diff --git a/cmd/tools/gen_vc.v b/cmd/tools/gen_vc.v
index f8350d1c2b..4115d8d53d 100644
--- a/cmd/tools/gen_vc.v
+++ b/cmd/tools/gen_vc.v
@@ -177,7 +177,7 @@ pub fn (ws &WebhookServer) reset() {
 
 
 // parse flags to FlagOptions struct
-fn parse_flags(fp mut flag.FlagParser) FlagOptions {
+fn parse_flags(mut fp flag.FlagParser) FlagOptions {
 	return FlagOptions{
 		serve    : fp.bool('serve', 0, false, 'run in webhook server mode')
 		work_dir : fp.string('work-dir', 0, work_dir, 'gen_vc working directory')
diff --git a/cmd/tools/modules/testing/common.v b/cmd/tools/modules/testing/common.v
index 9932a689af..bf79f7d3eb 100644
--- a/cmd/tools/modules/testing/common.v
+++ b/cmd/tools/modules/testing/common.v
@@ -127,7 +127,7 @@ pub fn (mut m TestMessageHandler) display_message() {
 	}
 }
 
-fn worker_trunner(p mut sync.PoolProcessor, idx int, thread_id int) voidptr {
+fn worker_trunner(mut p sync.PoolProcessor, idx int, thread_id int) voidptr {
 	mut ts := &TestSession(p.get_shared_context())
 	defer { ts.message_handler.display_message() }
 	tmpd := os.temp_dir()
diff --git a/cmd/tools/modules/vgit/vgit.v b/cmd/tools/modules/vgit/vgit.v
index 0bfd6c9396..27a89cc9b4 100644
--- a/cmd/tools/modules/vgit/vgit.v
+++ b/cmd/tools/modules/vgit/vgit.v
@@ -142,7 +142,7 @@ pub mut:
 	verbose       bool // should the tool be much more verbose
 }
 
-pub fn add_common_tool_options(context mut VGitOptions, fp mut flag.FlagParser) []string {
+pub fn add_common_tool_options(mut context VGitOptions, mut fp flag.FlagParser) []string {
 	tdir := os.temp_dir()
 	context.workdir = os.real_path(fp.string('workdir', `w`, tdir, 'A writable base folder. Default: $tdir'))
 	context.v_repo_url = fp.string('vrepo', 0, vgit.remote_v_repo_url, 'The url of the V repository. You can clone it locally too. See also --vcrepo below.')
diff --git a/examples/nbody.v b/examples/nbody.v
index 0d434c61ec..98443e2432 100644
--- a/examples/nbody.v
+++ b/examples/nbody.v
@@ -32,7 +32,7 @@ pub mut:
       s []Position
 }
 
-fn advance(sys mut System, dt f64) {
+fn advance(mut sys System, dt f64) {
     for i in 0..c_n - 1 {
         mut vx := sys.v[i].x
         mut vy := sys.v[i].y
@@ -68,7 +68,7 @@ fn advance(sys mut System, dt f64) {
     }
 }
 
-fn offsetmomentum(sys mut System) {
+fn offsetmomentum(mut sys System) {
     mut px := f64(0)
     mut py := f64(0)
     mut pz := f64(0)
diff --git a/examples/pico/pico.v b/examples/pico/pico.v
index 663a5426aa..43b430fdae 100644
--- a/examples/pico/pico.v
+++ b/examples/pico/pico.v
@@ -20,7 +20,7 @@ fn hello_response() string {
 }
 
 
-fn callback(req picohttpparser.Request, res mut picohttpparser.Response) {
+fn callback(req picohttpparser.Request, mut res picohttpparser.Response) {
 	if picohttpparser.cmpn(req.method, 'GET ', 4) {
 		if picohttpparser.cmp(req.path, '/t') {
 			res.http_ok().header_server().header_date().plain().body(hello_response())
diff --git a/examples/quick_sort.v b/examples/quick_sort.v
index d424dbdb81..c92413bf79 100644
--- a/examples/quick_sort.v
+++ b/examples/quick_sort.v
@@ -19,7 +19,7 @@ fn main() {
 	println('after quick sort whether array is sorted: ${is_sorted(arr)}')
 }
 
