Merge branch 'master' into sridhars

80 files changed, 1879 insertions, 741 deletions

diff --git a/autoload/ale.vim b/autoload/ale.vim
index 6d1e8521..f6c23d72 100644
--- a/autoload/ale.vim
+++ b/autoload/ale.vim
@@ -10,8 +10,7 @@ let g:ale_echo_msg_warning_str = get(g:, 'ale_echo_msg_warning_str', 'Warning')
 let g:ale_linters_ignore = get(g:, 'ale_linters_ignore', {})
 
 let s:lint_timer = -1
-let s:queued_buffer_number = -1
-let s:should_lint_file_for_buffer = {}
+let s:getcmdwintype_exists = exists('*getcmdwintype')
 
 " Return 1 if a file is too large for ALE to handle.
 function! ale#FileTooLarge(buffer) abort
@@ -20,14 +19,12 @@ function! ale#FileTooLarge(buffer) abort
     return l:max > 0 ? (line2byte(line('$') + 1) > l:max) : 0
 endfunction
 
-let s:getcmdwintype_exists = exists('*getcmdwintype')
-
 " A function for checking various conditions whereby ALE just shouldn't
 " attempt to do anything, say if particular buffer types are open in Vim.
 function! ale#ShouldDoNothing(buffer) abort
     " The checks are split into separate if statements to make it possible to
     " profile each check individually with Vim's profiling tools.
-
+    "
     " Do nothing if ALE is disabled.
     if !getbufvar(a:buffer, 'ale_enabled', get(g:, 'ale_enabled', 0))
         return 1
@@ -62,6 +59,11 @@ function! ale#ShouldDoNothing(buffer) abort
         return 1
     endif
 
+    " Don't start linting and so on when an operator is pending.
+    if ale#util#Mode(1) is# 'no'
+        return 1
+    endif
+
     " Do nothing if running in the sandbox.
     if ale#util#InSandbox()
         return 1
@@ -81,21 +83,47 @@ function! ale#ShouldDoNothing(buffer) abort
     return 0
 endfunction
 
+function! s:Lint(buffer, should_lint_file, timer_id) abort
+    " Use the filetype from the buffer
+    let l:filetype = getbufvar(a:buffer, '&filetype')
+    let l:linters = ale#linter#Get(l:filetype)
+
+    " Apply ignore lists for linters only if needed.
+    let l:ignore_config = ale#Var(a:buffer, 'linters_ignore')
+    let l:linters = !empty(l:ignore_config)
+    \   ? ale#engine#ignore#Exclude(l:filetype, l:linters, l:ignore_config)
+    \   : l:linters
+
+    " Tell other sources that they can start checking the buffer now.
+    let g:ale_want_results_buffer = a:buffer
+    silent doautocmd <nomodeline> User ALEWantResults
+    unlet! g:ale_want_results_buffer
+
+    " Don't set up buffer data and so on if there are no linters to run.
+    if !has_key(g:ale_buffer_info, a:buffer) && empty(l:linters)
+        return
+    endif
+
+    " Clear lint_file linters, or only run them if the file exists.
+    let l:lint_file = empty(l:linters)
+    \   || (a:should_lint_file && filereadable(expand('#' . a:buffer . ':p')))
+
+    call ale#engine#RunLinters(a:buffer, l:linters, l:lint_file)
+endfunction
+
 " (delay, [linting_flag, buffer_number])
 function! ale#Queue(delay, ...) abort
     if a:0 > 2
         throw 'too many arguments!'
     endif
 
-    " Default linting_flag to ''
-    let l:linting_flag = get(a:000, 0, '')
-    let l:buffer = get(a:000, 1, bufnr(''))
+    let l:buffer = get(a:000, 1, v:null)
 
-    if l:linting_flag isnot# '' && l:linting_flag isnot# 'lint_file'
-        throw "linting_flag must be either '' or 'lint_file'"
+    if l:buffer is v:null
+        let l:buffer = bufnr('')
     endif
 
-    if type(l:buffer) != type(0)
+    if type(l:buffer) isnot v:t_number
         throw 'buffer_number must be a Number'
     endif
 
@@ -103,80 +131,24 @@ function! ale#Queue(delay, ...) abort
         return
     endif
 
-    " Remember that we want to check files for this buffer.
-    " We will remember this until we finally run the linters, via any event.
-    if l:linting_flag is# 'lint_file'
-        let s:should_lint_file_for_buffer[l:buffer] = 1
-    endif
+    " Default linting_flag to ''
+    let l:should_lint_file = get(a:000, 0) is# 'lint_file'
 
     if s:lint_timer != -1
         call timer_stop(s:lint_timer)
         let s:lint_timer = -1
     endif
 
-    let l:linters = ale#linter#Get(getbufvar(l:buffer, '&filetype'))
-
-    " Don't set up buffer data and so on if there are no linters to run.
-    if empty(l:linters)
-        " If we have some previous buffer data, then stop any jobs currently
-        " running and clear everything.
-        if has_key(g:ale_buffer_info, l:buffer)
-            call ale#engine#RunLinters(l:buffer, [], 1)
-        endif
-
-        return
-    endif
-
     if a:delay > 0
-        let s:queued_buffer_number = l:buffer
-        let s:lint_timer = timer_start(a:delay, function('ale#Lint'))
+        let s:lint_timer = timer_start(
+        \   a:delay,
+        \   function('s:Lint', [l:buffer, l:should_lint_file])
+        \)
     else
-        call ale#Lint(-1, l:buffer)
+        call s:Lint(l:buffer, l:should_lint_file, 0)
     endif
 endfunction
 
-function! ale#Lint(...) abort
-    if a:0 > 1
-        " Use the buffer number given as the optional second argument.
-        let l:buffer = a:2
-    elseif a:0 > 0 && a:1 == s:lint_timer
-        " Use the buffer number for the buffer linting was queued for.
-        let l:buffer = s:queued_buffer_number
-    else
-        " Use the current buffer number.
-        let l:buffer = bufnr('')
-    endif
-
-    if ale#ShouldDoNothing(l:buffer)
-        return
-    endif
-
-    " Use the filetype from the buffer
-    let l:filetype = getbufvar(l:buffer, '&filetype')
-    let l:linters = ale#linter#Get(l:filetype)
-    let l:should_lint_file = 0
-
-    " Check if we previously requested checking the file.
-    if has_key(s:should_lint_file_for_buffer, l:buffer)
-        unlet s:should_lint_file_for_buffer[l:buffer]
-        " Lint files if they exist.
-        let l:should_lint_file = filereadable(expand('#' . l:buffer . ':p'))
-    endif
-
-    " Apply ignore lists for linters only if needed.
-    let l:ignore_config = ale#Var(l:buffer, 'linters_ignore')
-    let l:linters = !empty(l:ignore_config)
-    \   ? ale#engine#ignore#Exclude(l:filetype, l:linters, l:ignore_config)
-    \   : l:linters
-
-    call ale#engine#RunLinters(l:buffer, l:linters, l:should_lint_file)
-endfunction
-
-" Reset flags indicating that files should be checked for all buffers.
-function! ale#ResetLintFileMarkers() abort
-    let s:should_lint_file_for_buffer = {}
-endfunction
-
 let g:ale_has_override = get(g:, 'ale_has_override', {})
 
 " Call has(), but check a global Dictionary so we can force flags on or off
@@ -197,6 +169,11 @@ function! ale#Var(buffer, variable_name) abort
     return get(l:vars, l:full_name, g:[l:full_name])
 endfunction
 
+" As above, but curry the arguments so only the buffer number is required.
+function! ale#VarFunc(variable_name) abort
+    return {buf -> ale#Var(buf, a:variable_name)}
+endfunction
+
 " Initialize a variable with a default value, if it isn't already set.
 "
 " Every variable name will be prefixed with 'ale_'.
diff --git a/autoload/ale/assert.vim b/autoload/ale/assert.vim
index 55c39ee3..ed08ed09 100644
--- a/autoload/ale/assert.vim
+++ b/autoload/ale/assert.vim
@@ -30,7 +30,7 @@ function! ale#assert#Linter(expected_executable, expected_command) abort
         let l:callbacks = map(copy(l:linter.command_chain), 'v:val.callback')
 
         " If the expected command is a string, just check the last one.
-        if type(a:expected_command) is type('')
+        if type(a:expected_command) is v:t_string
             if len(l:callbacks) is 1
                 let l:command = call(l:callbacks[0], [l:buffer])
             else
@@ -54,9 +54,14 @@ function! ale#assert#Linter(expected_executable, expected_command) abort
         endif
     else
         let l:command = ale#linter#GetCommand(l:buffer, l:linter)
+    endif
+
+    if type(l:command) is v:t_string
         " Replace %e with the escaped executable, so tests keep passing after
         " linters are changed to use %e.
         let l:command = substitute(l:command, '%e', '\=ale#Escape(l:executable)', 'g')
+    else
+        call map(l:command, 'substitute(v:val, ''%e'', ''\=ale#Escape(l:executable)'', ''g'')')
     endif
 
     AssertEqual
@@ -80,6 +85,14 @@ function! ale#assert#LSPOptions(expected_options) abort
     AssertEqual a:expected_options, l:initialization_options
 endfunction
 
+function! ale#assert#LSPConfig(expected_config) abort
+    let l:buffer = bufnr('')
+    let l:linter = s:GetLinter()
+    let l:config = ale#lsp_linter#GetConfig(l:buffer, l:linter)
+
+    AssertEqual a:expected_config, l:config
+endfunction
+
 function! ale#assert#LSPLanguage(expected_language) abort
     let l:buffer = bufnr('')
     let l:linter = s:GetLinter()
@@ -96,6 +109,14 @@ function! ale#assert#LSPProject(expected_root) abort
     AssertEqual a:expected_root, l:root
 endfunction
 
+function! ale#assert#LSPAddress(expected_address) abort
+    let l:buffer = bufnr('')
+    let l:linter = s:GetLinter()
+    let l:address = ale#util#GetFunction(l:linter.address_callback)(l:buffer)
+
+    AssertEqual a:expected_address, l:address
+endfunction
+
 " A dummy function for making sure this module is loaded.
 function! ale#assert#SetUpLinterTest(filetype, name) abort
     " Set up a marker so ALE doesn't create real random temporary filenames.
@@ -126,28 +147,59 @@ function! ale#assert#SetUpLinterTest(filetype, name) abort
 
     execute 'runtime ale_linters/' . a:filetype . '/' . a:name . '.vim'
 
-    call ale#test#SetDirectory('/testplugin/test/command_callback')
+    if !exists('g:dir')
+        call ale#test#SetDirectory('/testplugin/test/command_callback')
+    endif
 
     command! -nargs=+ WithChainResults :call ale#assert#WithChainResults(<args>)
     command! -nargs=+ AssertLinter :call ale#assert#Linter(<args>)
     command! -nargs=0 AssertLinterNotExecuted :call ale#assert#LinterNotExecuted()
     command! -nargs=+ AssertLSPOptions :call ale#assert#LSPOptions(<args>)
+    command! -nargs=+ AssertLSPConfig :call ale#assert#LSPConfig(<args>)
     command! -nargs=+ AssertLSPLanguage :call ale#assert#LSPLanguage(<args>)
     command! -nargs=+ AssertLSPProject :call ale#assert#LSPProject(<args>)
+    command! -nargs=+ AssertLSPAddress :call ale#assert#LSPAddress(<args>)
 endfunction
 
 function! ale#assert#TearDownLinterTest() abort
     unlet! g:ale_create_dummy_temporary_file
     let s:chain_results = []
 
-    delcommand WithChainResults
-    delcommand AssertLinter
-    delcommand AssertLinterNotExecuted
-    delcommand AssertLSPOptions
-    delcommand AssertLSPLanguage
-    delcommand AssertLSPProject
+    if exists(':WithChainResults')
+        delcommand WithChainResults
+    endif
+
+    if exists(':AssertLinter')
+        delcommand AssertLinter
+    endif
+
+    if exists(':AssertLinterNotExecuted')
+        delcommand AssertLinterNotExecuted
+    endif
+
+    if exists(':AssertLSPOptions')
+        delcommand AssertLSPOptions
+    endif
+
+    if exists(':AssertLSPConfig')
+        delcommand AssertLSPConfig
+    endif
 
-    call ale#test#RestoreDirectory()
+    if exists(':AssertLSPLanguage')
+        delcommand AssertLSPLanguage
+    endif
+
+    if exists(':AssertLSPProject')
+        delcommand AssertLSPProject
+    endif
+
+    if exists(':AssertLSPAddress')
+        delcommand AssertLSPAddress
+    endif
+
+    if exists('g:dir')
+        call ale#test#RestoreDirectory()
+    endif
 
     Restore
 
diff --git a/autoload/ale/c.vim b/autoload/ale/c.vim
index fbfe9509..ce5105b6 100644
--- a/autoload/ale/c.vim
+++ b/autoload/ale/c.vim
@@ -2,11 +2,31 @@
 " Description: Functions for integrating with C-family linters.
 
 call ale#Set('c_parse_makefile', 0)
+call ale#Set('c_parse_compile_commands', 0)
 let s:sep = has('win32') ? '\' : '/'
 
 " Set just so tests can override it.
 let g:__ale_c_project_filenames = ['.git/HEAD', 'configure', 'Makefile', 'CMakeLists.txt']
 
+function! ale#c#GetBuildDirectory(buffer) abort
+    " Don't include build directory for header files, as compile_commands.json
+    " files don't consider headers to be translation units, and provide no
+    " commands for compiling header files.
+    if expand('#' . a:buffer) =~# '\v\.(h|hpp)$'
+        return ''
+    endif
+
+    let l:build_dir = ale#Var(a:buffer, 'c_build_dir')
+
+    " c_build_dir has the priority if defined
+    if !empty(l:build_dir)
+        return l:build_dir
+    endif
+
+    return ale#path#Dirname(ale#c#FindCompileCommands(a:buffer))
+endfunction
+
+
 function! ale#c#FindProjectRoot(buffer) abort
     for l:project_filename in g:__ale_c_project_filenames
         let l:full_path = ale#path#FindNearestFile(a:buffer, l:project_filename)
@@ -26,15 +46,21 @@ function! ale#c#FindProjectRoot(buffer) abort
     return ''
 endfunction
 
-function! ale#c#ParseCFlagsToList(path_prefix, cflags) abort
+function! ale#c#ParseCFlags(path_prefix, cflag_line) abort
     let l:cflags_list = []
     let l:previous_options = []
 
-    for l:option in a:cflags
+    let l:split_lines = split(a:cflag_line, '-')
+    let l:option_index = 0
+
+    while l:option_index < len(l:split_lines)
+        let l:option = l:split_lines[l:option_index]
+        let l:option_index = l:option_index + 1
         call add(l:previous_options, l:option)
         " Check if cflag contained a '-' and should not have been splitted
         let l:option_list = split(l:option, '\zs')
-        if l:option_list[-1] isnot# ' '
+
+        if len(l:option_list) > 0 && l:option_list[-1] isnot# ' ' && l:option_index < len(l:split_lines)
             continue
         endif
 
@@ -60,34 +86,134 @@ function! ale#c#ParseCFlagsToList(path_prefix, cflags) abort
                 call add(l:cflags_list, l:option)
             endif
         endif
-    endfor
+    endwhile
 
-    return l:cflags_list
+    return join(l:cflags_list, ' ')
 endfunction
 
-function! ale#c#ParseCFlags(buffer, stdout_make) abort
+function! ale#c#ParseCFlagsFromMakeOutput(buffer, make_output) abort
     if !g:ale_c_parse_makefile
-        return []
+        return ''
     endif
 
     let l:buffer_filename = expand('#' . a:buffer . ':t')
-    let l:cflags = []
-    for l:lines in split(a:stdout_make, '\\n')
-        if stridx(l:lines, l:buffer_filename) >= 0
-            let l:cflags = split(l:lines, '-')
+    let l:cflag_line = ''
+
+    " Find a line matching this buffer's filename in the make output.
+    for l:line in a:make_output
+        if stridx(l:line, l:buffer_filename) >= 0
+            let l:cflag_line = l:line
             break
         endif
     endfor
 
     let l:makefile_path = ale#path#FindNearestFile(a:buffer, 'Makefile')
-    return ale#c#ParseCFlagsToList(fnamemodify(l:makefile_path, ':p:h'), l:cflags)
+    let l:makefile_dir = fnamemodify(l:makefile_path, ':p:h')
+
+    return ale#c#ParseCFlags(l:makefile_dir, l:cflag_line)
+endfunction
+
+" Given a buffer number, find the build subdirectory with compile commands
+" The subdirectory is returned without the trailing /
+function! ale#c#FindCompileCommands(buffer) abort
+    " Look above the current source file to find compile_commands.json
+    let l:json_file = ale#path#FindNearestFile(a:buffer, 'compile_commands.json')
+
+    if !empty(l:json_file)
+        return l:json_file
+    endif
+
+    " Search in build directories if we can't find it in the project.
+    for l:path in ale#path#Upwards(expand('#' . a:buffer . ':p:h'))
+        for l:dirname in ale#Var(a:buffer, 'c_build_dir_names')
+            let l:c_build_dir = l:path . s:sep . l:dirname
+            let l:json_file = l:c_build_dir . s:sep . 'compile_commands.json'
+
+            if filereadable(l:json_file)
+                return l:json_file
+            endif
+        endfor
+    endfor
+
+    return ''
+endfunction
+
+" Cache compile_commands.json data in a Dictionary, so we don't need to read
+" the same files over and over again. The key in the dictionary will include
+" the last modified time of the file.
+if !exists('s:compile_commands_cache')
+    let s:compile_commands_cache = {}
+endif
+
+function! s:GetListFromCompileCommandsFile(compile_commands_file) abort
+    if empty(a:compile_commands_file)
+        return []
+    endif
+
+    let l:time = getftime(a:compile_commands_file)
+
+    if l:time < 0
+        return []
+    endif
+
+    let l:key = a:compile_commands_file . ':' . l:time
+
+    if has_key(s:compile_commands_cache, l:key)
+        return s:compile_commands_cache[l:key]
+    endif
+
+    let l:data = []
+    silent! let l:data = json_decode(join(readfile(a:compile_commands_file), ''))
+
+    if !empty(l:data)
+        let s:compile_commands_cache[l:key] = l:data
+
+        return l:data
+    endif
+
+    return []
+endfunction
+
+function! ale#c#ParseCompileCommandsFlags(buffer, dir, json_list) abort
+    " Search for an exact file match first.
+    for l:item in a:json_list
+        if bufnr(l:item.file) is a:buffer
+            return ale#c#ParseCFlags(a:dir, l:item.command)
+        endif
+    endfor
+
+    " Look for any file in the same directory if we can't find an exact match.
+    let l:dir = ale#path#Simplify(expand('#' . a:buffer . ':p:h'))
+
+    for l:item in a:json_list
+        if ale#path#Simplify(fnamemodify(l:item.file, ':h')) is? l:dir
+            return ale#c#ParseCFlags(a:dir, l:item.command)
+        endif
+    endfor
+
+    return ''
+endfunction
+
+function! ale#c#FlagsFromCompileCommands(buffer, compile_commands_file) abort
+    let l:dir = ale#path#Dirname(a:compile_commands_file)
+    let l:json_list = s:GetListFromCompileCommandsFile(a:compile_commands_file)
+
+    return ale#c#ParseCompileCommandsFlags(a:buffer, l:dir, l:json_list)
 endfunction
 
 function! ale#c#GetCFlags(buffer, output) abort
     let l:cflags = ' '
 
-    if g:ale_c_parse_makefile && !empty(a:output)
-        let l:cflags = join(ale#c#ParseCFlags(a:buffer, join(a:output, '\n')), ' ') . ' '
+    if ale#Var(a:buffer, 'c_parse_makefile') && !empty(a:output)
+        let l:cflags = ale#c#ParseCFlagsFromMakeOutput(a:buffer, a:output)
+    endif
+
+    if ale#Var(a:buffer, 'c_parse_compile_commands')
+        let l:json_file = ale#c#FindCompileCommands(a:buffer)
+
+        if !empty(l:json_file)
+            let l:cflags = ale#c#FlagsFromCompileCommands(a:buffer, l:json_file)
+        endif
     endif
 
     if l:cflags is# ' '
@@ -98,8 +224,9 @@ function! ale#c#GetCFlags(buffer, output) abort
 endfunction
 
 function! ale#c#GetMakeCommand(buffer) abort
-    if g:ale_c_parse_makefile
+    if ale#Var(a:buffer, 'c_parse_makefile')
         let l:makefile_path = ale#path#FindNearestFile(a:buffer, 'Makefile')
+
         if !empty(l:makefile_path)
             return 'cd '. fnamemodify(l:makefile_path, ':p:h') . ' && make -n'
         endif
@@ -154,26 +281,10 @@ function! ale#c#IncludeOptions(include_paths) abort
         return ''
     endif
 
-    return ' ' . join(l:option_list) . ' '
+    return join(l:option_list)
 endfunction
 
 let g:ale_c_build_dir_names = get(g:, 'ale_c_build_dir_names', [
 \   'build',
 \   'bin',
 \])
-
-" Given a buffer number, find the build subdirectory with compile commands
-" The subdirectory is returned without the trailing /
-function! ale#c#FindCompileCommands(buffer) abort
-    for l:path in ale#path#Upwards(expand('#' . a:buffer . ':p:h'))
-        for l:dirname in ale#Var(a:buffer, 'c_build_dir_names')
-            let l:c_build_dir = l:path . s:sep . l:dirname
-
-            if filereadable(l:c_build_dir . '/compile_commands.json')
-                return l:c_build_dir
-            endif
-        endfor
-    endfor
-
-    return ''
-endfunction
diff --git a/autoload/ale/completion.vim b/autoload/ale/completion.vim
index 7440f8cd..9dd913f5 100644
--- a/autoload/ale/completion.vim
+++ b/autoload/ale/completion.vim
@@ -39,10 +39,14 @@ let s:LSP_COMPLETION_COLOR_KIND = 16
 let s:LSP_COMPLETION_FILE_KIND = 17
 let s:LSP_COMPLETION_REFERENCE_KIND = 18
 
+let s:lisp_regex = '\v[a-zA-Z_\-][a-zA-Z_\-0-9]*$'
+
 " Regular expressions for checking the characters in the line before where
 " the insert cursor is. If one of these matches, we'll check for completions.
 let s:should_complete_map = {
 \   '<default>': '\v[a-zA-Z$_][a-zA-Z$_0-9]*$|\.$',
+\   'clojure': s:lisp_regex,
+\   'lisp': s:lisp_regex,
 \   'typescript': '\v[a-zA-Z$_][a-zA-Z$_0-9]*$|\.$|''$|"$',
 \   'rust': '\v[a-zA-Z$_][a-zA-Z$_0-9]*$|\.$|::$',
 \}
@@ -75,6 +79,7 @@ endfunction
 " Check if we should look for completions for a language.
 function! ale#completion#GetPrefix(filetype, line, column) abort
     let l:regex = s:GetFiletypeValue(s:should_complete_map, a:filetype)
+
     " The column we're using completions for is where we are inserting text,
     " like so:
     "   abc
@@ -93,14 +98,15 @@ function! ale#completion#GetTriggerCharacter(filetype, prefix) abort
     return ''
 endfunction
 
-function! ale#completion#Filter(buffer, suggestions, prefix) abort
+function! ale#completion#Filter(buffer, filetype, suggestions, prefix) abort
     let l:excluded_words = ale#Var(a:buffer, 'completion_excluded_words')
+    let l:triggers = s:GetFiletypeValue(s:trigger_character_map, a:filetype)
 
     " For completing...
     "   foo.
     "       ^
     " We need to include all of the given suggestions.
-    if a:prefix is# '.'
+    if index(l:triggers, a:prefix) >= 0
         let l:filtered_suggestions = a:suggestions
     else
         let l:filtered_suggestions = []
@@ -113,7 +119,7 @@ function! ale#completion#Filter(buffer, suggestions, prefix) abort
         for l:item in a:suggestions
             " A List of String values or a List of completion item Dictionaries
             " is accepted here.
-            let l:word = type(l:item) == type('') ? l:item : l:item.word
+            let l:word = type(l:item) is v:t_string ? l:item : l:item.word
 
