diff --git a/autoload/ale.vim b/autoload/ale.vim
index b25bcc9..44cd582 100644
--- a/autoload/ale.vim
+++ b/autoload/ale.vim
@@ -10,8 +10,8 @@ function! ale#Queue(delay) abort
         let s:lint_timer = -1
     endif
 
-    let linters = ale#linter#Get(&filetype)
-    if len(linters) == 0
+    let l:linters = ale#linter#Get(&filetype)
+    if len(l:linters) == 0
         " There are no linters to lint with, so stop here.
         return
     endif
@@ -24,18 +24,18 @@ function! ale#Queue(delay) abort
 endfunction
 
 function! ale#Lint(...) abort
-    let buffer = bufnr('%')
-    let linters = ale#linter#Get(&filetype)
+    let l:buffer = bufnr('%')
+    let l:linters = ale#linter#Get(&filetype)
 
     " Set a variable telling us to clear the loclist later.
-    let g:ale_buffer_should_reset_map[buffer] = 1
+    let g:ale_buffer_should_reset_map[l:buffer] = 1
 
-    for linter in linters
+    for l:linter in l:linters
         " Check if a given linter has a program which can be executed.
-        if has_key(linter, 'executable_callback')
-            let l:executable = ale#util#GetFunction(linter.executable_callback)(buffer)
+        if has_key(l:linter, 'executable_callback')
+            let l:executable = ale#util#GetFunction(l:linter.executable_callback)(l:buffer)
         else
-            let l:executable = linter.executable
+            let l:executable = l:linter.executable
         endif
 
         if !executable(l:executable)
@@ -43,6 +43,6 @@ function! ale#Lint(...) abort
             continue
         endif
 
-        call ale#engine#Invoke(buffer, linter)
+        call ale#engine#Invoke(l:buffer, l:linter)
     endfor
 endfunction
diff --git a/autoload/ale/cursor.vim b/autoload/ale/cursor.vim
index 71112b1..0c5844e 100644
--- a/autoload/ale/cursor.vim
+++ b/autoload/ale/cursor.vim
@@ -3,73 +3,73 @@
 
 " Return a formatted message according to g:ale_echo_msg_format variable
 function! s:GetMessage(linter, type, text) abort
-    let msg = g:ale_echo_msg_format
-    let type = a:type ==# 'E'
+    let l:msg = g:ale_echo_msg_format
+    let l:type = a:type ==# 'E'
     \   ? g:ale_echo_msg_error_str
     \   : g:ale_echo_msg_warning_str
     " Capitalize the 1st character
-    let text = toupper(a:text[0]) . a:text[1:-1]
+    let l:text = toupper(a:text[0]) . a:text[1:-1]
 
     " Replace handlers if they exist
-    for [k, v] in items({'linter': a:linter, 'severity': type})
-        let msg = substitute(msg, '\V%' . k . '%', v, '')
+    for [l:k, l:v] in items({'linter': a:linter, 'severity': l:type})
+        let l:msg = substitute(l:msg, '\V%' . l:k . '%', l:v, '')
     endfor
 
-    return printf(msg, text)
+    return printf(l:msg, l:text)
 endfunction
 
 " This function will perform a binary search to find a message from the
 " loclist to echo when the cursor moves.
 function! s:BinarySearch(loclist, line, column) abort
-    let min = 0
-    let max = len(a:loclist) - 1
-    let last_column_match = -1
+    let l:min = 0
+    let l:max = len(a:loclist) - 1
+    let l:last_column_match = -1
 
     while 1
-        if max < min
-            return last_column_match
+        if l:max < l:min
+            return l:last_column_match
         endif
 
-        let mid = (min + max) / 2
-        let obj = a:loclist[mid]
+        let l:mid = (l:min + l:max) / 2
+        let l:obj = a:loclist[l:mid]
 
