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<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width, initial-scale=1.0"><meta name="generator" content="rustdoc"><meta name="description" content="Used for checked casts."><title>CheckedAs in az - Rust</title><script>if(window.location.protocol!=="file:")document.head.insertAdjacentHTML("beforeend","SourceSerif4-Regular-6b053e98.ttf.woff2,FiraSans-Regular-0fe48ade.woff2,FiraSans-Medium-e1aa3f0a.woff2,SourceCodePro-Regular-8badfe75.ttf.woff2,SourceCodePro-Semibold-aa29a496.ttf.woff2".split(",").map(f=>`<link rel="preload" as="font" type="font/woff2" crossorigin href="../static.files/${f}">`).join(""))</script><link rel="stylesheet" href="../static.files/normalize-9960930a.css"><link rel="stylesheet" href="../static.files/rustdoc-42caa33d.css"><meta name="rustdoc-vars" data-root-path="../" data-static-root-path="../static.files/" data-current-crate="az" data-themes="" data-resource-suffix="" data-rustdoc-version="1.84.0 (9fc6b4312 2025-01-07)" data-channel="1.84.0" data-search-js="search-92e6798f.js" data-settings-js="settings-0f613d39.js" ><script src="../static.files/storage-59e33391.js"></script><script defer src="sidebar-items.js"></script><script defer src="../static.files/main-5f194d8c.js"></script><noscript><link rel="stylesheet" href="../static.files/noscript-893ab5e7.css"></noscript><link rel="alternate icon" type="image/png" href="../static.files/favicon-32x32-6580c154.png"><link rel="icon" type="image/svg+xml" href="../static.files/favicon-044be391.svg"></head><body class="rustdoc trait"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="mobile-topbar"><button class="sidebar-menu-toggle" title="show sidebar"></button></nav><nav class="sidebar"><div class="sidebar-crate"><h2><a href="../az/index.html">az</a><span class="version">1.2.1</span></h2></div><div class="sidebar-elems"><section id="rustdoc-toc"><h2 class="location"><a href="#">Checked<wbr>As</a></h2><h3><a href="#">Sections</a></h3><ul class="block top-toc"><li><a href="#examples" title="Examples">Examples</a></li></ul><h3><a href="#required-methods">Required Methods</a></h3><ul class="block"><li><a href="#tymethod.checked_as" title="checked_as">checked_as</a></li></ul><h3><a href="#dyn-compatibility">Dyn Compatibility</a></h3><h3><a href="#implementors">Implementors</a></h3></section><div id="rustdoc-modnav"><h2 class="in-crate"><a href="index.html">In crate az</a></h2></div></div></nav><div class="sidebar-resizer"></div><main><div class="width-limiter"><rustdoc-search></rustdoc-search><section id="main-content" class="content"><div class="main-heading"><span class="rustdoc-breadcrumbs"><a href="index.html">az</a></span><h1>Trait <span class="trait">CheckedAs</span><button id="copy-path" title="Copy item path to clipboard">Copy item path</button></h1><rustdoc-toolbar></rustdoc-toolbar><span class="sub-heading"><a class="src" href="../src/az/lib.rs.html#665-670">Source</a> </span></div><pre class="rust item-decl"><code>pub trait CheckedAs {
// Required method
fn <a href="#tymethod.checked_as" class="fn">checked_as</a>&lt;Dst&gt;(self) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.84.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;Dst&gt;
<span class="where">where Self: <a class="trait" href="trait.CheckedCast.html" title="trait az::CheckedCast">CheckedCast</a>&lt;Dst&gt;</span>;
}</code></pre><details class="toggle top-doc" open><summary class="hideme"><span>Expand description</span></summary><div class="docblock"><p>Used for checked casts.</p>
<p>This traits method returns <a href="https://doc.rust-lang.org/1.84.0/core/option/enum.Option.html#variant.None" title="variant core::option::Option::None"><code>None</code></a> if the value does not fit.</p>
<p>This is a convenience trait to enable writing
<code>src.<a href="trait.CheckedAs.html#tymethod.checked_as" title="method az::CheckedAs::checked_as">checked_as</a>::&lt;Dst&gt;()</code>. This
would not work with the
<code><a href="trait.CheckedCast.html" title="trait az::CheckedCast">CheckedCast</a>::<a href="trait.CheckedCast.html#tymethod.checked_cast" title="method az::CheckedCast::checked_cast">checked_cast</a></code>
method because the <a href="trait.CheckedCast.html" title="trait az::CheckedCast"><code>CheckedCast</code></a> trait is generic while its
<a href="trait.CheckedCast.html#tymethod.checked_cast" title="method az::CheckedCast::checked_cast"><code>checked_cast</code></a> method is not generic.</p>
<p>This traits method is suitable for chaining.</p>
<p>If there is an implementation of