             " Add suggestions if the suggestion starts with a case-insensitive
             " match for the prefix.
@@ -133,7 +139,7 @@ function! ale#completion#Filter(buffer, suggestions, prefix) abort
         " Remove suggestions with words in the exclusion List.
         call filter(
         \   l:filtered_suggestions,
-        \   'index(l:excluded_words, type(v:val) is type('''') ? v:val : v:val.word) < 0',
+        \   'index(l:excluded_words, type(v:val) is v:t_string ? v:val : v:val.word) < 0',
         \)
     endif
 
@@ -214,8 +220,10 @@ function! ale#completion#Show(response, completion_parser) abort
     " function, and then start omni-completion.
     let b:ale_completion_response = a:response
     let b:ale_completion_parser = a:completion_parser
+    " Replace completion options shortly before opening the menu.
     call s:ReplaceCompletionOptions()
-    call ale#util#FeedKeys("\<Plug>(ale_show_completion_menu)")
+
+    call timer_start(0, {-> ale#util#FeedKeys("\<Plug>(ale_show_completion_menu)")})
 endfunction
 
 function! s:CompletionStillValid(request_id) abort
@@ -257,7 +265,7 @@ function! ale#completion#ParseTSServerCompletionEntryDetails(response) abort
             call add(l:documentationParts, l:part.text)
         endfor
 
-        if l:suggestion.kind is# 'clasName'
+        if l:suggestion.kind is# 'className'
             let l:kind = 'f'
         elseif l:suggestion.kind is# 'parameterName'
             let l:kind = 'f'
@@ -315,10 +323,10 @@ function! ale#completion#ParseLSPCompletions(response) abort
 
     let l:item_list = []
 
-    if type(get(a:response, 'result')) is type([])
+    if type(get(a:response, 'result')) is v:t_list
         let l:item_list = a:response.result
-    elseif type(get(a:response, 'result')) is type({})
-    \&& type(get(a:response.result, 'items')) is type([])
+    elseif type(get(a:response, 'result')) is v:t_dict
+    \&& type(get(a:response.result, 'items')) is v:t_list
         let l:item_list = a:response.result.items
     endif
 
@@ -352,17 +360,23 @@ function! ale#completion#ParseLSPCompletions(response) abort
             let l:kind = 'v'
         endif
 
+        let l:doc = get(l:item, 'documentation', '')
+
+        if type(l:doc) is v:t_dict && has_key(l:doc, 'value')
+            let l:doc = l:doc.value
+        endif
+
         call add(l:results, {
         \   'word': l:word,
         \   'kind': l:kind,
         \   'icase': 1,
         \   'menu': get(l:item, 'detail', ''),
-        \   'info': get(l:item, 'documentation', ''),
+        \   'info': (type(l:doc) is v:t_string ? l:doc : ''),
         \})
     endfor
 
     if has_key(l:info, 'prefix')
-        return ale#completion#Filter(l:buffer, l:results, l:info.prefix)
+        return ale#completion#Filter(l:buffer, &filetype, l:results, l:info.prefix)
     endif
 
     return l:results
@@ -383,6 +397,7 @@ function! ale#completion#HandleTSServerResponse(conn_id, response) abort
     if l:command is# 'completions'
         let l:names = ale#completion#Filter(
         \   l:buffer,
+        \   &filetype,
         \   ale#completion#ParseTSServerCompletions(a:response),
         \   b:ale_completion_info.prefix,
         \)[: g:ale_completion_max_suggestions - 1]
@@ -422,6 +437,58 @@ function! ale#completion#HandleLSPResponse(conn_id, response) abort
     \)
 endfunction
 
+function! s:OnReady(linter, lsp_details, ...) abort
+    let l:buffer = a:lsp_details.buffer
+    let l:id = a:lsp_details.connection_id
+
+    " If we have sent a completion request already, don't send another.
+    if b:ale_completion_info.request_id
+        return
+    endif
+
+    let l:Callback = a:linter.lsp is# 'tsserver'
+    \   ? function('ale#completion#HandleTSServerResponse')
+    \   : function('ale#completion#HandleLSPResponse')
+    call ale#lsp#RegisterCallback(l:id, l:Callback)
+
+    if a:linter.lsp is# 'tsserver'
+        let l:message = ale#lsp#tsserver_message#Completions(
+        \   l:buffer,
+        \   b:ale_completion_info.line,
+        \   b:ale_completion_info.column,
+        \   b:ale_completion_info.prefix,
+        \)
+    else
+        " Send a message saying the buffer has changed first, otherwise
+        " completions won't know what text is nearby.
+        call ale#lsp#NotifyForChanges(l:id, l:buffer)
+
+        " For LSP completions, we need to clamp the column to the length of
+        " the line. python-language-server and perhaps others do not implement
+        " this correctly.
+        let l:message = ale#lsp#message#Completion(
+        \   l:buffer,
+        \   b:ale_completion_info.line,
+        \   min([
+        \       b:ale_completion_info.line_length,
+        \       b:ale_completion_info.column,
+        \   ]),
+        \   ale#completion#GetTriggerCharacter(&filetype, b:ale_completion_info.prefix),
+        \)
+    endif
+
+    let l:request_id = ale#lsp#Send(l:id, l:message)
+
+    if l:request_id
+        let b:ale_completion_info.conn_id = l:id
+        let b:ale_completion_info.request_id = l:request_id
+
+        if has_key(a:linter, 'completion_filter')
+            let b:ale_completion_info.completion_filter = a:linter.completion_filter
+        endif
+    endif
+endfunction
+
 function! s:GetLSPCompletions(linter) abort
     let l:buffer = bufnr('')
     let l:lsp_details = ale#lsp_linter#StartLSP(l:buffer, a:linter)
@@ -431,58 +498,10 @@ function! s:GetLSPCompletions(linter) abort
     endif
 
     let l:id = l:lsp_details.connection_id
-    let l:root = l:lsp_details.project_root
-
-    function! OnReady(...) abort closure
-        " If we have sent a completion request already, don't send another.
-        if b:ale_completion_info.request_id
-            return
-        endif
-
-        let l:Callback = a:linter.lsp is# 'tsserver'
-        \   ? function('ale#completion#HandleTSServerResponse')
-        \   : function('ale#completion#HandleLSPResponse')
-        call ale#lsp#RegisterCallback(l:id, l:Callback)
-
-        if a:linter.lsp is# 'tsserver'
-            let l:message = ale#lsp#tsserver_message#Completions(
-            \   l:buffer,
-            \   b:ale_completion_info.line,
-            \   b:ale_completion_info.column,
-            \   b:ale_completion_info.prefix,
-            \)
-        else
-            " Send a message saying the buffer has changed first, otherwise
-            " completions won't know what text is nearby.
-            call ale#lsp#NotifyForChanges(l:id, l:root, l:buffer)
-
-            " For LSP completions, we need to clamp the column to the length of
-            " the line. python-language-server and perhaps others do not implement
-            " this correctly.
-            let l:message = ale#lsp#message#Completion(
-            \   l:buffer,
-            \   b:ale_completion_info.line,
-            \   min([
-            \       b:ale_completion_info.line_length,
-            \       b:ale_completion_info.column,
-            \   ]),
-            \   ale#completion#GetTriggerCharacter(&filetype, b:ale_completion_info.prefix),
-            \)
-        endif
 
-        let l:request_id = ale#lsp#Send(l:id, l:message, l:lsp_details.project_root)
-
-        if l:request_id
-            let b:ale_completion_info.conn_id = l:id
-            let b:ale_completion_info.request_id = l:request_id
-
-            if has_key(a:linter, 'completion_filter')
-                let b:ale_completion_info.completion_filter = a:linter.completion_filter
-            endif
-        endif
-    endfunction
+    let l:OnReady = function('s:OnReady', [a:linter, l:lsp_details])
 
-    call ale#lsp#WaitForCapability(l:id, l:root, 'completion', function('OnReady'))
+    call ale#lsp#WaitForCapability(l:id, 'completion', l:OnReady)
 endfunction
 
 function! ale#completion#GetCompletions() abort
diff --git a/autoload/ale/cursor.vim b/autoload/ale/cursor.vim
index 73dbebb2..6672c349 100644
--- a/autoload/ale/cursor.vim
+++ b/autoload/ale/cursor.vim
@@ -1,4 +1,6 @@
+scriptencoding utf-8
 " Author: w0rp <devw0rp@gmail.com>
+" Author: João Paulo S. de Souza <joao.paulo.silvasouza@hotmail.com>
 " Description: Echoes lint message for the current line, if any
 
 " Controls the milliseconds delay before echoing a message.
@@ -24,7 +26,20 @@ function! ale#cursor#TruncatedEcho(original_message) abort
 
         " The message is truncated and saved to the history.
         setlocal shortmess+=T
-        exec "norm! :echomsg l:message\n"
+
+        try
+            exec "norm! :echomsg l:message\n"
+        catch /^Vim\%((\a\+)\)\=:E523/
+            " Fallback into manual truncate (#1987)
+            let l:winwidth = winwidth(0)
+
+            if l:winwidth < strdisplaywidth(l:message)
+                " Truncate message longer than window width with trailing '...'
+                let l:message = l:message[:l:winwidth - 4] . '...'
+            endif
+
+            exec 'echomsg l:message'
+        endtry
 
         " Reset the cursor position if we moved off the end of the line.
         " Using :norm and :echomsg can move the cursor off the end of the
@@ -37,17 +52,6 @@ function! ale#cursor#TruncatedEcho(original_message) abort
     endtry
 endfunction
 
-function! s:FindItemAtCursor() abort
-    let l:buf = bufnr('')
-    let l:info = get(g:ale_buffer_info, l:buf, {})
-    let l:loclist = get(l:info, 'loclist', [])
-    let l:pos = getcurpos()
-    let l:index = ale#util#BinarySearch(l:loclist, l:buf, l:pos[1], l:pos[2])
-    let l:loc = l:index >= 0 ? l:loclist[l:index] : {}
-
-    return [l:info, l:loc]
-endfunction
-
 function! s:StopCursorTimer() abort
     if s:cursor_timer != -1
         call timer_stop(s:cursor_timer)
@@ -56,42 +60,55 @@ function! s:StopCursorTimer() abort
 endfunction
 
 function! ale#cursor#EchoCursorWarning(...) abort
-    if !g:ale_echo_cursor
+    let l:buffer = bufnr('')
+
+    if !g:ale_echo_cursor && !g:ale_cursor_detail
         return
     endif
 
     " Only echo the warnings in normal mode, otherwise we will get problems.
-    if mode() isnot# 'n'
+    if mode(1) isnot# 'n'
         return
     endif
 
-    if ale#ShouldDoNothing(bufnr(''))
+    if ale#ShouldDoNothing(l:buffer)
         return
     endif
 
-    let l:buffer = bufnr('')
-    let [l:info, l:loc] = s:FindItemAtCursor()
+    let [l:info, l:loc] = ale#util#FindItemAtCursor(l:buffer)
+
+    if g:ale_echo_cursor
+        if !empty(l:loc)
+            let l:format = ale#Var(l:buffer, 'echo_msg_format')
+            let l:msg = ale#GetLocItemMessage(l:loc, l:format)
+            call ale#cursor#TruncatedEcho(l:msg)
+            let l:info.echoed = 1
+        elseif get(l:info, 'echoed')
+            " We'll only clear the echoed message when moving off errors once,
+            " so we don't continually clear the echo line.
+            execute 'echo'
+            let l:info.echoed = 0
+        endif
+    endif
 
-    if !empty(l:loc)
-        let l:format = ale#Var(l:buffer, 'echo_msg_format')
-        let l:msg = ale#GetLocItemMessage(l:loc, l:format)
-        call ale#cursor#TruncatedEcho(l:msg)
-        let l:info.echoed = 1
-    elseif get(l:info, 'echoed')
-        " We'll only clear the echoed message when moving off errors once,
-        " so we don't continually clear the echo line.
-        execute 'echo'
-        let l:info.echoed = 0
+    if g:ale_cursor_detail
+        if !empty(l:loc)
+            call s:ShowCursorDetailForItem(l:loc, {'stay_here': 1})
+        else
+            call ale#preview#CloseIfTypeMatches('ale-preview')
+        endif
     endif
 endfunction
 
 function! ale#cursor#EchoCursorWarningWithDelay() abort
-    if !g:ale_echo_cursor
+    let l:buffer = bufnr('')
+
+    if !g:ale_echo_cursor && !g:ale_cursor_detail
         return
     endif
 
     " Only echo the warnings in normal mode, otherwise we will get problems.
-    if mode() isnot# 'n'
+    if mode(1) isnot# 'n'
         return
     endif
 
@@ -104,7 +121,7 @@ function! ale#cursor#EchoCursorWarningWithDelay() abort
     " we should echo something. Otherwise we can end up doing processing
     " the echo message far too frequently.
     if l:pos != s:last_pos
-        let l:delay = ale#Var(bufnr(''), 'echo_delay')
+        let l:delay = ale#Var(l:buffer, 'echo_delay')
 
         let s:last_pos = l:pos
         let s:cursor_timer = timer_start(
@@ -114,24 +131,37 @@ function! ale#cursor#EchoCursorWarningWithDelay() abort
     endif
 endfunction
 
+function! s:ShowCursorDetailForItem(loc, options) abort
+    let l:stay_here = get(a:options, 'stay_here', 0)
+
+    let s:last_detailed_line = line('.')
+    let l:message = get(a:loc, 'detail', a:loc.text)
+    let l:lines = split(l:message, "\n")
+    call ale#preview#Show(l:lines, {'stay_here': l:stay_here})
+
+    " Clear the echo message if we manually displayed details.
+    if !l:stay_here
+        execute 'echo'
+    endif
+endfunction
+
 function! ale#cursor#ShowCursorDetail() abort
+    let l:buffer = bufnr('')
+
     " Only echo the warnings in normal mode, otherwise we will get problems.
     if mode() isnot# 'n'
         return
     endif
 
-    if ale#ShouldDoNothing(bufnr(''))
+    if ale#ShouldDoNothing(l:buffer)
         return
     endif
 
     call s:StopCursorTimer()
 
-    let [l:info, l:loc] = s:FindItemAtCursor()
+    let [l:info, l:loc] = ale#util#FindItemAtCursor(l:buffer)
 
     if !empty(l:loc)
-        let l:message = get(l:loc, 'detail', l:loc.text)
-
-        call ale#preview#Show(split(l:message, "\n"))
-        execute 'echo'
+        call s:ShowCursorDetailForItem(l:loc, {'stay_here': 0})
     endif
 endfunction
diff --git a/autoload/ale/d.vim b/autoload/ale/d.vim
new file mode 100644
index 00000000..0e232203
--- /dev/null
+++ b/autoload/ale/d.vim
@@ -0,0 +1,16 @@
+" Author: Auri <me@aurieh.me>
+" Description: Functions for integrating with D linters.
+
+function! ale#d#FindDUBConfig(buffer) abort
+    " Find a DUB configuration file in ancestor paths.
+    " The most DUB-specific names will be tried first.
+    for l:possible_filename in ['dub.sdl', 'dub.json', 'package.json']
+        let l:dub_file = ale#path#FindNearestFile(a:buffer, l:possible_filename)
+
+        if !empty(l:dub_file)
+            return l:dub_file
+        endif
+    endfor
+
+    return ''
+endfunction
diff --git a/autoload/ale/debugging.vim b/autoload/ale/debugging.vim
index 34c13770..6c2bfbee 100644
--- a/autoload/ale/debugging.vim
+++ b/autoload/ale/debugging.vim
@@ -22,14 +22,14 @@ let s:global_variable_list = [
 \    'ale_lint_delay',
 \    'ale_lint_on_enter',
 \    'ale_lint_on_filetype_changed',
+\    'ale_lint_on_insert_leave',
 \    'ale_lint_on_save',
 \    'ale_lint_on_text_changed',
-\    'ale_lint_on_insert_leave',
 \    'ale_linter_aliases',
 \    'ale_linters',
 \    'ale_linters_explicit',
-\    'ale_list_window_size',
 \    'ale_list_vertical',
+\    'ale_list_window_size',
 \    'ale_loclist_msg_format',
 \    'ale_max_buffer_history_size',
 \    'ale_max_signs',
@@ -52,6 +52,7 @@ let s:global_variable_list = [
 \    'ale_statusline_format',
 \    'ale_type_map',
 \    'ale_use_global_executables',
+\    'ale_virtualtext_cursor',
 \    'ale_warn_about_trailing_blank_lines',
 \    'ale_warn_about_trailing_whitespace',
 \]
diff --git a/autoload/ale/definition.vim b/autoload/ale/definition.vim
index 6c7d7d32..984a4f9d 100644
--- a/autoload/ale/definition.vim
+++ b/autoload/ale/definition.vim
@@ -40,16 +40,16 @@ function! ale#definition#HandleLSPResponse(conn_id, response) abort
         " The result can be a Dictionary item, a List of the same, or null.
         let l:result = get(a:response, 'result', v:null)
 
-        if type(l:result) is type({})
+        if type(l:result) is v:t_dict
             let l:result = [l:result]
-        elseif type(l:result) isnot type([])
+        elseif type(l:result) isnot v:t_list
             let l:result = []
         endif
 
         for l:item in l:result
             let l:filename = ale#path#FromURI(l:item.uri)
             let l:line = l:item.range.start.line + 1
-            let l:column = l:item.range.start.character
+            let l:column = l:item.range.start.character + 1
 
             call ale#util#Open(l:filename, l:line, l:column, l:options)
             break
@@ -57,6 +57,39 @@ function! ale#definition#HandleLSPResponse(conn_id, response) abort
     endif
 endfunction
 
+function! s:OnReady(linter, lsp_details, line, column, options, ...) abort
+    let l:buffer = a:lsp_details.buffer
+    let l:id = a:lsp_details.connection_id
+
+    let l:Callback = a:linter.lsp is# 'tsserver'
+    \   ? function('ale#definition#HandleTSServerResponse')
+    \   : function('ale#definition#HandleLSPResponse')
+    call ale#lsp#RegisterCallback(l:id, l:Callback)
+
+    if a:linter.lsp is# 'tsserver'
+        let l:message = ale#lsp#tsserver_message#Definition(
+        \   l:buffer,
+        \   a:line,
+        \   a:column
+        \)
+    else
+        " Send a message saying the buffer has changed first, or the
+        " definition position probably won't make sense.
+        call ale#lsp#NotifyForChanges(l:id, l:buffer)
+
+        " For LSP completions, we need to clamp the column to the length of
+        " the line. python-language-server and perhaps others do not implement
+        " this correctly.
+        let l:message = ale#lsp#message#Definition(l:buffer, a:line, a:column)
+    endif
+
+    let l:request_id = ale#lsp#Send(l:id, l:message)
+
+    let s:go_to_definition_map[l:request_id] = {
+    \   'open_in_tab': get(a:options, 'open_in_tab', 0),
+    \}
+endfunction
+
 function! s:GoToLSPDefinition(linter, options) abort
     let l:buffer = bufnr('')
     let [l:line, l:column] = getcurpos()[1:2]
@@ -71,39 +104,10 @@ function! s:GoToLSPDefinition(linter, options) abort
     endif
 
     let l:id = l:lsp_details.connection_id
-    let l:root = l:lsp_details.project_root
-
-    function! OnReady(...) abort closure
-        let l:Callback = a:linter.lsp is# 'tsserver'
-        \   ? function('ale#definition#HandleTSServerResponse')
-        \   : function('ale#definition#HandleLSPResponse')
-        call ale#lsp#RegisterCallback(l:id, l:Callback)
-
-        if a:linter.lsp is# 'tsserver'
-            let l:message = ale#lsp#tsserver_message#Definition(
-            \   l:buffer,
-            \   l:line,
-            \   l:column
-            \)
-        else
-            " Send a message saying the buffer has changed first, or the
-            " definition position probably won't make sense.
-            call ale#lsp#NotifyForChanges(l:id, l:root, l:buffer)
-
-            " For LSP completions, we need to clamp the column to the length of
-            " the line. python-language-server and perhaps others do not implement
-            " this correctly.
-            let l:message = ale#lsp#message#Definition(l:buffer, l:line, l:column)
-        endif
-
-        let l:request_id = ale#lsp#Send(l:id, l:message, l:lsp_details.project_root)
-
-        let s:go_to_definition_map[l:request_id] = {
-        \   'open_in_tab': get(a:options, 'open_in_tab', 0),
-        \}
-    endfunction
 
-    call ale#lsp#WaitForCapability(l:id, l:root, 'definition', function('OnReady'))
+    call ale#lsp#WaitForCapability(l:id, 'definition', function('s:OnReady', [
+    \   a:linter, l:lsp_details, l:line, l:column, a:options
+    \]))
 endfunction
 
 function! ale#definition#GoTo(options) abort
diff --git a/autoload/ale/engine.vim b/autoload/ale/engine.vim
index ec5ccb6d..b44be73c 100644
--- a/autoload/ale/engine.vim
+++ b/autoload/ale/engine.vim
@@ -18,6 +18,22 @@ if !has_key(s:, 'executable_cache_map')
     let s:executable_cache_map = {}
 endif
 
+
+function! ale#engine#CleanupEveryBuffer() abort
+    for l:key in keys(g:ale_buffer_info)
+        " The key could be a filename or a buffer number, so try and
+        " convert it to a number. We need a number for the other
+        " functions.
+        let l:buffer = str2nr(l:key)
+
+        if l:buffer > 0
+            " Stop all jobs and clear the results for everything, and delete
+            " all of the data we stored for the buffer.
+            call ale#engine#Cleanup(l:buffer)
+        endif
+    endfor
+endfunction
+
 function! ale#engine#ResetExecutableCache() abort
     let s:executable_cache_map = {}
 endfunction
@@ -63,6 +79,7 @@ function! ale#engine#InitBufferInfo(buffer) abort
         let g:ale_buffer_info[a:buffer] = {
         \   'job_list': [],
         \   'active_linter_list': [],
+        \   'active_other_sources_list': [],
         \   'loclist': [],
         \   'temporary_file_list': [],
         \   'temporary_directory_list': [],
@@ -81,6 +98,7 @@ function! ale#engine#IsCheckingBuffer(buffer) abort
     let l:info = get(g:ale_buffer_info, a:buffer, {})
 
     return !empty(get(l:info, 'active_linter_list', []))
+    \   || !empty(get(l:info, 'active_other_sources_list', []))
 endfunction
 
 " Register a temporary file to be managed with the ALE engine for
@@ -161,20 +179,27 @@ function! s:GatherOutput(job_id, line) abort
     endif
 endfunction
 
-function! ale#engine#HandleLoclist(linter_name, buffer, loclist) abort
+function! ale#engine#HandleLoclist(linter_name, buffer, loclist, from_other_source) abort
     let l:info = get(g:ale_buffer_info, a:buffer, {})
 
     if empty(l:info)
         return
     endif
 
-    " Remove this linter from the list of active linters.
-    " This may have already been done when the job exits.
-    call filter(l:info.active_linter_list, 'v:val isnot# a:linter_name')
+    if !a:from_other_source
+        " Remove this linter from the list of active linters.
+        " This may have already been done when the job exits.
+        call filter(l:info.active_linter_list, 'v:val isnot# a:linter_name')
+    endif
 
     " Make some adjustments to the loclists to fix common problems, and also
     " to set default values for loclist items.
-    let l:linter_loclist = ale#engine#FixLocList(a:buffer, a:linter_name, a:loclist)
+    let l:linter_loclist = ale#engine#FixLocList(
+    \   a:buffer,
+    \   a:linter_name,
+    \   a:from_other_source,
+    \   a:loclist,
+    \)
 
