7 files changed, 96 insertions, 17 deletions
diff --git a/autoload/ale/completion.vim b/autoload/ale/completion.vim
index 44d4e0e1..9f4e3c28 100644
--- a/autoload/ale/completion.vim
+++ b/autoload/ale/completion.vim
@@ -1,10 +1,6 @@
 " Author: w0rp <devw0rp@gmail.com>
 " Description: Completion support for LSP linters
 
-" A do-nothing function so we can load this autoload file in tests.
-function! ale#completion#Nop() abort
-endfunction
-
 let s:timer_id = -1
 
 function! s:GetRegex(map, filetype) abort
@@ -110,11 +106,6 @@ function! ale#completion#OmniFunc(findstart, base) abort
     endif
 endfunction
 
-" A wrapper function for feedkeys so we can test calls for it.
-function! ale#completion#FeedKeys(string, mode) abort
-    call feedkeys(a:string, a:mode)
-endfunction
-
 function! ale#completion#Show(response, completion_parser) abort
     " Remember the old omnifunc value, if there is one.
     " If we don't store an old one, we'll just never reset the option.
@@ -129,7 +120,7 @@ function! ale#completion#Show(response, completion_parser) abort
     let b:ale_completion_parser = a:completion_parser
     let &l:omnifunc = 'ale#completion#OmniFunc'
     call s:ReplaceCompleteopt()
-    call ale#completion#FeedKeys("\<C-x>\<C-o>", 'n')
+    call ale#util#FeedKeys("\<C-x>\<C-o>", 'n')
 endfunction
 
 function! s:CompletionStillValid(request_id) abort
diff --git a/autoload/ale/events.vim b/autoload/ale/events.vim
index a3b74677..c84954c1 100644
--- a/autoload/ale/events.vim
+++ b/autoload/ale/events.vim
@@ -45,3 +45,25 @@ function! ale#events#FileChangedEvent(buffer) abort
         call s:LintOnEnter(a:buffer)
     endif
 endfunction
+
+" When changing quickfix or a loclist window while the window is open
+" from autocmd events and while navigating from one buffer to another, Vim
+" will complain saying that the window has closed or that the lists have
+" changed.
+"
+" This timer callback just accepts those errors when they appear.
+function! s:HitReturn(...) abort
+    if ale#util#Mode() is# 'r'
+        redir => l:output
+            silent mess
+        redir end
+
+        if get(split(l:output, "\n"), -1, '') =~# '^E92[456]'
+            call ale#util#FeedKeys("\<CR>", 'n')
+        endif
+    endif
+endfunction
+
+function! ale#events#BufWinLeave() abort
+    call timer_start(0, function('s:HitReturn'))
+endfunction
diff --git a/autoload/ale/util.vim b/autoload/ale/util.vim
index fd538425..c46579b0 100644
--- a/autoload/ale/util.vim
+++ b/autoload/ale/util.vim
@@ -1,11 +1,23 @@
 " Author: w0rp <devw0rp@gmail.com>
 " Description: Contains miscellaneous functions
 
-" A null file for sending output to nothing.
-let g:ale#util#nul_file = '/dev/null'
+" A wrapper function for mode() so we can test calls for it.
+function! ale#util#Mode(...) abort
+    return call('mode', a:000)
+endfunction
+
+" A wrapper function for feedkeys so we can test calls for it.
+function! ale#util#FeedKeys(...) abort
+    return call('feedkeys', a:000)
+endfunction
 
-if has('win32')
-    let g:ale#util#nul_file = 'nul'
+if !exists('g:ale#util#nul_file')
+    " A null file for sending output to nothing.
+    let g:ale#util#nul_file = '/dev/null'
+
+    if has('win32')
+        let g:ale#util#nul_file = 'nul'
+    endif
 endif
 
