stmt in stmts {
 		g.stmt(stmt)
@@ -247,7 +247,7 @@ fn (g mut JsGen) stmts(stmts []ast.Stmt) {
 	g.dec_indent()
 }
 
-fn (g mut JsGen) stmt(node ast.Stmt) {
+fn (mut g JsGen) stmt(node ast.Stmt) {
 	g.stmt_start_pos = g.out.len
 
 	match node {
@@ -341,7 +341,7 @@ fn (g mut JsGen) stmt(node ast.Stmt) {
 	}
 }
 
-fn (g mut JsGen) expr(node ast.Expr) {
+fn (mut g JsGen) expr(node ast.Expr) {
 	match node {
 		ast.ArrayInit {
 			g.gen_array_init_expr(it)
@@ -436,7 +436,7 @@ fn (g mut JsGen) expr(node ast.Expr) {
 	}
 }
 
-fn (g mut JsGen) gen_string_inter_literal(it ast.StringInterLiteral) {
+fn (mut g JsGen) gen_string_inter_literal(it ast.StringInterLiteral) {
 	g.write('tos3(`')
 	for i, val in it.vals {
 		escaped_val := val.replace_each(['`', '\`', '\r\n', '\n'])
@@ -483,7 +483,7 @@ fn (g mut JsGen) gen_string_inter_literal(it ast.StringInterLiteral) {
 	g.write('`)')
 }
 
-fn (g mut JsGen) gen_array_init_expr(it ast.ArrayInit) {
+fn (mut g JsGen) gen_array_init_expr(it ast.ArrayInit) {
 	type_sym := g.table.get_type_symbol(it.typ)
 	if type_sym.kind != .array_fixed {
 		g.write('[')
@@ -497,7 +497,7 @@ fn (g mut JsGen) gen_array_init_expr(it ast.ArrayInit) {
 	} else {}
 }
 
-fn (g mut JsGen) gen_assert_stmt(a ast.AssertStmt) {
+fn (mut g JsGen) gen_assert_stmt(a ast.AssertStmt) {
 	g.writeln('// assert')
 	g.write('if( ')
 	g.expr(a.expr)
@@ -520,7 +520,7 @@ fn (g mut JsGen) gen_assert_stmt(a ast.AssertStmt) {
 	g.writeln('}')
 }
 
-fn (g mut JsGen) gen_assign_stmt(it ast.AssignStmt) {
+fn (mut g JsGen) gen_assign_stmt(it ast.AssignStmt) {
 	if it.left.len > it.right.len {
 		// multi return
 		jsdoc := strings.new_builder(50)
@@ -586,23 +586,23 @@ fn (g mut JsGen) gen_assign_stmt(it ast.AssignStmt) {
 	}
 }
 
-fn (g mut JsGen) gen_attr(it ast.Attr) {
+fn (mut g JsGen) gen_attr(it ast.Attr) {
 	g.writeln('/* [$it.name] */')
 }
 
-fn (g mut JsGen) gen_block(it ast.Block) {
+fn (mut g JsGen) gen_block(it ast.Block) {
 	g.writeln('{')
 	g.stmts(it.stmts)
 	g.writeln('}')
 }
 
-fn (g mut JsGen) gen_branch_stmt(it ast.BranchStmt) {
+fn (mut g JsGen) gen_branch_stmt(it ast.BranchStmt) {
 	// continue or break
 	g.write(it.tok.kind.str())
 	g.writeln(';')
 }
 
-fn (g mut JsGen) gen_const_decl(it ast.ConstDecl) {
+fn (mut g JsGen) gen_const_decl(it ast.ConstDecl) {
 	// old_indent := g.indents[g.namespace]
 	for i, field in it.fields {
 		// TODO hack. Cut the generated value and paste it into definitions.
@@ -622,7 +622,7 @@ fn (g mut JsGen) gen_const_decl(it ast.ConstDecl) {
 	g.constants.writeln('')
 }
 