         " Binary search to get on the same line
-        if a:loclist[mid]['lnum'] < a:line
-            let min = mid + 1
-        elseif a:loclist[mid]['lnum'] > a:line
-            let max = mid - 1
+        if a:loclist[l:mid]['lnum'] < a:line
+            let l:min = l:mid + 1
+        elseif a:loclist[l:mid]['lnum'] > a:line
+            let l:max = l:mid - 1
         else
-            let last_column_match = mid
+            let l:last_column_match = l:mid
 
             " Binary search to get the same column, or near it
-            if a:loclist[mid]['col'] < a:column
-                let min = mid + 1
-            elseif a:loclist[mid]['col'] > a:column
-                let max = mid - 1
+            if a:loclist[l:mid]['col'] < a:column
+                let l:min = l:mid + 1
+            elseif a:loclist[l:mid]['col'] > a:column
+                let l:max = l:mid - 1
             else
-                return mid
+                return l:mid
             endif
         endif
     endwhile
 endfunction
 
 function! ale#cursor#TruncatedEcho(message) abort
-    let message = a:message
+    let l:message = a:message
     " Change tabs to spaces.
-    let message = substitute(message, "\t", ' ', 'g')
+    let l:message = substitute(l:message, "\t", ' ', 'g')
     " Remove any newlines in the message.
-    let message = substitute(message, "\n", '', 'g')
+    let l:message = substitute(l:message, "\n", '', 'g')
 
     " We need to turn T for truncated messages on for shortmess,
     " and then then we need to reset the option back to what it was.
-    let shortmess_options = getbufvar('%', '&shortmess')
+    let l:shortmess_options = getbufvar('%', '&shortmess')
 
     try
         " Echo the message truncated to fit without creating a prompt.
         setlocal shortmess+=T
         exec "norm :echomsg message\n"
     finally
-        call setbufvar('%', '&shortmess', shortmess_options)
+        call setbufvar('%', '&shortmess', l:shortmess_options)
     endtry
 endfunction
 
@@ -79,22 +79,20 @@ function! ale#cursor#EchoCursorWarning(...) abort
         return
     endif
 
-    let buffer = bufnr('%')
+    let l:buffer = bufnr('%')
 
-    if !has_key(g:ale_buffer_loclist_map, buffer)
+    if !has_key(g:ale_buffer_loclist_map, l:buffer)
         return
     endif
 
-    let loclist = g:ale_buffer_loclist_map[buffer]
+    let l:pos = getcurpos()
+    let l:loclist = g:ale_buffer_loclist_map[l:buffer]
+    let l:index = s:BinarySearch(l:loclist, l:pos[1], l:pos[2])
 
-    let pos = getcurpos()
-
-    let index = s:BinarySearch(loclist, pos[1], pos[2])
-
-    if index >= 0
-        let l = loclist[index]
-        let msg = s:GetMessage(l.linter_name, l.type, l.text)
-        call ale#cursor#TruncatedEcho(msg)
+    if l:index >= 0
+        let l:loc = l:loclist[l:index]
+        let l:msg = s:GetMessage(l:loc.linter_name, l:loc.type, l:loc.text)
+        call ale#cursor#TruncatedEcho(l:msg)
     else
         echo
     endif
diff --git a/autoload/ale/engine.vim b/autoload/ale/engine.vim
index c56e1c3..7342a54 100644
--- a/autoload/ale/engine.vim
+++ b/autoload/ale/engine.vim
@@ -21,8 +21,8 @@ function! s:GetJobID(job) abort
 endfunction
 
 function! s:ClearJob(job) abort
-    let job_id = s:GetJobID(a:job)
-    let linter = s:job_info_map[job_id].linter
+    let l:job_id = s:GetJobID(a:job)
+    let l:linter = s:job_info_map[l:job_id].linter
 
     if has('nvim')
         call jobstop(a:job)
@@ -36,18 +36,18 @@ function! s:ClearJob(job) abort
         call job_stop(a:job)
     endif
 
