#574 Do not restore items with no columns for highlights from hidden buffers

Author: w0rp

autoload/ale/highlight.vim

@@ -109,7 +109,11 @@ function! ale#highlight#BufferHidden(buffer) abort
             endif
         endfor
 
-        let s:buffer_restore_map[a:buffer] = l:loclist
+        let s:buffer_restore_map[a:buffer] = filter(
+        \   copy(l:loclist),
+        \   'v:val.bufnr == a:buffer && v:val.col > 0'
+        \)
+
         call clearmatches()
     endif
 endfunction

test/test_highlight_placement.vader

@@ -96,8 +96,10 @@ Execute(Highlights set by ALE should be removed when buffer cleanup is done):
 
 Execute(Highlights should be cleared when buffers are hidden):
   call ale#engine#InitBufferInfo(bufnr('%'))
+  " The second item should be ignored, as it has no column infomration.
   let g:ale_buffer_info[bufnr('%')].loclist =  [
   \ {'bufnr': bufnr('%'), 'type': 'E', 'lnum': 3, 'col': 2},
+  \ {'bufnr': bufnr('%'), 'type': 'E', 'lnum': 4, 'col': 0},
   \]
   call ale#highlight#SetHighlights(
   \ bufnr('%'),