-fn (g mut JsGen) gen_defer_stmts() {
+fn (mut g JsGen) gen_defer_stmts() {
 	g.writeln('(function defer() {')
 	for defer_stmt in g.defer_stmts {
 		g.stmts(defer_stmt.stmts)
@@ -630,7 +630,7 @@ fn (g mut JsGen) gen_defer_stmts() {
 	g.writeln('})();')
 }
 
-fn (g mut JsGen) gen_enum_decl(it ast.EnumDecl) {
+fn (mut g JsGen) gen_enum_decl(it ast.EnumDecl) {
 	g.writeln('const ${js_name(it.name)} = Object.freeze({')
 	g.inc_indent()
 	for i, field in it.fields {
@@ -653,7 +653,7 @@ fn (g mut JsGen) gen_enum_decl(it ast.EnumDecl) {
 	}
 }
 
-fn (g mut JsGen) gen_expr_stmt(it ast.ExprStmt) {
+fn (mut g JsGen) gen_expr_stmt(it ast.ExprStmt) {
 	g.expr(it.expr)
 	expr := it.expr
 	match expr {
@@ -668,7 +668,7 @@ fn (g mut JsGen) gen_expr_stmt(it ast.ExprStmt) {
 	}
 }
 
-fn (g mut JsGen) gen_fn_decl(it ast.FnDecl) {
+fn (mut g JsGen) gen_fn_decl(it ast.FnDecl) {
 	if it.is_method {
 		// Struct methods are handled by class generation code.
 		return
@@ -679,7 +679,7 @@ fn (g mut JsGen) gen_fn_decl(it ast.FnDecl) {
 	g.gen_method_decl(it)
 }
 
-fn (g mut JsGen) gen_method_decl(it ast.FnDecl) {
+fn (mut g JsGen) gen_method_decl(it ast.FnDecl) {
 	g.fn_decl = &it
 	has_go := fn_has_go(it)
 	is_main := it.name == 'main'
@@ -739,7 +739,7 @@ fn (g mut JsGen) gen_method_decl(it ast.FnDecl) {
 	g.fn_decl = 0
 }
 
-fn (g mut JsGen) gen_for_c_stmt(it ast.ForCStmt) {
+fn (mut g JsGen) gen_for_c_stmt(it ast.ForCStmt) {
 	g.inside_loop = true
 	g.write('for (')
 	if it.has_init {
@@ -760,7 +760,7 @@ fn (g mut JsGen) gen_for_c_stmt(it ast.ForCStmt) {
 	g.inside_loop = false
 }
 
-fn (g mut JsGen) gen_for_in_stmt(it ast.ForInStmt) {
+fn (mut g JsGen) gen_for_in_stmt(it ast.ForInStmt) {
 	if it.is_range {
 		// `for x in 1..10 {`
 		i := it.val_var
@@ -813,7 +813,7 @@ fn (g mut JsGen) gen_for_in_stmt(it ast.ForInStmt) {
 	}
 }
 
-fn (g mut JsGen) gen_for_stmt(it ast.ForStmt) {
+fn (mut g JsGen) gen_for_stmt(it ast.ForStmt) {
 	g.write('while (')
 	if it.is_inf {
 		g.write('true')
@@ -825,7 +825,7 @@ fn (g mut JsGen) gen_for_stmt(it ast.ForStmt) {
 	g.writeln('}')
 }
 
-fn (g mut JsGen) fn_args(args []table.Arg, is_variadic bool) {
+fn (mut g JsGen) fn_args(args []table.Arg, is_variadic bool) {
 	// no_names := args.len > 0 && args[0].name == 'arg_1'
 	for i, arg in args {
 		name := js_name(arg.name)
@@ -842,7 +842,7 @@ fn (g mut JsGen) fn_args(args []table.Arg, is_variadic bool) {
 	}
 }
 
