Proper syntax for array.forEach() in coffeescript

I have a following code in coffeescript to recursively list directories (converted from javascript):

fs = require 'fs'

walk = (dir, done) ->
  results = []
  fs.readdir dir, (err, list) ->
    return done(err) if err
    pending = list.length
    return done(null, results) unless pending
    list.forEach (file) ->
      file = "#{dir}\\#{file}"
      fs.stat file, (err, stat) ->
        if stat and stat.isDirectory()
          walk file, (err, res) ->
            results = results.concat(res)
            done null, results  unless --pending
        else
          results.push file
          done null, results  unless --pending

walk __dirname, (err, results) ->
  throw err if err
  console.log results

As you can see I am using list.forEach (file) -> and it's working. But when I try to replace it with for file in list then it doesn't work properly. What do I do wrong?