// SPDX-License-Identifier: Apache-2.0 OR MIT use std::iter;use std::mem::ManuallyDrop;use std::ops::{Deref, DerefMut};use std::option;use std::slice; #[repr(transparent)]pub(crate) struct NoDrop<T: ?Sized>(ManuallyDrop<T>); impl<T> NoDrop<T> {    pub(crate) fn new(value: T) -> Self    where        T: TrivialDrop,    {        NoDrop(ManuallyDrop::new(value))    }} impl<T: ?Sized> Deref for NoDrop<T> {    type Target = T;    fn deref(&self) -> &Self::Target {        &self.0    }} impl<T: ?Sized> DerefMut for NoDrop<T> {    fn deref_mut(&mut self) -> &mut Self::Target {        &mut self.0    }} pub(crate) trait TrivialDrop {} impl<T> TrivialDrop for iter::Empty<T> {}impl<T> TrivialDrop for slice::Iter<'_, T> {}impl<T> TrivialDrop for slice::IterMut<'_, T> {}impl<T> TrivialDrop for option::IntoIter<&T> {}impl<T> TrivialDrop for option::IntoIter<&mut T> {} #[test]fn test_needs_drop() {    use std::mem::needs_drop;     struct NeedsDrop;     impl Drop for NeedsDrop {        fn drop(&mut self) {}    }     assert!(needs_drop::<NeedsDrop>());     // Test each of the types with a handwritten TrivialDrop impl above.    assert!(!needs_drop::<iter::Empty<NeedsDrop>>());    assert!(!needs_drop::<slice::Iter<NeedsDrop>>());    assert!(!needs_drop::<slice::IterMut<NeedsDrop>>());    assert!(!needs_drop::<option::IntoIter<&NeedsDrop>>());    assert!(!needs_drop::<option::IntoIter<&mut NeedsDrop>>());}