-    call remove(s:job_info_map, job_id)
-    call remove(linter, 'job')
+    call remove(s:job_info_map, l:job_id)
+    call remove(l:linter, 'job')
 endfunction
 
 function! s:GatherOutput(job, data) abort
-    let job_id = s:GetJobID(a:job)
+    let l:job_id = s:GetJobID(a:job)
 
-    if !has_key(s:job_info_map, job_id)
+    if !has_key(s:job_info_map, l:job_id)
         return
     endif
 
-    call extend(s:job_info_map[job_id].output, a:data)
+    call extend(s:job_info_map[l:job_id].output, a:data)
 endfunction
 
 function! s:GatherOutputVim(channel, data) abort
@@ -64,48 +64,48 @@ function! s:HandleExit(job) abort
         return
     endif
 
-    let job_id = s:GetJobID(a:job)
+    let l:job_id = s:GetJobID(a:job)
 
-    if !has_key(s:job_info_map, job_id)
+    if !has_key(s:job_info_map, l:job_id)
         return
     endif
 
-    let job_info = s:job_info_map[job_id]
+    let l:job_info = s:job_info_map[l:job_id]
 
     call s:ClearJob(a:job)
 
-    let linter = job_info.linter
-    let output = job_info.output
-    let buffer = job_info.buffer
+    let l:linter = l:job_info.linter
+    let l:output = l:job_info.output
+    let l:buffer = l:job_info.buffer
 
-    let linter_loclist = ale#util#GetFunction(linter.callback)(buffer, output)
+    let l:linter_loclist = ale#util#GetFunction(l:linter.callback)(l:buffer, l:output)
 
     " Make some adjustments to the loclists to fix common problems.
-    call s:FixLocList(buffer, linter_loclist)
+    call s:FixLocList(l:buffer, l:linter_loclist)
 
-    for item in linter_loclist
-        let item.linter_name = linter.name
+    for l:item in l:linter_loclist
+        let l:item.linter_name = l:linter.name
     endfor
 
-    if g:ale_buffer_should_reset_map[buffer]
-        let g:ale_buffer_should_reset_map[buffer] = 0
-        let g:ale_buffer_loclist_map[buffer] = []
+    if g:ale_buffer_should_reset_map[l:buffer]
+        let g:ale_buffer_should_reset_map[l:buffer] = 0
+        let g:ale_buffer_loclist_map[l:buffer] = []
     endif
 
     " Add the loclist items from the linter.
-    call extend(g:ale_buffer_loclist_map[buffer], linter_loclist)
+    call extend(g:ale_buffer_loclist_map[l:buffer], l:linter_loclist)
 
     " Sort the loclist again.
     " We need a sorted list so we can run a binary search against it
     " for efficient lookup of the messages in the cursor handler.
-    call sort(g:ale_buffer_loclist_map[buffer], 'ale#util#LocItemCompare')
+    call sort(g:ale_buffer_loclist_map[l:buffer], 'ale#util#LocItemCompare')
 
     if g:ale_set_loclist
-        call setloclist(0, g:ale_buffer_loclist_map[buffer])
+        call setloclist(0, g:ale_buffer_loclist_map[l:buffer])
     endif
 
     if g:ale_set_signs
-        call ale#sign#SetSigns(buffer, g:ale_buffer_loclist_map[buffer])
+        call ale#sign#SetSigns(l:buffer, g:ale_buffer_loclist_map[l:buffer])
     endif
 
     " Mark line 200, column 17 with a squiggly line or something
@@ -124,14 +124,14 @@ function! s:FixLocList(buffer, loclist) abort
     " Some errors have line numbers beyond the end of the file,
     " so we need to adjust them so they set the error at the last line
     " of the file instead.
-    let last_line_number = ale#util#GetLineCount(a:buffer)
+    let l:last_line_number = ale#util#GetLineCount(a:buffer)
 