-fn quick_sort(arr mut []int, l int, r int) {
+fn quick_sort(mut arr []int, l int, r int) {
 	if l>=r { return }
 	mut sep := l  // what is sep: [...all_value<arr[sep]...sep...all_value>=arr[sep]...]
 	for i in l+1..r+1 {
@@ -34,7 +34,7 @@ fn quick_sort(arr mut []int, l int, r int) {
 }
 
 [inline]
-fn swap(arr mut []int, i int, j int) {
+fn swap(mut arr []int, i int, j int) {
 	temp := arr[i]
 	arr[i] = arr[j]
 	arr[j] = temp
diff --git a/examples/sokol/fonts.v b/examples/sokol/fonts.v
index fa99a11161..2b79d5c66a 100644
--- a/examples/sokol/fonts.v
+++ b/examples/sokol/fonts.v
@@ -38,7 +38,7 @@ fn main() {
 	sapp.run(&desc)
 }
 
-fn init(state mut AppState) {
+fn init(mut state AppState) {
 	// dont actually alocate this on the heap in real life
 	gfx.setup(&C.sg_desc{
 		mtl_device: sapp.metal_get_device()
diff --git a/examples/spectral.v b/examples/spectral.v
index 02ba22cd3a..63efb57e50 100644
--- a/examples/spectral.v
+++ b/examples/spectral.v
@@ -18,7 +18,7 @@ fn evala(i, j int) int {
 	return ((i + j) * (i + j + 1) / 2 + i + 1)
 }
 
-fn times(v mut []f64, u []f64) {
+fn times(mut v []f64, u []f64) {
 	for i in 0..v.len {
 		mut a := f64(0)
 		for j in 0..u.len {
@@ -28,7 +28,7 @@ fn times(v mut []f64, u []f64) {
 	}
 }
 
-fn times_trans(v mut []f64, u []f64) {
+fn times_trans(mut v []f64, u []f64) {
 	for i in 0..v.len {
 		mut a := f64(0)
 		for j in 0..u.len {
@@ -38,7 +38,7 @@ fn times_trans(v mut []f64, u []f64) {
 	}
 }
 
-fn a_times_transp(v mut []f64, u []f64) {
+fn a_times_transp(mut v []f64, u []f64) {
 	mut x := []f64{len:u.len, init:0}
 	times(mut x, u)
 	times_trans(mut v, x)
@@ -69,4 +69,3 @@ fn main() {
 	ans := math.sqrt(vbv / vv)
 	println('${ans:0.9f}')
 }
-
diff --git a/examples/tetris/tetris.v b/examples/tetris/tetris.v
index 463bc7c629..04cb3b755e 100644
--- a/examples/tetris/tetris.v
+++ b/examples/tetris/tetris.v
@@ -402,7 +402,7 @@ fn parse_binary_tetro(t_ int) []Block {
 	return res
 }
 
-fn on_event(e &sapp.Event, game mut Game) {
+fn on_event(e &sapp.Event, mut game Game) {
 	if e.typ == .key_down {
 		game.key_down(e.key_code)
 	}
diff --git a/vlib/builtin/array_test.v b/vlib/builtin/array_test.v
index dfa510433e..62d35433dc 100644
--- a/vlib/builtin/array_test.v
+++ b/vlib/builtin/array_test.v
@@ -311,7 +311,7 @@ fn test_fixed() {
 	assert nums2[c_n - 1] == 0
 }
 
-fn modify(numbers mut []int) {
+fn modify(mut numbers []int) {
 	numbers[0] = 777
 }
 
@@ -328,13 +328,13 @@ fn test_mut_slice() {
 	*/
 }
 
-fn double_up(a mut []int) {
+fn double_up(mut a []int) {
 	for i := 0; i < a.len; i++ {
 		a[i] = a[i]*2
 	}
 }
 
-fn double_up_v2(a mut []int) {
+fn double_up_v2(mut a []int) {
 	for i, _ in a {
 		a[i] = a[i]*2 // or val*2, doesn't matter
 	}
diff --git a/vlib/builtin/map_test.v b/vlib/builtin/map_test.v
index 0b4a44eaf3..810d0c5463 100644
--- a/vlib/builtin/map_test.v
+++ b/vlib/builtin/map_test.v
@@ -160,7 +160,7 @@ fn test_string_arr() {
 	assert m['a'][1] == 'two'
 }
 
