anchor.diff:  
   class TextSerializationVerifier implements Visitor<void> {
     /// List of errors produced during round trips on the visited nodes.
  -  final List<RoundTripFailure> errors = <RoundTripFailure>[];
  +  final List<RoundTripFailure> failures = <RoundTripFailure>[];
   
     Uri lastSeenUri = noUri;
   
  
positive.code:     try {
        serializer.writeTo(buffer, node);
      } catch (exception) {
        errors.add(
            new RoundTripSerializationFailure(exception.toString(), uri, offset));
      }
      return buffer.toString();
  
negative.code:         writeNode(deserialized, dartTypeSerializer, uri, offset);
  
      if (initial != serialized) {
        failures
            .add(new RoundTripMismatchFailure(initial, serialized, uri, offset));
      }
    }
  