anchor.diff:  
   class ComputedValue {
     final _computation;
  -  bool _evaluated;
  +  bool _evaluated = false;
     dynamic _value;
     ComputedValue(dynamic this._computation(ConfigMap config));
   
  
positive.code: 
  class Configuration {
  
    static final Map<String, Map > _configurations = {};
  
    /**
     * Register configuration under [name].
     */
    void add(String name, Map configuration, {String parent}) {
      _configurations[name] = {
        "parent": parent,
        "configMap": new ConfigMap(other:configuration)
  
negative.code:   /**
     * Recursively converts [other] to [ConfigMap].
     */
    ConfigMap({ConfigMap this.root: null, Map other: const {}}) {
      if (root == null) root = this;
      _data = {};
      other.forEach((k,v) {
        if (v is! Map) {
          _data[k] = v;
  