-    for item in a:loclist
-        if item.lnum == 0
+    for l:item in a:loclist
+        if l:item.lnum == 0
             " When errors appear at line 0, put them at line 1 instead.
-            let item.lnum = 1
-        elseif item.lnum > last_line_number
-            let item.lnum = last_line_number
+            let l:item.lnum = 1
+        elseif l:item.lnum > l:last_line_number
+            let l:item.lnum = l:last_line_number
         endif
     endfor
 endfunction
@@ -144,38 +144,38 @@ function! ale#engine#Invoke(buffer, linter) abort
 
     if has_key(a:linter, 'command_callback')
         " If there is a callback for generating a command, call that instead.
-        let command = ale#util#GetFunction(a:linter.command_callback)(a:buffer)
+        let l:command = ale#util#GetFunction(a:linter.command_callback)(a:buffer)
     else
-        let command = a:linter.command
+        let l:command = a:linter.command
     endif
 
-    if command =~# '%s'
+    if l:command =~# '%s'
         " If there is a '%s' in the command string, replace it with the name
         " of the file.
-        let command = printf(command, shellescape(fnamemodify(bufname(a:buffer), ':p')))
+        let l:command = printf(l:command, shellescape(fnamemodify(bufname(a:buffer), ':p')))
     endif
 
     if has('nvim')
         if a:linter.output_stream ==# 'stderr'
             " Read from stderr instead of stdout.
-            let job = jobstart(command, {
+            let l:job = jobstart(l:command, {
             \   'on_stderr': 's:GatherOutputNeoVim',
             \   'on_exit': 's:HandleExitNeoVim',
             \})
         elseif a:linter.output_stream ==# 'both'
-            let job = jobstart(command, {
+            let l:job = jobstart(l:command, {
             \   'on_stdout': 's:GatherOutputNeoVim',
             \   'on_stderr': 's:GatherOutputNeoVim',
             \   'on_exit': 's:HandleExitNeoVim',
             \})
         else
-            let job = jobstart(command, {
+            let l:job = jobstart(l:command, {
             \   'on_stdout': 's:GatherOutputNeoVim',
             \   'on_exit': 's:HandleExitNeoVim',
             \})
         endif
     else
-        let job_options = {
+        let l:job_options = {
         \   'in_mode': 'nl',
         \   'out_mode': 'nl',
         \   'err_mode': 'nl',
@@ -184,13 +184,13 @@ function! ale#engine#Invoke(buffer, linter) abort
 
         if a:linter.output_stream ==# 'stderr'
             " Read from stderr instead of stdout.
-            let job_options.err_cb = function('s:GatherOutputVim')
+            let l:job_options.err_cb = function('s:GatherOutputVim')
         elseif a:linter.output_stream ==# 'both'
             " Read from both streams.
-            let job_options.out_cb = function('s:GatherOutputVim')
-            let job_options.err_cb = function('s:GatherOutputVim')
+            let l:job_options.out_cb = function('s:GatherOutputVim')
+            let l:job_options.err_cb = function('s:GatherOutputVim')
         else
-            let job_options.out_cb = function('s:GatherOutputVim')
+            let l:job_options.out_cb = function('s:GatherOutputVim')
         endif
 
         if has('win32')
@@ -204,20 +204,20 @@ function! ale#engine#Invoke(buffer, linter) abort
 
             " On Unix machines, we can send the Vim buffer directly.
             " This is faster than reading the lines ourselves.
-            let job_options.in_io = 'buffer'
-            let job_options.in_buf = a:buffer
+            let l:job_options.in_io = 'buffer'
+            let l:job_options.in_buf = a:buffer
         endif
 
         " Vim 8 will read the stdin from the file's buffer.
-        let job = job_start(l:command, l:job_options)
+        let l:job = job_start(l:command, l:job_options)
     endif
 
