#[optfield(attrs)] critically (and unexpectedly) depends on attribute ordering

[cyqsimon]

First of all, thanks for your amazing work on this crate. It made my work a hell lot easier.

Currently, #[optfield(attrs)] only works on attributes declared after it. The ones before it are not picked up. This behaviour is confusing and is not mentioned anywhere in the documentation (I think).

---

Example:

fn main() {
    let bar0 = Bar::default(); // works
    let bar1 = bar0.clone(); // errors
}

#[derive(Clone)]
#[optfield(Bar, attrs)]
#[derive(Default)]
struct Foo {
    foo: u8,
}

---

Moreover, it is extremely rare for attribute order to be important in the entire Rust ecosystem, so I guess it's fair to say that this behaviour is not very idiomatic. I think it would be ideal if this is not the case, but if there are technical limitations that prevent a fix, this idiosyncrasy should at be noted in the documentation.

[cyqsimon]

$ rustc --version
rustc 1.69.0 (84c898d65 2023-04-16)
$ uname -msr
Linux 6.3.1-arch2-1 x86_64

[roignpar]

Thanks for pointing this out!
I'm happy to hear that you found optfield useful.
I haven't touched it in quite some time. I now ran into some difficulties while updating the github actions, but will look into this issue after those are solved.

[roignpar]

@cyqsimon apparently it's a Rust thing: rust-lang/rust#111589 (comment)
I'm going to make a new release and will add this detail to documentation.

[roignpar]

Added to documentation at end of Attributes section.