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

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

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

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

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

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

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

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

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

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

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

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

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

impl<A: Step> TrustedLen for Range<A>

impl<A: Step> TrustedLen for RangeFrom<A>

impl<A: Step> TrustedLen for RangeInclusive<A>

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

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

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 + ?Sized> TrustedLen for &mut I

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

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 core::slice::Iter<'_, T>

impl<T> TrustedLen for core::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> TrustedLen for Empty<T>

impl<T> TrustedLen for Once<T>

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

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

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

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