#![allow(unused)]use std::borrow::Borrow; #[derive(Clone)]pub enum Owned {    Sha1([u8; 20]),    Sha256([u8; 32]),} impl Owned {    pub fn sha1() -> Self {        Owned::Sha1([0; 20])    }    pub fn sha256() -> Self {        Owned::Sha256([0; 32])    }} #[repr(transparent)]pub struct Borrowed {    bytes: [u8],} impl Borrowed {    #[inline]    pub fn from_bytes(slice: &[u8]) -> &Borrowed {        unsafe { &*(slice as *const [u8] as *const Borrowed) }    }} impl AsRef<Borrowed> for &Borrowed {    fn as_ref(&self) -> &Borrowed {        self    }} impl AsRef<Borrowed> for Owned {    fn as_ref(&self) -> &Borrowed {        match self {            Owned::Sha1(b) => Borrowed::from_bytes(b.as_ref()),            Owned::Sha256(b) => Borrowed::from_bytes(b.as_ref()),        }    }} fn lookup(id: impl AsRef<Borrowed>) {} fn call_lookup() {    lookup(Owned::sha1());    lookup(&Owned::sha256());    lookup(Borrowed::from_bytes(b"hello"))} fn use_owned(_id: Owned) {}fn use_by_ref(_id: &Owned) {} fn use_by_ref_impl_as_ref(id: impl AsRef<Owned>) {    use_by_ref(id.as_ref())} pub fn use_by_ref_impl_borrow(id: impl Borrow<Owned>) {    use_by_ref(id.borrow());} fn call_use_owned() {    use_owned(Owned::sha1())}fn call_by_ref() {    use_by_ref(&Owned::sha1())} fn call_by_ref_impl_as_ref_with_owned() {    // use_by_ref_impl_as_ref(Owned::sha1()) // does not work as it requires types like String/str, Vec/slice} fn call_by_ref_impl_as_ref_with_reference() {    // use_by_ref_impl_as_ref(&Owned::sha1()) // does not work as it requires types like String/str, Vec/slice} fn call_by_ref_impl_borrow_with_owned() {    use_by_ref_impl_borrow(Owned::sha1())} fn call_by_ref_impl_borrow_with_reference() {    use_by_ref_impl_borrow(&Owned::sha1())}