<!DOCTYPE html><htmllang="en"><head><metacharset="utf-8"><metaname="viewport"content="width=device-width, initial-scale=1.0"><metaname="generator"content="rustdoc"><metaname="description"content="`VariantAccess` is a visitor that is created by the `Deserializer` and passed to the `Deserialize` to deserialize the content of a particular enum variant."><title>VariantAccess in serde::de - Rust</title><script>if(window.location.protocol!=="file:")document.write(`<link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/SourceSerif4-Regular-46f98efaafac5295.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/FiraSans-Regular-018c141bf0843ffd.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/FiraSans-Medium-8f9a781e4970d388.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/SourceCodePro-Regular-562dcc5011b6de7d.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../static.files/SourceCodePro-Semibold-d899c5a5c4aeb14a.ttf.woff2">`)</script><linkrel="stylesheet"href="../../static.files/normalize-76eba96aa4d2e634.css"><linkrel="stylesheet"href="../../static.files/rustdoc-e935ef01ae1c1829.css"><metaname="rustdoc-vars"data-root-path="../../"data-static-root-path="../../static.files/"data-current-crate="serde"data-themes=""data-resource-suffix=""data-rustdoc-version="1.78.0 (9b00956e5 2024-04-29)"data-channel="1.78.0"data-search-js="search-42d8da7a6b9792c2.js"data-settings-js="settings-4313503d2e1961c2.js"><scriptsrc="../../static.files/storage-4c98445ec4002617.js"></script><scriptdefersrc="sidebar-items.js"></script><scriptdefersrc="../../static.files/main-12cf3b4f4f9dc36d.js"></script><noscript><linkrel="stylesheet"href="../../static.files/noscript-04d5337699b92874.css"></noscript><linkrel="alternate icon"type="image/png"href="../../static.files/favicon-16x16-8b506e7a72182f1c.png"><linkrel="alternate icon"type="image/png"href="../../static.files/favicon-32x32-422f7d1d52889060.png"><linkrel="icon"type="image/svg+xml"href="../../static.files/favicon-2c020d218678b618.svg"></head><bodyclass="rustdoc trait"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><navclass="mobile-topbar"><buttonclass="sidebar-menu-toggle"title="show sidebar"></button></nav><navclass="sidebar"><divclass="sidebar-crate"><h2><ahref="../../serde/index.html">serde</a><spanclass="version">1.0.200</span></h2></div><h2class="location"><ahref="#">VariantAccess</a></h2><divclass="sidebar-elems"><section><h3><ahref="#required-associated-types">Required Associated Types</a></h3><ulclass="block"><li><ahref="#associatedtype.Error">Error</a></li></ul><h3><ahref="#required-methods">Required Methods</a></h3><ulclass="block"><li><ahref="#tymethod.newtype_variant_seed">newtype_variant_seed</a></li><li><ahref="#tymethod.struct_variant">struct_variant</a></li><li><ahref="#tymethod.tuple_variant">tuple_variant</a></li><li><ahref="#tymethod.unit_variant">unit_variant</a></li></ul><h3><ahref="#provided-methods">Provided Methods</a></h3><ulclass="block"><li><ahref="#method.newtype_variant">newtype_variant</a></li></ul><h3><ahref="#object-safety">Object Safety</a></h3><h3><ahref="#implementors">Implementors</a></h3></section><h2><ahref="index.html">In serde::de</a></h2></div></nav><divclass="sidebar-resizer"></div>
<main><divclass="width-limiter"><navclass="sub"><formclass="search-form"><span></span><divid="sidebar-button"tabindex="-1"><ahref="../../serde/all.html"title="show sidebar"></a></div><inputclass="search-input"name="search"aria-label="Run search in the documentation"autocomplete="off"spellcheck="false"placeholder="Click or press ‘S’ to search, ‘?’ for more options…"type="search"><divid="help-button"tabindex="-1"><ahref="../../help.html"title="help">?</a></div><divid="settings-menu"tabindex="-1"><ahref="../../settings.html"title="settings"><imgwidth="22"height="22"alt="Change settings"src="../../static.files/wheel-7b819b6101059cd0.svg"></a></div></form></nav><sectionid="main-content"class="content"><divclass="main-heading"><h1>Trait <ahref="../index.html">serde</a>::<wbr><ahref="index.html">de</a>::<wbr><aclass="trait"href="#">VariantAccess</a><buttonid="copy-path"title="Copy item path to clipboard"><imgsrc="../../static.files/clipboard-7571035ce49a181d.svg"width="19"height="18"alt="Copy item path"></button></h1><spanclass="out-of-band"><aclass="src"href="../../src/serde/de/mod.rs.html#2025-2217">source</a> · <buttonid="toggle-all-docs"title="collapse all docs">[<span>−</span>]</button></span></div><preclass="rust item-decl"><code>pub trait VariantAccess<'de>: <aclass="trait"href="https://doc.rust-lang.org/1.78.0/core/marker/trait.Sized.html"title="trait core::marker::Sized">Sized</a> {
