Derive Macro Parse 

#[derive(Parse)]
{
    // Attributes available to this derive:
    #[parse]
}

use object_rainbow::{Parse, ParseInline, ParseInput};

#[derive(Parse)]
struct Three<A, B, C> {
    a: A,
    b: B,
    c: C,
}

object_rainbow::assert_impl!(
    impl<A, B, C, I> Parse<I> for Three<A, B, C>
    where
        A: ParseInline<I>,
        B: ParseInline<I>,
        C: Parse<I>,
        I: ParseInput,
    {}
);