anchor.diff:  
     JSON.decode(rawJson).forEach((Map e) {
       String source = resolver.resolve(e["source"]);
  -    if (source == null) { 
  +    if (source == null) {
         // Couldnt resolve import, so skip this entry.
         return;
       }
  
positive.code: /// to env.output.
  ///
  /// Returns a [Future] that completes as soon as all map entries have been
  /// emitted. 
  Future prettyPrint(Map hitMap, List failedLoads) {
    var emitOne = (key) {
      var v = hitMap[key];
  
negative.code:         } else {
            result[file][line] += cnt;
          }
        });
      } else {
        result[file] = v;
      }
  