> You mean, we would need to make sure the error type is always created via a new() constructor method, and that the new() method also has the `#[track_caller]`

> You mean, we would need to make sure the error type is always created via a new() constructor method, and that the new() method also has the `#[track_caller]` attribute? Something like this? Exactly. Although I think because `T: Impl Into<T>` it may not be necessary.