-fn mut_map(m mut map[string]int) {
+fn mut_map(mut m map[string]int) {
 	m['a'] = 10
 }
 
diff --git a/vlib/builtin/sorted_map.v b/vlib/builtin/sorted_map.v
index 2e35c7ee57..4b92ca2b7b 100644
--- a/vlib/builtin/sorted_map.v
+++ b/vlib/builtin/sorted_map.v
@@ -112,7 +112,7 @@ fn (mut m SortedMap) set(key string, value voidptr) {
 	}
 }
 
-fn (mut n mapnode) split_child(child_index int, y mut mapnode) {
+fn (mut n mapnode) split_child(child_index int, mut y mapnode) {
 	mut z := new_node()
 	z.size = mid_index
 	y.size = mid_index
@@ -353,7 +353,7 @@ pub fn (mut m SortedMap) delete(key string) {
 
 // Insert all keys of the subtree into array `keys`
 // starting at `at`. Keys are inserted in order.
-fn (n &mapnode) subkeys(keys mut []string, at int) int {
+fn (n &mapnode) subkeys(mut keys []string, at int) int {
 	mut position := at
 	if !isnil(n.children) {
 		// Traverse children and insert
diff --git a/vlib/crypto/aes/aes_cbc.v b/vlib/crypto/aes/aes_cbc.v
index 99ef4e8418..9694bc7c87 100644
--- a/vlib/crypto/aes/aes_cbc.v
+++ b/vlib/crypto/aes/aes_cbc.v
@@ -46,7 +46,7 @@ pub fn new_cbc(b AesCipher, iv []byte) AesCbc {
 
 pub fn (x &AesCbc) block_size() int { return x.block_size }
 
-pub fn (x &AesCbc) encrypt_blocks(dst mut []byte, src_ []byte) {
+pub fn (x &AesCbc) encrypt_blocks(mut dst []byte, src_ []byte) {
 	mut src := src_
 	if src.len%x.block_size != 0 {
 		panic('crypto.cipher: input not full blocks')
@@ -79,7 +79,7 @@ pub fn (x &AesCbc) encrypt_blocks(dst mut []byte, src_ []byte) {
 	copy(x.iv, iv)
 }
 
-pub fn (mut x AesCbc) decrypt_blocks(dst mut []byte, src []byte) {
+pub fn (mut x AesCbc) decrypt_blocks(mut dst []byte, src []byte) {
 	if src.len%x.block_size != 0 {
 		panic('crypto.cipher: input not full blocks')
 	}
diff --git a/vlib/crypto/aes/block_generic.v b/vlib/crypto/aes/block_generic.v
index f3f833d97d..6b63937917 100644
--- a/vlib/crypto/aes/block_generic.v
+++ b/vlib/crypto/aes/block_generic.v
@@ -156,7 +156,7 @@ fn rotw(w u32) u32 { return (w<<8) | (w>>24) }
 
 // Key expansion algorithm. See FIPS-197, Figure 11.
 // Their rcon[i] is our powx[i-1] << 24.
-fn expand_key_generic(key []byte, enc mut []u32, dec mut []u32) {
+fn expand_key_generic(key []byte, mut enc []u32, mut dec []u32) {
 	// Encryption key setup.
 	mut i := 0
 	nk := key.len / 4
diff --git a/vlib/crypto/cipher/xor_generic.v b/vlib/crypto/cipher/xor_generic.v
index d93336b7b9..71ae4f010b 100644
--- a/vlib/crypto/cipher/xor_generic.v
+++ b/vlib/crypto/cipher/xor_generic.v
@@ -8,7 +8,7 @@ module cipher
 