-fn (g mut JsGen) gen_go_stmt(node ast.GoStmt) {
+fn (mut g JsGen) gen_go_stmt(node ast.GoStmt) {
 	// x := node.call_expr as ast.CallEpxr // TODO
 	match node.call_expr {
 		ast.CallExpr {
@@ -869,7 +869,7 @@ fn (g mut JsGen) gen_go_stmt(node ast.GoStmt) {
 	}
 }
 
-fn (g mut JsGen) gen_map_init_expr(it ast.MapInit) {
+fn (mut g JsGen) gen_map_init_expr(it ast.MapInit) {
 	// key_typ_sym := g.table.get_type_symbol(it.key_type)
 	// value_typ_sym := g.table.get_type_symbol(it.value_type)
 	// key_typ_str := key_typ_sym.name.replace('.', '__')
@@ -896,7 +896,7 @@ fn (g mut JsGen) gen_map_init_expr(it ast.MapInit) {
 	}
 }
 
-fn (g mut JsGen) gen_return_stmt(it ast.Return) {
+fn (mut g JsGen) gen_return_stmt(it ast.Return) {
 	g.write('return ')
 
 	if g.fn_decl.name == 'main' {
@@ -922,7 +922,7 @@ fn (g mut JsGen) gen_return_stmt(it ast.Return) {
 	g.writeln(';')
 }
 
-fn (g mut JsGen) enum_expr(node ast.Expr) {
+fn (mut g JsGen) enum_expr(node ast.Expr) {
 	match node {
 		ast.EnumVal {
 			g.write(it.val)
@@ -933,7 +933,7 @@ fn (g mut JsGen) enum_expr(node ast.Expr) {
 	}
 }
 
-fn (g mut JsGen) gen_struct_decl(node ast.StructDecl) {
+fn (mut g JsGen) gen_struct_decl(node ast.StructDecl) {
   	g.writeln('class ${js_name(node.name)} {')
 	g.inc_indent()
 	g.writeln(g.doc.gen_ctor(node.fields))
@@ -968,7 +968,7 @@ fn (g mut JsGen) gen_struct_decl(node ast.StructDecl) {
 	}
 }
 
-fn (g mut JsGen) gen_struct_init(it ast.StructInit) {
+fn (mut g JsGen) gen_struct_init(it ast.StructInit) {
 	type_sym := g.table.get_type_symbol(it.typ)
 	g.writeln('new ${type_sym.name}({')
 	g.inc_indent()
@@ -984,7 +984,7 @@ fn (g mut JsGen) gen_struct_init(it ast.StructInit) {
 	g.write('})')
 }
 
-fn (g mut JsGen) gen_ident(node ast.Ident) {
+fn (mut g JsGen) gen_ident(node ast.Ident) {
 	if node.kind == .constant {
 		g.write('CONSTANTS.')
 	}
@@ -996,12 +996,12 @@ fn (g mut JsGen) gen_ident(node ast.Ident) {
 	g.write(name)
 }
 
-fn (g mut JsGen) gen_selector_expr(it ast.SelectorExpr) {
+fn (mut g JsGen) gen_selector_expr(it ast.SelectorExpr) {
 	g.expr(it.expr)
 	g.write('.$it.field_name')
 }
 
-fn (g mut JsGen) gen_if_expr(node ast.IfExpr) {
+fn (mut g JsGen) gen_if_expr(node ast.IfExpr) {
 	type_sym := g.table.get_type_symbol(node.typ)
 
