There's something that behaves strangely in this code, what's wrong? Tip: Mutable variables and closures.

WhatsWrong.directive.js

var doStuff = function($scope) {
  var model = [];
  var items = $scope.items;
  
  for(var i = 0; i < items.length; i++) {
    var source = items[i];
    
    doAsyncThings().then(function(newValue){
      model[i].src = newValue;
    });
  }
}