 // xor_bytes xors the bytes in a and b. The destination should have enough
 // space, otherwise xor_bytes will panic. Returns the number of bytes xor'd.
-pub fn xor_bytes(dst mut []byte, a, b []byte) int {
+pub fn xor_bytes(mut dst []byte, a, b []byte) int {
 	mut n := a.len
 	if b.len < n {
 		n = b.len
@@ -23,7 +23,7 @@ pub fn xor_bytes(dst mut []byte, a, b []byte) int {
 }
 
 // n needs to be smaller or equal than the length of a and b.
-pub fn safe_xor_bytes(dst mut []byte, a, b []byte, n int) {
+pub fn safe_xor_bytes(mut dst []byte, a, b []byte, n int) {
 	for i in 0..n {
 		dst[i] = a[i] ^ b[i]
 	}
@@ -31,6 +31,6 @@ pub fn safe_xor_bytes(dst mut []byte, a, b []byte, n int) {
 
 // fast_xor_words XORs multiples of 4 or 8 bytes (depending on architecture.)
 // The slice arguments a and b are assumed to be of equal length.
-pub fn xor_words(dst mut []byte, a, b []byte) {
+pub fn xor_words(mut dst []byte, a, b []byte) {
 	safe_xor_bytes(mut dst, a, b, b.len)
 }
diff --git a/vlib/crypto/md5/md5.v b/vlib/crypto/md5/md5.v
index 396d012cab..d822175200 100644
--- a/vlib/crypto/md5/md5.v
+++ b/vlib/crypto/md5/md5.v
@@ -133,7 +133,7 @@ pub fn sum(data []byte) []byte {
 	return d.checksum()
 }
 
-fn block(dig mut Digest, p []byte) {
+fn block(mut dig Digest, p []byte) {
     // For now just use block_generic until we have specific
 	// architecture optimized versions
     block_generic(mut dig, p)
diff --git a/vlib/crypto/md5/md5block_generic.v b/vlib/crypto/md5/md5block_generic.v
index f2eaabcef6..f381bd6709 100644
--- a/vlib/crypto/md5/md5block_generic.v
+++ b/vlib/crypto/md5/md5block_generic.v
@@ -11,7 +11,7 @@ module md5
 import math.bits
 import encoding.binary
 
-fn block_generic(dig mut Digest, p []byte) {
+fn block_generic(mut dig Digest, p []byte) {
 	// load state
 	mut a := dig.s[0]
 	mut b := dig.s[1]
diff --git a/vlib/crypto/rc4/rc4.v b/vlib/crypto/rc4/rc4.v
index 4c7d2f3d63..2f97c560bb 100644
--- a/vlib/crypto/rc4/rc4.v
+++ b/vlib/crypto/rc4/rc4.v
@@ -59,7 +59,7 @@ pub fn (mut c 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 (mut c Cipher) xor_key_stream(dst mut []byte, src []byte) {
+pub fn (mut c Cipher) xor_key_stream(mut dst []byte, src []byte) {
 	if src.len == 0 {
 		return
 	}
diff --git a/vlib/crypto/sha1/sha1block_generic.v b/vlib/crypto/sha1/sha1block_generic.v
index 8258f98a68..55d7a1f1fe 100644
--- a/vlib/crypto/sha1/sha1block_generic.v
+++ b/vlib/crypto/sha1/sha1block_generic.v
@@ -17,7 +17,7 @@ const (
 	_k3 = 0xCA62C1D6
 )
 
-fn block_generic(dig mut Digest, p_ []byte) {
+fn block_generic(mut dig Digest, p_ []byte) {
 	mut p := p_
 	mut w := [u32(0)].repeat(16)
 	mut h0 := dig.h[0]
@@ -113,7 +113,7 @@ fn block_generic(dig mut Digest, p_ []byte) {
 		} else {
 			p = p[chunk..]
 		}
-		
+
 	}
 
 	dig.h[0] = h0
diff --git a/vlib/crypto/sha256/sha256.v b/vlib/crypto/sha256/sha256.v
index f39dbacba8..5aa34ec382 100644
--- a/vlib/crypto/sha256/sha256.v
+++ b/vlib/crypto/sha256/sha256.v
@@ -199,7 +199,7 @@ pub fn sum224(data []byte) []byte {
 	return sum224
 }
 
