anchor.diff:          writeNode(deserialized, dartTypeSerializer, uri, offset);
   
       if (initial != serialized) {
  -      errors
  +      failures
             .add(new RoundTripMismatchFailure(initial, serialized, uri, offset));
       }
     }
  
positive.code:     try {
        result = serializer.readFrom(stream);
      } catch (exception) {
        errors.add(new RoundTripDeserializationFailure(
            exception.toString(), uri, offset));
      }
      if (stream.moveNext()) {
        errors.add(new RoundTripDeserializationFailure(
            "unexpected trailing text", uri, offset));
      }
      return result;
  
negative.code:         writeNode(deserialized, expressionSerializer, uri, offset);
  
      if (initial != serialized) {
        failures
            .add(new RoundTripMismatchFailure(initial, serialized, uri, offset));
      }
    }
  