 	// one line ?:
diff --git a/vlib/v/parser/fn.v b/vlib/v/parser/fn.v
index 356e25e910..91f844cfff 100644
--- a/vlib/v/parser/fn.v
+++ b/vlib/v/parser/fn.v
@@ -134,6 +134,9 @@ fn (mut p Parser) fn_decl() ast.FnDecl {
 		rec_name = p.check_name()
 		if !rec_mut {
 			rec_mut = p.tok.kind == .key_mut
+			if rec_mut {
+				p.warn_with_pos('use `(mut f Foo)` instead of `(f mut Foo)`', p.tok.position())
+			}
 		}
 		receiver_pos = rec_start_pos.extend(p.tok.position())
 		is_amp := p.tok.kind == .amp
diff --git a/vlib/v/parser/module.v b/vlib/v/parser/module.v
index ae31c5bc47..b5b23ce42c 100644
--- a/vlib/v/parser/module.v
+++ b/vlib/v/parser/module.v
@@ -28,7 +28,7 @@ fn (mut p Parser) register_used_import(alias string) {
 	}
 }
 
-fn (p mut Parser) check_unused_imports() {
+fn (mut p Parser) check_unused_imports() {
 	mut output := ''
 	for alias, mod in p.imports {
 		if !p.is_used_import(alias) {
diff --git a/vlib/v/scanner/scanner.v b/vlib/v/scanner/scanner.v
index b9a8c4685c..cbbebe9b23 100644
--- a/vlib/v/scanner/scanner.v
+++ b/vlib/v/scanner/scanner.v
@@ -85,7 +85,7 @@ fn (s &Scanner) new_token(tok_kind token.Kind, lit string, len int) token.Token
 	}
 }
 
-fn (s mut Scanner) ident_name() string {
+fn (mut s Scanner) ident_name() string {
 	start := s.pos
 	s.pos++
 	for s.pos < s.text.len && (util.is_name_char(s.text[s.pos]) || s.text[s.pos].is_digit()) {
@@ -97,7 +97,7 @@ fn (s mut Scanner) ident_name() string {
 }
 
 // ident_fn_name look ahead and return name of function if possible, otherwise empty string
-fn (s mut Scanner) ident_fn_name() string {
+fn (mut s Scanner) ident_fn_name() string {
 	start := s.pos
 	mut pos := s.pos
 	pos++
@@ -155,7 +155,7 @@ fn filter_num_sep(txt byteptr, start int, end int) string {
 	}
 }
 
-fn (s mut Scanner) ident_bin_number() string {
+fn (mut s Scanner) ident_bin_number() string {
 	mut has_wrong_digit := false
 	mut first_wrong_digit := `\0`
 	start_pos := s.pos
@@ -184,7 +184,7 @@ fn (s mut Scanner) ident_bin_number() string {
 	return number
 }
 
-fn (s mut Scanner) ident_hex_number() string {
+fn (mut s Scanner) ident_hex_number() string {
 	mut has_wrong_digit := false
 	mut first_wrong_digit := `\0`
 	start_pos := s.pos
@@ -213,7 +213,7 @@ fn (s mut Scanner) ident_hex_number() string {
 	return number
 }
 
-fn (s mut Scanner) ident_oct_number() string {
+fn (mut s Scanner) ident_oct_number() string {
 	mut has_wrong_digit := false
 	mut first_wrong_digit := `\0`
 	start_pos := s.pos
@@ -242,7 +242,7 @@ fn (s mut Scanner) ident_oct_number() string {
 	return number
 }
 
-fn (s mut Scanner) ident_dec_number() string {
+fn (mut s Scanner) ident_dec_number() string {
 	mut has_wrong_digit := false
 	mut first_wrong_digit := `\0`
 	start_pos := s.pos
@@ -355,7 +355,7 @@ fn (s mut Scanner) ident_dec_number() string {
 	return number
 }
 
-fn (s mut Scanner) ident_number() string {
+fn (mut s Scanner) ident_number() string {
 	if s.expect('0b', s.pos) {
 		return s.ident_bin_number()
 	}
@@ -370,7 +370,7 @@ fn (s mut Scanner) ident_number() string {
 	}
 }
 