-fn block(dig mut Digest, p []byte) {
+fn block(mut dig Digest, p []byte) {
 	// For now just use block_generic until we have specific
 	// architecture optimized versions
 	block_generic(mut dig, p)
diff --git a/vlib/crypto/sha256/sha256block_generic.v b/vlib/crypto/sha256/sha256block_generic.v
index 12328b240c..dafc014364 100644
--- a/vlib/crypto/sha256/sha256block_generic.v
+++ b/vlib/crypto/sha256/sha256block_generic.v
@@ -80,11 +80,11 @@ const (
 	]
 )
 
-fn block_generic(dig mut Digest, p_ []byte) {
+fn block_generic(mut dig Digest, p_ []byte) {
 	mut p := p_
 
 	mut w := [u32(0)].repeat(64)
-	
+
 	mut h0 := dig.h[0]
 	mut h1 := dig.h[1]
 	mut h2 := dig.h[2]
diff --git a/vlib/crypto/sha512/sha512.v b/vlib/crypto/sha512/sha512.v
index 377481ad68..3e87dac01d 100644
--- a/vlib/crypto/sha512/sha512.v
+++ b/vlib/crypto/sha512/sha512.v
@@ -279,7 +279,7 @@ pub fn sum512_256(data []byte) []byte {
 	return sum256
 }
 
-fn block(dig mut Digest, p []byte) {
+fn block(mut dig Digest, p []byte) {
 	// For now just use block_generic until we have specific
 	// architecture optimized versions
 	block_generic(mut dig, p)
diff --git a/vlib/crypto/sha512/sha512block_generic.v b/vlib/crypto/sha512/sha512block_generic.v
index fcb36f5f14..9b90960ddf 100644
--- a/vlib/crypto/sha512/sha512block_generic.v
+++ b/vlib/crypto/sha512/sha512block_generic.v
@@ -93,7 +93,7 @@ const (
 	]
 )
 
-fn block_generic(dig mut Digest, p_ []byte) {
+fn block_generic(mut dig Digest, p_ []byte) {
 	mut p := p_
 	mut w := [u64(0)].repeat(80)
 	mut h0 := dig.h[0]
@@ -160,4 +160,3 @@ fn block_generic(dig mut Digest, p_ []byte) {
 	dig.h[6] = h6
 	dig.h[7] = h7
 }
-
diff --git a/vlib/encoding/binary/binary.v b/vlib/encoding/binary/binary.v
index 8ef0e0f6eb..e649cfaf6b 100644
--- a/vlib/encoding/binary/binary.v
+++ b/vlib/encoding/binary/binary.v
@@ -10,7 +10,7 @@ pub fn little_endian_u16(b []byte) u16 {
 }
 
 [inline]
-pub fn little_endian_put_u16(b mut []byte, v u16) {
+pub fn little_endian_put_u16(mut b []byte, v u16) {
 	_ = b[1] // bounds check
 	b[0] = byte(v)
 	b[1] = byte(v>>u16(8))
@@ -23,7 +23,7 @@ pub fn little_endian_u32(b []byte) u32 {
 }
 
 [inline]
-pub fn little_endian_put_u32(b mut []byte, v u32) {
+pub fn little_endian_put_u32(mut b []byte, v u32) {
 	_ = b[3] // bounds check
 	b[0] = byte(v)
 	b[1] = byte(v>>u32(8))
@@ -38,7 +38,7 @@ pub fn little_endian_u64(b []byte) u64 {
 }
 
 [inline]
-pub fn little_endian_put_u64(b mut []byte, v u64) {
+pub fn little_endian_put_u64(mut b []byte, v u64) {
 	_ = b[7] // bounds check
 	b[0] = byte(v)
 	b[1] = byte(v>>u64(8))
@@ -58,7 +58,7 @@ pub fn big_endian_u16(b []byte) u16 {
 }
 
 [inline]
-pub fn big_endian_put_u16(b mut []byte, v u16) {
+pub fn big_endian_put_u16(mut b []byte, v u16) {
 	_ = b[1] // bounds check
 	b[0] = byte(v>>u16(8))
 	b[1] = byte(v)
@@ -71,7 +71,7 @@ pub fn big_endian_u32(b []byte) u32 {
 }
 
