#538 Suport highlight sizes by looking at end column numbers

autoload/ale/engine.vim

@@ -288,6 +288,11 @@ function! ale#engine#FixLocList(buffer, linter, loclist) abort
             let l:item.detail = l:old_item.detail
         endif
 
+        " Pass on a col_length key if set, used for highlights.
+        if has_key(l:old_item, 'end_col')
+            let l:item.end_col = str2nr(l:old_item.end_col)
+        endif
+
         if l:item.lnum == 0
             " When errors appear at line 0, put them at line 1 instead.
             let l:item.lnum = 1

autoload/ale/highlight.vim

@@ -86,7 +86,7 @@ function! ale#highlight#UpdateHighlights() abort
             let l:col = l:item.col
             let l:group = l:item.type ==# 'E' ? 'ALEError' : 'ALEWarning'
             let l:line = l:item.lnum
-            let l:size = 1
+            let l:size = has_key(l:item, 'end_col') ? l:item.end_col - l:col : 1
 
             " Rememeber the match ID for the item.
             " This ID will be used to preserve loclist items which are set

test/test_highlight_placement.vader

@@ -137,3 +137,16 @@ Execute(Only ALE highlights should be restored when buffers are restored):
 
   " Only our matches should appear again.
   AssertEqual 1, len(getmatches()), 'The highlights weren''t set again!'
+
+Execute(Higlight end columns should set an appropriate size):
+  call ale#highlight#SetHighlights(bufnr('%'), [
+  \ {'bufnr': bufnr('%'), 'type': 'E', 'lnum': 3, 'col': 2, 'end_col': 5},
+  \ {'bufnr': bufnr('%'), 'type': 'W', 'lnum': 4, 'col': 1, 'end_col': 5},
+  \])
+
+  AssertEqual
+  \ [
+  \   {'group': 'ALEError', 'id': 15, 'priority': 10, 'pos1': [3, 2, 3]},
+  \   {'group': 'ALEWarning', 'id': 16, 'priority': 10, 'pos1': [4, 1, 4]},
+  \ ],
+  \ getmatches()

test/test_loclist_corrections.vader

@@ -128,3 +128,39 @@ Execute(FixLocList should convert line and column numbers correctly):
   \   {'name': 'foobar'},
   \   [{'text': 'a', 'lnum': '010', 'col': '010'}],
   \ )
+
+Execute(FixLocList should pass on col_length values):
+  " The numbers should be 10, not 8 as octals.
+  AssertEqual
+  \ [
+  \   {
+  \     'text': 'a',
+  \     'lnum': 10,
+  \     'col': 10,
+  \     'end_col': 12,
+  \     'bufnr': bufnr('%'),
+  \     'vcol': 0,
+  \     'type': 'E',
+  \     'nr': -1,
+  \     'linter_name': 'foobar',
+  \   },
+  \   {
+  \     'text': 'a',
+  \     'lnum': 10,
+  \     'col': 11,
+  \     'end_col': 12,
+  \     'bufnr': bufnr('%'),
+  \     'vcol': 0,
+  \     'type': 'E',
+  \     'nr': -1,
+  \     'linter_name': 'foobar',
+  \   },
+  \],
+  \ ale#engine#FixLocList(
+  \   bufnr('%'),
+  \   {'name': 'foobar'},
+  \   [
+  \     {'text': 'a', 'lnum': '010', 'col': '010', 'end_col': '012'},
+  \     {'text': 'a', 'lnum': '010', 'col': '011', 'end_col': 12},
+  \   ],
+  \ )