     " Remove previous items for this linter.
     call filter(l:info.loclist, 'v:val.linter_name isnot# a:linter_name')
@@ -231,6 +256,7 @@ function! s:HandleExit(job_id, exit_code) abort
 
     if l:next_chain_index < len(get(l:linter, 'command_chain', []))
         call s:InvokeChain(l:buffer, l:executable, l:linter, l:next_chain_index, l:output)
+
         return
     endif
 
@@ -246,7 +272,7 @@ function! s:HandleExit(job_id, exit_code) abort
         let l:loclist = []
     endtry
 
-    call ale#engine#HandleLoclist(l:linter.name, l:buffer, l:loclist)
+    call ale#engine#HandleLoclist(l:linter.name, l:buffer, l:loclist, 0)
 endfunction
 
 function! ale#engine#SetResults(buffer, loclist) abort
@@ -278,6 +304,12 @@ function! ale#engine#SetResults(buffer, loclist) abort
             call ale#cursor#EchoCursorWarning()
         endif
 
+        if g:ale_virtualtext_cursor
+            " Try and show the warning now.
+            " This will only do something meaningful if we're in normal mode.
+            call ale#virtualtext#ShowCursorWarning()
+        endif
+
         " Reset the save event marker, used for opening windows, etc.
         call setbufvar(a:buffer, 'ale_save_event_fired', 0)
         " Set a marker showing how many times a buffer has been checked.
@@ -318,7 +350,7 @@ function! s:RemapItemTypes(type_map, loclist) abort
     endfor
 endfunction
 
-function! ale#engine#FixLocList(buffer, linter_name, loclist) abort
+function! ale#engine#FixLocList(buffer, linter_name, from_other_source, loclist) abort
     let l:bufnr_map = {}
     let l:new_loclist = []
 
@@ -351,6 +383,10 @@ function! ale#engine#FixLocList(buffer, linter_name, loclist) abort
         \   'linter_name': a:linter_name,
         \}
 
+        if a:from_other_source
+            let l:item.from_other_source = 1
+        endif
+
         if has_key(l:old_item, 'code')
             let l:item.code = l:old_item.code
         endif
@@ -557,7 +593,7 @@ function! s:RunJob(options) abort
     if get(g:, 'ale_run_synchronously') == 1
         " Run a command synchronously if this test option is set.
         let s:job_info_map[l:job_id].output = systemlist(
-        \   type(l:command) == type([])
+        \   type(l:command) is v:t_list
         \   ?  join(l:command[0:1]) . ' ' . ale#Escape(l:command[2])
         \   : l:command
         \)
@@ -595,9 +631,8 @@ function! ale#engine#ProcessChain(buffer, linter, chain_index, input) abort
                 \)
             endif
 
+            " If we have a command to run, execute that.
             if !empty(l:command)
-                " We hit a command to run, so we'll execute that
-
                 " The chain item can override the output_stream option.
                 if has_key(l:chain_item, 'output_stream')
                     let l:output_stream = l:chain_item.output_stream
@@ -675,6 +710,7 @@ endfunction
 function! s:RemoveProblemsForDisabledLinters(buffer, linters) abort
     " Figure out which linters are still enabled, and remove
     " problems for linters which are no longer enabled.
+    " Problems from other sources will be kept.
     let l:name_map = {}
 
     for l:linter in a:linters
@@ -683,7 +719,7 @@ function! s:RemoveProblemsForDisabledLinters(buffer, linters) abort
 
     call filter(
     \   get(g:ale_buffer_info[a:buffer], 'loclist', []),
-    \   'get(l:name_map, get(v:val, ''linter_name''))',
+    \   'get(v:val, ''from_other_source'') || get(l:name_map, get(v:val, ''linter_name''))',
     \)
 endfunction
 
diff --git a/autoload/ale/engine/ignore.vim b/autoload/ale/engine/ignore.vim
index 65347e21..2db2c6c1 100644
--- a/autoload/ale/engine/ignore.vim
+++ b/autoload/ale/engine/ignore.vim
@@ -4,11 +4,11 @@
 " Given a filetype and a configuration for ignoring linters, return a List of
 " Strings for linter names to ignore.
 function! ale#engine#ignore#GetList(filetype, config) abort
-    if type(a:config) is type([])
+    if type(a:config) is v:t_list
         return a:config
     endif
 
-    if type(a:config) is type({})
+    if type(a:config) is v:t_dict
         let l:names_to_remove = []
 
         for l:part in split(a:filetype , '\.')
diff --git a/autoload/ale/events.vim b/autoload/ale/events.vim
index 300aefcc..c3dbd378 100644
--- a/autoload/ale/events.vim
+++ b/autoload/ale/events.vim
@@ -29,7 +29,7 @@ function! ale#events#SaveEvent(buffer) abort
         call setbufvar(a:buffer, 'ale_save_event_fired', 1)
     endif
 
-    if ale#Var(a:buffer, 'fix_on_save')
+    if ale#Var(a:buffer, 'fix_on_save') && !ale#events#QuitRecently(a:buffer)
         let l:will_fix = ale#fix#Fix(a:buffer, 'save_file')
         let l:should_lint = l:should_lint && !l:will_fix
     endif
@@ -131,13 +131,25 @@ function! ale#events#Init() abort
                 autocmd InsertLeave * call ale#Queue(0)
             endif
 
-            if g:ale_echo_cursor
+            if g:ale_echo_cursor || g:ale_cursor_detail
                 autocmd CursorMoved,CursorHold * if exists('*ale#engine#Cleanup') | call ale#cursor#EchoCursorWarningWithDelay() | endif
                 " Look for a warning to echo as soon as we leave Insert mode.
                 " The script's position variable used when moving the cursor will
                 " not be changed here.
                 autocmd InsertLeave * if exists('*ale#engine#Cleanup') | call ale#cursor#EchoCursorWarning() | endif
             endif
+
+            if g:ale_virtualtext_cursor
+                autocmd CursorMoved,CursorHold * if exists('*ale#engine#Cleanup') | call ale#virtualtext#ShowCursorWarningWithDelay() | endif
+                " Look for a warning to echo as soon as we leave Insert mode.
+                " The script's position variable used when moving the cursor will
+                " not be changed here.
+                autocmd InsertLeave * if exists('*ale#engine#Cleanup') | call ale#virtualtext#ShowCursorWarning() | endif
+            endif
+
+            if g:ale_close_preview_on_insert
+                autocmd InsertEnter * if exists('*ale#preview#CloseIfTypeMatches') | call ale#preview#CloseIfTypeMatches('ale-preview') | endif
+            endif
         endif
     augroup END
 endfunction
diff --git a/autoload/ale/fix.vim b/autoload/ale/fix.vim
index 8dfdeca8..03652ecf 100644
--- a/autoload/ale/fix.vim
+++ b/autoload/ale/fix.vim
@@ -30,7 +30,14 @@ function! ale#fix#ApplyQueuedFixes() abort
             call winrestview(l:save)
         endif
 
-        call setline(1, l:data.output)
+        " If the file is in DOS mode, we have to remove carriage returns from
+        " the ends of lines before calling setline(), or we will see them
+        " twice.
+        let l:lines_to_set = getbufvar(l:buffer, '&fileformat') is# 'dos'
+        \   ? map(copy(l:data.output), 'substitute(v:val, ''\r\+$'', '''', '''')')
+        \   : l:data.output
+
+        call setline(1, l:lines_to_set)
 
         if l:data.should_save
             if empty(&buftype)
@@ -71,6 +78,7 @@ function! ale#fix#ApplyFixes(buffer, output) abort
         if l:data.lines_before != l:lines
             call remove(g:ale_fix_buffer_data, a:buffer)
             execute 'echoerr ''The file was changed before fixing finished'''
+
             return
         endif
     endif
@@ -275,7 +283,7 @@ function! s:RunJob(options) abort
     if get(g:, 'ale_run_synchronously') == 1
         " Run a command synchronously if this test option is set.
         let l:output = systemlist(
-        \   type(l:command) == type([])
+        \   type(l:command) is v:t_list
         \   ?  join(l:command[0:1]) . ' ' . ale#Escape(l:command[2])
         \   : l:command
         \)
@@ -313,10 +321,10 @@ function! s:RunFixer(options) abort
             \   : call(l:Function, [l:buffer, copy(l:input)])
         endif
 
-        if type(l:result) == type(0) && l:result == 0
+        if type(l:result) is v:t_number && l:result == 0
             " When `0` is returned, skip this item.
             let l:index += 1
-        elseif type(l:result) == type([])
+        elseif type(l:result) is v:t_list
             let l:input = l:result
             let l:index += 1
         else
@@ -351,9 +359,9 @@ function! s:RunFixer(options) abort
 endfunction
 
 function! s:AddSubCallbacks(full_list, callbacks) abort
-    if type(a:callbacks) == type('')
+    if type(a:callbacks) is v:t_string
         call add(a:full_list, a:callbacks)
-    elseif type(a:callbacks) == type([])
+    elseif type(a:callbacks) is v:t_list
         call extend(a:full_list, a:callbacks)
     else
         return 0
@@ -365,7 +373,7 @@ endfunction
 function! s:GetCallbacks(buffer, fixers) abort
     if len(a:fixers)
         let l:callback_list = a:fixers
-    elseif type(get(b:, 'ale_fixers')) is type([])
+    elseif type(get(b:, 'ale_fixers')) is v:t_list
         " Lists can be used for buffer-local variables only
         let l:callback_list = b:ale_fixers
     else
@@ -396,7 +404,7 @@ function! s:GetCallbacks(buffer, fixers) abort
     " Variables with capital characters are needed, or Vim will complain about
     " funcref variables.
     for l:Item in l:callback_list
-        if type(l:Item) == type('')
+        if type(l:Item) is v:t_string
             let l:Func = ale#fix#registry#GetFunc(l:Item)
 
             if !empty(l:Func)
diff --git a/autoload/ale/fix/registry.vim b/autoload/ale/fix/registry.vim
index e148ecd6..a54be420 100644
--- a/autoload/ale/fix/registry.vim
+++ b/autoload/ale/fix/registry.vim
@@ -56,7 +56,7 @@ let s:default_registry = {
 \   },
 \   'prettier': {
 \       'function': 'ale#fixers#prettier#Fix',
-\       'suggested_filetypes': ['javascript', 'typescript', 'css', 'less', 'scss', 'json', 'json5', 'graphql', 'markdown', 'vue'],
+\       'suggested_filetypes': ['javascript', 'typescript', 'css', 'less', 'scss', 'json', 'json5', 'graphql', 'markdown', 'vue', 'html', 'yaml'],
 \       'description': 'Apply prettier to a file.',
 \   },
 \   'prettier_eslint': {
@@ -145,6 +145,11 @@ let s:default_registry = {
 \       'suggested_filetypes': ['go'],
 \       'description': 'Fix Go files imports with goimports.',
 \   },
+\   'gomod': {
+\       'function': 'ale#fixers#gomod#Fix',
+\       'suggested_filetypes': ['gomod'],
+\       'description': 'Fix Go module files with go mod edit -fmt.',
+\   },
 \   'tslint': {
 \       'function': 'ale#fixers#tslint#Fix',
 \       'suggested_filetypes': ['typescript'],
@@ -157,7 +162,7 @@ let s:default_registry = {
 \   },
 \   'hackfmt': {
 \       'function': 'ale#fixers#hackfmt#Fix',
-\       'suggested_filetypes': ['php'],
+\       'suggested_filetypes': ['hack'],
 \       'description': 'Fix Hack files with hackfmt.',
 \   },
 \   'hfmt': {
@@ -170,6 +175,21 @@ let s:default_registry = {
 \       'suggested_filetypes': ['haskell'],
 \       'description': 'Fix Haskell files with brittany.',
 \   },
+\   'hlint': {
+\       'function': 'ale#fixers#hlint#Fix',
+\       'suggested_filetypes': ['haskell'],
+\       'description': 'Refactor Haskell files with hlint.',
+\   },
+\   'stylish-haskell': {
+\       'function': 'ale#fixers#stylish_haskell#Fix',
+\       'suggested_filetypes': ['haskell'],
+\       'description': 'Refactor Haskell files with stylish-haskell.',
+\   },
+\   'ocamlformat': {
+\       'function': 'ale#fixers#ocamlformat#Fix',
+\       'suggested_filetypes': ['ocaml'],
+\       'description': 'Fix OCaml files with ocamlformat.',
+\   },
 \   'refmt': {
 \       'function': 'ale#fixers#refmt#Fix',
 \       'suggested_filetypes': ['reason'],
@@ -180,6 +200,11 @@ let s:default_registry = {
 \       'suggested_filetypes': ['sh'],
 \       'description': 'Fix sh files with shfmt.',
 \   },
+\   'sqlfmt': {
+\       'function': 'ale#fixers#sqlfmt#Fix',
+\       'suggested_filetypes': ['sql'],
+\       'description': 'Fix SQL files with sqlfmt.',
+\   },
 \   'google_java_format': {
 \       'function': 'ale#fixers#google_java_format#Fix',
 \       'suggested_filetypes': ['java'],
@@ -215,6 +240,21 @@ let s:default_registry = {
 \       'suggested_filetypes': ['dart'],
 \       'description': 'Fix Dart files with dartfmt.',
 \   },
+\   'xmllint': {
+\       'function': 'ale#fixers#xmllint#Fix',
+\       'suggested_filetypes': ['xml'],
+\       'description': 'Fix XML files with xmllint.',
+\   },
+\   'uncrustify': {
+\       'function': 'ale#fixers#uncrustify#Fix',
+\       'suggested_filetypes': ['c', 'cpp', 'cs', 'objc', 'objcpp', 'd', 'java', 'p', 'vala' ],
+\       'description': 'Fix C, C++, C#, ObjectiveC, ObjectiveC++, D, Java, Pawn, and VALA files with uncrustify.',
+\   },
+\   'terraform': {
+\       'function': 'ale#fixers#terraform#Fix',
+\       'suggested_filetypes': ['hcl', 'terraform'],
+\       'description': 'Fix tf and hcl files with terraform fmt.',
+\   },
 \}
 
 " Reset the function registry to the default entries.
@@ -243,34 +283,34 @@ endfunction
 " (name, func, filetypes, desc, aliases)
 function! ale#fix#registry#Add(name, func, filetypes, desc, ...) abort
     " This command will throw from the sandbox.
-    let &equalprg=&equalprg
+    let &l:equalprg=&l:equalprg
 
-    if type(a:name) != type('')
+    if type(a:name) isnot v:t_string
         throw '''name'' must be a String'
     endif
 
-    if type(a:func) != type('')
+    if type(a:func) isnot v:t_string
         throw '''func'' must be a String'
     endif
 
-    if type(a:filetypes) != type([])
+    if type(a:filetypes) isnot v:t_list
         throw '''filetypes'' must be a List'
     endif
 
     for l:type in a:filetypes
-        if type(l:type) != type('')
+        if type(l:type) isnot v:t_string
             throw 'Each entry of ''filetypes'' must be a String'
         endif
     endfor
 
-    if type(a:desc) != type('')
+    if type(a:desc) isnot v:t_string
         throw '''desc'' must be a String'
     endif
 
     let l:aliases = get(a:000, 0, [])
 
-    if type(l:aliases) != type([])
-    \|| !empty(filter(copy(l:aliases), 'type(v:val) != type('''')'))
+    if type(l:aliases) isnot v:t_list
+    \|| !empty(filter(copy(l:aliases), 'type(v:val) isnot v:t_string'))
         throw '''aliases'' must be a List of String values'
     endif
 
diff --git a/autoload/ale/fixers/brittany.vim b/autoload/ale/fixers/brittany.vim
index 57c77325..c2448348 100644
--- a/autoload/ale/fixers/brittany.vim
+++ b/autoload/ale/fixers/brittany.vim
@@ -3,11 +3,17 @@
 
 call ale#Set('haskell_brittany_executable', 'brittany')
 
-function! ale#fixers#brittany#Fix(buffer) abort
+function! ale#fixers#brittany#GetExecutable(buffer) abort
     let l:executable = ale#Var(a:buffer, 'haskell_brittany_executable')
 
+    return ale#handlers#haskell_stack#EscapeExecutable(l:executable, 'brittany')
+endfunction
+
+function! ale#fixers#brittany#Fix(buffer) abort
+    let l:executable = ale#fixers#brittany#GetExecutable(a:buffer)
+
     return {
-    \   'command': ale#Escape(l:executable)
+    \   'command': l:executable
     \       . ' --write-mode inplace'
     \       . ' %t',
     \   'read_temporary_file': 1,
diff --git a/autoload/ale/fixers/eslint.vim b/autoload/ale/fixers/eslint.vim
index 36f47510..ea5b2a63 100644
--- a/autoload/ale/fixers/eslint.vim
+++ b/autoload/ale/fixers/eslint.vim
@@ -25,7 +25,7 @@ endfunction
 function! ale#fixers#eslint#ProcessEslintDOutput(buffer, output) abort
     " If the output is an error message, don't use it.
     for l:line in a:output[:10]
-        if l:line =~# '^Error:'
+        if l:line =~# '\v^Error:|^Could not connect'
             return []
         endif
     endfor
diff --git a/autoload/ale/fixers/fixjson.vim b/autoload/ale/fixers/fixjson.vim
index 64c6ba81..33ce0af3 100644
--- a/autoload/ale/fixers/fixjson.vim
+++ b/autoload/ale/fixers/fixjson.vim
@@ -17,6 +17,7 @@ function! ale#fixers#fixjson#Fix(buffer) abort
     let l:command = l:executable . ' --stdin-filename ' . l:filename
 
     let l:options = ale#Var(a:buffer, 'json_fixjson_options')
+
     if l:options isnot# ''
         let l:command .= ' ' . l:options
     endif
diff --git a/autoload/ale/fixers/generic_python.vim b/autoload/ale/fixers/generic_python.vim
index 124146be..d55a23c3 100644
--- a/autoload/ale/fixers/generic_python.vim
+++ b/autoload/ale/fixers/generic_python.vim
@@ -6,13 +6,28 @@ function! ale#fixers#generic_python#AddLinesBeforeControlStatements(buffer, line
     let l:new_lines = []
     let l:last_indent_size = 0
     let l:last_line_is_blank = 0
+    let l:in_docstring = 0
 
     for l:line in a:lines
         let l:indent_size = len(matchstr(l:line, '^ *'))
 
+        if !l:in_docstring
+            " Make sure it is not just a single line docstring and then verify
+            " it's starting a new docstring
+            if match(l:line, '\v^ *("""|'''''').*("""|'''''')') == -1
+            \&& match(l:line, '\v^ *("""|'''''')') >= 0
+                let l:in_docstring = 1
+            endif
+        else
+            if match(l:line, '\v^ *.*("""|'''''')') >= 0
+                let l:in_docstring = 0
+            endif
+        endif
+
         if !l:last_line_is_blank
+        \&& !l:in_docstring
         \&& l:indent_size <= l:last_indent_size
-        \&& match(l:line, '\v^ *(return|if|for|while|break|continue)') >= 0
+        \&& match(l:line, '\v^ *(return|if|for|while|break|continue)(\(| |$)') >= 0
             call add(l:new_lines, '')
         endif
 
diff --git a/autoload/ale/fixers/gomod.vim b/autoload/ale/fixers/gomod.vim
new file mode 100644
index 00000000..68895f9b
--- /dev/null
+++ b/autoload/ale/fixers/gomod.vim
@@ -0,0 +1,10 @@
+call ale#Set('go_go_executable', 'go')
+
+function! ale#fixers#gomod#Fix(buffer) abort
+    let l:executable = ale#Var(a:buffer, 'go_go_executable')
+
+    return {
+    \   'command': ale#Escape(l:executable) . ' mod edit -fmt %t',
+    \   'read_temporary_file': 1,
+    \}
+endfunction
diff --git a/autoload/ale/fixers/google_java_format.vim b/autoload/ale/fixers/google_java_format.vim
index 6a2f5491..20086c73 100644
--- a/autoload/ale/fixers/google_java_format.vim
+++ b/autoload/ale/fixers/google_java_format.vim
@@ -1,13 +1,13 @@
 " Author: butlerx <butlerx@notthe,cloud>
 " Description: Integration of Google-java-format with ALE.
 
-call ale#Set('google_java_format_executable', 'google-java-format')
-call ale#Set('google_java_format_use_global', get(g:, 'ale_use_global_executables', 0))
-call ale#Set('google_java_format_options', '')
+call ale#Set('java_google_java_format_executable', 'google-java-format')
+call ale#Set('java_google_java_format_use_global', get(g:, 'ale_use_global_executables', 0))
+call ale#Set('java_google_java_format_options', '')
 
 function! ale#fixers#google_java_format#Fix(buffer) abort
-    let l:options = ale#Var(a:buffer, 'google_java_format_options')
-    let l:executable = ale#Var(a:buffer, 'google_java_format_executable')
+    let l:options = ale#Var(a:buffer, 'java_google_java_format_options')
+    let l:executable = ale#Var(a:buffer, 'java_google_java_format_executable')
 
     if !executable(l:executable)
         return 0
diff --git a/autoload/ale/fixers/hackfmt.vim b/autoload/ale/fixers/hackfmt.vim
index b5bf0dc5..bf2d4f71 100644
--- a/autoload/ale/fixers/hackfmt.vim
+++ b/autoload/ale/fixers/hackfmt.vim
@@ -1,12 +1,12 @@
 " Author: Sam Howie <samhowie@gmail.com>
 " Description: Integration of hackfmt with ALE.
 
-call ale#Set('php_hackfmt_executable', 'hackfmt')
-call ale#Set('php_hackfmt_options', '')
+call ale#Set('hack_hackfmt_executable', 'hackfmt')
+call ale#Set('hack_hackfmt_options', '')
 
 function! ale#fixers#hackfmt#Fix(buffer) abort
-    let l:executable = ale#Var(a:buffer, 'php_hackfmt_executable')
-    let l:options = ale#Var(a:buffer, 'php_hackfmt_options')
+    let l:executable = ale#Var(a:buffer, 'hack_hackfmt_executable')
+    let l:options = ale#Var(a:buffer, 'hack_hackfmt_options')
 
     return {
     \   'command': ale#Escape(l:executable)
diff --git a/autoload/ale/fixers/hfmt.vim b/autoload/ale/fixers/hfmt.vim
index ea061da4..0407b713 100644
--- a/autoload/ale/fixers/hfmt.vim
+++ b/autoload/ale/fixers/hfmt.vim
@@ -7,7 +7,7 @@ function! ale#fixers#hfmt#Fix(buffer) abort
     let l:executable = ale#Var(a:buffer, 'haskell_hfmt_executable')
 
     return {
-    \   'command': ale#Escape(l:executable)
+    \   'command': ale#handlers#haskell_stack#EscapeExecutable(l:executable, 'hfmt')
     \       . ' -w'
     \       . ' %t',
     \   'read_temporary_file': 1,
diff --git a/autoload/ale/fixers/hlint.vim b/autoload/ale/fixers/hlint.vim
new file mode 100644
index 00000000..88779a55
--- /dev/null
+++ b/autoload/ale/fixers/hlint.vim
@@ -0,0 +1,13 @@
+" Author: eborden <evan@evan-borden.com>
+" Description: Integration of hlint refactor with ALE.
+"
+
+function! ale#fixers#hlint#Fix(buffer) abort
+    return {
+    \   'command': ale#handlers#hlint#GetExecutable(a:buffer)
+    \       . ' --refactor'
+    \       . ' --refactor-options="--inplace"'
+    \       . ' %t',
+    \   'read_temporary_file': 1,
+    \}
+endfunction
diff --git a/autoload/ale/fixers/importjs.vim b/autoload/ale/fixers/importjs.vim
index e8eedb12..b5487b2c 100644
--- a/autoload/ale/fixers/importjs.vim
+++ b/autoload/ale/fixers/importjs.vim
@@ -1,15 +1,16 @@
 " Author: Jeff Willette <jrwillette88@gmail.com>
 " Description: Integration of importjs with ALE.
 
