Function try_extract_option

validify_derive/src/fields.rs:447–471

(ty: &syn::Type)

}

fn try_extract_option(ty: &syn::Type) -> Option<&syn::Type> {
    let syn::Type::Path(p) = ty else {
        return None;
    };

    // Always check the last arg such as in `std::vec::Vec`
    let seg = p.path.segments.last()?;

    if &seg.ident != "Option" {
        return None;
    }

    let syn::PathArguments::AngleBracketed(ref ab) = seg.arguments else {
        return None;
    };

    let Some(arg) = ab.args.last() else {
        return None;
    };

    match arg {
        syn::GenericArgument::Type(ty) => Some(ty),
        _ => None,
    }
}