Method error_ext_chain

crates/core/src/error/error.rs:858–865

(&'a self)

    #[inline]
    fn error_ext_chain<'a>(&'a self) -> impl Iterator<Item = &'a Error> + 'a {
        let mut cur = Some(self);
        core::iter::from_fn(move || {
            let ret = cur.take()?;
            cur = ret.inner.source();
            Some(ret)
        })
    }

    #[inline]
    fn error_ext_chain_mut<T>(