-call ale#Set('js_importjs_executable', 'importjs')
+call ale#Set('javascript_importjs_executable', 'importjs')
 
 function! ale#fixers#importjs#ProcessOutput(buffer, output) abort
     let l:result = ale#util#FuzzyJSONDecode(a:output, [])
+
     return split(get(l:result, 'fileContent', ''), "\n")
 endfunction
 
 function! ale#fixers#importjs#Fix(buffer) abort
-    let l:executable = ale#Var(a:buffer, 'js_importjs_executable')
+    let l:executable = ale#Var(a:buffer, 'javascript_importjs_executable')
 
     if !executable(l:executable)
         return 0
diff --git a/autoload/ale/fixers/jq.vim b/autoload/ale/fixers/jq.vim
index b0a43fe2..1b743e49 100644
--- a/autoload/ale/fixers/jq.vim
+++ b/autoload/ale/fixers/jq.vim
@@ -1,5 +1,6 @@
 call ale#Set('json_jq_executable', 'jq')
 call ale#Set('json_jq_options', '')
+call ale#Set('json_jq_filters', '.')
 
 function! ale#fixers#jq#GetExecutable(buffer) abort
     return ale#Var(a:buffer, 'json_jq_executable')
@@ -7,9 +8,15 @@ endfunction
 
 function! ale#fixers#jq#Fix(buffer) abort
      let l:options = ale#Var(a:buffer, 'json_jq_options')
+     let l:filters = ale#Var(a:buffer, 'json_jq_filters')
+
+     if empty(l:filters)
+         return 0
+     endif
 
      return {
      \  'command': ale#Escape(ale#fixers#jq#GetExecutable(a:buffer))
-     \      . ' . ' . l:options,
+     \      . ' ' . l:filters . ' '
+     \      . l:options,
      \}
 endfunction
diff --git a/autoload/ale/fixers/ocamlformat.vim b/autoload/ale/fixers/ocamlformat.vim
new file mode 100644
index 00000000..9b7c3e12
--- /dev/null
+++ b/autoload/ale/fixers/ocamlformat.vim
@@ -0,0 +1,18 @@
+" Author: Stephen Lumenta <@sbl>
+" Description: Integration of ocamlformat with ALE.
+
+call ale#Set('ocaml_ocamlformat_executable', 'ocamlformat')
+call ale#Set('ocaml_ocamlformat_options', '')
+
+function! ale#fixers#ocamlformat#Fix(buffer) abort
+    let l:filename = expand('#' . a:buffer . ':p')
+    let l:executable = ale#Var(a:buffer, 'ocaml_ocamlformat_executable')
+    let l:options = ale#Var(a:buffer, 'ocaml_ocamlformat_options')
+
+    return {
+    \   'command': ale#Escape(l:executable)
+    \       . (empty(l:options) ? '' : ' ' . l:options)
+    \       . ' --name=' . ale#Escape(l:filename)
+    \       . ' -'
+    \}
+endfunction
diff --git a/autoload/ale/fixers/php_cs_fixer.vim b/autoload/ale/fixers/php_cs_fixer.vim
index 26b8e5de..5c59e262 100644
--- a/autoload/ale/fixers/php_cs_fixer.vim
+++ b/autoload/ale/fixers/php_cs_fixer.vim
@@ -14,6 +14,7 @@ endfunction
 
 function! ale#fixers#php_cs_fixer#Fix(buffer) abort
     let l:executable = ale#fixers#php_cs_fixer#GetExecutable(a:buffer)
+
     return {
     \   'command': ale#Escape(l:executable)
     \       . ' ' . ale#Var(a:buffer, 'php_cs_fixer_options')
diff --git a/autoload/ale/fixers/phpcbf.vim b/autoload/ale/fixers/phpcbf.vim
index 487f369a..f14b8406 100644
--- a/autoload/ale/fixers/phpcbf.vim
+++ b/autoload/ale/fixers/phpcbf.vim
@@ -18,6 +18,7 @@ function! ale#fixers#phpcbf#Fix(buffer) abort
     let l:standard_option = !empty(l:standard)
     \   ? '--standard=' . l:standard
     \   : ''
+
     return {
     \   'command': ale#Escape(l:executable) . ' --stdin-path=%s ' . l:standard_option . ' -'
     \}
diff --git a/autoload/ale/fixers/prettier.vim b/autoload/ale/fixers/prettier.vim
index e8f4e92e..58dea159 100644
--- a/autoload/ale/fixers/prettier.vim
+++ b/autoload/ale/fixers/prettier.vim
@@ -27,6 +27,17 @@ function! ale#fixers#prettier#Fix(buffer) abort
     \}
 endfunction
 
+function! ale#fixers#prettier#ProcessPrettierDOutput(buffer, output) abort
+    " If the output is an error message, don't use it.
+    for l:line in a:output[:10]
+        if l:line =~# '^\w*Error:'
+            return []
+        endif
+    endfor
+
+    return a:output
+endfunction
+
 function! ale#fixers#prettier#ApplyFixForVersion(buffer, version_output) abort
     let l:executable = ale#fixers#prettier#GetExecutable(a:buffer)
     let l:options = ale#Var(a:buffer, 'javascript_prettier_options')
@@ -36,12 +47,24 @@ function! ale#fixers#prettier#ApplyFixForVersion(buffer, version_output) abort
     " Append the --parser flag depending on the current filetype (unless it's
     " already set in g:javascript_prettier_options).
     if empty(expand('#' . a:buffer . ':e')) && match(l:options, '--parser') == -1
-        let l:prettier_parsers = ['typescript', 'css', 'less', 'scss', 'json', 'json5', 'graphql', 'markdown', 'vue']
-        let l:parser = 'babylon'
+        let l:prettier_parsers = {
+        \    'typescript': 'typescript',
+        \    'css': 'css',
+        \    'less': 'less',
+        \    'scss': 'scss',
+        \    'json': 'json',
+        \    'json5': 'json5',
+        \    'graphql': 'graphql',
+        \    'markdown': 'markdown',
+        \    'vue': 'vue',
+        \    'yaml': 'yaml',
+        \    'html': 'html',
+        \}
+        let l:parser = ''
 
         for l:filetype in split(getbufvar(a:buffer, '&filetype'), '\.')
-            if index(l:prettier_parsers, l:filetype) > -1
-                let l:parser = l:filetype
+            if has_key(l:prettier_parsers, l:filetype)
+                let l:parser = l:prettier_parsers[l:filetype]
                 break
             endif
         endfor
@@ -51,6 +74,17 @@ function! ale#fixers#prettier#ApplyFixForVersion(buffer, version_output) abort
         let l:options = (!empty(l:options) ? l:options . ' ' : '') . '--parser ' . l:parser
     endif
 
+    " Special error handling needed for prettier_d
+    if l:executable =~# 'prettier_d$'
+        return {
+        \   'command': ale#path#BufferCdString(a:buffer)
+        \       . ale#Escape(l:executable)
+        \       . (!empty(l:options) ? ' ' . l:options : '')
+        \       . ' --stdin-filepath %s --stdin',
+        \   'process_with': 'ale#fixers#prettier#ProcessPrettierDOutput',
+        \}
+    endif
+
     " 1.4.0 is the first version with --stdin-filepath
     if ale#semver#GTE(l:version, [1, 4, 0])
         return {
diff --git a/autoload/ale/fixers/puppetlint.vim b/autoload/ale/fixers/puppetlint.vim
index 81f34e89..bf36e486 100644
--- a/autoload/ale/fixers/puppetlint.vim
+++ b/autoload/ale/fixers/puppetlint.vim
@@ -4,6 +4,7 @@
 if !exists('g:ale_puppet_puppetlint_executable')
     let g:ale_puppet_puppetlint_executable = 'puppet-lint'
 endif
+
 if !exists('g:ale_puppet_puppetlint_options')
     let g:ale_puppet_puppetlint_options = ''
 endif
diff --git a/autoload/ale/fixers/rubocop.vim b/autoload/ale/fixers/rubocop.vim
index 35569b19..33ba6887 100644
--- a/autoload/ale/fixers/rubocop.vim
+++ b/autoload/ale/fixers/rubocop.vim
@@ -1,16 +1,15 @@
+call ale#Set('ruby_rubocop_options', '')
+call ale#Set('ruby_rubocop_executable', 'rubocop')
+
 function! ale#fixers#rubocop#GetCommand(buffer) abort
-    let l:executable = ale#handlers#rubocop#GetExecutable(a:buffer)
-    let l:exec_args = l:executable =~? 'bundle$'
-    \   ? ' exec rubocop'
-    \   : ''
+    let l:executable = ale#Var(a:buffer, 'ruby_rubocop_executable')
     let l:config = ale#path#FindNearestFile(a:buffer, '.rubocop.yml')
     let l:options = ale#Var(a:buffer, 'ruby_rubocop_options')
 
-    return ale#Escape(l:executable) . l:exec_args
+    return ale#handlers#ruby#EscapeExecutable(l:executable, 'rubocop')
     \   . (!empty(l:config) ? ' --config ' . ale#Escape(l:config) : '')
     \   . (!empty(l:options) ? ' ' . l:options : '')
-    \   . ' --auto-correct %t'
-
+    \   . ' --auto-correct --force-exclusion %t'
 endfunction
 
 function! ale#fixers#rubocop#Fix(buffer) abort
diff --git a/autoload/ale/fixers/scalafmt.vim b/autoload/ale/fixers/scalafmt.vim
index 07d28275..dd0e7745 100644
--- a/autoload/ale/fixers/scalafmt.vim
+++ b/autoload/ale/fixers/scalafmt.vim
@@ -15,7 +15,6 @@ function! ale#fixers#scalafmt#GetCommand(buffer) abort
     return ale#Escape(l:executable) . l:exec_args
     \   . (empty(l:options) ? '' : ' ' . l:options)
     \   . ' %t'
-
 endfunction
 
 function! ale#fixers#scalafmt#Fix(buffer) abort
diff --git a/autoload/ale/fixers/shfmt.vim b/autoload/ale/fixers/shfmt.vim
index 882cf3a4..06e8da57 100644
--- a/autoload/ale/fixers/shfmt.vim
+++ b/autoload/ale/fixers/shfmt.vim
@@ -5,13 +5,27 @@ scriptencoding utf-8
 call ale#Set('sh_shfmt_executable', 'shfmt')
 call ale#Set('sh_shfmt_options', '')
 
+function! s:DefaultOption(buffer) abort
+    if getbufvar(a:buffer, '&expandtab') == 0
+        " Tab is used by default
+        return ''
+    endif
+
+    let l:tabsize = getbufvar(a:buffer, '&shiftwidth')
+
+    if l:tabsize == 0
+        let l:tabsize = getbufvar(a:buffer, '&tabstop')
+    endif
+
+    return ' -i ' . l:tabsize
+endfunction
+
 function! ale#fixers#shfmt#Fix(buffer) abort
     let l:executable = ale#Var(a:buffer, 'sh_shfmt_executable')
     let l:options = ale#Var(a:buffer, 'sh_shfmt_options')
 
     return {
     \   'command': ale#Escape(l:executable)
-    \       . (empty(l:options) ? '' : ' ' . l:options)
+    \       . (empty(l:options) ? s:DefaultOption(a:buffer) : ' ' . l:options)
     \}
-
 endfunction
diff --git a/autoload/ale/fixers/sqlfmt.vim b/autoload/ale/fixers/sqlfmt.vim
new file mode 100644
index 00000000..c88a8ec2
--- /dev/null
+++ b/autoload/ale/fixers/sqlfmt.vim
@@ -0,0 +1,13 @@
+call ale#Set('sql_sqlfmt_executable', 'sqlfmt')
+call ale#Set('sql_sqlfmt_options', '')
+
+function! ale#fixers#sqlfmt#Fix(buffer) abort
+    let l:executable = ale#Var(a:buffer, 'sql_sqlfmt_executable')
+    let l:options = ale#Var(a:buffer, 'sql_sqlfmt_options')
+
+    return {
+    \   'command': ale#Escape(l:executable)
+    \       . ' -w'
+    \       . (empty(l:options) ? '' : ' ' . l:options),
+    \}
+endfunction
diff --git a/autoload/ale/fixers/stylish_haskell.vim b/autoload/ale/fixers/stylish_haskell.vim
new file mode 100644
index 00000000..ce71c1ce
--- /dev/null
+++ b/autoload/ale/fixers/stylish_haskell.vim
@@ -0,0 +1,21 @@
+" Author: eborden <evan@evan-borden.com>
+" Description: Integration of stylish-haskell formatting with ALE.
+"
+call ale#Set('haskell_stylish_haskell_executable', 'stylish-haskell')
+
+function! ale#fixers#stylish_haskell#GetExecutable(buffer) abort
+    let l:executable = ale#Var(a:buffer, 'haskell_stylish_haskell_executable')
+
+    return ale#handlers#haskell_stack#EscapeExecutable(l:executable, 'stylish-haskell')
+endfunction
+
+function! ale#fixers#stylish_haskell#Fix(buffer) abort
+    let l:executable = ale#fixers#stylish_haskell#GetExecutable(a:buffer)
+
+    return {
+    \   'command': l:executable
+    \       . ' --inplace'
+    \       . ' %t',
+    \   'read_temporary_file': 1,
+    \}
+endfunction
diff --git a/autoload/ale/fixers/terraform.vim b/autoload/ale/fixers/terraform.vim
new file mode 100644
index 00000000..bc05380a
--- /dev/null
+++ b/autoload/ale/fixers/terraform.vim
@@ -0,0 +1,17 @@
+" Author: dsifford <dereksifford@gmail.com>
+" Description: Fixer for terraform and .hcl files
+
+call ale#Set('terraform_fmt_executable', 'terraform')
+call ale#Set('terraform_fmt_options', '')
+
+function! ale#fixers#terraform#Fix(buffer) abort
+    let l:executable = ale#Var(a:buffer, 'terraform_fmt_executable')
+    let l:options = ale#Var(a:buffer, 'terraform_fmt_options')
+
+    return {
+    \   'command': ale#Escape(l:executable)
+    \       . ' fmt'
+    \       . (empty(l:options) ? '' : ' ' . l:options)
+    \       . ' -'
+    \}
+endfunction
diff --git a/autoload/ale/fixers/uncrustify.vim b/autoload/ale/fixers/uncrustify.vim
new file mode 100644
index 00000000..ffec18ef
--- /dev/null
+++ b/autoload/ale/fixers/uncrustify.vim
@@ -0,0 +1,16 @@
+" Author: Derek P Sifford <dereksifford@gmail.com>
+" Description: Fixer for C, C++, C#, ObjectiveC, D, Java, Pawn, and VALA.
+
+call ale#Set('c_uncrustify_executable', 'uncrustify')
+call ale#Set('c_uncrustify_options', '')
+
+function! ale#fixers#uncrustify#Fix(buffer) abort
+    let l:executable = ale#Var(a:buffer, 'c_uncrustify_executable')
+    let l:options = ale#Var(a:buffer, 'c_uncrustify_options')
+
+    return {
+    \   'command': ale#Escape(l:executable)
+    \       . ' --no-backup'
+    \       . (empty(l:options) ? '' : ' ' . l:options)
+    \}
+endfunction
diff --git a/autoload/ale/fixers/xmllint.vim b/autoload/ale/fixers/xmllint.vim
new file mode 100644
index 00000000..b14ffd36
--- /dev/null
+++ b/autoload/ale/fixers/xmllint.vim
@@ -0,0 +1,29 @@
+" Author: Cyril Roelandt <tipecaml@gmail.com>
+" Description: Integration of xmllint with ALE.
+
+call ale#Set('xml_xmllint_executable', 'xmllint')
+call ale#Set('xml_xmllint_options', '')
+call ale#Set('xml_xmllint_indentsize', 2)
+
+function! ale#fixers#xmllint#Fix(buffer) abort
+    let l:executable = ale#Escape(ale#Var(a:buffer, 'xml_xmllint_executable'))
+    let l:filename = ale#Escape(bufname(a:buffer))
+    let l:command = l:executable . ' --format ' . l:filename
+
+    let l:indent = ale#Var(a:buffer, 'xml_xmllint_indentsize')
+
+    if l:indent isnot# ''
+        let l:env = ale#Env('XMLLINT_INDENT', repeat(' ', l:indent))
+        let l:command = l:env . l:command
+    endif
+
+    let l:options = ale#Var(a:buffer, 'xml_xmllint_options')
+
+    if l:options isnot# ''
+        let l:command .= ' ' . l:options
+    endif
+
+    return {
+    \   'command': l:command
+    \}
+endfunction
diff --git a/autoload/ale/go.vim b/autoload/ale/go.vim
new file mode 100644
index 00000000..a166480a
--- /dev/null
+++ b/autoload/ale/go.vim
@@ -0,0 +1,27 @@
+" Author: Horacio Sanson https://github.com/hsanson
+" Description: Functions for integrating with Go tools
+
+" Find the nearest dir listed in GOPATH and assume it the root of the go
+" project.
+function! ale#go#FindProjectRoot(buffer) abort
+    let l:sep = has('win32') ? ';' : ':'
+
+    let l:filename = ale#path#Simplify(expand('#' . a:buffer . ':p'))
+
+    for l:name in split($GOPATH, l:sep)
+      let l:path_dir = ale#path#Simplify(l:name)
+
+      " Use the directory from GOPATH if the current filename starts with it.
+      if l:filename[: len(l:path_dir) - 1] is? l:path_dir
+          return l:path_dir
+      endif
+    endfor
+
+    let l:default_go_path = ale#path#Simplify(expand('~/go'))
+
+    if isdirectory(l:default_go_path)
+      return l:default_go_path
+    endif
+
+    return ''
+endfunction
diff --git a/autoload/ale/handlers/ccls.vim b/autoload/ale/handlers/ccls.vim
new file mode 100644
index 00000000..29dd6aed
--- /dev/null
+++ b/autoload/ale/handlers/ccls.vim
@@ -0,0 +1,17 @@
+scriptencoding utf-8
+" Author: Ye Jingchen <ye.jingchen@gmail.com>
+" Description: Utilities for ccls
+
+function! ale#handlers#ccls#GetProjectRoot(buffer) abort
+    let l:project_root = ale#path#FindNearestFile(a:buffer, '.ccls-root')
+
+    if empty(l:project_root)
+        let l:project_root = ale#path#FindNearestFile(a:buffer, 'compile_commands.json')
+    endif
+
+    if empty(l:project_root)
+        let l:project_root = ale#path#FindNearestFile(a:buffer, '.ccls')
+    endif
+
+    return !empty(l:project_root) ? fnamemodify(l:project_root, ':h') : ''
+endfunction
diff --git a/autoload/ale/handlers/elixir.vim b/autoload/ale/handlers/elixir.vim
new file mode 100644
index 00000000..2fddf8e7
--- /dev/null
+++ b/autoload/ale/handlers/elixir.vim
@@ -0,0 +1,28 @@
+" Author: Matteo Centenaro (bugant) - https://github.com/bugant
+" Author: Jon Parise <jon@indelible.org>
+" Description: Functions for working with Elixir projects
+
+" Find the root directory for an elixir project that uses mix.
+function! ale#handlers#elixir#FindMixProjectRoot(buffer) abort
+    let l:mix_file = ale#path#FindNearestFile(a:buffer, 'mix.exs')
+
+    if !empty(l:mix_file)
+        return fnamemodify(l:mix_file, ':p:h')
+    endif
+
+    return '.'
+endfunction
+
+" Similar to ale#handlers#elixir#FindMixProjectRoot but also continue the
+" search upward for a potential umbrella project root. If an umbrella root
+" does not exist, the initial project root will be returned.
+function! ale#handlers#elixir#FindMixUmbrellaRoot(buffer) abort
+    let l:app_root = ale#handlers#elixir#FindMixProjectRoot(a:buffer)
+    let l:umbrella_root = fnamemodify(l:app_root, ':h:h')
+
+    if filereadable(l:umbrella_root . '/mix.exs')
+        return l:umbrella_root
+    endif
+
+    return l:app_root
+endfunction
diff --git a/autoload/ale/handlers/eslint.vim b/autoload/ale/handlers/eslint.vim
index bc10ec21..eda033e4 100644
--- a/autoload/ale/handlers/eslint.vim
+++ b/autoload/ale/handlers/eslint.vim
@@ -99,6 +99,13 @@ function! ale#handlers#eslint#Handle(buffer, lines) abort
         \}]
     endif
 
+    if a:lines == ['Could not connect']
+        return [{
+        \   'lnum': 1,
+        \   'text': 'Could not connect to eslint_d. Try updating eslint_d or killing it.',
+        \}]
+    endif
+
     " Matches patterns line the following:
     "
     " /path/to/some-filename.js:47:14: Missing trailing comma. [Warning/comma-dangle]
diff --git a/autoload/ale/handlers/gawk.vim b/autoload/ale/handlers/gawk.vim
index 942bc2b2..50bc4c45 100644
--- a/autoload/ale/handlers/gawk.vim
+++ b/autoload/ale/handlers/gawk.vim
@@ -9,9 +9,11 @@ function! ale#handlers#gawk#HandleGawkFormat(buffer, lines) abort
 
     for l:match in ale#util#GetMatches(a:lines, l:pattern)
         let l:ecode = 'E'
+
         if l:match[2] is? 'warning:'
             let l:ecode = 'W'
         endif
+
         call add(l:output, {
         \   'lnum': l:match[1] + 0,
         \   'col': 0,
diff --git a/autoload/ale/handlers/gcc.vim b/autoload/ale/handlers/gcc.vim
index 4b53652a..72d639da 100644
--- a/autoload/ale/handlers/gcc.vim
+++ b/autoload/ale/handlers/gcc.vim
@@ -5,6 +5,13 @@ scriptencoding utf-8
 
 let s:pragma_error = '#pragma once in main file'
 
+" Look for lines like the following.
+"
+" <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 s:pattern = '\v^([a-zA-Z]?:?[^:]+):(\d+):(\d+)?:? ([^:]+): (.+)$'
+
 function! s:IsHeaderFile(filename) abort
     return a:filename =~? '\v\.(h|hpp)$'
 endfunction
@@ -18,16 +25,63 @@ function! s:RemoveUnicodeQuotes(text) abort
     return l:text
 endfunction
 
+" Report problems inside of header files just for gcc and clang
+function! s:ParseProblemsInHeaders(buffer, lines) abort
+    let l:output = []
+    let l:include_item = {}
+
+    for l:line in a:lines[: -2]
+        let l:include_match = matchlist(l:line, '\v^In file included from')
+
+        if !empty(l:include_item)
+            let l:pattern_match = matchlist(l:line, s:pattern)
+
+            if !empty(l:pattern_match) && l:pattern_match[1] is# '<stdin>'
+                if has_key(l:include_item, 'lnum')
+                    call add(l:output, l:include_item)
+                endif
+
+                let l:include_item = {}
+
+                continue
+            endif
+
+            let l:include_item.detail .= "\n" . l:line
+        endif
+
+        if !empty(l:include_match)
+            if empty(l:include_item)
+                let l:include_item = {
+                \   'text': 'Error found in header. See :ALEDetail',
+                \   'detail': l:line,
+                \}
+            endif
+        endif
+
+        if !empty(l:include_item)
+            let l:stdin_match = matchlist(l:line, '\vfrom \<stdin\>:(\d+):(\d*):?$')
+
+            if !empty(l:stdin_match)
+                let l:include_item.lnum = str2nr(l:stdin_match[1])
+
+                if str2nr(l:stdin_match[2])
+                    let l:include_item.col = str2nr(l:stdin_match[2])
+                endif
+            endif
+        endif
+    endfor
+
+    if !empty(l:include_item) && has_key(l:include_item, 'lnum')
+        call add(l:output, l:include_item)
+    endif
+
+    return l:output
+endfunction
+
 function! ale#handlers#gcc#HandleGCCFormat(buffer, lines) abort
-    " Look for lines like the following.
-    "
-    " <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 l:pattern = '\v^([a-zA-Z]?:?[^:]+):(\d+):(\d+)?:? ([^:]+): (.+)$'
     let l:output = []
 