}</code></pre><detailsclass="toggle top-doc"open><summaryclass="hideme"><span>Expand description</span></summary><divclass="docblock"><p><code>VariantAccess</code> is a visitor that is created by the <code>Deserializer</code> and
passed to the <code>Deserialize</code> to deserialize the content of a particular enum
<p>The <ahref="https://serde.rs/data-format.html">example data format</a> presented on the website demonstrates an
implementation of <code>VariantAccess</code> for a basic JSON data format.</p>
</div></details><h2id="required-associated-types"class="section-header">Required Associated Types<ahref="#required-associated-types"class="anchor">§</a></h2><divclass="methods"><detailsclass="toggle"open><summary><sectionid="associatedtype.Error"class="method"><aclass="src rightside"href="../../src/serde/de/mod.rs.html#2028">source</a><h4class="code-header">type <ahref="#associatedtype.Error"class="associatedtype">Error</a>: <aclass="trait"href="trait.Error.html"title="trait serde::de::Error">Error</a></h4></section></summary><divclass="docblock"><p>The error type that can be returned if some error occurs during
deserialization. Must match the error type of our <code>EnumAccess</code>.</p>
</div></details></div><h2id="required-methods"class="section-header">Required Methods<ahref="#required-methods"class="anchor">§</a></h2><divclass="methods"><detailsclass="toggle method-toggle"open><summary><sectionid="tymethod.unit_variant"class="method"><aclass="src rightside"href="../../src/serde/de/mod.rs.html#2065">source</a><h4class="code-header">fn <ahref="#tymethod.unit_variant"class="fn">unit_variant</a>(self) -><aclass="enum"href="https://doc.rust-lang.org/1.78.0/core/result/enum.Result.html"title="enum core::result::Result">Result</a><<aclass="primitive"href="https://doc.rust-lang.org/1.78.0/std/primitive.unit.html">()</a>, Self::<aclass="associatedtype"href="trait.VariantAccess.html#associatedtype.Error"title="type serde::de::VariantAccess::Error">Error</a>></h4></section></summary><divclass="docblock"><p>Called when deserializing a variant with no values.</p>
T: <aclass="trait"href="trait.DeserializeSeed.html"title="trait serde::de::DeserializeSeed">DeserializeSeed</a><'de>,</div></h4></section></summary><divclass="docblock"><p>Called when deserializing a variant with a single value.</p>
<p><code>Deserialize</code> implementations should typically use
V: <aclass="trait"href="trait.Visitor.html"title="trait serde::de::Visitor">Visitor</a><'de>,</div></h4></section></summary><divclass="docblock"><p>Called when deserializing a tuple-like variant.</p>
<p>The <code>len</code> is the number of fields expected in the tuple variant.</p>
<p>If the data contains a different type of variant, the following
<code>invalid_type</code> error should be constructed:</p>
<divclass="example-wrap edition"><ahref="#"class="tooltip"title="This example runs with edition 2021">ⓘ</a><preclass="rust rust-example-rendered"><code><spanclass="kw">fn </span>tuple_variant<V>(<spanclass="self">self</span>, _len: usize, _visitor: V) -><spanclass="prelude-ty">Result</span><V::Value, <spanclass="self">Self</span>::Error>
V: <aclass="trait"href="trait.Visitor.html"title="trait serde::de::Visitor">Visitor</a><'de>,</div></h4></section></summary><divclass="docblock"><p>Called when deserializing a struct-like variant.</p>
<p>The <code>fields</code> are the names of the fields of the struct variant.</p>
<p>If the data contains a different type of variant, the following
<code>invalid_type</code> error should be constructed:</p>
<divclass="example-wrap edition"><ahref="#"class="tooltip"title="This example runs with edition 2021">ⓘ</a><preclass="rust rust-example-rendered"><code><spanclass="kw">fn </span>struct_variant<V>(
T: <aclass="trait"href="../trait.Deserialize.html"title="trait serde::Deserialize">Deserialize</a><'de>,</div></h4></section></summary><divclass="docblock"><p>Called when deserializing a variant with a single value.</p>
<p>This method exists as a convenience for <code>Deserialize</code> implementations.
<code>VariantAccess</code> implementations should not override the default
