# Trait core::iter::FusedIterator [−] [src]

    pub trait FusedIterator: Iterator { }

🔬 This is a nightly-only experimental API. (`fused` #35602)

An iterator that always continues to yield `None` when exhausted.

Calling next on a fused iterator that has returned `None` once is guaranteed to return `None` again. This trait is should be implemented by all iterators that behave this way because it allows for some significant optimizations.

Note: In general, you should not use `FusedIterator` in generic bounds if you need a fused iterator. Instead, you should just call `Iterator::fuse()` on the iterator. If the iterator is already fused, the additional `Fuse` wrapper will be a no-op with no performance penalty.

## Implementors

- `impl FusedIterator for EscapeUnicode`
- `impl FusedIterator for EscapeDefault`
- `impl FusedIterator for EscapeDebug`
- `impl<I: FusedIterator<Item=u8>> FusedIterator for DecodeUtf8<I>`
- `impl<A> FusedIterator for StepBy<A, RangeFrom<A>> where A: Clone,
  &'a A: Add<&'a A, Output=A>`
- `impl<A: Step + Clone> FusedIterator for StepBy<A, Range<A>>`
- `impl<A: Step + Clone> FusedIterator for StepBy<A, RangeInclusive<A>>`
- `impl<A> FusedIterator for Range<A> where A: Step, &'a A: Add<&'a A, Output=A>`
- `impl<A> FusedIterator for RangeFrom<A> where A: Step,
  &'a A: Add<&'a A, Output=A>`
- `impl<A> FusedIterator for RangeInclusive<A> where A: Step,
  &'a A: Add<&'a A, Output=A>`
- `impl<A: Clone> FusedIterator for Repeat<A>`
- `impl<T> FusedIterator for Empty<T>`
- `impl<T> FusedIterator for Once<T>`
- `impl<'a, I: FusedIterator + ?Sized> FusedIterator for &'a mut I`
- `impl<I> FusedIterator for Rev<I> where I: FusedIterator + DoubleEndedIterator`
- `impl<'a, I, T: 'a> FusedIterator for Cloned<I> where I: FusedIterator<Item=&'a T>,
  T: Clone`
- `impl<I> FusedIterator for Cycle<I> where I: Clone + Iterator`
- `impl<A, B> FusedIterator for Chain<A, B> where A: FusedIterator,
  B: FusedIterator<Item=A::Item>`
- `impl<A, B> FusedIterator for Zip<A, B> where A: FusedIterator, B: FusedIterator`
- `impl<B, I: FusedIterator, F> FusedIterator for Map<I, F> where F: FnMut(I::Item) -> B`
- `impl<I: FusedIterator, P> FusedIterator for Filter<I, P> where P: FnMut(&I::Item) -> bool`
- `impl<B, I: FusedIterator, F> FusedIterator for FilterMap<I, F> where F: FnMut(I::Item) -> Option<B>`
- `impl<I> FusedIterator for Enumerate<I> where I: FusedIterator`
- `impl<I: FusedIterator> FusedIterator for Peekable<I>`
- `impl<I, P> FusedIterator for SkipWhile<I, P> where I: FusedIterator,
  P: FnMut(&I::Item) -> bool`
- `impl<I, P> FusedIterator for TakeWhile<I, P> where I: FusedIterator,
  P: FnMut(&I::Item) -> bool`
- `impl<I> FusedIterator for Skip<I> where I: FusedIterator`
- `impl<I> FusedIterator for Take<I> where I: FusedIterator`
- `impl<B, I, St, F> FusedIterator for Scan<I, St, F> where I: FusedIterator,
  F: FnMut(&mut St, I::Item) -> Option<B>`
- `impl<I, U, F> FusedIterator for FlatMap<I, U, F> where I: FusedIterator,
  U: IntoIterator,
  F: FnMut(I::Item) -> U`
- `impl<I> FusedIterator for Fuse<I> where I: Iterator`
- `impl<I: FusedIterator, F> FusedIterator for Inspect<I, F> where F: FnMut(&I::Item)`
- `impl<'a, A> FusedIterator for core::option::Iter<'a, A>`
- `impl<'a, A> FusedIterator for core::option::IterMut<'a, A>`
- `impl<A> FusedIterator for core::option::IntoIter<A>`
- `impl<'a, T> FusedIterator for core::result::Iter<'a, T>`
- `impl<'a, T> FusedIterator for core::result::IterMut<'a, T>`
- `impl<T> FusedIterator for core::result::IntoIter<T>`
- `impl<'a, T> FusedIterator for core::slice::Iter<'a, T>`
- `impl<'a, T> FusedIterator for core::slice::IterMut<'a, T>`
- `impl<'a, T, P> FusedIterator for core::slice::Split<'a, T, P> where P: FnMut(&T) -> bool`
- `impl<'a, T, P> FusedIterator for SplitMut<'a, T, P> where P: FnMut(&T) -> bool`
- `impl<'a, T, P> FusedIterator for core::slice::SplitN<'a, T, P> where P: FnMut(&T) -> bool`
- `impl<'a, T, P> FusedIterator for core::slice::RSplitN<'a, T, P> where P: FnMut(&T) -> bool`
- `impl<'a, T, P> FusedIterator for SplitNMut<'a, T, P> where P: FnMut(&T) -> bool`
- `impl<'a, T, P> FusedIterator for RSplitNMut<'a, T, P> where P: FnMut(&T) -> bool`
- `impl<'a, T> FusedIterator for Windows<'a, T>`
- `impl<'a, T> FusedIterator for Chunks<'a, T>`
- `impl<'a, T> FusedIterator for ChunksMut<'a, T>`
- `impl<'a> FusedIterator for Chars<'a>`
- `impl<'a> FusedIterator for CharIndices<'a>`
- `impl<'a> FusedIterator for Bytes<'a>`
- `impl<'a, P: Pattern<'a>> FusedIterator for core::str::Split<'a, P>`
- `impl<'a, P: Pattern<'a>> FusedIterator for RSplit<'a, P> where P::Searcher: ReverseSearcher<'a>`
- `impl<'a, P: Pattern<'a>> FusedIterator for SplitTerminator<'a, P>`
- `impl<'a, P: Pattern<'a>> FusedIterator for RSplitTerminator<'a, P> where P::Searcher: ReverseSearcher<'a>`
- `impl<'a, P: Pattern<'a>> FusedIterator for core::str::SplitN<'a, P>`
- `impl<'a, P: Pattern<'a>> FusedIterator for core::str::RSplitN<'a, P> where P::Searcher: ReverseSearcher<'a>`
- `impl<'a, P: Pattern<'a>> FusedIterator for MatchIndices<'a, P>`
- `impl<'a, P: Pattern<'a>> FusedIterator for RMatchIndices<'a, P> where P::Searcher: ReverseSearcher<'a>`
- `impl<'a, P: Pattern<'a>> FusedIterator for Matches<'a, P>`
- `impl<'a, P: Pattern<'a>> FusedIterator for RMatches<'a, P> where P::Searcher: ReverseSearcher<'a>`
- `impl<'a> FusedIterator for Lines<'a>`
- `impl<'a> FusedIterator for LinesAny<'a>`

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