-fn (s mut Scanner) skip_whitespace() {
+fn (mut s Scanner) skip_whitespace() {
 	// if s.is_vh { println('vh') return }
 	for s.pos < s.text.len && s.text[s.pos].is_space() {
 		if util.is_nl(s.text[s.pos]) && s.is_vh {
@@ -384,13 +384,13 @@ fn (s mut Scanner) skip_whitespace() {
 	}
 }
 
-fn (s mut Scanner) end_of_file() token.Token {
+fn (mut s Scanner) end_of_file() token.Token {
 	s.pos = s.text.len
 	s.inc_line_number()
 	return s.new_token(.eof, '', 1)
 }
 
-pub fn (s mut Scanner) scan() token.Token {
+pub fn (mut s Scanner) scan() token.Token {
 	// if s.comments_mode == .parse_comments {
 	// println('\nscan()')
 	// }
@@ -868,7 +868,7 @@ fn (s &Scanner) count_symbol_before(p int, sym byte) int {
 	return count
 }
 
-fn (s mut Scanner) ident_string() string {
+fn (mut s Scanner) ident_string() string {
 	q := s.text[s.pos]
 	is_quote := q == single_quote || q == double_quote
 	is_raw := is_quote && s.pos > 0 && s.text[s.pos - 1] == `r`
@@ -956,7 +956,7 @@ fn trim_slash_line_break(s string) string {
 	return ret_str
 }
 
-fn (s mut Scanner) ident_char() string {
+fn (mut s Scanner) ident_char() string {
 	start := s.pos
 	slash := `\\`
 	mut len := 0
@@ -1005,7 +1005,7 @@ fn (s &Scanner) expect(want string, start_pos int) bool {
 	return true
 }
 
-fn (s mut Scanner) debug_tokens() {
+fn (mut s Scanner) debug_tokens() {
 	s.pos = 0
 	s.is_started = false
 	s.is_debug = true
@@ -1029,18 +1029,18 @@ fn (s mut Scanner) debug_tokens() {
 	}
 }
 
-fn (s mut Scanner) ignore_line() {
+fn (mut s Scanner) ignore_line() {
 	s.eat_to_end_of_line()
 	s.inc_line_number()
 }
 
-fn (s mut Scanner) eat_to_end_of_line() {
+fn (mut s Scanner) eat_to_end_of_line() {
 	for s.pos < s.text.len && s.text[s.pos] != `\n` {
 		s.pos++
 	}
 }
 
-fn (s mut Scanner) inc_line_number() {
+fn (mut s Scanner) inc_line_number() {
 	s.last_nl_pos = s.pos
 	s.line_nr++
 	s.line_ends << s.pos
diff --git a/vlib/v/tests/generic_test.v b/vlib/v/tests/generic_test.v
index 54e01d0947..98afaa0ac8 100644
--- a/vlib/v/tests/generic_test.v
+++ b/vlib/v/tests/generic_test.v
@@ -74,7 +74,7 @@ mut:
     y f64
 }
 
-fn (p mut Point) translate<T>(x, y T) {
+fn (mut p Point) translate<T>(x, y T) {
     p.x += x
     p.y += y
 }
diff --git a/vlib/v/tests/interfaces_map_test.v b/vlib/v/tests/interfaces_map_test.v
index f0e7562acb..6a21aad9f3 100644
--- a/vlib/v/tests/interfaces_map_test.v
+++ b/vlib/v/tests/interfaces_map_test.v
@@ -19,7 +19,7 @@ fn new_room() &ChatRoom {
 	}
 }
 
-fn (r mut ChatRoom) add(name string, s Speaker) {
+fn (mut r ChatRoom) add(name string, s Speaker) {
 	r.talkers[name] = s
 }
 
diff --git a/vlib/v/vmod/vmod.v b/vlib/v/vmod/vmod.v
index be219ad17a..31bc8515c5 100644
--- a/vlib/v/vmod/vmod.v
+++ b/vlib/v/vmod/vmod.v
@@ -58,7 +58,7 @@ pub fn (mcache &ModFileCacher) dump() {
 	}
 }
 
