Rinat G

Can we just throw panic with clear error message instead of returning fmt::Error? https://github.com/chronotope/chrono/blob/3467172c31188006147585f6ed3727629d642fed/src/format/mod.rs#L537

Same. ```dart // doesn't rebuild Widget build(BuildContext context) { final notifier = watchOnly((SomeChangeNotifier v) => v); ... ``` ```dart // rebuild Widget build(BuildContext context) { final someField = watchOnly((SomeChangeNotifier v)...