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<p class='location'>Trait TrustedLen</p><div class="sidebar-elems"><div class="block items"><a class="sidebar-title" href="#implementors">Implementors</a></div><p class='location'><a href='../index.html'>core</a>::<wbr><a href='index.html'>iter</a></p><script>window.sidebarCurrent = {name: 'TrustedLen', ty: 'trait', relpath: ''};</script><script defer src="sidebar-items.js"></script></div>
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<h1 class='fqn'><span class='in-band'>Trait <a href='../index.html'>core</a>::<wbr><a href='index.html'>iter</a>::<wbr><a class="trait" href=''>TrustedLen</a></span><span class='out-of-band'><span class='since' title='Stable since Rust version '></span><span id='render-detail'>
<a id="toggle-all-docs" href="javascript:void(0)" title="collapse all docs">
[<span class='inner'>−</span>]
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</span><a class='srclink' href='../../src/core/iter/traits.rs.html#988' title='goto source code'>[src]</a></span></h1>
<pre class='rust trait'>pub unsafe trait TrustedLen: <a class="trait" href="../../core/iter/trait.Iterator.html" title="trait core::iter::Iterator">Iterator</a> { }</pre><div class='stability'><div class='stab unstable'><span class=microscope>🔬</span> This is a nightly-only experimental API. (<code>trusted_len </code><a href="https://github.com/rust-lang/rust/issues/37572">#37572</a>)</div></div><div class='docblock'><p>An iterator that reports an accurate length using size_hint.</p>
<p>The iterator reports a size hint where it is either exact
(lower bound is equal to upper bound), or the upper bound is <a href="../../std/option/enum.Option.html#variant.None"><code>None</code></a>.
The upper bound must only be <a href="../../std/option/enum.Option.html#variant.None"><code>None</code></a> if the actual iterator length is
larger than <a href="../../std/usize/constant.MAX.html"><code>usize::MAX</code></a>. In that case, the lower bound must be
<a href="../../std/usize/constant.MAX.html"><code>usize::MAX</code></a>, resulting in a <a href="../../std/iter/trait.Iterator.html#method.size_hint"><code>.size_hint</code></a> of <code>(usize::MAX, None)</code>.</p>
<p>The iterator must produce exactly the number of elements it reported
or diverge before reaching the end.</p>
<h1 id="safety" class="section-header"><a href="#safety">Safety</a></h1>
<p>This trait must only be implemented when the contract is upheld.
Consumers of this trait must inspect <a href="../../std/iter/trait.Iterator.html#method.size_hint"><code>.size_hint</code></a>’s upper bound.</p>
</div>
<h2 id='implementors' class='small-section-header'>
Implementors<a href='#implementors' class='anchor'></a>
</h2>
<ul class='item-list' id='implementors-list'>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#199' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.Range.html" title="struct core::ops::Range">Range</a><usize></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#199' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.Range.html" title="struct core::ops::Range">Range</a><isize></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#199' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.Range.html" title="struct core::ops::Range">Range</a><u8></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#199' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.Range.html" title="struct core::ops::Range">Range</a><i8></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#199' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.Range.html" title="struct core::ops::Range">Range</a><u16></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#199' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.Range.html" title="struct core::ops::Range">Range</a><i16></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#199' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.Range.html" title="struct core::ops::Range">Range</a><u32></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#199' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.Range.html" title="struct core::ops::Range">Range</a><i32></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#199' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.Range.html" title="struct core::ops::Range">Range</a><i64></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#199' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.Range.html" title="struct core::ops::Range">Range</a><u64></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#208' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.RangeInclusive.html" title="struct core::ops::RangeInclusive">RangeInclusive</a><usize></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#208' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.RangeInclusive.html" title="struct