     " Only proceed if the job is being run.
-    if has('nvim') || (job !=# 'no process' && job_status(job) ==# 'run')
-        let a:linter.job = job
+    if has('nvim') || (l:job !=# 'no process' && job_status(l:job) ==# 'run')
+        let a:linter.job = l:job
 
         " Store the ID for the job in the map to read back again.
-        let s:job_info_map[s:GetJobID(job)] = {
+        let s:job_info_map[s:GetJobID(l:job)] = {
         \   'linter': a:linter,
         \   'buffer': a:buffer,
         \   'output': [],
@@ -225,18 +225,18 @@ function! ale#engine#Invoke(buffer, linter) abort
 
         if has('nvim')
             " In NeoVim, we have to send the buffer lines ourselves.
-            let input = join(getbufline(a:buffer, 1, '$'), "\n") . "\n"
+            let l:input = join(getbufline(a:buffer, 1, '$'), "\n") . "\n"
 
-            call jobsend(job, input)
-            call jobclose(job, 'stdin')
+            call jobsend(l:job, l:input)
+            call jobclose(l:job, 'stdin')
         elseif has('win32')
             " On some Vim versions, we have to send the buffer data ourselves.
-            let input = join(getbufline(a:buffer, 1, '$'), "\n") . "\n"
-            let channel = job_getchannel(job)
+            let l:input = join(getbufline(a:buffer, 1, '$'), "\n") . "\n"
+            let l:channel = job_getchannel(l:job)
 
-            if ch_status(channel) ==# 'open'
-                call ch_sendraw(channel, input)
-                call ch_close_in(channel)
+            if ch_status(l:channel) ==# 'open'
+                call ch_sendraw(l:channel, l:input)
+                call ch_close_in(l:channel)
             endif
         endif
     endif
diff --git a/autoload/ale/handlers.vim b/autoload/ale/handlers.vim
index 6a8bd24..e595ae4 100644
--- a/autoload/ale/handlers.vim
+++ b/autoload/ale/handlers.vim
@@ -10,17 +10,17 @@ function! ale#handlers#HandleGCCFormat(buffer, lines) abort
     " <stdin>:8:5: warning: conversion lacks type at end of format [-Wformat=]
     " <stdin>:10:27: error: invalid operands to binary - (have ‘int’ and ‘char *’)
     " -:189:7: note: $/${} is unnecessary on arithmetic variables. [SC2004]
-    let pattern = '^.\+:\(\d\+\):\(\d\+\): \([^:]\+\): \(.\+\)$'
-    let output = []
+    let l:pattern = '^.\+:\(\d\+\):\(\d\+\): \([^:]\+\): \(.\+\)$'
+    let l:output = []
 
-    for line in a:lines
-        let l:match = matchlist(line, pattern)
+    for l:line in a:lines
+        let l:match = matchlist(l:line, l:pattern)
 
         if len(l:match) == 0
             continue
         endif
 
-        call add(output, {
+        call add(l:output, {
         \   'bufnr': a:buffer,
         \   'lnum': l:match[1] + 0,
         \   'vcol': 0,
@@ -31,7 +31,7 @@ function! ale#handlers#HandleGCCFormat(buffer, lines) abort
         \})
     endfor
 
-    return output
+    return l:output
 endfunction
 
 function! ale#handlers#HandleCSSLintFormat(buffer, lines) abort
@@ -42,35 +42,35 @@ function! ale#handlers#HandleCSSLintFormat(buffer, lines) abort
     "
     " These errors can be very massive, so the type will be moved to the front
     " so you can actually read the error type.
-    let pattern = '^.*: line \(\d\+\), col \(\d\+\), \(Error\|Warning\) - \(.\+\) (\([^)]\+\))$'
-    let output = []
+    let l:pattern = '^.*: line \(\d\+\), col \(\d\+\), \(Error\|Warning\) - \(.\+\) (\([^)]\+\))$'
+    let l:output = []
 
