anchor.diff:     * child (installed) modules.
      */
     Map<Type, _Provider> get _bindings {
  -    if (_providersCache == null) {
  +    if (_isDirty) {
         _providersCache = <Type, _Provider>{};
         _childModules.forEach((child) => _providersCache.addAll(child._bindings));
         _providersCache.addAll(_providers);
  
positive.code:    */
    void factory(Type id, FactoryFn factoryFn,
        {CreationStrategy creation, Visibility visibility}) {
      _providersCache = null;
      _providers[id] = new _FactoryProvider(factoryFn, creation, visibility);
    }
  
  
negative.code:    */
    void type(Type id, {Type implementedBy, CreationStrategy creation,
        Visibility visibility}) {
      _dirty();
      _providers[id] = new _TypeProvider(
          implementedBy == null ? id : implementedBy, creation, visibility);
    }
  