core::ops::RangeInclusive">RangeInclusive</a><isize></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#208' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.RangeInclusive.html" title="struct core::ops::RangeInclusive">RangeInclusive</a><u8></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#208' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.RangeInclusive.html" title="struct core::ops::RangeInclusive">RangeInclusive</a><i8></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#208' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.RangeInclusive.html" title="struct core::ops::RangeInclusive">RangeInclusive</a><u16></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#208' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.RangeInclusive.html" title="struct core::ops::RangeInclusive">RangeInclusive</a><i16></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#208' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.RangeInclusive.html" title="struct core::ops::RangeInclusive">RangeInclusive</a><u32></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#208' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.RangeInclusive.html" title="struct core::ops::RangeInclusive">RangeInclusive</a><i32></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#208' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.RangeInclusive.html" title="struct core::ops::RangeInclusive">RangeInclusive</a><i64></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#208' title='goto source code'>[src]</a></div><code>impl TrustedLen for <a class="struct" href="../../core/ops/struct.RangeInclusive.html" title="struct core::ops::RangeInclusive">RangeInclusive</a><u64></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/range.rs.html#329' title='goto source code'>[src]</a></div><code>impl<A: <a class="trait" href="../../core/iter/trait.Step.html" title="trait core::iter::Step">Step</a>> TrustedLen for <a class="struct" href="../../core/ops/struct.RangeFrom.html" title="struct core::ops::RangeFrom">RangeFrom</a><A></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/sources.rs.html#48' title='goto source code'>[src]</a></div><code>impl<A: <a class="trait" href="../../core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>> TrustedLen for <a class="struct" href="../../core/iter/struct.Repeat.html" title="struct core::iter::Repeat">Repeat</a><A></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/sources.rs.html#145' title='goto source code'>[src]</a></div><code>impl<T> TrustedLen for <a class="struct" href="../../core/iter/struct.Empty.html" title="struct core::iter::Empty">Empty</a><T></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/sources.rs.html#226' title='goto source code'>[src]</a></div><code>impl<T> TrustedLen for <a class="struct" href="../../core/iter/struct.Once.html" title="struct core::iter::Once">Once</a><T></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/traits.rs.html#991' title='goto source code'>[src]</a></div><code>impl<'a, I: <a class="trait" href="../../core/iter/trait.TrustedLen.html" title="trait core::iter::TrustedLen">TrustedLen</a> + ?<a class="trait" href="../../core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a>> TrustedLen for &'a mut I</code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/mod.rs.html#512-513' title='goto source code'>[src]</a></div><code>impl<I> TrustedLen for <a class="struct" href="../../core/iter/struct.Rev.html" title="struct core::iter::Rev">Rev</a><I> <span class="where fmt-newline">where<br> I: <a class="trait" href="../../core/iter/trait.TrustedLen.html" title="trait core::iter::TrustedLen">TrustedLen</a> + <a class="trait" href="../../core/iter/trait.DoubleEndedIterator.html" title="trait core::iter::DoubleEndedIterator">DoubleEndedIterator</a>, </span></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/mod.rs.html#620-623' title='goto source code'>[src]</a></div><code>impl<'a, I, T: 'a> TrustedLen for <a class="struct" href="../../core/iter/struct.Cloned.html" title="struct core::iter::Cloned">Cloned</a><I> <span class="where fmt-newline">where<br> I: <a class="trait" href="../../core/iter/trait.TrustedLen.html" title="trait core::iter::TrustedLen">TrustedLen</a><Item = &'a T>,<br> T: <a class="trait" href="../../core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>, </span></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/mod.rs.html#1010-1012' title='goto source code'>[src]</a></div><code>impl<A, B> TrustedLen for <a class="struct" href="../../core/iter/struct.Chain.html" title="struct core::iter::Chain">Chain</a><A, B> <span class="where fmt-newline">where<br> A: <a class="trait" href="../../core/iter/trait.TrustedLen.html" title="trait core::iter::TrustedLen">TrustedLen</a>,<br> B: <a class="trait" href="../../core/iter/trait.TrustedLen.html" title="trait core::iter::TrustedLen">TrustedLen</a><Item = A::<a class="type" href="../../core/iter/trait.Iterator.html#associatedtype.Item" title="type core::iter::Iterator::Item">Item</a>>, </span></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/mod.rs.html#1232-1234' title='goto source code'>[src]</a></div><code>impl<A, B> TrustedLen for <a class="struct" href="../../core/iter/struct.Zip.html" title="struct core::iter::Zip">Zip</a><A, B> <span class="where fmt-newline">where<br> A: <a class="trait" href="../../core/iter/trait.TrustedLen.html" title="trait core::iter::TrustedLen">TrustedLen</a>,<br> B: <a class="trait" href="../../core/iter/trait.TrustedLen.html" title="trait core::iter::TrustedLen">TrustedLen</a>, </span></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/mod.rs.html#1374-1376' title='goto source code'>[src]</a></div><code>impl<B, I, F> TrustedLen for <a class="struct" href="../../core/iter/struct.Map.html" title="struct core::iter::Map">Map</a><I, F> <span class="where fmt-newline">where<br> I: <a class="trait" href="../../core/iter/trait.TrustedLen.html" title="trait core::iter::TrustedLen">TrustedLen</a>,<br> F: <a class="trait" href="../../core/ops/trait.FnMut.html" title="trait core::ops::FnMut">FnMut</a>(I::<a class="type" href="../../core/iter/trait.Iterator.html#associatedtype.Item" title="type core::iter::Iterator::Item">Item</a>) -> B, </span></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/mod.rs.html#1787-1789' title='goto source code'>[src]</a></div><code>impl<I> TrustedLen for <a class="struct" href="../../core/iter/struct.Enumerate.html" title="struct core::iter::Enumerate">Enumerate</a><I> <span class="where fmt-newline">where<br> I: <a class="trait" href="../../core/iter/trait.TrustedLen.html" title="trait core::iter::TrustedLen">TrustedLen</a>, </span></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/iter/mod.rs.html#2340' title='goto source code'>[src]</a></div><code>impl<I: <a class="trait" href="../../core/iter/trait.TrustedLen.html" title="trait core::iter::TrustedLen">TrustedLen</a>> TrustedLen for <a class="struct" href="../../core/iter/struct.Take.html" title="struct core::iter::Take">Take</a><I></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/option.rs.html#1058' title='goto source code'>[src]</a></div><code>impl<'a, A> TrustedLen for core::option::<a class="struct" href="../../core/option/struct.Iter.html" title="struct core::option::Iter">Iter</a><'a, A></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/option.rs.html#1102' title='goto source code'>[src]</a></div><code>impl<'a, A> TrustedLen for core::option::<a class="struct" href="../../core/option/struct.IterMut.html" title="struct core::option::IterMut">IterMut</a><'a, A></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/option.rs.html#1140' title='goto source code'>[src]</a></div><code>impl<A> TrustedLen for core::option::<a class="struct" href="../../core/option/struct.IntoIter.html" title="struct core::option::IntoIter">IntoIter</a><A></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/result.rs.html#1045' title='goto source code'>[src]</a></div><code>impl<'a, A> TrustedLen for core::result::<a class="struct" href="../../core/result/struct.Iter.html" title="struct core::result::Iter">Iter</a><'a, A></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/result.rs.html#1089' title='goto source code'>[src]</a></div><code>impl<'a, A> TrustedLen for core::result::<a class="struct" href="../../core/result/struct.IterMut.html" title="struct core::result::IterMut">IterMut</a><'a, A></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/result.rs.html#1132' title='goto source code'>[src]</a></div><code>impl<A> TrustedLen for core::result::<a class="struct" href="../../core/result/struct.IntoIter.html" title="struct core::result::IntoIter">IntoIter</a><A></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/slice/mod.rs.html#1468' title='goto source code'>[src]</a></div><code>impl<'a, T> TrustedLen for core::slice::<a class="struct" href="../../core/slice/struct.Iter.html" title="struct core::slice::Iter">Iter</a><'a, T></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/slice/mod.rs.html#1596' title='goto source code'>[src]</a></div><code>impl<'a, T> TrustedLen for core::slice::<a class="struct" href="../../core/slice/struct.IterMut.html" title="struct core::slice::IterMut">IterMut</a><'a, T></code></li>
<li><div class='out-of-band'><a class='srclink' href='../../src/core/str/mod.rs.html#824' title='goto source code'>[src]</a></div><code>impl<'a> TrustedLen for <a class="struct" href="../../core/str/struct.Bytes.html" title="struct core::str::Bytes">Bytes</a><'a></code></li>
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