 " Return the number of lines for a given buffer.
diff --git a/plugin/ale.vim b/plugin/ale.vim
index a9ab88a1..d33f3c5a 100644
--- a/plugin/ale.vim
+++ b/plugin/ale.vim
@@ -226,6 +226,7 @@ function! ALEInitAuGroups() abort
             autocmd BufWinEnter,BufRead * call ale#Queue(0, 'lint_file', str2nr(expand('<abuf>')))
             " Track when the file is changed outside of Vim.
             autocmd FileChangedShellPost * call ale#events#FileChangedEvent(str2nr(expand('<abuf>')))
+            autocmd BufWinLeave * call ale#events#BufWinLeave()
         endif
     augroup END
 
diff --git a/test/test_ale_init_au_groups.vader b/test/test_ale_init_au_groups.vader
index 216e7cfb..109f84ae 100644
--- a/test/test_ale_init_au_groups.vader
+++ b/test/test_ale_init_au_groups.vader
@@ -128,6 +128,7 @@ Execute (g:ale_lint_on_enter = 1 should bind the required events):
   \ 'BufEnter * call ale#events#EnterEvent(str2nr(expand(''<abuf>'')))',
   \ 'BufReadPost * call ale#Queue(0, ''lint_file'', str2nr(expand(''<abuf>'')))',
   \ 'BufWinEnter * call ale#Queue(0, ''lint_file'', str2nr(expand(''<abuf>'')))',
+  \ 'BufWinLeave * call ale#events#BufWinLeave()',
   \ 'FileChangedShellPost * call ale#events#FileChangedEvent(str2nr(expand(''<abuf>'')))',
   \], CheckAutocmd('ALERunOnEnterGroup')
 
diff --git a/test/test_completion.vader b/test/test_completion.vader
index f3f552b7..811a2645 100644
--- a/test/test_completion.vader
+++ b/test/test_completion.vader
@@ -9,9 +9,7 @@ Before:
   \ 'feedkeys_calls': [],
   \}
 
-  call ale#completion#Nop()
-
-  function! ale#completion#FeedKeys(string, mode) abort
+  function! ale#util#FeedKeys(string, mode) abort
     call add(g:test_vars.feedkeys_calls, [a:string, a:mode])
   endfunction
 
diff --git a/test/test_list_modification_error_cancelling.vader b/test/test_list_modification_error_cancelling.vader
new file mode 100644
index 00000000..06449621
--- /dev/null
+++ b/test/test_list_modification_error_cancelling.vader
@@ -0,0 +1,54 @@
+Before:
+  let b:fake_mode = 'r'
+  let b:feedkeys_calls = []
+
+  " Mock mode() and feedkeys() for the check
+  function! ale#util#Mode(...) abort
+    return b:fake_mode
+  endfunction
+
+  function! ale#util#FeedKeys(...) abort
+    call add(b:feedkeys_calls, a:000)
+  endfunction
+
+  function! CheckError(mode, message, expected_list) abort
+    let b:fake_mode = a:mode
+
+    echom a:message
+
+    call ale#events#BufWinLeave()
+    AssertEqual [], b:feedkeys_calls
+
+    sleep 1ms
+    AssertEqual a:expected_list, b:feedkeys_calls
+  endfunction
+
+After:
+  unlet! b:fake_mode
+  unlet! b:feedkeys_calls
+
+  delfunction CheckError
+
+  runtime autoload/ale/util.vim
+
+Execute(The BufWinLeave event function should hide E924 errors):
+  " For some reason, this test fails the first time when running in NeoVim
+  " in Docker, so just execute this twice.
+  echom 'E924'
+  call ale#events#BufWinLeave()
+  sleep 1ms
+  let b:feedkeys_calls = []
+
+  call CheckError('r', 'E924', [["\<CR>", 'n']])
+
+Execute(The BufWinLeave event function should hide E925 errors):
+  call CheckError('r', 'E925', [["\<CR>", 'n']])
+
+Execute(The BufWinLeave event function should hide E926 errors):
+  call CheckError('r', 'E926', [["\<CR>", 'n']])
+
+Execute(The BufWinLeave event function should ignore other errors):
+  call CheckError('r', 'E999', [])
+
+Execute(The BufWinLeave event function not send keys for other modes):
+  call CheckError('n', 'E924', [])