Show warnings for `dart_analyze` linter (#4237)

ale_linters/dart/dart_analyze.vim

@@ -4,15 +4,16 @@
 call ale#Set('dart_analyze_executable', 'dart')
 
 function! ale_linters#dart#dart_analyze#Handle(buffer, lines) abort
-    let l:pattern = '\v^  ([a-z]+) - (.+):(\d+):(\d+) - (.+) - (.+)$'
+    let l:pattern = '\v([a-z]+) - (.+):(\d+):(\d+) - (.+) - (.+)$'
     let l:output = []
 
     for l:match in ale#util#GetMatches(a:lines, l:pattern)
+        let [l:type, l:filename, l:lnum, l:col, l:message, l:code] = l:match[1:6]
         call add(l:output, {
-        \   'type': l:match[1] is# 'error' ? 'E' : 'W',
+        \   'type': l:type is# 'error' ? 'E' : l:type is# 'info' ? 'I' : 'W',
-        \   'text': l:match[6] . ': ' . l:match[5],
+        \   'text': l:code . ': ' . l:message,
-        \   'lnum': str2nr(l:match[3]),
+        \   'lnum': str2nr(l:lnum),
-        \   'col': str2nr(l:match[4]),
+        \   'col': str2nr(l:col),
         \})
     endfor
 
@@ -22,7 +23,7 @@ endfunction
 call ale#linter#Define('dart', {
 \   'name': 'dart_analyze',
 \   'executable': {b -> ale#Var(b, 'dart_analyze_executable')},
-\   'command': '%e analyze %s',
+\   'command': '%e analyze --fatal-infos %s',
 \   'callback': 'ale_linters#dart#dart_analyze#Handle',
 \   'lint_file': 1,
 \})

test/handler/test_dart_analyze_handler.vader

@@ -19,10 +19,17 @@ Execute(Basic problems should be parsed correctly):
   \     'lnum': 2,
   \     'col': 16,
   \   },
+  \   {
+  \     'type': 'I',
+  \     'text': 'dead_code: Dead code. Try removing the code, or fixing the code before it so that it can be reached.',
+  \     'lnum': 8,
+  \     'col': 3,
+  \   },
   \ ],
   \ ale_linters#dart#dart_analyze#Handle(bufnr(''), [
   \ 'Analyzing main.dart...',
   \ '  error - main.dart:5:1 - Expected to find ''}'' - expected_token',
-  \ '  warning - main.dart:2:16 - A value of type ''String'' can''t be assigned to a variable of type ''int'' - invalid_assignment',
+  \ 'warning - main.dart:2:16 - A value of type ''String'' can''t be assigned to a variable of type ''int'' - invalid_assignment',
-  \ '1 error and 1 warning found.',
+  \ '   info - main.dart:8:3 - Dead code. Try removing the code, or fixing the code before it so that it can be reached. - dead_code',
+  \ '3 issues found.',
   \ ])