diff --git a/autoload/ale/engine.vim b/autoload/ale/engine.vim
index 40cc7ad3..2cd691b7 100644
--- a/autoload/ale/engine.vim
+++ b/autoload/ale/engine.vim
@@ -333,6 +333,7 @@ function! s:RemapItemTypes(type_map, loclist) abort
 endfunction
 
 function! ale#engine#FixLocList(buffer, linter_name, loclist) abort
+    let l:bufnr_map = {}
     let l:new_loclist = []
 
     " Some errors have line numbers beyond the end of the file,
@@ -357,13 +358,36 @@ function! ale#engine#FixLocList(buffer, linter_name, loclist) abort
         \   'text': l:old_item.text,
         \   'lnum': str2nr(l:old_item.lnum),
         \   'col': str2nr(get(l:old_item, 'col', 0)),
-        \   'bufnr': get(l:old_item, 'bufnr', a:buffer),
         \   'vcol': get(l:old_item, 'vcol', 0),
         \   'type': get(l:old_item, 'type', 'E'),
         \   'nr': get(l:old_item, 'nr', -1),
         \   'linter_name': a:linter_name,
         \}
 
+        if has_key(l:old_item, 'filename')
+            " Use the filename given.
+            let l:filename = l:old_item.filename
+            let l:item.filename = l:filename
+
+            if has_key(l:old_item, 'bufnr')
+                " If a buffer number is also given, include that too.
+                " If Vim detects that he buffer number is valid, it will
+                " be used instead of the filename.
+                let l:item.bufnr = l:old_item.bufnr
+            elseif has_key(l:bufnr_map, l:filename)
+                " Get the buffer number from the map, which can be faster.
+                let l:item.bufnr = l:bufnr_map[l:filename]
+            else
+                " Look up the buffer number.
+                let l:item.bufnr = bufnr(l:filename)
+                let l:bufnr_map[l:filename] = l:item.bufnr
+            endif
+        elseif has_key(l:old_item, 'bufnr')
+            let l:item.bufnr = l:old_item.bufnr
+        else
+            let l:item.bufnr = a:buffer
+        endif
+
         if has_key(l:old_item, 'detail')
             let l:item.detail = l:old_item.detail
         endif
diff --git a/test/test_loclist_corrections.vader b/test/test_loclist_corrections.vader
index e23109ed..a00eb21a 100644
--- a/test/test_loclist_corrections.vader
+++ b/test/test_loclist_corrections.vader
@@ -1,3 +1,6 @@
+After:
+  unlet! b:other_bufnr
+
 Given foo (Some file with lines to count):
   foo12345678
   bar12345678
@@ -202,7 +205,6 @@ Execute(FixLocList should pass on end_lnum values):
   \   ],
   \ )
 
-
 Execute(FixLocList should allow subtypes to be set):
   AssertEqual
   \ [
@@ -223,3 +225,69 @@ Execute(FixLocList should allow subtypes to be set):
   \   'foobar',
   \   [{'text': 'a', 'lnum': 11, 'sub_type': 'style'}],
   \ )
+
+Execute(FixLocList should accept filenames):
+  let b:other_bufnr = bufnr('/foo/bar/baz', 1)
+
+  " Make sure we actually get another buffer number, or the test is invalid.
+  AssertNotEqual -1, b:other_bufnr
+
+  call ale#test#SetFilename('test.txt')
+
+  AssertEqual
+  \ [
+  \   {
+  \     'text': 'a',
+  \     'lnum': 2,
+  \     'col': 0,
+  \     'bufnr': bufnr('%'),
+  \     'filename': expand('%:p'),
+  \     'vcol': 0,
+  \     'type': 'E',
+  \     'nr': -1,
+  \     'linter_name': 'foobar',
+  \   },
+  \   {
+  \     'text': 'a',
+  \     'lnum': 3,
+  \     'col': 0,
+  \     'bufnr': bufnr('%'),
+  \     'filename': expand('%:p'),
+  \     'vcol': 0,
+  \     'type': 'E',
+  \     'nr': -1,
+  \     'linter_name': 'foobar',
+  \   },
+  \   {
+  \     'text': 'a',
+  \     'lnum': 4,
+  \     'col': 0,
+  \     'bufnr': b:other_bufnr,
+  \     'filename': '/foo/bar/baz',
+  \     'vcol': 0,
+  \     'type': 'E',
+  \     'nr': -1,
+  \     'linter_name': 'foobar',
+  \   },
+  \   {
+  \     'text': 'a',
+  \     'lnum': 5,
+  \     'col': 0,
+  \     'bufnr': b:other_bufnr,
+  \     'filename': '/foo/bar/baz',
+  \     'vcol': 0,
+  \     'type': 'E',
+  \     'nr': -1,
+  \     'linter_name': 'foobar',
+  \   },
+  \],
+  \ ale#engine#FixLocList(
+  \   bufnr('%'),
+  \   'foobar',
+  \   [
+  \     {'text': 'a', 'lnum': 2, 'filename': expand('%:p')},
+  \     {'text': 'a', 'lnum': 3, 'filename': expand('%:p')},
+  \     {'text': 'a', 'lnum': 4, 'filename': '/foo/bar/baz'},
+  \     {'text': 'a', 'lnum': 5, 'filename': '/foo/bar/baz'},
+  \   ],
+  \ )