-    for l:match in ale#util#GetMatches(a:lines, l:pattern)
+    for l:match in ale#util#GetMatches(a:lines, s:pattern)
         " Filter out the pragma errors
         if s:IsHeaderFile(bufname(bufnr('')))
         \&& l:match[5][:len(s:pragma_error) - 1] is# s:pragma_error
@@ -38,9 +92,12 @@ function! ale#handlers#gcc#HandleGCCFormat(buffer, lines) abort
         " the previous error parsed in output
         if l:match[4] is# 'note'
             if !empty(l:output)
-                let l:output[-1]['detail'] =
-                \   get(l:output[-1], 'detail', '')
-                \   . s:RemoveUnicodeQuotes(l:match[0]) . "\n"
+                if !has_key(l:output[-1], 'detail')
+                    let l:output[-1].detail = l:output[-1].text
+                endif
+
+                let l:output[-1].detail = l:output[-1].detail . "\n"
+                \   . s:RemoveUnicodeQuotes(l:match[0])
             endif
 
             continue
@@ -67,3 +124,12 @@ function! ale#handlers#gcc#HandleGCCFormat(buffer, lines) abort
 
     return l:output
 endfunction
+
+" Handle problems with the GCC format, but report problems inside of headers.
+function! ale#handlers#gcc#HandleGCCFormatWithIncludes(buffer, lines) abort
+    let l:output = ale#handlers#gcc#HandleGCCFormat(a:buffer, a:lines)
+
+    call extend(l:output, s:ParseProblemsInHeaders(a:buffer, a:lines))
+
+    return l:output
+endfunction
diff --git a/autoload/ale/handlers/go.vim b/autoload/ale/handlers/go.vim
index 224df664..f17cd862 100644
--- a/autoload/ale/handlers/go.vim
+++ b/autoload/ale/handlers/go.vim
@@ -21,5 +21,6 @@ function! ale#handlers#go#Handler(buffer, lines) abort
         \   'type': 'E',
         \})
     endfor
+
     return l:output
 endfunction
diff --git a/autoload/ale/handlers/haskell.vim b/autoload/ale/handlers/haskell.vim
index 9223b650..9e495b36 100644
--- a/autoload/ale/handlers/haskell.vim
+++ b/autoload/ale/handlers/haskell.vim
@@ -1,5 +1,15 @@
 " Author: w0rp <devw0rp@gmail.com>
 " Description: Error handling for the format GHC outputs.
+"
+function! ale#handlers#haskell#GetStackExecutable(bufnr) abort
+    if ale#path#FindNearestFile(a:bufnr, 'stack.yaml') isnot# ''
+        return 'stack'
+    endif
+
+    " if there is no stack.yaml file, we don't use stack even if it exists,
+    " so we return '', because executable('') apparently always fails
+    return ''
+endfunction
 
 " Remember the directory used for temporary files for Vim.
 let s:temp_dir = fnamemodify(ale#util#Tempname(), ':h')
diff --git a/autoload/ale/handlers/haskell_stack.vim b/autoload/ale/handlers/haskell_stack.vim
new file mode 100644
index 00000000..108301a9
--- /dev/null
+++ b/autoload/ale/handlers/haskell_stack.vim
@@ -0,0 +1,7 @@
+function! ale#handlers#haskell_stack#EscapeExecutable(executable, stack_exec) abort
+    let l:exec_args = a:executable =~? 'stack$'
+    \   ? ' exec ' . ale#Escape(a:stack_exec) . ' --'
+    \   : ''
+
+    return ale#Escape(a:executable) . l:exec_args
+endfunction
diff --git a/autoload/ale/handlers/hlint.vim b/autoload/ale/handlers/hlint.vim
new file mode 100644
index 00000000..b9a8c322
--- /dev/null
+++ b/autoload/ale/handlers/hlint.vim
@@ -0,0 +1,8 @@
+call ale#Set('haskell_hlint_executable', 'hlint')
+call ale#Set('haskell_hlint_options', get(g:, 'hlint_options', ''))
+
+function! ale#handlers#hlint#GetExecutable(buffer) abort
+    let l:executable = ale#Var(a:buffer, 'haskell_hlint_executable')
+
+    return ale#handlers#haskell_stack#EscapeExecutable(l:executable, 'hlint')
+endfunction
diff --git a/autoload/ale/handlers/ols.vim b/autoload/ale/handlers/ols.vim
index 1dda7f92..74130a26 100644
--- a/autoload/ale/handlers/ols.vim
+++ b/autoload/ale/handlers/ols.vim
@@ -3,6 +3,7 @@
 
 function! ale#handlers#ols#GetExecutable(buffer) abort
     let l:ols_setting = ale#handlers#ols#GetLanguage(a:buffer) . '_ols'
+
     return ale#node#FindExecutable(a:buffer, l:ols_setting, [
     \   'node_modules/.bin/ocaml-language-server',
     \])
diff --git a/autoload/ale/handlers/pony.vim b/autoload/ale/handlers/pony.vim
index 0ac18e76..ea84ac4b 100644
--- a/autoload/ale/handlers/pony.vim
+++ b/autoload/ale/handlers/pony.vim
@@ -14,7 +14,6 @@ endfunction
 function! ale#handlers#pony#HandlePonycFormat(buffer, lines) abort
     " Look for lines like the following.
     " /home/code/pony/classes/Wombat.pony:22:30: can't lookup private fields from outside the type
-
     let l:pattern = '\v^([^:]+):(\d+):(\d+)?:? (.+)$'
     let l:output = []
 
diff --git a/autoload/ale/handlers/redpen.vim b/autoload/ale/handlers/redpen.vim
index c136789c..84e331ed 100644
--- a/autoload/ale/handlers/redpen.vim
+++ b/autoload/ale/handlers/redpen.vim
@@ -6,15 +6,18 @@ function! ale#handlers#redpen#HandleRedpenOutput(buffer, lines) abort
     " element.
     let l:res = json_decode(join(a:lines))[0]
     let l:output = []
+
     for l:err in l:res.errors
         let l:item = {
         \   'text': l:err.message,
         \   'type': 'W',
         \   'code': l:err.validator,
         \}
+
         if has_key(l:err, 'startPosition')
             let l:item.lnum = l:err.startPosition.lineNum
             let l:item.col = l:err.startPosition.offset + 1
+
             if has_key(l:err, 'endPosition')
                 let l:item.end_lnum = l:err.endPosition.lineNum
                 let l:item.end_col = l:err.endPosition.offset
@@ -28,29 +31,35 @@ function! ale#handlers#redpen#HandleRedpenOutput(buffer, lines) abort
 
         " Adjust column number for multibyte string
         let l:line = getline(l:item.lnum)
+
         if l:line is# ''
             let l:line = l:err.sentence
         endif
+
         let l:line = split(l:line, '\zs')
 
         if l:item.col >= 2
             let l:col = 0
+
             for l:strlen in map(l:line[0:(l:item.col - 2)], 'strlen(v:val)')
                 let l:col = l:col + l:strlen
             endfor
+
             let l:item.col = l:col + 1
         endif
 
         if has_key(l:item, 'end_col')
             let l:col = 0
+
             for l:strlen in map(l:line[0:(l:item.end_col - 1)], 'strlen(v:val)')
                 let l:col = l:col + l:strlen
             endfor
+
             let l:item.end_col = l:col
         endif
 
         call add(l:output, l:item)
     endfor
+
     return l:output
 endfunction
-
diff --git a/autoload/ale/handlers/rubocop.vim b/autoload/ale/handlers/rubocop.vim
deleted file mode 100644
index f6367cf5..00000000
--- a/autoload/ale/handlers/rubocop.vim
+++ /dev/null
@@ -1,6 +0,0 @@
-call ale#Set('ruby_rubocop_options', '')
-call ale#Set('ruby_rubocop_executable', 'rubocop')
-
-function! ale#handlers#rubocop#GetExecutable(buffer) abort
-    return ale#Var(a:buffer, 'ruby_rubocop_executable')
-endfunction
diff --git a/autoload/ale/handlers/ruby.vim b/autoload/ale/handlers/ruby.vim
index 555c13b1..c28b8b75 100644
--- a/autoload/ale/handlers/ruby.vim
+++ b/autoload/ale/handlers/ruby.vim
@@ -13,8 +13,10 @@ function! s:HandleSyntaxError(buffer, lines) abort
 
     for l:line in a:lines
         let l:match = matchlist(l:line, l:pattern)
+
         if len(l:match) == 0
             let l:match = matchlist(l:line, l:column)
+
             if len(l:match) != 0
                 let l:output[len(l:output) - 1]['col'] = len(l:match[1])
             endif
@@ -35,3 +37,10 @@ function! ale#handlers#ruby#HandleSyntaxErrors(buffer, lines) abort
     return s:HandleSyntaxError(a:buffer, a:lines)
 endfunction
 
+function! ale#handlers#ruby#EscapeExecutable(executable, bundle_exec) abort
+    let l:exec_args = a:executable =~? 'bundle'
+    \   ? ' exec ' . a:bundle_exec
+    \   : ''
+
+    return ale#Escape(a:executable) . l:exec_args
+endfunction
diff --git a/autoload/ale/handlers/rust.vim b/autoload/ale/handlers/rust.vim
index 537bc731..c6a4b670 100644
--- a/autoload/ale/handlers/rust.vim
+++ b/autoload/ale/handlers/rust.vim
@@ -7,6 +7,10 @@ if !exists('g:ale_rust_ignore_error_codes')
     let g:ale_rust_ignore_error_codes = []
 endif
 
+if !exists('g:ale_rust_ignore_secondary_spans')
+    let g:ale_rust_ignore_secondary_spans = 0
+endif
+
 function! s:FindSpan(buffer, span) abort
     if ale#path#IsBufferPath(a:buffer, a:span.file_name) || a:span.file_name is# '<anon>'
         return a:span
@@ -32,7 +36,7 @@ function! ale#handlers#rust#HandleRustErrors(buffer, lines) abort
 
         let l:error = json_decode(l:errorline)
 
-        if has_key(l:error, 'message') && type(l:error.message) == type({})
+        if has_key(l:error, 'message') && type(l:error.message) is v:t_dict
             let l:error = l:error.message
         endif
 
@@ -47,6 +51,10 @@ function! ale#handlers#rust#HandleRustErrors(buffer, lines) abort
         for l:root_span in l:error.spans
             let l:span = s:FindSpan(a:buffer, l:root_span)
 
+            if ale#Var(a:buffer, 'rust_ignore_secondary_spans') && !get(l:span, 'is_primary', 1)
+                continue
+            endif
+
             if !empty(l:span)
                 call add(l:output, {
                 \   'lnum': l:span.line_start,
diff --git a/autoload/ale/handlers/sml.vim b/autoload/ale/handlers/sml.vim
index 377eade5..92c5f83b 100644
--- a/autoload/ale/handlers/sml.vim
+++ b/autoload/ale/handlers/sml.vim
@@ -11,8 +11,10 @@ function! ale#handlers#sml#GetCmFile(buffer) abort
     let l:as_list = 1
 
     let l:cmfile = ''
+
     for l:path in ale#path#Upwards(expand('#' . a:buffer . ':p:h'))
         let l:results = glob(l:path . '/' . l:pattern, 0, l:as_list)
+
         if len(l:results) > 0
             " If there is more than one CM file, we take the first one
             " See :help ale-sml-smlnj for how to configure this.
@@ -46,6 +48,7 @@ endfunction
 function! ale#handlers#sml#GetExecutableSmlnjCm(buffer) abort
     return s:GetExecutable(a:buffer, 'smlnj-cm')
 endfunction
+
 function! ale#handlers#sml#GetExecutableSmlnjFile(buffer) abort
     return s:GetExecutable(a:buffer, 'smlnj-file')
 endfunction
@@ -53,7 +56,6 @@ endfunction
 function! ale#handlers#sml#Handle(buffer, lines) abort
     " Try to match basic sml errors
     " TODO(jez) We can get better errorfmt strings from Syntastic
-
     let l:out = []
     let l:pattern = '^.*\:\([0-9\.]\+\)\ \(\w\+\)\:\ \(.*\)'
     let l:pattern2 = '^.*\:\([0-9]\+\)\.\?\([0-9]\+\).* \(\(Warning\|Error\): .*\)'
@@ -83,7 +85,6 @@ function! ale#handlers#sml#Handle(buffer, lines) abort
           \})
           continue
         endif
-
     endfor
 
     return l:out
diff --git a/autoload/ale/handlers/vale.vim b/autoload/ale/handlers/vale.vim
index 9dc0872f..2da72fc7 100644
--- a/autoload/ale/handlers/vale.vim
+++ b/autoload/ale/handlers/vale.vim
@@ -23,6 +23,7 @@ function! ale#handlers#vale#Handle(buffer, lines) abort
     endif
 
     let l:output = []
+
     for l:error in l:errors[keys(l:errors)[0]]
         call add(l:output, {
         \   'lnum': l:error['Line'],
diff --git a/autoload/ale/hover.vim b/autoload/ale/hover.vim
index 5e97e16e..69db276e 100644
--- a/autoload/ale/hover.vim
+++ b/autoload/ale/hover.vim
@@ -63,19 +63,19 @@ function! ale#hover#HandleLSPResponse(conn_id, response) abort
 
         let l:result = l:result.contents
 
-        if type(l:result) is type('')
+        if type(l:result) is v:t_string
              " The result can be just a string.
              let l:result = [l:result]
         endif
 
-        if type(l:result) is type({})
+        if type(l:result) is v:t_dict
             " If the result is an object, then it's markup content.
             let l:result = [l:result.value]
         endif
 
-        if type(l:result) is type([])
+        if type(l:result) is v:t_list
             " Replace objects with text values.
-            call map(l:result, 'type(v:val) is type('''') ? v:val : v:val.value')
+            call map(l:result, 'type(v:val) is v:t_string ? v:val : v:val.value')
             let l:str = join(l:result, "\n")
             let l:str = substitute(l:str, '^\s*\(.\{-}\)\s*$', '\1', '')
 
@@ -92,7 +92,44 @@ function! ale#hover#HandleLSPResponse(conn_id, response) abort
     endif
 endfunction
 
-function! s:ShowDetails(linter, buffer, line, column, opt) abort
+function! s:OnReady(linter, lsp_details, line, column, opt, ...) abort
+    let l:buffer = a:lsp_details.buffer
+    let l:id = a:lsp_details.connection_id
+
+    let l:Callback = a:linter.lsp is# 'tsserver'
+    \   ? function('ale#hover#HandleTSServerResponse')
+    \   : function('ale#hover#HandleLSPResponse')
+    call ale#lsp#RegisterCallback(l:id, l:Callback)
+
+    if a:linter.lsp is# 'tsserver'
+        let l:column = a:column
+
+        let l:message = ale#lsp#tsserver_message#Quickinfo(
+        \   l:buffer,
+        \   a:line,
+        \   l:column
+        \)
+    else
+        " Send a message saying the buffer has changed first, or the
+        " hover position probably won't make sense.
+        call ale#lsp#NotifyForChanges(l:id, l:buffer)
+
+        let l:column = min([a:column, len(getbufline(l:buffer, a:line)[0])])
+
+        let l:message = ale#lsp#message#Hover(l:buffer, a:line, l:column)
+    endif
+
+    let l:request_id = ale#lsp#Send(l:id, l:message)
+
+    let s:hover_map[l:request_id] = {
+    \   'buffer': l:buffer,
+    \   'line': a:line,
+    \   'column': l:column,
+    \   'hover_from_balloonexpr': get(a:opt, 'called_from_balloonexpr', 0),
+    \}
+endfunction
+
+function! s:ShowDetails(linter, buffer, line, column, opt, ...) abort
     let l:lsp_details = ale#lsp_linter#StartLSP(a:buffer, a:linter)
 
     if empty(l:lsp_details)
@@ -100,44 +137,10 @@ function! s:ShowDetails(linter, buffer, line, column, opt) abort
     endif
 
     let l:id = l:lsp_details.connection_id
-    let l:root = l:lsp_details.project_root
-    let l:language_id = l:lsp_details.language_id
-
-    function! OnReady(...) abort closure
-        let l:Callback = a:linter.lsp is# 'tsserver'
-        \   ? function('ale#hover#HandleTSServerResponse')
-        \   : function('ale#hover#HandleLSPResponse')
-        call ale#lsp#RegisterCallback(l:id, l:Callback)
-
-        if a:linter.lsp is# 'tsserver'
-            let l:column = a:column
-
-            let l:message = ale#lsp#tsserver_message#Quickinfo(
-            \   a:buffer,
-            \   a:line,
-            \   l:column
-            \)
-        else
-            " Send a message saying the buffer has changed first, or the
-            " hover position probably won't make sense.
-            call ale#lsp#NotifyForChanges(l:id, l:root, a:buffer)
-
-            let l:column = min([a:column, len(getbufline(a:buffer, a:line)[0])])
-
-            let l:message = ale#lsp#message#Hover(a:buffer, a:line, l:column)
-        endif
-
-        let l:request_id = ale#lsp#Send(l:id, l:message, l:lsp_details.project_root)
-
-        let s:hover_map[l:request_id] = {
-        \   'buffer': a:buffer,
-        \   'line': a:line,
-        \   'column': l:column,
-        \   'hover_from_balloonexpr': get(a:opt, 'called_from_balloonexpr', 0),
-        \}
-    endfunction
 
-    call ale#lsp#WaitForCapability(l:id, l:root, 'hover', function('OnReady'))
+    call ale#lsp#WaitForCapability(l:id, 'hover', function('s:OnReady', [
+    \   a:linter, l:lsp_details, a:line, a:column, a:opt
+    \]))
 endfunction
 
 " Obtain Hover information for the specified position
diff --git a/autoload/ale/java.vim b/autoload/ale/java.vim
new file mode 100644
index 00000000..b7fd10bd
--- /dev/null
+++ b/autoload/ale/java.vim
@@ -0,0 +1,20 @@
+" Author: Horacio Sanson https://github.com/hsanson
+" Description: Functions for integrating with Java tools
+
+" Find the nearest dir contining a gradle or pom file and asume it
+" the root of a java app.
+function! ale#java#FindProjectRoot(buffer) abort
+    let l:gradle_root = ale#gradle#FindProjectRoot(a:buffer)
+
+    if !empty(l:gradle_root)
+        return l:gradle_root
+    endif
+
+    let l:maven_pom_file = ale#path#FindNearestFile(a:buffer, 'pom.xml')
+
+    if !empty(l:maven_pom_file)
+        return fnamemodify(l:maven_pom_file, ':h')
+    endif
+
+    return ''
+endfunction
diff --git a/autoload/ale/job.vim b/autoload/ale/job.vim
index e0266cba..0117c7dd 100644
--- a/autoload/ale/job.vim
+++ b/autoload/ale/job.vim
@@ -249,6 +249,11 @@ function! ale#job#Start(command, options) abort
             let l:job_options.exit_cb = function('s:VimExitCallback')
         endif
 
+        " Use non-blocking writes for Vim versions that support the option.
+        if has('patch-8.1.350')
+            let l:job_options.noblock = 1
+        endif
+
         " Vim 8 will read the stdin from the file's buffer.
         let l:job_info.job = job_start(a:command, l:job_options)
         let l:job_id = ale#job#ParseVim8ProcessID(string(l:job_info.job))
@@ -278,11 +283,13 @@ function! ale#job#IsRunning(job_id) abort
         try
             " In NeoVim, if the job isn't running, jobpid() will throw.
             call jobpid(a:job_id)
+
             return 1
         catch
         endtry
     elseif has_key(s:job_map, a:job_id)
         let l:job = s:job_map[a:job_id].job
+
         return job_status(l:job) is# 'run'
     endif
 
diff --git a/autoload/ale/julia.vim b/autoload/ale/julia.vim
new file mode 100644
index 00000000..18dd9ad7
--- /dev/null
+++ b/autoload/ale/julia.vim
@@ -0,0 +1,19 @@
+" Author: Bartolomeo Stellato bartolomeo.stellato@gmail.com
+" Description: Functions for integrating with Julia tools
+
+" Find the nearest dir containing a julia project
+let s:__ale_julia_project_filenames = ['REQUIRE', 'Manifest.toml', 'Project.toml']
+
+function! ale#julia#FindProjectRoot(buffer) abort
+    for l:project_filename in s:__ale_julia_project_filenames
+        let l:full_path = ale#path#FindNearestFile(a:buffer, l:project_filename)
+
+        if !empty(l:full_path)
+            let l:path = fnamemodify(l:full_path, ':p:h')
+
+            return l:path
+        endif
+    endfor
+
+    return ''
+endfunction
diff --git a/autoload/ale/linter.vim b/autoload/ale/linter.vim
index aa602f7e..1cbc9ffe 100644
--- a/autoload/ale/linter.vim
+++ b/autoload/ale/linter.vim
@@ -16,6 +16,7 @@ let s:default_ale_linter_aliases = {
 \   'systemverilog': 'verilog',
 \   'verilog_systemverilog': ['verilog_systemverilog', 'verilog'],
 \   'vimwiki': 'markdown',
+\   'vue': ['vue', 'javascript'],
 \   'zsh': 'sh',
 \}
 
@@ -26,17 +27,22 @@ let s:default_ale_linter_aliases = {
 "
 " Only cargo is enabled for Rust by default.
 " rpmlint is disabled by default because it can result in code execution.
+" hhast is disabled by default because it executes code in the project root.
 "
 " NOTE: Update the g:ale_linters documentation when modifying this.
 let s:default_ale_linters = {
 \   'csh': ['shell'],
+\   'elixir': ['credo', 'dialyxir', 'dogma', 'elixir-ls'],
 \   'go': ['gofmt', 'golint', 'go vet'],
+\   'hack': ['hack'],
 \   'help': [],
 \   'perl': ['perlcritic'],
+\   'perl6': [],
 \   'python': ['flake8', 'mypy', 'pylint'],
 \   'rust': ['cargo'],
 \   'spec': [],
 \   'text': [],
+\   'vue': ['eslint', 'vls'],
 \   'zsh': ['shell'],
 \}
 
@@ -51,17 +57,17 @@ endfunction
 " Do not call this function.
 function! ale#linter#GetLintersLoaded() abort
     " This command will throw from the sandbox.
-    let &equalprg=&equalprg
+    let &l:equalprg=&l:equalprg
 
     return s:linters
 endfunction
 
 function! s:IsCallback(value) abort
-    return type(a:value) == type('') || type(a:value) == type(function('type'))
+    return type(a:value) is v:t_string || type(a:value) is v:t_func
 endfunction
 
 function! s:IsBoolean(value) abort
-    return type(a:value) == type(0) && (a:value == 0 || a:value == 1)
+    return type(a:value) is v:t_number && (a:value == 0 || a:value == 1)
 endfunction
 
 function! s:LanguageGetter(buffer) dict abort
@@ -69,7 +75,7 @@ function! s:LanguageGetter(buffer) dict abort
 endfunction
 
 function! ale#linter#PreProcess(filetype, linter) abort
-    if type(a:linter) != type({})
+    if type(a:linter) isnot v:t_dict
         throw 'The linter object must be a Dictionary'
     endif
 
@@ -79,7 +85,7 @@ function! ale#linter#PreProcess(filetype, linter) abort
     \   'lsp': get(a:linter, 'lsp', ''),
     \}
 
-    if type(l:obj.name) != type('')
+    if type(l:obj.name) isnot v:t_string
         throw '`name` must be defined to name the linter'
     endif
 
@@ -97,7 +103,7 @@ function! ale#linter#PreProcess(filetype, linter) abort
     endif
 
     if index(['', 'socket', 'stdio', 'tsserver'], l:obj.lsp) < 0
-        throw '`lsp` must be either `''lsp''` or `''tsserver''` if defined'
+        throw '`lsp` must be either `''lsp''`, `''stdio''`, `''socket''` or `''tsserver''` if defined'
     endif
 
     if !l:needs_executable
@@ -114,7 +120,7 @@ function! ale#linter#PreProcess(filetype, linter) abort
     elseif has_key(a:linter, 'executable')
         let l:obj.executable = a:linter.executable
 