-pub fn (mcache mut ModFileCacher) get(mfolder string) ModFileAndFolder {
+pub fn (mut mcache ModFileCacher) get(mfolder string) ModFileAndFolder {
 	if mfolder in mcache.cache {
 		return mcache.cache[ mfolder ]
 	}
@@ -69,11 +69,11 @@ pub fn (mcache mut ModFileCacher) get(mfolder string) ModFileAndFolder {
 	return res
 }
 
-fn (cacher mut ModFileCacher) add(path string, result ModFileAndFolder) {
+fn (mut cacher ModFileCacher) add(path string, result ModFileAndFolder) {
 	cacher.cache[ path ] = result
 }
 
-fn (mcache mut ModFileCacher) traverse(mfolder string) ([]string, ModFileAndFolder) {
+fn (mut mcache ModFileCacher) traverse(mfolder string) ([]string, ModFileAndFolder) {
 	mut cfolder := mfolder
 	mut folders_so_far := [cfolder]
 	mut levels := 0
@@ -111,13 +111,13 @@ fn (mcache mut ModFileCacher) traverse(mfolder string) ([]string, ModFileAndFold
 	return [mfolder], ModFileAndFolder{ vmod_file: '', vmod_folder: mfolder }
 }
 
-fn (mcache mut ModFileCacher) mark_folders_with_vmod( folders_so_far []string, vmod ModFileAndFolder ) {
+fn (mut mcache ModFileCacher) mark_folders_with_vmod( folders_so_far []string, vmod ModFileAndFolder ) {
 	for f in folders_so_far {
 		mcache.add( f, vmod )
 	}
 }
 
-fn (mcache mut ModFileCacher) mark_folders_as_vmod_free( folders_so_far []string ) {
+fn (mut mcache ModFileCacher) mark_folders_as_vmod_free( folders_so_far []string ) {
 	// No need to check these folders anymore,
 	// because their parents do not contain v.mod files
 	for f in folders_so_far {
@@ -135,7 +135,7 @@ fn (mcache &ModFileCacher) check_for_stop(cfolder string, files []string) bool {
 	return false
 }
 
-fn (mcache mut ModFileCacher) get_files(cfolder string) []string {
+fn (mut mcache ModFileCacher) get_files(cfolder string) []string {
 	if cfolder in mcache.folder_files {
 		return mcache.folder_files[ cfolder ]
 	}
diff --git a/vlib/vweb/assets/assets.v b/vlib/vweb/assets/assets.v
index f6258a7e3c..bcd9da5612 100644
--- a/vlib/vweb/assets/assets.v
+++ b/vlib/vweb/assets/assets.v
@@ -33,12 +33,12 @@ pub fn new_manager() &AssetManager {
 }
 
 // add_css adds a css asset
-pub fn (am mut AssetManager) add_css(file string) bool {
+pub fn (mut am AssetManager) add_css(file string) bool {
 	return am.add('css', file)
 }
 
 // add_js adds a js asset
-pub fn (am mut AssetManager) add_js(file string) bool {
+pub fn (mut am AssetManager) add_js(file string) bool {
 	return am.add('js', file)
 }
 
@@ -149,8 +149,8 @@ fn (am AssetManager) include(asset_type string, combine bool) string {
 }
 
 // dont return option until size limit is removed
-// fn (am mut AssetManager) add(asset_type, file string) ?bool {
-fn (am mut AssetManager) add(asset_type, file string) bool {
+// fn (mut am AssetManager) add(asset_type, file string) ?bool {
+fn (mut am AssetManager) add(asset_type, file string) bool {
 	if !os.exists(file) {
 		// return error('vweb.assets: cannot add asset $file, it does not exist')
 		return false
diff --git a/vlib/vweb/vweb.v b/vlib/vweb/vweb.v
index bb43a742fe..4384a6baff 100644
--- a/vlib/vweb/vweb.v
+++ b/vlib/vweb/vweb.v
@@ -48,7 +48,7 @@ mut:
 	done bool
 }
 
