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//! Provider of [`RefMutIterator`].
use crate::prelude::*;
use crate::util::msg;
use core::ops::DerefMut;
#[cfg(feature = "alloc")]
use alloc::boxed::Box;
/// Mutable dynamic borrowing iterator.
#[must_use = msg::iter_must_use!()]
pub trait RefMutIterator: RefIterator {
/// Advances the iterator and returns the next mutable value.
///
/// # Examples
///
/// ```
/// # use ref_iter::prelude::*;
/// # use std::cell::RefCell;
/// #
/// let samples = vec![1, 2];
/// let src = RefCell::new(samples.clone());
/// let mut iter = RefMutIter::new(src.borrow_mut(), |x| x.iter_mut());
/// assert_eq!(iter.next_mut(), Some(&mut 1));
/// assert_eq!(iter.next_mut(), Some(&mut 2));
/// assert_eq!(iter.next_mut(), None);
/// ```
fn next_mut(&mut self) -> Option<&mut Self::Item>;
}
impl<I> RefMutIterator for Box<I>
where
I: RefMutIterator + ?Sized,
{
fn next_mut(&mut self) -> Option<&mut Self::Item> {
self.deref_mut().next_mut()
}
}