 [inline]
-pub fn big_endian_put_u32(b mut []byte, v u32) {
+pub fn big_endian_put_u32(mut b []byte, v u32) {
 	_ = b[3] // bounds check
 	b[0] = byte(v>>u32(24))
 	b[1] = byte(v>>u32(16))
@@ -86,7 +86,7 @@ pub fn big_endian_u64(b []byte) u64 {
 }
 
 [inline]
-pub fn big_endian_put_u64(b mut []byte, v u64) {
+pub fn big_endian_put_u64(mut b []byte, v u64) {
 	_ = b[7] // bounds check
 	b[0] = byte(v>>u64(56))
 	b[1] = byte(v>>u64(48))
@@ -97,4 +97,3 @@ pub fn big_endian_put_u64(b mut []byte, v u64) {
 	b[6] = byte(v>>u64(8))
 	b[7] = byte(v)
 }
-
diff --git a/vlib/glm/glm.v b/vlib/glm/glm.v
index 40b5c3878d..e55cf5fa5b 100644
--- a/vlib/glm/glm.v
+++ b/vlib/glm/glm.v
@@ -315,7 +315,7 @@ pub fn rotate(angle f32, axis Vec3, src Mat4) Mat4 {
 	dest[10] = data[2] * f20 + data[6] * f21 + data[10] * f22
 	dest[11] = data[3] * f20 + data[7] * f21 + data[11] * f22
 
-	dest[0] = t00	dest[1] = t01	dest[2] = t02	dest[3] = t03 
+	dest[0] = t00	dest[1] = t01	dest[2] = t02	dest[3] = t03
 	dest[4] = t10	dest[5] = t11	dest[6] = t12	dest[7] = t13
 
 	return mat4(dest)
@@ -370,7 +370,7 @@ pub fn identity() Mat4 {
 }
 
 // returns *f32 without allocation
-pub fn identity2(res mut &f32) {
+pub fn identity2(mut res &f32) {
 	res[0] = 1
 	res[5] = 1
 	res[10] = 1
diff --git a/vlib/live/executable/reloader.v b/vlib/live/executable/reloader.v
index 1f0677ab68..ac17dc0243 100644
--- a/vlib/live/executable/reloader.v
+++ b/vlib/live/executable/reloader.v
@@ -31,7 +31,7 @@ pub fn new_live_reload_info(original string, vexe string, vopts string, live_fn_
 // NB: start_reloader will be called by generated code inside main(), to start
 // the hot code reloader thread. start_reloader is executed in the context of
 // the original main thread.
-pub fn start_reloader(r mut live.LiveReloadInfo) {
+pub fn start_reloader(mut r live.LiveReloadInfo) {
 	// The shared library should be loaded once in the main thread
 	// If that fails, the program would crash anyway, just provide
 	// an error message to the user and exit:
@@ -48,7 +48,7 @@ fn elog(r &live.LiveReloadInfo, s string){
 	eprintln(s)
 }
 
-fn compile_and_reload_shared_lib(r mut live.LiveReloadInfo) ?bool {
+fn compile_and_reload_shared_lib(mut r live.LiveReloadInfo) ?bool {
 	sw := time.new_stopwatch({})
 	new_lib_path := compile_lib(mut r) or {
 		return error('errors while compiling $r.original')
@@ -59,7 +59,7 @@ fn compile_and_reload_shared_lib(r mut live.LiveReloadInfo) ?bool {
 	return true
 }
 
-fn compile_lib(r mut live.LiveReloadInfo) ?string {
+fn compile_lib(mut r live.LiveReloadInfo) ?string {
 	new_lib_path, new_lib_path_with_extension := current_shared_library_path(mut r)
 	cmd := '$r.vexe $r.vopts -o $new_lib_path $r.original'
 	elog(r,'>       compilation cmd: $cmd')
@@ -81,13 +81,13 @@ fn compile_lib(r mut live.LiveReloadInfo) ?string {
 	return new_lib_path_with_extension
 }
 