-    for line in a:lines
-        let l:match = matchlist(line, pattern)
+    for l:line in a:lines
+        let l:match = matchlist(l:line, l:pattern)
 
         if len(l:match) == 0
             continue
         endif
 
-        let text = l:match[4]
-        let type = l:match[3]
-        let errorGroup = l:match[5]
+        let l:text = l:match[4]
+        let l:type = l:match[3]
+        let l:errorGroup = l:match[5]
 
         " Put the error group at the front, so we can see what kind of error
         " it is on small echo lines.
-        let text = '(' . errorGroup . ') ' . text
+        let l:text = '(' . l:errorGroup . ') ' . l:text
 
         " vcol is Needed to indicate that the column is a character.
-        call add(output, {
+        call add(l:output, {
         \   'bufnr': a:buffer,
         \   'lnum': l:match[1] + 0,
         \   'vcol': 0,
         \   'col': l:match[2] + 0,
-        \   'text': text,
-        \   'type': type ==# 'Warning' ? 'W' : 'E',
+        \   'text': l:text,
+        \   'type': l:type ==# 'Warning' ? 'W' : 'E',
         \   'nr': -1,
         \})
     endfor
 
-    return output
+    return l:output
 endfunction
diff --git a/autoload/ale/linter.vim b/autoload/ale/linter.vim
index c87fa8d..010256d 100644
--- a/autoload/ale/linter.vim
+++ b/autoload/ale/linter.vim
@@ -9,32 +9,32 @@ function! ale#linter#Define(filetype, linter) abort
         let s:linters[a:filetype] = []
     endif
 
-    let new_linter = {
+    let l:new_linter = {
     \   'name': a:linter.name,
     \   'callback': a:linter.callback,
     \}
 
     if has_key(a:linter, 'executable_callback')
-        let new_linter.executable_callback = a:linter.executable_callback
+        let l:new_linter.executable_callback = a:linter.executable_callback
     else
-        let new_linter.executable = a:linter.executable
+        let l:new_linter.executable = a:linter.executable
     endif
 
     if has_key(a:linter, 'command_callback')
-        let new_linter.command_callback = a:linter.command_callback
+        let l:new_linter.command_callback = a:linter.command_callback
     else
-        let new_linter.command = a:linter.command
+        let l:new_linter.command = a:linter.command
     endif
 
     if has_key(a:linter, 'output_stream')
-        let new_linter.output_stream = a:linter.output_stream
+        let l:new_linter.output_stream = a:linter.output_stream
     else
-        let new_linter.output_stream = 'stdout'
+        let l:new_linter.output_stream = 'stdout'
     endif
 
     " TODO: Assert the value of the output_stream to be something sensible.
 
-    call add(s:linters[a:filetype], new_linter)
+    call add(s:linters[a:filetype], l:new_linter)
 endfunction
 
 function! ale#linter#Get(filetype) abort
@@ -50,8 +50,8 @@ function! ale#linter#Get(filetype) abort
 
     if has_key(g:ale_linters, a:filetype)
         " Filter loaded linters according to list of linters specified in option.
-        for linter in g:ale_linters[a:filetype]
-            execute 'runtime! ale_linters/' . a:filetype . '/' . linter . '.vim'
+        for l:linter in g:ale_linters[a:filetype]
+            execute 'runtime! ale_linters/' . a:filetype . '/' . l:linter . '.vim'
         endfor
     else
         execute 'runtime! ale_linters/' . a:filetype . '/*.vim'
diff --git a/autoload/ale/sign.vim b/autoload/ale/sign.vim
index 5cdd97c..9aba868 100644
--- a/autoload/ale/sign.vim
+++ b/autoload/ale/sign.vim
@@ -39,64 +39,64 @@ function! ale#sign#FindCurrentSigns(buffer) abort
     " Matches output like :
     " line=4  id=1  name=ALEErrorSign
     " строка=1  id=1000001  имя=ALEErrorSign
-    let pattern = 'id=\(\d\+\).*=ALE\(Warning\|Error\)Sign'
+    let l:pattern = 'id=\(\d\+\).*=ALE\(Warning\|Error\)Sign'
 