-        if type(l:obj.executable) != type('')
+        if type(l:obj.executable) isnot v:t_string
             throw '`executable` must be a string if defined'
         endif
     else
@@ -130,7 +136,7 @@ function! ale#linter#PreProcess(filetype, linter) abort
     elseif has_key(a:linter, 'command_chain')
         let l:obj.command_chain = a:linter.command_chain
 
-        if type(l:obj.command_chain) != type([])
+        if type(l:obj.command_chain) isnot v:t_list
             throw '`command_chain` must be a List'
         endif
 
@@ -148,7 +154,7 @@ function! ale#linter#PreProcess(filetype, linter) abort
             endif
 
             if has_key(l:link, 'output_stream')
-                if type(l:link.output_stream) != type('')
+                if type(l:link.output_stream) isnot v:t_string
                 \|| index(['stdout', 'stderr', 'both'], l:link.output_stream) < 0
                     throw l:err_prefix . '`output_stream` flag must be '
                     \   . "'stdout', 'stderr', or 'both'"
@@ -170,7 +176,7 @@ function! ale#linter#PreProcess(filetype, linter) abort
     elseif has_key(a:linter, 'command')
         let l:obj.command = a:linter.command
 
-        if type(l:obj.command) != type('')
+        if type(l:obj.command) isnot v:t_string
             throw '`command` must be a string if defined'
         endif
     else
@@ -217,7 +223,7 @@ function! ale#linter#PreProcess(filetype, linter) abort
             " Default to using the filetype as the language.
             let l:obj.language = get(a:linter, 'language', a:filetype)
 
-            if type(l:obj.language) != type('')
+            if type(l:obj.language) isnot v:t_string
                 throw '`language` must be a string'
             endif
 
@@ -253,11 +259,29 @@ function! ale#linter#PreProcess(filetype, linter) abort
         elseif has_key(a:linter, 'initialization_options')
             let l:obj.initialization_options = a:linter.initialization_options
         endif
+
+        if has_key(a:linter, 'lsp_config_callback')
+            if has_key(a:linter, 'lsp_config')
+                throw 'Only one of `lsp_config` or `lsp_config_callback` should be set'
+            endif
+
+            let l:obj.lsp_config_callback = a:linter.lsp_config_callback
+
+            if !s:IsCallback(l:obj.lsp_config_callback)
+                throw '`lsp_config_callback` must be a callback if defined'
+            endif
+        elseif has_key(a:linter, 'lsp_config')
+            if type(a:linter.lsp_config) isnot v:t_dict
+                throw '`lsp_config` must be a Dictionary'
+            endif
+
+            let l:obj.lsp_config = a:linter.lsp_config
+        endif
     endif
 
     let l:obj.output_stream = get(a:linter, 'output_stream', 'stdout')
 
-    if type(l:obj.output_stream) != type('')
+    if type(l:obj.output_stream) isnot v:t_string
     \|| index(['stdout', 'stderr', 'both'], l:obj.output_stream) < 0
         throw "`output_stream` must be 'stdout', 'stderr', or 'both'"
     endif
@@ -283,8 +307,8 @@ function! ale#linter#PreProcess(filetype, linter) abort
 
     let l:obj.aliases = get(a:linter, 'aliases', [])
 
-    if type(l:obj.aliases) != type([])
-    \|| len(filter(copy(l:obj.aliases), 'type(v:val) != type('''')')) > 0
+    if type(l:obj.aliases) isnot v:t_list
+    \|| len(filter(copy(l:obj.aliases), 'type(v:val) isnot v:t_string')) > 0
         throw '`aliases` must be a List of String values'
     endif
 
@@ -293,7 +317,7 @@ endfunction
 
 function! ale#linter#Define(filetype, linter) abort
     " This command will throw from the sandbox.
-    let &equalprg=&equalprg
+    let &l:equalprg=&l:equalprg
 
     if !has_key(s:linters, a:filetype)
         let s:linters[a:filetype] = []
@@ -335,8 +359,9 @@ endfunction
 function! s:GetAliasedFiletype(original_filetype) abort
     let l:buffer_aliases = get(b:, 'ale_linter_aliases', {})
 
-    " b:ale_linter_aliases can be set to a List.
-    if type(l:buffer_aliases) is type([])
+    " b:ale_linter_aliases can be set to a List or String.
+    if type(l:buffer_aliases) is v:t_list
+    \|| type(l:buffer_aliases) is v:t_string
         return l:buffer_aliases
     endif
 
@@ -360,7 +385,7 @@ endfunction
 function! ale#linter#ResolveFiletype(original_filetype) abort
     let l:filetype = s:GetAliasedFiletype(a:original_filetype)
 
-    if type(l:filetype) != type([])
+    if type(l:filetype) isnot v:t_list
         return [l:filetype]
     endif
 
@@ -376,7 +401,7 @@ function! s:GetLinterNames(original_filetype) abort
     endif
 
     " b:ale_linters can be set to a List.
-    if type(l:buffer_ale_linters) is type([])
+    if type(l:buffer_ale_linters) is v:t_list
         return l:buffer_ale_linters
     endif
 
@@ -414,9 +439,9 @@ function! ale#linter#Get(original_filetypes) abort
         let l:all_linters = ale#linter#GetAll(l:filetype)
         let l:filetype_linters = []
 
-        if type(l:linter_names) == type('') && l:linter_names is# 'all'
+        if type(l:linter_names) is v:t_string && l:linter_names is# 'all'
             let l:filetype_linters = l:all_linters
-        elseif type(l:linter_names) == type([])
+        elseif type(l:linter_names) is v:t_list
             " Select only the linters we or the user has specified.
             for l:linter in l:all_linters
                 let l:name_list = [l:linter.name] + l:linter.aliases
diff --git a/autoload/ale/list.vim b/autoload/ale/list.vim
index 35304a09..3417575c 100644
--- a/autoload/ale/list.vim
+++ b/autoload/ale/list.vim
@@ -25,6 +25,7 @@ function! ale#list#IsQuickfixOpen() abort
             return 1
         endif
     endfor
+
     return 0
 endfunction
 
@@ -112,9 +113,11 @@ function! s:SetListsImpl(timer_id, buffer, loclist) abort
 
         " open windows vertically instead of default horizontally
         let l:open_type = ''
+
         if ale#Var(a:buffer, 'list_vertical') == 1
             let l:open_type = 'vert '
         endif
+
         if g:ale_set_quickfix
             if !ale#list#IsQuickfixOpen()
                 silent! execute l:open_type . 'copen ' . str2nr(ale#Var(a:buffer, 'list_window_size'))
diff --git a/autoload/ale/loclist_jumping.vim b/autoload/ale/loclist_jumping.vim
index 7ed9e6ba..fd5ff922 100644
--- a/autoload/ale/loclist_jumping.vim
+++ b/autoload/ale/loclist_jumping.vim
@@ -66,6 +66,7 @@ function! ale#loclist_jumping#Jump(direction, wrap) abort
     let l:nearest = ale#loclist_jumping#FindNearest(a:direction, a:wrap)
 
     if !empty(l:nearest)
+        normal! m`
         call cursor(l:nearest)
     endif
 endfunction
@@ -82,6 +83,7 @@ function! ale#loclist_jumping#JumpToIndex(index) abort
     let l:item = l:loclist[a:index]
 
     if !empty(l:item)
+        normal! m`
         call cursor([l:item.lnum, l:item.col])
     endif
 endfunction
diff --git a/autoload/ale/lsp.vim b/autoload/ale/lsp.vim
index 312319ab..f55096c2 100644
--- a/autoload/ale/lsp.vim
+++ b/autoload/ale/lsp.vim
@@ -1,62 +1,70 @@
 " Author: w0rp <devw0rp@gmail.com>
 " Description: Language Server Protocol client code
 
-" A List of connections, used for tracking servers which have been connected
-" to, and programs which are run.
-let s:connections = get(s:, 'connections', [])
+" A Dictionary for tracking connections.
+let s:connections = get(s:, 'connections', {})
 let g:ale_lsp_next_message_id = 1
 
-" Exposed only so tests can get at it.
-" Do not call this function basically anywhere.
-function! ale#lsp#NewConnection(initialization_options) abort
-    " id: The job ID as a Number, or the server address as a string.
-    " data: The message data received so far.
-    " executable: An executable only set for program connections.
-    " open_documents: A Dictionary mapping buffers to b:changedtick, keeping
-    "   track of when documents were opened, and when we last changed them.
-    " callback_list: A list of callbacks for handling LSP responses.
-    " initialization_options: Options to send to the server.
-    " capabilities: Features the server supports.
-    let l:conn = {
-    \   'is_tsserver': 0,
-    \   'id': '',
-    \   'data': '',
-    \   'projects': {},
-    \   'open_documents': {},
-    \   'callback_list': [],
-    \   'initialization_options': a:initialization_options,
-    \   'capabilities': {
-    \       'hover': 0,
-    \       'references': 0,
-    \       'completion': 0,
-    \       'completion_trigger_characters': [],
-    \       'definition': 0,
-    \   },
-    \}
-
-    call add(s:connections, l:conn)
+" Given an id, which can be an executable or address, and a project path,
+" create a new connection if needed. Return a unique ID for the connection.
+function! ale#lsp#Register(executable_or_address, project, init_options) abort
+    let l:conn_id = a:executable_or_address . ':' . a:project
+
+    if !has_key(s:connections, l:conn_id)
+        " is_tsserver: 1 if the connection is for tsserver.
+        " data: The message data received so far.
+        " root: The project root.
+        " open_documents: A Dictionary mapping buffers to b:changedtick, keeping
+        "   track of when documents were opened, and when we last changed them.
+        " initialized: 0 if the connection is ready, 1 otherwise.
+        " init_request_id: The ID for the init request.
+        " init_options: Options to send to the server.
+        " config: Configuration settings to send to the server.
+        " callback_list: A list of callbacks for handling LSP responses.
+        " message_queue: Messages queued for sending to callbacks.
+        " capabilities_queue: The list of callbacks to call with capabilities.
+        " capabilities: Features the server supports.
+        let s:connections[l:conn_id] = {
+        \   'id': l:conn_id,
+        \   'is_tsserver': 0,
+        \   'data': '',
+        \   'root': a:project,
+        \   'open_documents': {},
+        \   'initialized': 0,
+        \   'init_request_id': 0,
+        \   'init_options': a:init_options,
+        \   'config': {},
+        \   'callback_list': [],
+        \   'message_queue': [],
+        \   'capabilities_queue': [],
+        \   'capabilities': {
+        \       'hover': 0,
+        \       'references': 0,
+        \       'completion': 0,
+        \       'completion_trigger_characters': [],
+        \       'definition': 0,
+        \       'symbol_search': 0,
+        \   },
+        \}
+    endif
 
-    return l:conn
+    return l:conn_id
 endfunction
 
 " Remove an LSP connection with a given ID. This is only for tests.
 function! ale#lsp#RemoveConnectionWithID(id) abort
-    call filter(s:connections, 'v:val.id isnot a:id')
+    if has_key(s:connections, a:id)
+        call remove(s:connections, a:id)
+    endif
 endfunction
 
-function! s:FindConnection(key, value) abort
-    for l:conn in s:connections
-        if has_key(l:conn, a:key) && get(l:conn, a:key) is# a:value
-            return l:conn
-        endif
-    endfor
-
-    return {}
-endfunction
+" This is only needed for tests
+function! ale#lsp#MarkDocumentAsOpen(id, buffer) abort
+    let l:conn = get(s:connections, a:id, {})
 
-" Get the capabilities for a connection, or an empty Dictionary.
-function! ale#lsp#GetConnectionCapabilities(id) abort
-    return get(s:FindConnection('id', a:id), 'capabilities', {})
+    if !empty(l:conn)
+        let l:conn.open_documents[a:buffer] = -1
+    endif
 endfunction
 
 function! ale#lsp#GetNextMessageID() abort
@@ -94,13 +102,14 @@ function! s:CreateTSServerMessageData(message) abort
     endif
 
     let l:data = json_encode(l:obj) . "\n"
+
     return [l:is_notification ? 0 : l:obj.seq, l:data]
 endfunction
 
 " Given a List of one or two items, [method_name] or [method_name, params],
 " return a List containing [message_id, message_data]
 function! ale#lsp#CreateMessageData(message) abort
-    if a:message[1] =~# '^ts@'
+    if a:message[1][:2] is# 'ts@'
         return s:CreateTSServerMessageData(a:message)
     endif
 
@@ -167,53 +176,10 @@ function! ale#lsp#ReadMessageData(data) abort
     return [l:remainder, l:response_list]
 endfunction
 
-function! s:FindProjectWithInitRequestID(conn, init_request_id) abort
-    for l:project_root in keys(a:conn.projects)
-        let l:project = a:conn.projects[l:project_root]
-
-        if l:project.init_request_id == a:init_request_id
-            return l:project
-        endif
-    endfor
-
-    return {}
-endfunction
-
-function! s:MarkProjectAsInitialized(conn, project) abort
-    let a:project.initialized = 1
-
-    " After the server starts, send messages we had queued previously.
-    for l:message_data in a:project.message_queue
-        call s:SendMessageData(a:conn, l:message_data)
-    endfor
-
-    " Remove the messages now.
-    let a:conn.message_queue = []
-
-    " Call capabilities callbacks queued for the project.
-    for [l:capability, l:Callback] in a:project.capabilities_queue
-        if a:conn.is_tsserver || a:conn.capabilities[l:capability]
-            call call(l:Callback, [a:conn.id, a:project.root])
-        endif
-    endfor
-
-    " Clear the queued callbacks now.
-    let a:project.capabilities_queue = []
-endfunction
-
-function! s:HandleInitializeResponse(conn, response) abort
-    let l:request_id = a:response.request_id
-    let l:project = s:FindProjectWithInitRequestID(a:conn, l:request_id)
-
-    if !empty(l:project)
-        call s:MarkProjectAsInitialized(a:conn, l:project)
-    endif
-endfunction
-
 " Update capabilities from the server, so we know which features the server
 " supports.
 function! s:UpdateCapabilities(conn, capabilities) abort
-    if type(a:capabilities) != type({})
+    if type(a:capabilities) isnot v:t_dict
         return
     endif
 
@@ -229,10 +195,10 @@ function! s:UpdateCapabilities(conn, capabilities) abort
         let a:conn.capabilities.completion = 1
     endif
 
-    if type(get(a:capabilities, 'completionProvider')) is type({})
+    if type(get(a:capabilities, 'completionProvider')) is v:t_dict
         let l:chars = get(a:capabilities.completionProvider, 'triggerCharacters')
 
-        if type(l:chars) is type([])
+        if type(l:chars) is v:t_list
             let a:conn.capabilities.completion_trigger_characters = l:chars
         endif
     endif
@@ -240,180 +206,164 @@ function! s:UpdateCapabilities(conn, capabilities) abort
     if get(a:capabilities, 'definitionProvider') is v:true
         let a:conn.capabilities.definition = 1
     endif
-endfunction
 
-function! ale#lsp#HandleOtherInitializeResponses(conn, response) abort
-    let l:uninitialized_projects = []
+    if get(a:capabilities, 'workspaceSymbolProvider') is v:true
+        let a:conn.capabilities.symbol_search = 1
+    endif
+endfunction
 
-    for [l:key, l:value] in items(a:conn.projects)
-        if l:value.initialized == 0
-            call add(l:uninitialized_projects, [l:key, l:value])
-        endif
-    endfor
+" Update a connection's configuration dictionary and notify LSP servers
+" of any changes since the last update. Returns 1 if a configuration
+" update was sent; otherwise 0 will be returned.
+function! ale#lsp#UpdateConfig(conn_id, buffer, config) abort
+    let l:conn = get(s:connections, a:conn_id, {})
 
-    if empty(l:uninitialized_projects)
-        return
+    if empty(l:conn) || a:config ==# l:conn.config " no-custom-checks
+        return 0
     endif
 
-    if get(a:response, 'method', '') is# ''
-        if has_key(get(a:response, 'result', {}), 'capabilities')
-            call s:UpdateCapabilities(a:conn, a:response.result.capabilities)
+    let l:conn.config = a:config
+    let l:message = ale#lsp#message#DidChangeConfiguration(a:buffer, a:config)
 
-            for [l:dir, l:project] in l:uninitialized_projects
-                call s:MarkProjectAsInitialized(a:conn, l:project)
-            endfor
-        endif
-    elseif get(a:response, 'method', '') is# 'textDocument/publishDiagnostics'
-        let l:filename = ale#path#FromURI(a:response.params.uri)
+    call ale#lsp#Send(a:conn_id, l:message)
 
-        for [l:dir, l:project] in l:uninitialized_projects
-            if l:filename[:len(l:dir) - 1] is# l:dir
-                call s:MarkProjectAsInitialized(a:conn, l:project)
-            endif
-        endfor
-    endif
+    return 1
 endfunction
 
-function! ale#lsp#HandleMessage(conn, message) abort
-    if type(a:message) != type('')
-        " Ignore messages that aren't strings.
-        return
+
+function! ale#lsp#HandleInitResponse(conn, response) abort
+    if get(a:response, 'method', '') is# 'initialize'
+        let a:conn.initialized = 1
+    elseif type(get(a:response, 'result')) is v:t_dict
+    \&& has_key(a:response.result, 'capabilities')
+        call s:UpdateCapabilities(a:conn, a:response.result.capabilities)
+
+        let a:conn.initialized = 1
     endif
 
-    let a:conn.data .= a:message
+    if !a:conn.initialized
+        return
+    endif
 
-    " Parse the objects now if we can, and keep the remaining text.
-    let [a:conn.data, l:response_list] = ale#lsp#ReadMessageData(a:conn.data)
+    " After the server starts, send messages we had queued previously.
+    for l:message_data in a:conn.message_queue
+        call s:SendMessageData(a:conn, l:message_data)
+    endfor
 
-    " Call our callbacks.
-    for l:response in l:response_list
-        if get(l:response, 'method', '') is# 'initialize'
-            call s:HandleInitializeResponse(a:conn, l:response)
-        else
-            call ale#lsp#HandleOtherInitializeResponses(a:conn, l:response)
+    " Remove the messages now.
+    let a:conn.message_queue = []
 
-            " Call all of the registered handlers with the response.
-            for l:Callback in a:conn.callback_list
-                call ale#util#GetFunction(l:Callback)(a:conn.id, l:response)
-            endfor
+    " Call capabilities callbacks queued for the project.
+    for [l:capability, l:Callback] in a:conn.capabilities_queue
+        if a:conn.capabilities[l:capability]
+            call call(l:Callback, [a:conn.id])
         endif
     endfor
+
+    let a:conn.capabilities_queue = []
 endfunction
 
-function! s:HandleChannelMessage(channel_id, message) abort
-    let l:address = ale#socket#GetAddress(a:channel_id)
-    let l:conn = s:FindConnection('id', l:address)
+function! ale#lsp#HandleMessage(conn_id, message) abort
+    let l:conn = get(s:connections, a:conn_id, {})
 
-    call ale#lsp#HandleMessage(l:conn, a:message)
-endfunction
+    if empty(l:conn)
+        return
+    endif
 
-function! s:HandleCommandMessage(job_id, message) abort
-    let l:conn = s:FindConnection('id', a:job_id)
+    if type(a:message) isnot v:t_string
+        " Ignore messages that aren't strings.
+        return
+    endif
 
-    call ale#lsp#HandleMessage(l:conn, a:message)
-endfunction
+    let l:conn.data .= a:message
 
-" Given a connection ID, mark it as a tsserver connection, so it will be
-" handled that way.
-function! ale#lsp#MarkConnectionAsTsserver(conn_id) abort
-    let l:conn = s:FindConnection('id', a:conn_id)
+    " Parse the objects now if we can, and keep the remaining text.
+    let [l:conn.data, l:response_list] = ale#lsp#ReadMessageData(l:conn.data)
 
-    if !empty(l:conn)
-        let l:conn.is_tsserver = 1
+    " Look for initialize responses first.
+    if !l:conn.initialized
+        for l:response in l:response_list
+            call ale#lsp#HandleInitResponse(l:conn, l:response)
+        endfor
     endif
-endfunction
 
-" Register a project for an LSP connection.
-"
-" This function will throw if the connection doesn't exist.
-function! ale#lsp#RegisterProject(conn_id, project_root) abort
-    let l:conn = s:FindConnection('id', a:conn_id)
-
-    " Empty strings can't be used for Dictionary keys in NeoVim, due to E713.
-    " This appears to be a nonsensical bug in NeoVim.
-    let l:key = empty(a:project_root) ? '<<EMPTY>>' : a:project_root
-
-    if !has_key(l:conn.projects, l:key)
-        " Tools without project roots are ready right away, like tsserver.
-        let l:conn.projects[l:key] = {
-        \   'root': a:project_root,
-        \   'initialized': empty(a:project_root),
-        \   'init_request_id': 0,
-        \   'message_queue': [],
-        \   'capabilities_queue': [],
-        \}
+    " If the connection is marked as initialized, call the callbacks with the
+    " responses.
+    if l:conn.initialized
+        for l:response in l:response_list
+            " Call all of the registered handlers with the response.
+            for l:Callback in l:conn.callback_list
+                call ale#util#GetFunction(l:Callback)(a:conn_id, l:response)
+            endfor
+        endfor
     endif
 endfunction
 
-function! ale#lsp#GetProject(conn, project_root) abort
-    if empty(a:conn)
-        return {}
-    endif
-
-    let l:key = empty(a:project_root) ? '<<EMPTY>>' : a:project_root
-
-    return get(a:conn.projects, l:key, {})
+" Given a connection ID, mark it as a tsserver connection, so it will be
+" handled that way.
+function! ale#lsp#MarkConnectionAsTsserver(conn_id) abort
+    let l:conn = s:connections[a:conn_id]
+    let l:conn.is_tsserver = 1
+    let l:conn.initialized = 1
+    " Set capabilities which are supported by tsserver.
+    let l:conn.capabilities.hover = 1
+    let l:conn.capabilities.references = 1
+    let l:conn.capabilities.completion = 1
+    let l:conn.capabilities.completion_trigger_characters = ['.']
+    let l:conn.capabilities.definition = 1
+    let l:conn.capabilities.symbol_search = 1
 endfunction
 
-" Start a program for LSP servers which run with executables.
+" Start a program for LSP servers.
 "
-" The job ID will be returned for for the program if it ran, otherwise
-" 0 will be returned.
-function! ale#lsp#StartProgram(executable, command, init_options) abort
-    if !executable(a:executable)
-        return 0
-    endif
-
-    let l:conn = s:FindConnection('executable', a:executable)
+" 1 will be returned if the program is running, or 0 if the program could
+" not be started.
+function! ale#lsp#StartProgram(conn_id, executable, command) abort
+    let l:conn = s:connections[a:conn_id]
 
-    " Get the current connection or a new one.
-    let l:conn = !empty(l:conn) ? l:conn : ale#lsp#NewConnection(a:init_options)
-    let l:conn.executable = a:executable
-
-    if !has_key(l:conn, 'id') || !ale#job#IsRunning(l:conn.id)
+    if !has_key(l:conn, 'job_id') || !ale#job#IsRunning(l:conn.job_id)
         let l:options = {
         \   'mode': 'raw',
-        \   'out_cb': function('s:HandleCommandMessage'),
+        \   'out_cb': {_, message -> ale#lsp#HandleMessage(a:conn_id, message)},
         \}
         let l:job_id = ale#job#Start(a:command, l:options)
     else
-        let l:job_id = l:conn.id
+        let l:job_id = l:conn.job_id
     endif
 
-    if l:job_id <= 0
-        return 0
+    if l:job_id > 0
+        let l:conn.job_id = l:job_id
     endif
 