-fn current_shared_library_path(r mut live.LiveReloadInfo) (string, string) {
+fn current_shared_library_path(mut r live.LiveReloadInfo) (string, string) {
 	lib_path := strconv.v_sprintf(r.so_name_template.replace('\\', '\\\\'), r.reloads)
 	lib_path_with_extension := lib_path + r.so_extension
 	return lib_path, lib_path_with_extension
 }
 
-fn load_lib(r mut live.LiveReloadInfo, new_lib_path string) {
+fn load_lib(mut r live.LiveReloadInfo, new_lib_path string) {
 	elog(r,'live mutex locking...')
 	C.pthread_mutex_lock(r.live_fn_mutex)
 	elog(r,'live mutex locked')
@@ -108,7 +108,7 @@ fn load_lib(r mut live.LiveReloadInfo, new_lib_path string) {
 	elog(r,'live mutex unlocked')
 }
 
-fn protected_load_lib(r mut live.LiveReloadInfo, new_lib_path string) {
+fn protected_load_lib(mut r live.LiveReloadInfo, new_lib_path string) {
 	if r.live_lib != 0 {
 		dl.close( r.live_lib )
 		r.live_lib = 0
@@ -126,7 +126,7 @@ fn protected_load_lib(r mut live.LiveReloadInfo, new_lib_path string) {
 }
 
 // NB: r.reloader() is executed in a new, independent thread
-fn reloader(r mut live.LiveReloadInfo) {
+fn reloader(mut r live.LiveReloadInfo) {
 //	elog(r,'reloader, r: $r')
 	mut last_ts := os.file_last_mod_unix( r.original )
 	for {
diff --git a/vlib/net/urllib/urllib.v b/vlib/net/urllib/urllib.v
index be1cfefc7c..d22d69953a 100644
--- a/vlib/net/urllib/urllib.v
+++ b/vlib/net/urllib/urllib.v
@@ -836,7 +836,7 @@ fn parse_query_silent(query string) Values {
 	return m
 }
 
-fn parse_query_values(m mut Values, query string) ?bool {
+fn parse_query_values(mut m Values, query string) ?bool {
 	mut had_error := false
 	mut q := query
 	for q != '' {
diff --git a/vlib/net/websocket/examples/client.v b/vlib/net/websocket/examples/client.v
index 33f9d8d902..7bf4a0a44d 100644
--- a/vlib/net/websocket/examples/client.v
+++ b/vlib/net/websocket/examples/client.v
@@ -95,7 +95,7 @@ fn on_message(sender voidptr, mut ws websocket.Client, msg websocket.Message) {
 	}
 }
 
-fn start_tests(ws mut websocket.Client, num int) {
+fn start_tests(mut ws websocket.Client, num int) {
 	for i := 1; i < num; i++ {
 		println('Running test: ' + i.str())
 		ws.uri = 'ws://localhost:9001/runCase?case=${i.str()}&agent=vws/1.0a'
diff --git a/vlib/picoev/picoev.v b/vlib/picoev/picoev.v
index 230003e0a1..cb25a6d641 100644
--- a/vlib/picoev/picoev.v
+++ b/vlib/picoev/picoev.v
@@ -64,7 +64,7 @@ struct C.picoev_loop {}
 
 struct Picoev {
 	loop &C.picoev_loop
-	cb   fn(req picohttpparser.Request, res mut picohttpparser.Response)
+	cb   fn(req picohttpparser.Request, mut res picohttpparser.Response)
 mut:
 	date byteptr
 	buf  byteptr
@@ -229,7 +229,7 @@ pub fn (p Picoev) serve() {
 	}
 }
 
-fn update_date(p mut Picoev) {
+fn update_date(mut p Picoev) {
 	for {
 		p.date = C.get_date()
 		C.usleep(1000000)
diff --git a/vlib/strconv/atof.v b/vlib/strconv/atof.v
index 1c0f60a945..eca5aa217a 100644
--- a/vlib/strconv/atof.v
+++ b/vlib/strconv/atof.v
@@ -360,7 +360,7 @@ fn parser(s string) (int,PrepNumber) {
 **********************************************************************/
 
