Trait std::iter::TrustedLen

pub unsafe trait TrustedLen: Iterator { }

🔬 This is a nightly-only experimental API. (trusted_len #37572)

An iterator that reports an accurate length using size_hint.

The iterator reports a size hint where it is either exact (lower bound is equal to upper bound), or the upper bound is None. The upper bound must only be None if the actual iterator length is larger than usize::MAX. In that case, the lower bound must be usize::MAX, resulting in an Iterator::size_hint() of (usize::MAX, None).

The iterator must produce exactly the number of elements it reported or diverge before reaching the end.

Safety

This trait must only be implemented when the contract is upheld. Consumers of this trait must inspect Iterator::size_hint()’s upper bound.

Implementors

impl<'_> TrustedLen for Bytes<'_>

impl<'_, A> TrustedLen for std::option::Iter<'_, A>

impl<'_, A> TrustedLen for std::option::IterMut<'_, A>

impl<'_, A> TrustedLen for std::result::Iter<'_, A>

impl<'_, A> TrustedLen for std::result::IterMut<'_, A>

impl<'_, I> TrustedLen for &'_ mut I where
    I: TrustedLen + ?Sized, 

impl<'_, T> TrustedLen for DrainSorted<'_, T> where
    T: Ord, 

impl<'_, T> TrustedLen for std::collections::vec_deque::Iter<'_, T>

impl<'_, T> TrustedLen for std::collections::vec_deque::IterMut<'_, T>

impl<'_, T> TrustedLen for Chunks<'_, T>

impl<'_, T> TrustedLen for ChunksExact<'_, T>

impl<'_, T> TrustedLen for ChunksExactMut<'_, T>

impl<'_, T> TrustedLen for ChunksMut<'_, T>

impl<'_, T> TrustedLen for std::slice::Iter<'_, T>

impl<'_, T> TrustedLen for std::slice::IterMut<'_, T>

impl<'_, T> TrustedLen for RChunks<'_, T>

impl<'_, T> TrustedLen for RChunksExact<'_, T>

impl<'_, T> TrustedLen for RChunksExactMut<'_, T>

impl<'_, T> TrustedLen for RChunksMut<'_, T>

impl<'_, T> TrustedLen for Windows<'_, T>

impl<'_, T, A> TrustedLen for Drain<'_, T, A> where
    A: Allocator, 

impl<'_, T, const N: usize> TrustedLen for ArrayChunks<'_, T, N>

impl<'_, T, const N: usize> TrustedLen for ArrayChunksMut<'_, T, N>

impl<'a, I, T> TrustedLen for Cloned<I> where
    T: 'a + Clone,
    I: TrustedLen<Item = &'a T>, 

impl<'a, I, T> TrustedLen for Copied<I> where
    T: 'a + Copy,
    I: TrustedLen<Item = &'a T>, 

impl<'a, T, I, F, const N: usize> TrustedLen for FlatMap<I, &'a [T; N], F> where
    I: TrustedLen,
    F: FnMut(<I as Iterator>::Item) -> &'a [T; N], 

impl<'a, T, I, F, const N: usize> TrustedLen for FlatMap<I, &'a mut [T; N], F> where
    I: TrustedLen,
    F: FnMut(<I as Iterator>::Item) -> &'a mut [T; N], 

impl<A> TrustedLen for Range<A> where
    A: TrustedStep, 

impl<A> TrustedLen for RangeFrom<A> where
    A: TrustedStep, 

impl<A> TrustedLen for RangeInclusive<A> where
    A: TrustedStep, 

impl<A> TrustedLen for std::option::IntoIter<A>

impl<A> TrustedLen for std::result::IntoIter<A>

impl<A> TrustedLen for Repeat<A> where
    A: Clone, 

impl<A, B> TrustedLen for Chain<A, B> where
    A: TrustedLen,
    B: TrustedLen<Item = <A as Iterator>::Item>, 

impl<A, B> TrustedLen for Zip<A, B> where
    A: TrustedLen,
    B: TrustedLen, 

impl<A, F> TrustedLen for OnceWith<F> where
    F: FnOnce() -> A, 

impl<A, F> TrustedLen for RepeatWith<F> where
    F: FnMut() -> A, 

impl<B, I, F> TrustedLen for Map<I, F> where
    I: TrustedLen,
    F: FnMut(<I as Iterator>::Item) -> B, 

impl<I> TrustedLen for Enumerate<I> where
    I: TrustedLen, 

impl<I> TrustedLen for Flatten<I> where
    I: TrustedLen,
    <I as Iterator>::Item: TrustedConstSize, 

impl<I> TrustedLen for Fuse<I> where
    I: TrustedLen, 

impl<I> TrustedLen for Peekable<I> where
    I: TrustedLen, 

impl<I> TrustedLen for Rev<I> where
    I: TrustedLen + DoubleEndedIterator, 

impl<I> TrustedLen for Take<I> where
    I: TrustedLen, 

impl<T> TrustedLen for IntoIterSorted<T> where
    T: Ord, 

impl<T> TrustedLen for Empty<T>

impl<T> TrustedLen for Once<T>

impl<T, A> TrustedLen for std::collections::vec_deque::IntoIter<T, A> where
    A: Allocator, 

impl<T, A> TrustedLen for std::vec::IntoIter<T, A> where
    A: Allocator, 

impl<T, I, F, const N: usize> TrustedLen for FlatMap<I, [T; N], F> where
    I: TrustedLen,
    F: FnMut(<I as Iterator>::Item) -> [T; N], 

impl<T, const N: usize> TrustedLen for std::array::IntoIter<T, N>