-    let l:conn.id = l:job_id
-
-    return l:job_id
+    return l:job_id > 0
 endfunction
 
-" Connect to an address and set up a callback for handling responses.
-function! ale#lsp#ConnectToAddress(address, init_options) abort
-    let l:conn = s:FindConnection('id', a:address)
-    " Get the current connection or a new one.
-    let l:conn = !empty(l:conn) ? l:conn : ale#lsp#NewConnection(a:init_options)
+" Connect to an LSP server via TCP.
+"
+" 1 will be returned if the connection is running, or 0 if the connection could
+" not be opened.
+function! ale#lsp#ConnectToAddress(conn_id, address) abort
+    let l:conn = s:connections[a:conn_id]
 
     if !has_key(l:conn, 'channel_id') || !ale#socket#IsOpen(l:conn.channel_id)
-        let l:conn.channel_id = ale#socket#Open(a:address, {
-        \   'callback': function('s:HandleChannelMessage'),
+        let l:channel_id = ale#socket#Open(a:address, {
+        \   'callback': {_, mess -> ale#lsp#HandleMessage(a:conn_id, mess)},
         \})
+    else
+        let l:channel_id = l:conn.channel_id
     endif
 
-    if l:conn.channel_id < 0
-        return ''
+    if l:channel_id >= 0
+        let l:conn.channel_id = l:channel_id
     endif
 
-    let l:conn.id = a:address
-
-    return a:address
+    return l:channel_id >= 0
 endfunction
 
 " Given a connection ID and a callback, register that callback for handling
 " messages if the connection exists.
 function! ale#lsp#RegisterCallback(conn_id, callback) abort
-    let l:conn = s:FindConnection('id', a:conn_id)
+    let l:conn = get(s:connections, a:conn_id, {})
 
     if !empty(l:conn)
         " Add the callback to the List if it's not there already.
@@ -421,23 +371,33 @@ function! ale#lsp#RegisterCallback(conn_id, callback) abort
     endif
 endfunction
 
-" Stop all LSP connections, closing all jobs and channels, and removing any
-" queued messages.
-function! ale#lsp#StopAll() abort
-    for l:conn in s:connections
+" Stop a single LSP connection.
+function! ale#lsp#Stop(conn_id) abort
+    if has_key(s:connections, a:conn_id)
+        let l:conn = remove(s:connections, a:conn_id)
+
         if has_key(l:conn, 'channel_id')
             call ale#socket#Close(l:conn.channel_id)
-        else
-            call ale#job#Stop(l:conn.id)
+        elseif has_key(l:conn, 'job_id')
+            call ale#job#Stop(l:conn.job_id)
         endif
-    endfor
+    endif
+endfunction
 
-    let s:connections = []
+function! ale#lsp#CloseDocument(conn_id) abort
+endfunction
+
+" Stop all LSP connections, closing all jobs and channels, and removing any
+" queued messages.
+function! ale#lsp#StopAll() abort
+    for l:conn_id in keys(s:connections)
+        call ale#lsp#Stop(l:conn_id)
+    endfor
 endfunction
 
 function! s:SendMessageData(conn, data) abort
-    if has_key(a:conn, 'executable')
-        call ale#job#SendRaw(a:conn.id, a:data)
+    if has_key(a:conn, 'job_id')
+        call ale#job#SendRaw(a:conn.job_id, a:data)
     elseif has_key(a:conn, 'channel_id') && ale#socket#IsOpen(a:conn.channel_id)
         " Send the message to the server
         call ale#socket#Send(a:conn.channel_id, a:data)
@@ -454,38 +414,32 @@ endfunction
 " Returns -1 when a message is sent, but no response is expected
 "          0 when the message is not sent and
 "          >= 1 with the message ID when a response is expected.
-function! ale#lsp#Send(conn_id, message, ...) abort
-    let l:project_root = get(a:000, 0, '')
+function! ale#lsp#Send(conn_id, message) abort
+    let l:conn = get(s:connections, a:conn_id, {})
 
-    let l:conn = s:FindConnection('id', a:conn_id)
-    let l:project = ale#lsp#GetProject(l:conn, l:project_root)
-
-    if empty(l:project)
+    if empty(l:conn)
         return 0
     endif
 
     " If we haven't initialized the server yet, then send the message for it.
-    if !l:project.initialized
-        " Only send the init message once.
-        if !l:project.init_request_id
-            let [l:init_id, l:init_data] = ale#lsp#CreateMessageData(
-            \   ale#lsp#message#Initialize(l:project_root, l:conn.initialization_options),
-            \)
+    if !l:conn.initialized && !l:conn.init_request_id
+        let [l:init_id, l:init_data] = ale#lsp#CreateMessageData(
+        \   ale#lsp#message#Initialize(l:conn.root, l:conn.init_options),
+        \)
 
-            let l:project.init_request_id = l:init_id
+        let l:conn.init_request_id = l:init_id
 
-            call s:SendMessageData(l:conn, l:init_data)
-        endif
+        call s:SendMessageData(l:conn, l:init_data)
     endif
 
     let [l:id, l:data] = ale#lsp#CreateMessageData(a:message)
 
-    if l:project.initialized
+    if l:conn.initialized
         " Send the message now.
         call s:SendMessageData(l:conn, l:data)
     else
         " Add the message we wanted to send to a List to send later.
-        call add(l:project.message_queue, l:data)
+        call add(l:conn.message_queue, l:data)
     endif
 
     return l:id == 0 ? -1 : l:id
@@ -493,11 +447,10 @@ endfunction
 
 " Notify LSP servers or tsserver if a document is opened, if needed.
 " If a document is opened, 1 will be returned, otherwise 0 will be returned.
-function! ale#lsp#OpenDocument(conn_id, project_root, buffer, language_id) abort
-    let l:conn = s:FindConnection('id', a:conn_id)
+function! ale#lsp#OpenDocument(conn_id, buffer, language_id) abort
+    let l:conn = get(s:connections, a:conn_id, {})
     let l:opened = 0
 
-    " FIXME: Return 1 if the document is already open?
     if !empty(l:conn) && !has_key(l:conn.open_documents, a:buffer)
         if l:conn.is_tsserver
             let l:message = ale#lsp#tsserver_message#Open(a:buffer)
@@ -505,7 +458,7 @@ function! ale#lsp#OpenDocument(conn_id, project_root, buffer, language_id) abort
             let l:message = ale#lsp#message#DidOpen(a:buffer, a:language_id)
         endif
 
-        call ale#lsp#Send(a:conn_id, l:message, a:project_root)
+        call ale#lsp#Send(a:conn_id, l:message)
         let l:conn.open_documents[a:buffer] = getbufvar(a:buffer, 'changedtick')
         let l:opened = 1
     endif
@@ -515,8 +468,8 @@ endfunction
 
 " Notify LSP servers or tsserver that a document has changed, if needed.
 " If a notification is sent, 1 will be returned, otherwise 0 will be returned.
-function! ale#lsp#NotifyForChanges(conn_id, project_root, buffer) abort
-    let l:conn = s:FindConnection('id', a:conn_id)
+function! ale#lsp#NotifyForChanges(conn_id, buffer) abort
+    let l:conn = get(s:connections, a:conn_id, {})
     let l:notified = 0
 
     if !empty(l:conn) && has_key(l:conn.open_documents, a:buffer)
@@ -529,7 +482,7 @@ function! ale#lsp#NotifyForChanges(conn_id, project_root, buffer) abort
                 let l:message = ale#lsp#message#DidChange(a:buffer)
             endif
 
-            call ale#lsp#Send(a:conn_id, l:message, a:project_root)
+            call ale#lsp#Send(a:conn_id, l:message)
             let l:conn.open_documents[a:buffer] = l:new_tick
             let l:notified = 1
         endif
@@ -540,25 +493,24 @@ endfunction
 
 " Given some LSP details that must contain at least `connection_id` and
 " `project_root` keys,
-function! ale#lsp#WaitForCapability(conn_id, project_root, capability, callback) abort
-    let l:conn = s:FindConnection('id', a:conn_id)
-    let l:project = ale#lsp#GetProject(l:conn, a:project_root)
+function! ale#lsp#WaitForCapability(conn_id, capability, callback) abort
+    let l:conn = get(s:connections, a:conn_id, {})
 
-    if empty(l:project)
-        return 0
+    if empty(l:conn)
+        return
     endif
 
-    if type(get(l:conn.capabilities, a:capability, v:null)) isnot type(0)
+    if type(get(l:conn.capabilities, a:capability, v:null)) isnot v:t_number
         throw 'Invalid capability ' . a:capability
     endif
 
-    if l:project.initialized
-        if l:conn.is_tsserver || l:conn.capabilities[a:capability]
+    if l:conn.initialized
+        if l:conn.capabilities[a:capability]
             " The project has been initialized, so call the callback now.
-            call call(a:callback, [a:conn_id, a:project_root])
+            call call(a:callback, [a:conn_id])
         endif
     else
         " Call the callback later, once we have the information we need.
-        call add(l:project.capabilities_queue, [a:capability, a:callback])
+        call add(l:conn.capabilities_queue, [a:capability, a:callback])
     endif
 endfunction
diff --git a/autoload/ale/lsp/message.vim b/autoload/ale/lsp/message.vim
index 9e05156d..9fffb83a 100644
--- a/autoload/ale/lsp/message.vim
+++ b/autoload/ale/lsp/message.vim
@@ -130,6 +130,12 @@ function! ale#lsp#message#References(buffer, line, column) abort
     \}]
 endfunction
 
+function! ale#lsp#message#Symbol(query) abort
+    return [0, 'workspace/symbol', {
+    \   'query': a:query,
+    \}]
+endfunction
+
 function! ale#lsp#message#Hover(buffer, line, column) abort
     return [0, 'textDocument/hover', {
     \   'textDocument': {
@@ -138,3 +144,9 @@ function! ale#lsp#message#Hover(buffer, line, column) abort
     \   'position': {'line': a:line - 1, 'character': a:column},
     \}]
 endfunction
+
+function! ale#lsp#message#DidChangeConfiguration(buffer, config) abort
+    return [0, 'workspace/didChangeConfiguration', {
+    \   'settings': a:config,
+    \}]
+endfunction
diff --git a/autoload/ale/lsp/reset.vim b/autoload/ale/lsp/reset.vim
index c7c97a47..2fc7f0a2 100644
--- a/autoload/ale/lsp/reset.vim
+++ b/autoload/ale/lsp/reset.vim
@@ -17,7 +17,7 @@ function! ale#lsp#reset#StopAllLSPs() abort
 
             for l:linter in ale#linter#Get(getbufvar(l:buffer, '&filetype'))
                 if !empty(l:linter.lsp)
-                    call ale#engine#HandleLoclist(l:linter.name, l:buffer, [])
+                    call ale#engine#HandleLoclist(l:linter.name, l:buffer, [], 0)
                 endif
             endfor
         endfor
diff --git a/autoload/ale/lsp/response.vim b/autoload/ale/lsp/response.vim
index a0e1984d..08b36808 100644
--- a/autoload/ale/lsp/response.vim
+++ b/autoload/ale/lsp/response.vim
@@ -47,7 +47,23 @@ function! ale#lsp#response#ReadDiagnostics(response) abort
         endif
 
         if has_key(l:diagnostic, 'code')
-            let l:loclist_item.nr = l:diagnostic.code
+            if type(l:diagnostic.code) == v:t_string
+                let l:loclist_item.code = l:diagnostic.code
+            elseif type(l:diagnostic.code) == v:t_number && l:diagnostic.code != -1
+                let l:loclist_item.code = string(l:diagnostic.code)
+                let l:loclist_item.nr = l:diagnostic.code
+            endif
+        endif
+
+        if has_key(l:diagnostic, 'relatedInformation')
+            let l:related = deepcopy(l:diagnostic.relatedInformation)
+            call map(l:related, {key, val ->
+                \ ale#path#FromURI(val.location.uri) .
+                \ ':' . (val.location.range.start.line + 1) .
+                \ ':' . (val.location.range.start.character + 1) .
+                \ ":\n\t" . val.message
+                \ })
+            let l:loclist_item.detail = l:diagnostic.message . "\n" . join(l:related, "\n")
         endif
 
         if has_key(l:diagnostic, 'source')
@@ -74,7 +90,12 @@ function! ale#lsp#response#ReadTSServerDiagnostics(response) abort
         \}
 
         if has_key(l:diagnostic, 'code')
-            let l:loclist_item.nr = l:diagnostic.code
+            if type(l:diagnostic.code) == v:t_string
+                let l:loclist_item.code = l:diagnostic.code
+            elseif type(l:diagnostic.code) == v:t_number && l:diagnostic.code != -1
+                let l:loclist_item.code = string(l:diagnostic.code)
+                let l:loclist_item.nr = l:diagnostic.code
+            endif
         endif
 
         if get(l:diagnostic, 'category') is# 'warning'
@@ -92,7 +113,7 @@ function! ale#lsp#response#ReadTSServerDiagnostics(response) abort
 endfunction
 
 function! ale#lsp#response#GetErrorMessage(response) abort
-    if type(get(a:response, 'error', 0)) isnot type({})
+    if type(get(a:response, 'error', 0)) isnot v:t_dict
         return ''
     endif
 
@@ -112,12 +133,12 @@ function! ale#lsp#response#GetErrorMessage(response) abort
     " Include the traceback or error data as details, if present.
     let l:error_data = get(a:response.error, 'data', {})
 
-    if type(l:error_data) is type('')
+    if type(l:error_data) is v:t_string
         let l:message .= "\n" . l:error_data
-    else
+    elseif type(l:error_data) is v:t_dict
         let l:traceback = get(l:error_data, 'traceback', [])
 
-        if type(l:traceback) is type([]) && !empty(l:traceback)
+        if type(l:traceback) is v:t_list && !empty(l:traceback)
             let l:message .= "\n" . join(l:traceback, "\n")
         endif
     endif
diff --git a/autoload/ale/lsp_linter.vim b/autoload/ale/lsp_linter.vim
index 87aee759..42d67398 100644
--- a/autoload/ale/lsp_linter.vim
+++ b/autoload/ale/lsp_linter.vim
@@ -38,7 +38,7 @@ function! s:HandleLSPDiagnostics(conn_id, response) abort
 
     let l:loclist = ale#lsp#response#ReadDiagnostics(a:response)
 
-    call ale#engine#HandleLoclist(l:linter_name, l:buffer, l:loclist)
+    call ale#engine#HandleLoclist(l:linter_name, l:buffer, l:loclist, 0)
 endfunction
 
 function! s:HandleTSServerDiagnostics(response, error_type) abort
@@ -55,20 +55,33 @@ function! s:HandleTSServerDiagnostics(response, error_type) abort
     endif
 
     let l:thislist = ale#lsp#response#ReadTSServerDiagnostics(a:response)
+    let l:no_changes = 0
 
     " tsserver sends syntax and semantic errors in separate messages, so we
     " have to collect the messages separately for each buffer and join them
     " back together again.
     if a:error_type is# 'syntax'
+        if len(l:thislist) is 0 && len(get(l:info, 'syntax_loclist', [])) is 0
+            let l:no_changes = 1
+        endif
+
         let l:info.syntax_loclist = l:thislist
     else
+        if len(l:thislist) is 0 && len(get(l:info, 'semantic_loclist', [])) is 0
+            let l:no_changes = 1
+        endif
+
         let l:info.semantic_loclist = l:thislist
     endif
 
+    if l:no_changes
+        return
+    endif
+
     let l:loclist = get(l:info, 'semantic_loclist', [])
     \   + get(l:info, 'syntax_loclist', [])
 
-    call ale#engine#HandleLoclist(l:linter_name, l:buffer, l:loclist)
+    call ale#engine#HandleLoclist(l:linter_name, l:buffer, l:loclist, 0)
 endfunction
 
 function! s:HandleLSPErrorMessage(linter_name, response) abort
@@ -99,9 +112,10 @@ endfunction
 
 function! ale#lsp_linter#HandleLSPResponse(conn_id, response) abort
     let l:method = get(a:response, 'method', '')
-    let l:linter_name = get(s:lsp_linter_map, a:conn_id, '')
 
     if get(a:response, 'jsonrpc', '') is# '2.0' && has_key(a:response, 'error')
+        let l:linter_name = get(s:lsp_linter_map, a:conn_id, '')
+
         call s:HandleLSPErrorMessage(l:linter_name, a:response)
     elseif l:method is# 'textDocument/publishDiagnostics'
         call s:HandleLSPDiagnostics(a:conn_id, a:response)
@@ -126,6 +140,18 @@ function! ale#lsp_linter#GetOptions(buffer, linter) abort
     return l:initialization_options
 endfunction
 
+function! ale#lsp_linter#GetConfig(buffer, linter) abort
+    let l:config = {}
+
+    if has_key(a:linter, 'lsp_config_callback')
+        let l:config = ale#util#GetFunction(a:linter.lsp_config_callback)(a:buffer)
+    elseif has_key(a:linter, 'lsp_config')
+        let l:config = a:linter.lsp_config
+    endif
+
+    return l:config
+endfunction
+
 " Given a buffer, an LSP linter, start up an LSP linter and get ready to
 " receive messages for the document.
 function! ale#lsp_linter#StartLSP(buffer, linter) abort
@@ -143,7 +169,8 @@ function! ale#lsp_linter#StartLSP(buffer, linter) abort
 
     if a:linter.lsp is# 'socket'
         let l:address = ale#linter#GetAddress(a:buffer, a:linter)
-        let l:conn_id = ale#lsp#ConnectToAddress(l:address, l:init_options)
+        let l:conn_id = ale#lsp#Register(l:address, l:root, l:init_options)
+        let l:ready = ale#lsp#ConnectToAddress(l:conn_id, l:address)
     else
         let l:executable = ale#linter#GetExecutable(a:buffer, a:linter)
 
@@ -151,18 +178,16 @@ function! ale#lsp_linter#StartLSP(buffer, linter) abort
             return {}
         endif
 
+        let l:conn_id = ale#lsp#Register(l:executable, l:root, l:init_options)
+
         let l:command = ale#linter#GetCommand(a:buffer, a:linter)
         " Format the command, so %e can be formatted into it.
         let l:command = ale#command#FormatCommand(a:buffer, l:executable, l:command, 0)[1]
         let l:command = ale#job#PrepareCommand(a:buffer, l:command)
-        let l:conn_id = ale#lsp#StartProgram(
-        \   l:executable,
-        \   l:command,
-        \   l:init_options,
-        \)
+        let l:ready = ale#lsp#StartProgram(l:conn_id, l:executable, l:command)
     endif
 
-    if empty(l:conn_id)
+    if !l:ready
         if g:ale_history_enabled && !empty(l:command)
             call ale#history#Add(a:buffer, 'failed', l:conn_id, l:command)
         endif
@@ -175,9 +200,7 @@ function! ale#lsp_linter#StartLSP(buffer, linter) abort
         call ale#lsp#MarkConnectionAsTsserver(l:conn_id)
     endif
 
-    " Register the project now the connection is ready.
-    call ale#lsp#RegisterProject(l:conn_id, l:root)
-
+    let l:config = ale#lsp_linter#GetConfig(a:buffer, a:linter)
     let l:language_id = ale#util#GetFunction(a:linter.language_callback)(a:buffer)
 
     let l:details = {
@@ -188,7 +211,9 @@ function! ale#lsp_linter#StartLSP(buffer, linter) abort
     \   'language_id': l:language_id,
     \}
 
-    if ale#lsp#OpenDocument(l:conn_id, l:root, a:buffer, l:language_id)
+    call ale#lsp#UpdateConfig(l:conn_id, a:buffer, l:config)
+
+    if ale#lsp#OpenDocument(l:conn_id, a:buffer, l:language_id)
         if g:ale_history_enabled && !empty(l:command)
             call ale#history#Add(a:buffer, 'started', l:conn_id, l:command)
         endif
@@ -196,7 +221,7 @@ function! ale#lsp_linter#StartLSP(buffer, linter) abort
 
     " The change message needs to be sent for tsserver before doing anything.
     if a:linter.lsp is# 'tsserver'
-        call ale#lsp#NotifyForChanges(l:conn_id, l:root, a:buffer)
+        call ale#lsp#NotifyForChanges(l:conn_id, a:buffer)
     endif
 
     return l:details
@@ -211,7 +236,6 @@ function! ale#lsp_linter#CheckWithLSP(buffer, linter) abort
     endif
 
     let l:id = l:lsp_details.connection_id
-    let l:root = l:lsp_details.project_root
 
     " Register a callback now for handling errors now.
     let l:Callback = function('ale#lsp_linter#HandleLSPResponse')
@@ -222,16 +246,16 @@ function! ale#lsp_linter#CheckWithLSP(buffer, linter) abort
 
     if a:linter.lsp is# 'tsserver'
         let l:message = ale#lsp#tsserver_message#Geterr(a:buffer)
-        let l:notified = ale#lsp#Send(l:id, l:message, l:root) != 0
+        let l:notified = ale#lsp#Send(l:id, l:message) != 0
     else
-        let l:notified = ale#lsp#NotifyForChanges(l:id, l:root, a:buffer)
+        let l:notified = ale#lsp#NotifyForChanges(l:id, a:buffer)
     endif
 
     " If this was a file save event, also notify the server of that.
     if a:linter.lsp isnot# 'tsserver'
     \&& getbufvar(a:buffer, 'ale_save_event_fired', 0)
         let l:save_message = ale#lsp#message#DidSave(a:buffer)
-        let l:notified = ale#lsp#Send(l:id, l:save_message, l:root) != 0
+        let l:notified = ale#lsp#Send(l:id, l:save_message) != 0
     endif
 
     if l:notified
diff --git a/autoload/ale/node.vim b/autoload/ale/node.vim
index f75280b7..5c579c75 100644
--- a/autoload/ale/node.vim
+++ b/autoload/ale/node.vim
@@ -23,6 +23,11 @@ function! ale#node#FindExecutable(buffer, base_var_name, path_list) abort
     return ale#Var(a:buffer, a:base_var_name . '_executable')
 endfunction
 
+" As above, but curry the arguments so only the buffer number is required.
+function! ale#node#FindExecutableFunc(base_var_name, path_list) abort
+    return {buf -> ale#node#FindExecutable(buf, a:base_var_name, a:path_list)}
+endfunction
+
 " Create a executable string which executes a Node.js script command with a
 " Node.js executable if needed.
 "
diff --git a/autoload/ale/other_source.vim b/autoload/ale/other_source.vim
new file mode 100644
index 00000000..1a092034
--- /dev/null
+++ b/autoload/ale/other_source.vim
@@ -0,0 +1,21 @@
+" Tell ALE that another source has started checking a buffer.
+function! ale#other_source#StartChecking(buffer, linter_name) abort
+    call ale#engine#InitBufferInfo(a:buffer)
+    let l:list = g:ale_buffer_info[a:buffer].active_other_sources_list
+
+    call add(l:list, a:linter_name)
+    call uniq(sort(l:list))
+endfunction
+
+" Show some results, and stop checking a buffer.
+" To clear results or cancel checking a buffer, an empty List can be given.
+function! ale#other_source#ShowResults(buffer, linter_name, loclist) abort
+    call ale#engine#InitBufferInfo(a:buffer)
+    let l:info = g:ale_buffer_info[a:buffer]
+
+    " Remove this linter name from the active list.
+    let l:list = l:info.active_other_sources_list
+    call filter(l:list, 'v:val isnot# a:linter_name')
+
+    call ale#engine#HandleLoclist(a:linter_name, a:buffer, a:loclist, 1)
+endfunction
diff --git a/autoload/ale/path.vim b/autoload/ale/path.vim
index 45da3709..89b119f4 100644
--- a/autoload/ale/path.vim
+++ b/autoload/ale/path.vim
@@ -65,7 +65,11 @@ endfunction
 " Output 'cd <directory> && '
 " This function can be used changing the directory for a linter command.
 function! ale#path#CdString(directory) abort
-    return 'cd ' . ale#Escape(a:directory) . ' && '
+    if has('win32')
+        return 'cd /d ' . ale#Escape(a:directory) . ' && '
+    else
+        return 'cd ' . ale#Escape(a:directory) . ' && '
+    endif
 endfunction
 
 " Output 'cd <buffer_filename_directory> && '
@@ -105,6 +109,21 @@ function! ale#path#GetAbsPath(base_directory, filename) abort
     return ale#path#Simplify(a:base_directory . l:sep . a:filename)
 endfunction
 
+" Given a path, return the directory name for that path, with no trailing
+" slashes. If the argument is empty(), return an empty string.
+function! ale#path#Dirname(path) abort
+    if empty(a:path)
+        return ''
+    endif
+
+    " For /foo/bar/ we need :h:h to get /foo
+    if a:path[-1:] is# '/'
+        return fnamemodify(a:path, ':h:h')
+    endif
+
+    return fnamemodify(a:path, ':h')
+endfunction
+
 " Given a buffer number and a relative or absolute path, return 1 if the
 " two paths represent the same file on disk.
 function! ale#path#IsBufferPath(buffer, complex_filename) abort
diff --git a/autoload/ale/preview.vim b/autoload/ale/preview.vim
index aefbb691..1f50e0ad 100644
--- a/autoload/ale/preview.vim
+++ b/autoload/ale/preview.vim
@@ -15,13 +15,13 @@ function! ale#preview#Show(lines, ...) abort
     setlocal modifiable
     setlocal noreadonly
     setlocal nobuflisted
-    let &l:filetype = get(l:options, 'filetype', 'ale-preview')
     setlocal buftype=nofile
     setlocal bufhidden=wipe
     :%d
     call setline(1, a:lines)
     setlocal nomodifiable
     setlocal readonly
+    let &l:filetype = get(l:options, 'filetype', 'ale-preview')
 
     if get(l:options, 'stay_here')
         wincmd p
@@ -46,11 +46,14 @@ function! ale#preview#ShowSelection(item_list) abort
 
     " Create lines to display to users.
     for l:item in a:item_list
+        let l:match = get(l:item, 'match', '')
+
         call add(
         \   l:lines,
         \   l:item.filename
         \       . ':' . l:item.line
-        \       . ':' . l:item.column,
+        \       . ':' . l:item.column
+        \       . (!empty(l:match) ? ' ' . l:match : ''),
         \)
     endfor
 
diff --git a/autoload/ale/python.vim b/autoload/ale/python.vim
index bc1cc980..8d6bf1f0 100644
--- a/autoload/ale/python.vim
+++ b/autoload/ale/python.vim
@@ -1,6 +1,8 @@
 " Author: w0rp <devw0rp@gmail.com>
 " Description: Functions for integrating with Python linters.
 