-    redir => output
+    redir => l:output
        silent exec 'sign place buffer=' . a:buffer
     redir END
 
-    let id_list = []
+    let l:id_list = []
 
-    for line in split(output, "\n")
-        let match = matchlist(line, pattern)
+    for l:line in split(l:output, "\n")
+        let l:match = matchlist(l:line, l:pattern)
 
-        if len(match) > 0
-            call add(id_list, match[1] + 0)
+        if len(l:match) > 0
+            call add(l:id_list, l:match[1] + 0)
         endif
     endfor
 
-    return id_list
+    return l:id_list
 endfunction
 
 " Given a loclist, combine the loclist into a list of signs such that only
 " one sign appears per line. Error lines will take precedence.
 " The loclist will have been previously sorted.
 function! ale#sign#CombineSigns(loclist) abort
-    let signlist = []
+    let l:signlist = []
 
-    for obj in a:loclist
-        let should_append = 1
+    for l:obj in a:loclist
+        let l:should_append = 1
 
-        if obj.lnum < 1
+        if l:obj.lnum < 1
             " Skip warnings and errors at line 0, etc.
             continue
         endif
 
-        if len(signlist) > 0 && signlist[-1].lnum == obj.lnum
+        if len(l:signlist) > 0 && l:signlist[-1].lnum == l:obj.lnum
             " We can't add the same line twice, because signs must be
             " unique per line.
-            let should_append = 0
+            let l:should_append = 0
 
-            if signlist[-1].type ==# 'W' && obj.type ==# 'E'
+            if l:signlist[-1].type ==# 'W' && l:obj.type ==# 'E'
                 " If we had a warning previously, but now have an error,
                 " we replace the object to set an error instead.
-                let signlist[-1] = obj
+                let l:signlist[-1] = l:obj
             endif
         endif
 
-        if should_append
-            call add(signlist, obj)
+        if l:should_append
+            call add(l:signlist, l:obj)
         endif
     endfor
 
-    return signlist
+    return l:signlist
 endfunction
 
 " This function will set the signs which show up on the left.
 function! ale#sign#SetSigns(buffer, loclist) abort
-    let signlist = ale#sign#CombineSigns(a:loclist)
+    let l:signlist = ale#sign#CombineSigns(a:loclist)
 
-    if len(signlist) > 0 || g:ale_sign_column_always
+    if len(l:signlist) > 0 || g:ale_sign_column_always
         if !get(g:ale_buffer_sign_dummy_map, a:buffer, 0)
             " Insert a dummy sign if one is missing.
             execute 'sign place ' .  g:ale_sign_offset
@@ -108,27 +108,27 @@ function! ale#sign#SetSigns(buffer, loclist) abort
     endif
 
     " Find the current signs with the markers we use.
-    let current_id_list = ale#sign#FindCurrentSigns(a:buffer)
+    let l:current_id_list = ale#sign#FindCurrentSigns(a:buffer)
 
     " Remove those markers.
-    for current_id in current_id_list
-        exec 'sign unplace ' . current_id . ' buffer=' . a:buffer
+    for l:current_id in l:current_id_list
+        exec 'sign unplace ' . l:current_id . ' buffer=' . a:buffer
     endfor
 
     " Now set all of the signs.
-    for i in range(0, len(signlist) - 1)
-        let obj = signlist[i]
-        let name = obj['type'] ==# 'W' ? 'ALEWarningSign' : 'ALEErrorSign'
+    for l:index in range(0, len(l:signlist) - 1)
+        let l:sign = l:signlist[l:index]
+        let l:type = l:sign['type'] ==# 'W' ? 'ALEWarningSign' : 'ALEErrorSign'
 