 // converter return a u64 with the bit image of the f64 number
-fn converter(pn mut PrepNumber) u64 {
+fn converter(mut pn PrepNumber) u64 {
 	mut binexp := 92
 	mut s2 := u32(0) // 96-bit precision integer
 	mut s1 := u32(0)
diff --git a/vlib/sync/pool.v b/vlib/sync/pool.v
index 52ed9b08e9..7e2cb5834d 100644
--- a/vlib/sync/pool.v
+++ b/vlib/sync/pool.v
@@ -124,7 +124,7 @@ pub fn (mut pool PoolProcessor) work_on_pointers(items []voidptr) {
 // process_in_thread does the actual work of worker thread.
 // It is a workaround for the current inability to pass a
 // method in a callback.
-fn process_in_thread(pool mut PoolProcessor, task_id int) {
+fn process_in_thread(mut pool PoolProcessor, task_id int) {
 	cb := ThreadCB(pool.thread_cb)
 	mut idx := 0
 	ilen := pool.items.len
diff --git a/vlib/v/fmt/fmt.v b/vlib/v/fmt/fmt.v
index 9ac5ccbb93..afe355ece0 100644
--- a/vlib/v/fmt/fmt.v
+++ b/vlib/v/fmt/fmt.v
@@ -64,7 +64,7 @@ pub fn fmt(file ast.File, table &table.Table, is_debug bool) string {
 }
 
 /*
-fn (f mut Fmt) find_comment(line_nr int) {
+fn (mut f Fmt) find_comment(line_nr int) {
 	for comment in f.file.comments {
 		if comment.line_nr == line_nr {
 			f.writeln('// FFF $comment.line_nr $comment.text')
diff --git a/vlib/v/pref/pref.v b/vlib/v/pref/pref.v
index 9c1cd6db77..f719ad170c 100644
--- a/vlib/v/pref/pref.v
+++ b/vlib/v/pref/pref.v
@@ -327,7 +327,7 @@ pub fn backend_from_string(s string) ?Backend {
 	}
 }
 
-fn parse_define(prefs mut Preferences, define string) {
+fn parse_define(mut prefs Preferences, define string) {
     define_parts := define.split('=')
     if define_parts.len == 1 {
         prefs.compile_defines << define
diff --git a/vlib/v/tests/defer_test.v b/vlib/v/tests/defer_test.v
index b0e48870d2..684dc9f6e7 100644
--- a/vlib/v/tests/defer_test.v
+++ b/vlib/v/tests/defer_test.v
@@ -19,7 +19,7 @@ fn test_defer() {
 	assert foo2() == 'foo'
 }
 
-fn set_num(i int, n mut Num) {
+fn set_num(i int, mut n Num) {
 	defer {
 		println('exiting')
 		n.val++
@@ -33,7 +33,7 @@ fn set_num(i int, n mut Num) {
 	}
 }
 
-fn set_num_opt(n mut Num) ?int {
+fn set_num_opt(mut n Num) ?int {
 	defer {
 		n.val = 1
 	}
diff --git a/vlib/v/tests/mut_test.v b/vlib/v/tests/mut_test.v
index 3b3b4437b6..f4e5f02c74 100644
--- a/vlib/v/tests/mut_test.v
+++ b/vlib/v/tests/mut_test.v
@@ -8,7 +8,7 @@ pub mut:
 	a []Aaa
 }
 
-fn foo(b int, a mut []int) {
+fn foo(b int, mut a []int) {
 	a[0] = 7
 	// a << 4
 }
diff --git a/vlib/v/tests/repl/repl_test.v b/vlib/v/tests/repl/repl_test.v
index e81ba8b4f3..e4858a7a12 100644
--- a/vlib/v/tests/repl/repl_test.v
+++ b/vlib/v/tests/repl/repl_test.v
@@ -53,7 +53,7 @@ fn test_all_v_repl_files() {
 	println(session.bmark.total_message('total time spent running REPL files'))
 }
 
-fn worker_repl(p mut sync.PoolProcessor, idx int, thread_id int) voidptr {
+fn worker_repl(mut p sync.PoolProcessor, idx int, thread_id int) voidptr {
 	cdir := os.cache_dir()
 	mut session := &Session(p.get_shared_context())
 	mut tls_bench := &benchmark.Benchmark(p.get_thread_context(idx))