-fn (ctx mut Context) send_response_to_client(mimetype string, res string) bool {
+fn (mut ctx Context) send_response_to_client(mimetype string, res string) bool {
 	if ctx.done { return false }
 	ctx.done = true
 	mut sb := strings.new_builder(1024)
@@ -63,31 +63,31 @@ fn (ctx mut Context) send_response_to_client(mimetype string, res string) bool {
 	return true
 }
 
-pub fn (ctx mut Context) html(s string) {
+pub fn (mut ctx Context) html(s string) {
 	ctx.send_response_to_client('text/html', s)
 }
 
-pub fn (ctx mut Context) text(s string) {
+pub fn (mut ctx Context) text(s string) {
 	ctx.send_response_to_client('text/plain', s)
 }
 
-pub fn (ctx mut Context) json(s string) {
+pub fn (mut ctx Context) json(s string) {
 	ctx.send_response_to_client('application/json', s)
 }
 
-pub fn (ctx mut Context) redirect(url string) {
+pub fn (mut ctx Context) redirect(url string) {
 	if ctx.done { return }
 	ctx.done = true
 	ctx.conn.send_string('HTTP/1.1 302 Found\r\nLocation: ${url}${ctx.headers}\r\n${HEADERS_CLOSE}') or { return }
 }
 
-pub fn (ctx mut Context) not_found(s string) {
+pub fn (mut ctx Context) not_found(s string) {
 	if ctx.done { return }
 	ctx.done = true
 	ctx.conn.send_string(HTTP_404) or { return }
 }
 
-pub fn (ctx mut Context) set_cookie(key, val string) {
+pub fn (mut ctx Context) set_cookie(key, val string) {
 	// TODO support directives, escape cookie value (https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Set-Cookie)
 	//println('Set-Cookie $key=$val')
 	ctx.add_header('Set-Cookie', '${key}=${val};  Secure; HttpOnly')
@@ -112,7 +112,7 @@ pub fn (ctx &Context) get_cookie(key string) ?string { // TODO refactor
 	return error('Cookie not found')
 }
 
-pub fn (ctx mut Context) add_header(key, val string) {
+pub fn (mut ctx Context) add_header(key, val string) {
 	//println('add_header($key, $val)')
 	ctx.headers = ctx.headers + '\r\n$key: $val'
 	//println(ctx.headers)
@@ -290,7 +290,7 @@ fn handle_conn<T>(conn net.Socket, app mut T) {
 	app.reset()
 }
 
-fn (ctx mut Context) parse_form(s string) {
+fn (mut ctx Context) parse_form(s string) {
 	if ctx.req.method !in methods_with_form {
 		return
 	}
@@ -319,7 +319,7 @@ fn (ctx mut Context) parse_form(s string) {
 	// ...
 }
 
-fn (ctx mut Context) scan_static_directory(directory_path, mount_path string) {
+fn (mut ctx Context) scan_static_directory(directory_path, mount_path string) {
 	files := os.ls(directory_path) or { panic(err) }
 
 	if files.len > 0 {
@@ -340,7 +340,7 @@ fn (ctx mut Context) scan_static_directory(directory_path, mount_path string) {
 	}
 }
 
-pub fn (ctx mut Context) handle_static(directory_path string) bool {
+pub fn (mut ctx Context) handle_static(directory_path string) bool {
 	if ctx.done || ! os.exists(directory_path) {
 		return false
 	}
@@ -358,7 +358,7 @@ pub fn (ctx mut Context) handle_static(directory_path string) bool {
 	return true
 }
 
-pub fn (ctx mut Context) serve_static(url, file_path, mime_type string) {
+pub fn (mut ctx Context) serve_static(url, file_path, mime_type string) {
 	ctx.static_files[url] = file_path
 	ctx.static_mime_types[url] = mime_type
 }