-        let sign_line = 'sign place ' . (i + g:ale_sign_offset + 1)
-            \. ' line=' . obj['lnum']
-            \. ' name=' . name
+        let l:sign_line = 'sign place ' . (l:index + g:ale_sign_offset + 1)
+            \. ' line=' . l:sign['lnum']
+            \. ' name=' . l:type
             \. ' buffer=' . a:buffer
 
-        exec sign_line
+        exec l:sign_line
     endfor
 
-    if !g:ale_sign_column_always && len(signlist) > 0
+    if !g:ale_sign_column_always && len(l:signlist) > 0
         if get(g:ale_buffer_sign_dummy_map, a:buffer, 0)
             execute 'sign unplace ' . g:ale_sign_offset . ' buffer=' . a:buffer
 
diff --git a/autoload/ale/statusline.vim b/autoload/ale/statusline.vim
index ded5283..995fcd9 100644
--- a/autoload/ale/statusline.vim
+++ b/autoload/ale/statusline.vim
@@ -5,35 +5,35 @@ function! ale#statusline#Status() abort
     " Returns a formatted string that can be integrated in the
     " statusline
 
-    let buf = bufnr('%')
-    let bufLoclist = g:ale_buffer_loclist_map
+    let l:buffer = bufnr('%')
+    let l:loclist = g:ale_buffer_loclist_map
 
-    if !has_key(bufLoclist, buf)
+    if !has_key(l:loclist, l:buffer)
         return ''
     endif
 
-    let errors = 0
-    let warnings = 0
-    for e in bufLoclist[buf]
-        if e.type ==# 'E'
-            let errors += 1
+    let l:errors = 0
+    let l:warnings = 0
+    for l:entry in l:loclist[l:buffer]
+        if l:entry.type ==# 'E'
+            let l:errors += 1
         else
-            let warnings += 1
+            let l:warnings += 1
         endif
     endfor
 
-    let errors = errors ? printf(g:ale_statusline_format[0], errors) : ''
-    let warnings = warnings ? printf(g:ale_statusline_format[1], warnings) : ''
-    let no_errors = g:ale_statusline_format[2]
+    let l:errors = l:errors ? printf(g:ale_statusline_format[0], l:errors) : ''
+    let l:warnings = l:warnings ? printf(g:ale_statusline_format[1], l:warnings) : ''
+    let l:no_errors = g:ale_statusline_format[2]
 
     " Different formats if no errors or no warnings
-    if empty(errors) && empty(warnings)
-        let res = no_errors
-    elseif !empty(errors) && !empty(warnings)
-        let res = printf('%s %s', errors, warnings)
+    if empty(l:errors) && empty(l:warnings)
+        let l:res = l:no_errors
+    elseif !empty(l:errors) && !empty(l:warnings)
+        let l:res = printf('%s %s', l:errors, l:warnings)
     else
-        let res = empty(errors) ? warnings : errors
+        let l:res = empty(l:errors) ? l:warnings : l:errors
     endif
 
-    return res
+    return l:res
 endfunction
diff --git a/autoload/ale/util.vim b/autoload/ale/util.vim
index e292c99..17ce7c4 100644
--- a/autoload/ale/util.vim
+++ b/autoload/ale/util.vim
@@ -2,16 +2,16 @@
 " Description: Contains miscellaneous functions
 
 function! s:FindWrapperScript() abort
-    for parent in split(&runtimepath, ',')
+    for l:parent in split(&runtimepath, ',')
         " Expand the path to deal with ~ issues.
-        let path = expand(parent . '/' . 'stdin-wrapper')
+        let l:path = expand(l:parent . '/' . 'stdin-wrapper')
 
-        if filereadable(path)
+        if filereadable(l:path)
             if has('win32')
-                return path . '.exe'
+                return l:path . '.exe'
             endif
 
-            return path
+            return l:path
         endif
     endfor
 endfunction