<code><a href="trait.CheckedCast.html" title="trait az::CheckedCast">CheckedCast</a>&lt;Dst&gt;</code> for <code>&amp;Src</code> but
not for <code>Src</code>, and the variable <code>src</code> is of type <code>Src</code>, then
<code>src.<a href="trait.CheckedAs.html#tymethod.checked_as" title="method az::CheckedAs::checked_as">checked_as</a>::&lt;Dst&gt;()</code> would not
work and
<code>(&amp;src).<a href="trait.CheckedAs.html#tymethod.checked_as" title="method az::CheckedAs::checked_as">checked_as</a>::&lt;Dst&gt;()</code> is not
easy to use with chaining, but
<code>src.<a href="https://doc.rust-lang.org/1.84.0/core/borrow/trait.Borrow.html#tymethod.borrow" title="method core::borrow::Borrow::borrow">borrow</a>().<a href="trait.CheckedAs.html#tymethod.checked_as" title="method az::CheckedAs::checked_as">checked_as</a>::&lt;Dst&gt;()</code>
works.</p>
<h2 id="examples"><a class="doc-anchor" href="#examples">§</a>Examples</h2>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>az::CheckedAs;
<span class="kw">use </span>core::f32;
<span class="macro">assert_eq!</span>(<span class="number">5i32</span>.checked_as::&lt;u32&gt;(), <span class="prelude-val">Some</span>(<span class="number">5</span>));
<span class="macro">assert_eq!</span>((-<span class="number">5i32</span>).checked_as::&lt;u32&gt;(), <span class="prelude-val">None</span>);
<span class="macro">assert_eq!</span>(<span class="number">17.1f32</span>.checked_as::&lt;u8&gt;(), <span class="prelude-val">Some</span>(<span class="number">17</span>));
<span class="macro">assert_eq!</span>(f32::NAN.checked_as::&lt;u8&gt;(), <span class="prelude-val">None</span>);</code></pre></div>
<p>The following example shows how this trait can be used when
<a href="trait.CheckedCast.html" title="trait az::CheckedCast"><code>CheckedCast</code></a> is implemented for a reference type.</p>
<div class="example-wrap"><pre class="rust rust-example-rendered"><code><span class="kw">use </span>az::{CheckedAs, CheckedCast};
<span class="kw">use </span>core::borrow::Borrow;
<span class="kw">struct </span>I(i32);
<span class="kw">impl </span>CheckedCast&lt;u32&gt; <span class="kw">for </span><span class="kw-2">&amp;</span><span class="lifetime">'_ </span>I {
<span class="kw">fn </span>checked_cast(<span class="self">self</span>) -&gt; <span class="prelude-ty">Option</span>&lt;u32&gt; { <span class="self">self</span>.<span class="number">0</span>.checked_cast() }
}
<span class="kw">let </span>r = <span class="kw-2">&amp;</span>I(-<span class="number">5</span>);
<span class="macro">assert_eq!</span>(r.checked_as::&lt;u32&gt;(), <span class="prelude-val">None</span>);
<span class="kw">let </span>owned = I(<span class="number">12</span>);
<span class="macro">assert_eq!</span>(owned.borrow().checked_as::&lt;u32&gt;(), <span class="prelude-val">Some</span>(<span class="number">12</span>));</code></pre></div>
</div></details><h2 id="required-methods" class="section-header">Required Methods<a href="#required-methods" class="anchor">§</a></h2><div class="methods"><details class="toggle method-toggle" open><summary><section id="tymethod.checked_as" class="method"><a class="src rightside" href="../src/az/lib.rs.html#667-669">Source</a><h4 class="code-header">fn <a href="#tymethod.checked_as" class="fn">checked_as</a>&lt;Dst&gt;(self) -&gt; <a class="enum" href="https://doc.rust-lang.org/1.84.0/core/option/enum.Option.html" title="enum core::option::Option">Option</a>&lt;Dst&gt;<div class="where">where
Self: <a class="trait" href="trait.CheckedCast.html" title="trait az::CheckedCast">CheckedCast</a>&lt;Dst&gt;,</div></h4></section></summary><div class="docblock"><p>Casts the value.</p>
</div></details></div><h2 id="dyn-compatibility" class="section-header">Dyn Compatibility<a href="#dyn-compatibility" class="anchor">§</a></h2><div class="dyn-compatibility-info"><p>This trait is <b>not</b> <a href="https://doc.rust-lang.org/1.84.0/reference/items/traits.html#object-safety">dyn compatible</a>.</p><p><i>In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.</i></p></div><h2 id="implementors" class="section-header">Implementors<a href="#implementors" class="anchor">§</a></h2><div id="implementors-list"><section id="impl-CheckedAs-for-T" class="impl"><a class="src rightside" href="../src/az/lib.rs.html#672-681">Source</a><a href="#impl-CheckedAs-for-T" class="anchor">§</a><h3 class="code-header">impl&lt;T&gt; <a class="trait" href="trait.CheckedAs.html" title="trait az::CheckedAs">CheckedAs</a> for T</h3></section></div><script src="../trait.impl/az/trait.CheckedAs.js" async></script></section></div></main></body></html>