+call ale#Set('python_auto_pipenv', '0')
+
 let s:sep = has('win32') ? '\' : '/'
 " bin is used for Unix virtualenv directories, and Scripts is for Windows.
 let s:bin_dir = has('unix') ? 'bin' : 'Scripts'
@@ -24,6 +26,7 @@ function! ale#python#FindProjectRootIni(buffer) abort
         \|| filereadable(l:path . '/mypy.ini')
         \|| filereadable(l:path . '/pycodestyle.cfg')
         \|| filereadable(l:path . '/flake8.cfg')
+        \|| filereadable(l:path . '/.flake8rc')
         \|| filereadable(l:path . '/Pipfile')
         \|| filereadable(l:path . '/Pipfile.lock')
             return l:path
@@ -106,3 +109,8 @@ function! ale#python#FindExecutable(buffer, base_var_name, path_list) abort
 
     return ale#Var(a:buffer, a:base_var_name . '_executable')
 endfunction
+
+" Detects whether a pipenv environment is present.
+function! ale#python#PipenvPresent(buffer) abort
+    return findfile('Pipfile.lock', expand('#' . a:buffer . ':p:h') . ';') isnot# ''
+endfunction
diff --git a/autoload/ale/references.vim b/autoload/ale/references.vim
index 3a710b7b..d00a1fa9 100644
--- a/autoload/ale/references.vim
+++ b/autoload/ale/references.vim
@@ -64,6 +64,35 @@ function! ale#references#HandleLSPResponse(conn_id, response) abort
     endif
 endfunction
 
+function! s:OnReady(linter, lsp_details, line, column, ...) abort
+    let l:buffer = a:lsp_details.buffer
+    let l:id = a:lsp_details.connection_id
+
+    let l:Callback = a:linter.lsp is# 'tsserver'
+    \   ? function('ale#references#HandleTSServerResponse')
+    \   : function('ale#references#HandleLSPResponse')
+
+    call ale#lsp#RegisterCallback(l:id, l:Callback)
+
+    if a:linter.lsp is# 'tsserver'
+        let l:message = ale#lsp#tsserver_message#References(
+        \   l:buffer,
+        \   a:line,
+        \   a:column
+        \)
+    else
+        " Send a message saying the buffer has changed first, or the
+        " references position probably won't make sense.
+        call ale#lsp#NotifyForChanges(l:id, l:buffer)
+
+        let l:message = ale#lsp#message#References(l:buffer, a:line, a:column)
+    endif
+
+    let l:request_id = ale#lsp#Send(l:id, l:message)
+
+    let s:references_map[l:request_id] = {}
+endfunction
+
 function! s:FindReferences(linter) abort
     let l:buffer = bufnr('')
     let [l:line, l:column] = getcurpos()[1:2]
@@ -79,35 +108,10 @@ function! s:FindReferences(linter) abort
     endif
 
     let l:id = l:lsp_details.connection_id
-    let l:root = l:lsp_details.project_root
-
-    function! OnReady(...) abort closure
-        let l:Callback = a:linter.lsp is# 'tsserver'
-        \   ? function('ale#references#HandleTSServerResponse')
-        \   : function('ale#references#HandleLSPResponse')
-
-        call ale#lsp#RegisterCallback(l:id, l:Callback)
-
-        if a:linter.lsp is# 'tsserver'
-            let l:message = ale#lsp#tsserver_message#References(
-            \   l:buffer,
-            \   l:line,
-            \   l:column
-            \)
-        else
-            " Send a message saying the buffer has changed first, or the
-            " references position probably won't make sense.
-            call ale#lsp#NotifyForChanges(l:id, l:root, l:buffer)
-
-            let l:message = ale#lsp#message#References(l:buffer, l:line, l:column)
-        endif
-
-        let l:request_id = ale#lsp#Send(l:id, l:message, l:lsp_details.project_root)
-
-        let s:references_map[l:request_id] = {}
-    endfunction
 
-    call ale#lsp#WaitForCapability(l:id, l:root, 'references', function('OnReady'))
+    call ale#lsp#WaitForCapability(l:id, 'references', function('s:OnReady', [
+    \   a:linter, l:lsp_details, l:line, l:column
+    \]))
 endfunction
 
 function! ale#references#Find() abort
diff --git a/autoload/ale/ruby.vim b/autoload/ale/ruby.vim
index b981ded6..5f0aa50d 100644
--- a/autoload/ale/ruby.vim
+++ b/autoload/ale/ruby.vim
@@ -20,3 +20,25 @@ function! ale#ruby#FindRailsRoot(buffer) abort
 
     return ''
 endfunction
+
+" Find the nearest dir containing a potential ruby project.
+function! ale#ruby#FindProjectRoot(buffer) abort
+    let l:dir = ale#ruby#FindRailsRoot(a:buffer)
+
+    if isdirectory(l:dir)
+      return l:dir
+    endif
+
+    for l:name in ['.solargraph.yml', 'Rakefile', 'Gemfile']
+        let l:dir = fnamemodify(
+        \   ale#path#FindNearestFile(a:buffer, l:name),
+        \   ':h'
+        \)
+
+        if l:dir isnot# '.' && isdirectory(l:dir)
+            return l:dir
+        endif
+    endfor
+
+    return ''
+endfunction
diff --git a/autoload/ale/sign.vim b/autoload/ale/sign.vim
index a0dde359..af863682 100644
--- a/autoload/ale/sign.vim
+++ b/autoload/ale/sign.vim
@@ -211,7 +211,7 @@ function! s:BuildSignMap(buffer, current_sign_list, grouped_items) abort
 
     if l:max_signs is 0
         let l:selected_grouped_items = []
-    elseif type(l:max_signs) is type(0) && l:max_signs > 0
+    elseif type(l:max_signs) is v:t_number && l:max_signs > 0
         let l:selected_grouped_items = a:grouped_items[:l:max_signs - 1]
     else
         let l:selected_grouped_items = a:grouped_items
diff --git a/autoload/ale/socket.vim b/autoload/ale/socket.vim
index 0ca4dea6..7e069fb5 100644
--- a/autoload/ale/socket.vim
+++ b/autoload/ale/socket.vim
@@ -55,11 +55,18 @@ function! ale#socket#Open(address, options) abort
 
     if !has('nvim')
         " Vim
-        let l:channel_info.channel = ch_open(a:address, {
+        let l:channel_options = {
         \   'mode': l:mode,
         \   'waittime': 0,
         \   'callback': function('s:VimOutputCallback'),
-        \})
+        \}
+
+        " Use non-blocking writes for Vim versions that support the option.
+        if has('patch-8.1.350')
+            let l:channel_options.noblock = 1
+        endif
+
+        let l:channel_info.channel = ch_open(a:address, l:channel_options)
         let l:vim_info = ch_info(l:channel_info.channel)
         let l:channel_id = !empty(l:vim_info) ? l:vim_info.id : -1
     elseif exists('*chansend') && exists('*sockconnect')
@@ -104,6 +111,7 @@ function! ale#socket#IsOpen(channel_id) abort
     endif
 
     let l:channel = s:channel_map[a:channel_id].channel
+
     return ch_status(l:channel) is# 'open'
 endfunction
 
diff --git a/autoload/ale/symbol.vim b/autoload/ale/symbol.vim
new file mode 100644
index 00000000..5180cb86
--- /dev/null
+++ b/autoload/ale/symbol.vim
@@ -0,0 +1,109 @@
+let s:symbol_map = {}
+
+" Used to get the symbol map in tests.
+function! ale#symbol#GetMap() abort
+    return deepcopy(s:symbol_map)
+endfunction
+
+" Used to set the symbol map in tests.
+function! ale#symbol#SetMap(map) abort
+    let s:symbol_map = a:map
+endfunction
+
+function! ale#symbol#ClearLSPData() abort
+    let s:symbol_map = {}
+endfunction
+
+function! ale#symbol#HandleLSPResponse(conn_id, response) abort
+    if has_key(a:response, 'id')
+    \&& has_key(s:symbol_map, a:response.id)
+        let l:options = remove(s:symbol_map, a:response.id)
+
+        let l:result = get(a:response, 'result', v:null)
+        let l:item_list = []
+
+        if type(l:result) is v:t_list
+            " Each item looks like this:
+            " {
+            "   'name': 'foo',
+            "   'kind': 123,
+            "   'deprecated': v:false,
+            "   'location': {
+            "     'uri': 'file://...',
+            "     'range': {
+            "       'start': {'line': 0, 'character': 0},
+            "       'end': {'line': 0, 'character': 0},
+            "     },
+            "   },
+            "   'containerName': 'SomeContainer',
+            " }
+            for l:response_item in l:result
+                let l:location = l:response_item.location
+
+                call add(l:item_list, {
+                \ 'filename': ale#path#FromURI(l:location.uri),
+                \ 'line': l:location.range.start.line + 1,
+                \ 'column': l:location.range.start.character + 1,
+                \ 'match': l:response_item.name,
+                \})
+            endfor
+        endif
+
+        if empty(l:item_list)
+            call ale#util#Execute('echom ''No symbols found.''')
+        else
+            call ale#preview#ShowSelection(l:item_list)
+        endif
+    endif
+endfunction
+
+function! s:OnReady(linter, lsp_details, query, ...) abort
+    let l:buffer = a:lsp_details.buffer
+
+    " If we already made a request, stop here.
+    if getbufvar(l:buffer, 'ale_symbol_request_made', 0)
+        return
+    endif
+
+    let l:id = a:lsp_details.connection_id
+
+    let l:Callback = function('ale#symbol#HandleLSPResponse')
+    call ale#lsp#RegisterCallback(l:id, l:Callback)
+
+    let l:message = ale#lsp#message#Symbol(a:query)
+    let l:request_id = ale#lsp#Send(l:id, l:message)
+
+    call setbufvar(l:buffer, 'ale_symbol_request_made', 1)
+    let s:symbol_map[l:request_id] = {
+    \   'buffer': l:buffer,
+    \}
+endfunction
+
+function! s:Search(linter, buffer, query) abort
+    let l:lsp_details = ale#lsp_linter#StartLSP(a:buffer, a:linter)
+
+    if !empty(l:lsp_details)
+        call ale#lsp#WaitForCapability(
+        \   l:lsp_details.connection_id,
+        \   'symbol_search',
+        \   function('s:OnReady', [a:linter, l:lsp_details, a:query]),
+        \)
+    endif
+endfunction
+
+function! ale#symbol#Search(query) abort
+    if type(a:query) isnot v:t_string || empty(a:query)
+        throw 'A non-empty string must be provided!'
+    endif
+
+    let l:buffer = bufnr('')
+
+    " Set a flag so we only make one request.
+    call setbufvar(l:buffer, 'ale_symbol_request_made', 0)
+
+    for l:linter in ale#linter#Get(getbufvar(l:buffer, '&filetype'))
+        if !empty(l:linter.lsp) && l:linter.lsp isnot# 'tsserver'
+            call s:Search(l:linter, l:buffer, a:query)
+        endif
+    endfor
+endfunction
diff --git a/autoload/ale/toggle.vim b/autoload/ale/toggle.vim
index da108782..8e642b3f 100644
--- a/autoload/ale/toggle.vim
+++ b/autoload/ale/toggle.vim
@@ -15,21 +15,6 @@ function! s:DisablePostamble() abort
     endif
 endfunction
 
-function! s:CleanupEveryBuffer() abort
-    for l:key in keys(g:ale_buffer_info)
-        " The key could be a filename or a buffer number, so try and
-        " convert it to a number. We need a number for the other
-        " functions.
-        let l:buffer = str2nr(l:key)
-
-        if l:buffer > 0
-            " Stop all jobs and clear the results for everything, and delete
-            " all of the data we stored for the buffer.
-            call ale#engine#Cleanup(l:buffer)
-        endif
-    endfor
-endfunction
-
 function! ale#toggle#Toggle() abort
     let g:ale_enabled = !get(g:, 'ale_enabled')
 
@@ -40,7 +25,7 @@ function! ale#toggle#Toggle() abort
             call ale#balloon#Enable()
         endif
     else
-        call s:CleanupEveryBuffer()
+        call ale#engine#CleanupEveryBuffer()
         call s:DisablePostamble()
 
         if exists('*ale#balloon#Disable')
@@ -64,7 +49,7 @@ function! ale#toggle#Disable() abort
 endfunction
 
 function! ale#toggle#Reset() abort
-    call s:CleanupEveryBuffer()
+    call ale#engine#CleanupEveryBuffer()
     call ale#highlight#UpdateHighlights()
 endfunction
 
@@ -76,6 +61,7 @@ function! ale#toggle#ToggleBuffer(buffer) abort
     " linting locally when linting is disabled globally
     if l:enabled && !g:ale_enabled
         execute 'echom ''ALE cannot be enabled locally when disabled globally'''
+
         return
     endif
 
diff --git a/autoload/ale/util.vim b/autoload/ale/util.vim
index fb6dc085..bb478957 100644
--- a/autoload/ale/util.vim
+++ b/autoload/ale/util.vim
@@ -54,6 +54,7 @@ endif
 function! ale#util#JoinNeovimOutput(job, last_line, data, mode, callback) abort
     if a:mode is# 'raw'
         call a:callback(a:job, join(a:data, "\n"))
+
         return ''
     endif
 
@@ -79,7 +80,7 @@ function! ale#util#GetLineCount(buffer) abort
 endfunction
 
 function! ale#util#GetFunction(string_or_ref) abort
-    if type(a:string_or_ref) == type('')
+    if type(a:string_or_ref) is v:t_string
         return function(a:string_or_ref)
     endif
 
@@ -88,12 +89,12 @@ endfunction
 
 function! ale#util#Open(filename, line, column, options) abort
     if get(a:options, 'open_in_tab', 0)
-        call ale#util#Execute('tabedit ' . fnameescape(a:filename))
-    else
+        call ale#util#Execute('tabedit +' . a:line . ' ' . fnameescape(a:filename))
+    elseif bufnr(a:filename) isnot bufnr('')
         " Open another file only if we need to.
-        if bufnr(a:filename) isnot bufnr('')
-            call ale#util#Execute('edit ' . fnameescape(a:filename))
-        endif
+        call ale#util#Execute('edit +' . a:line . ' ' . fnameescape(a:filename))
+    else
+        normal! m`
     endif
 
     call cursor(a:line, a:column)
@@ -268,7 +269,7 @@ endfunction
 " See :help sandbox
 function! ale#util#InSandbox() abort
     try
-        let &equalprg=&equalprg
+        let &l:equalprg=&l:equalprg
     catch /E48/
         " E48 is the sandbox error.
         return 1
@@ -303,8 +304,8 @@ endfunction
 " Only the first pattern which matches a line will be returned.
 function! ale#util#GetMatches(lines, patterns) abort
     let l:matches = []
-    let l:lines = type(a:lines) == type([]) ? a:lines : [a:lines]
-    let l:patterns = type(a:patterns) == type([]) ? a:patterns : [a:patterns]
+    let l:lines = type(a:lines) is v:t_list ? a:lines : [a:lines]
+    let l:patterns = type(a:patterns) is v:t_list ? a:patterns : [a:patterns]
 
     for l:line in l:lines
         for l:pattern in l:patterns
@@ -382,7 +383,7 @@ function! ale#util#FuzzyJSONDecode(data, default) abort
         return a:default
     endif
 
-    let l:str = type(a:data) == type('') ? a:data : join(a:data, '')
+    let l:str = type(a:data) is v:t_string ? a:data : join(a:data, '')
 
     try
         let l:result = json_decode(l:str)
@@ -404,7 +405,7 @@ endfunction
 " the buffer.
 function! ale#util#Writefile(buffer, lines, filename) abort
     let l:corrected_lines = getbufvar(a:buffer, '&fileformat') is# 'dos'
-    \   ? map(copy(a:lines), 'v:val . "\r"')
+    \   ? map(copy(a:lines), 'substitute(v:val, ''\r*$'', ''\r'', '''')')
     \   : a:lines
 
     call writefile(l:corrected_lines, a:filename) " no-custom-checks
@@ -451,3 +452,14 @@ function! ale#util#Col(str, chr) abort
 
     return strlen(join(split(a:str, '\zs')[0:a:chr - 2], '')) + 1
 endfunction
+
+function! ale#util#FindItemAtCursor(buffer) abort
+    let l:info = get(g:ale_buffer_info, a:buffer, {})
+    let l:loclist = get(l:info, 'loclist', [])
+    let l:pos = getcurpos()
+    let l:index = ale#util#BinarySearch(l:loclist, a:buffer, l:pos[1], l:pos[2])
+    let l:loc = l:index >= 0 ? l:loclist[l:index] : {}
+
+    return [l:info, l:loc]
+endfunction
+
diff --git a/autoload/ale/virtualtext.vim b/autoload/ale/virtualtext.vim
new file mode 100644
index 00000000..c4ce37dd
--- /dev/null
+++ b/autoload/ale/virtualtext.vim
@@ -0,0 +1,136 @@
+scriptencoding utf-8
+" Author: w0rp <devw0rp@gmail.com>
+" Author: Luan Santos <cfcluan@gmail.com>
+" Description: Shows lint message for the current line as virtualtext, if any
+
+" Controls the milliseconds delay before showing a message.
+let g:ale_virtualtext_delay = get(g:, 'ale_virtualtext_delay', 10)
+let s:cursor_timer = -1
+let s:last_pos = [0, 0, 0]
+
+if has('nvim-0.3.2')
+    let s:ns_id = nvim_create_namespace('ale')
+endif
+
+if !hlexists('ALEVirtualTextError')
+    highlight link ALEVirtualTextError ALEError
+endif
+
+if !hlexists('ALEVirtualTextStyleError')
+    highlight link ALEVirtualTextStyleError ALEVirtualTextError
+endif
+
+if !hlexists('ALEVirtualTextWarning')
+    highlight link ALEVirtualTextWarning ALEWarning
+endif
+
+if !hlexists('ALEVirtualTextStyleWarning')
+    highlight link ALEVirtualTextStyleWarning ALEVirtualTextWarning
+endif
+
+if !hlexists('ALEVirtualTextInfo')
+    highlight link ALEVirtualTextInfo ALEVirtualTextWarning
+endif
+
+function! ale#virtualtext#Clear() abort
+    if !has('nvim-0.3.2')
+        return
+    endif
+
+    let l:buffer = bufnr('')
+
+    call nvim_buf_clear_highlight(l:buffer, s:ns_id, 0, -1)
+endfunction
+
+function! ale#virtualtext#ShowMessage(message, hl_group) abort
+    if !has('nvim-0.3.2')
+        return
+    endif
+
+    let l:cursor_position = getcurpos()
+    let l:line = line('.')
+    let l:buffer = bufnr('')
+    let l:prefix = get(g:, 'ale_virtualtext_prefix', '> ')
+
+    call nvim_buf_set_virtual_text(l:buffer, s:ns_id, l:line-1, [[l:prefix.a:message, a:hl_group]], {})
+endfunction
+
+function! s:StopCursorTimer() abort
+    if s:cursor_timer != -1
+        call timer_stop(s:cursor_timer)
+        let s:cursor_timer = -1
+    endif
+endfunction
+
+function! ale#virtualtext#ShowCursorWarning(...) abort
+    if !g:ale_virtualtext_cursor
+        return
+    endif
+
+    let l:buffer = bufnr('')
+
+    if mode(1) isnot# 'n'
+        return
+    endif
+
+    if ale#ShouldDoNothing(l:buffer)
+        return
+    endif
+
+    let [l:info, l:loc] = ale#util#FindItemAtCursor(l:buffer)
+
+    call ale#virtualtext#Clear()
+
+    if !empty(l:loc)
+        let l:msg = get(l:loc, 'detail', l:loc.text)
+        let l:hl_group = 'ALEVirtualTextInfo'
+        let l:type = get(l:loc, 'type', 'E')
+
+        if l:type is# 'E'
+            if get(l:loc, 'sub_type', '') is# 'style'
+                let l:hl_group = 'ALEVirtualTextStyleError'
+            else
+                let l:hl_group = 'ALEVirtualTextError'
+            endif
+        elseif l:type is# 'W'
+            if get(l:loc, 'sub_type', '') is# 'style'
+                let l:hl_group = 'ALEVirtualTextStyleWarning'
+            else
+                let l:hl_group = 'ALEVirtualTextWarning'
+            endif
+        endif
+
+        call ale#virtualtext#ShowMessage(l:msg, l:hl_group)
+    endif
+endfunction
+
+function! ale#virtualtext#ShowCursorWarningWithDelay() abort
+    let l:buffer = bufnr('')
+
+    if !g:ale_virtualtext_cursor
+        return
+    endif
+
+    if mode(1) isnot# 'n'
+        return
+    endif
+
+    call s:StopCursorTimer()
+
+    let l:pos = getcurpos()[0:2]
+
+    " Check the current buffer, line, and column number against the last
+    " recorded position. If the position has actually changed, *then*
+    " we should show something. Otherwise we can end up doing processing
+    " the show message far too frequently.
+    if l:pos != s:last_pos
+        let l:delay = ale#Var(l:buffer, 'virtualtext_delay')
+
+        let s:last_pos = l:pos
+        let s:cursor_timer = timer_start(
+        \   l:delay,
+        \   function('ale#virtualtext#ShowCursorWarning')
+        \)
+    endif
+endfunction
+