| <!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="Source of the Rust file `/root/.cargo/registry/src/github.com-1ecc6299db9ec823/syn-2.0.18/src/drops.rs`."><meta name="keywords" content="rust, rustlang, rust-lang"><title>drops.rs - source</title><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Regular.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../FiraSans-Medium.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Regular.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceSerif4-Bold.ttf.woff2"><link rel="preload" as="font" type="font/woff2" crossorigin href="../../SourceCodePro-Semibold.ttf.woff2"><link rel="stylesheet" href="../../normalize.css"><link rel="stylesheet" href="../../rustdoc.css" id="mainThemeStyle"><link rel="stylesheet" href="../../ayu.css" disabled><link rel="stylesheet" href="../../dark.css" disabled><link rel="stylesheet" href="../../light.css" id="themeStyle"><script id="default-settings" ></script><script src="../../storage.js"></script><script defer src="../../source-script.js"></script><script defer src="../../source-files.js"></script><script defer src="../../main.js"></script><noscript><link rel="stylesheet" href="../../noscript.css"></noscript><link rel="alternate icon" type="image/png" href="../../favicon-16x16.png"><link rel="alternate icon" type="image/png" href="../../favicon-32x32.png"><link rel="icon" type="image/svg+xml" href="../../favicon.svg"></head><body class="rustdoc source"><!--[if lte IE 11]><div class="warning">This old browser is unsupported and will most likely display funky things.</div><![endif]--><nav class="sidebar"><a class="sidebar-logo" href="../../syn/index.html"><div class="logo-container"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></div></a></nav><main><div class="width-limiter"><nav class="sub"><a class="sub-logo-container" href="../../syn/index.html"><img class="rust-logo" src="../../rust-logo.svg" alt="logo"></a><form class="search-form"><div class="search-container"><span></span><input class="search-input" name="search" autocomplete="off" spellcheck="false" placeholder="Click or press ‘S’ to search, ‘?’ for more options…" type="search"><div id="help-button" title="help" tabindex="-1"><a href="../../help.html">?</a></div><div id="settings-menu" tabindex="-1"><a href="../../settings.html" title="settings"><img width="22" height="22" alt="Change settings" src="../../wheel.svg"></a></div></div></form></nav><section id="main-content" class="content"><div class="example-wrap"><pre class="src-line-numbers"><span id="1">1</span> |
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| </pre><pre class="rust"><code><span class="kw">use </span>std::iter; |
| <span class="kw">use </span>std::mem::ManuallyDrop; |
| <span class="kw">use </span>std::ops::{Deref, DerefMut}; |
| <span class="kw">use </span>std::option; |
| <span class="kw">use </span>std::slice; |
| |
| <span class="attribute">#[repr(transparent)] |
| </span><span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">struct </span>NoDrop<T: <span class="question-mark">?</span>Sized>(ManuallyDrop<T>); |
| |
| <span class="kw">impl</span><T> NoDrop<T> { |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">fn </span>new(value: T) -> <span class="self">Self |
| </span><span class="kw">where |
| </span>T: TrivialDrop, |
| { |
| NoDrop(ManuallyDrop::new(value)) |
| } |
| } |
| |
| <span class="kw">impl</span><T: <span class="question-mark">?</span>Sized> Deref <span class="kw">for </span>NoDrop<T> { |
| <span class="kw">type </span>Target = T; |
| <span class="kw">fn </span>deref(<span class="kw-2">&</span><span class="self">self</span>) -> <span class="kw-2">&</span><span class="self">Self</span>::Target { |
| <span class="kw-2">&</span><span class="self">self</span>.<span class="number">0 |
| </span>} |
| } |
| |
| <span class="kw">impl</span><T: <span class="question-mark">?</span>Sized> DerefMut <span class="kw">for </span>NoDrop<T> { |
| <span class="kw">fn </span>deref_mut(<span class="kw-2">&mut </span><span class="self">self</span>) -> <span class="kw-2">&mut </span><span class="self">Self</span>::Target { |
| <span class="kw-2">&mut </span><span class="self">self</span>.<span class="number">0 |
| </span>} |
| } |
| |
| <span class="kw">pub</span>(<span class="kw">crate</span>) <span class="kw">trait </span>TrivialDrop {} |
| |
| <span class="kw">impl</span><T> TrivialDrop <span class="kw">for </span>iter::Empty<T> {} |
| <span class="kw">impl</span><<span class="lifetime">'a</span>, T> TrivialDrop <span class="kw">for </span>slice::Iter<<span class="lifetime">'a</span>, T> {} |
| <span class="kw">impl</span><<span class="lifetime">'a</span>, T> TrivialDrop <span class="kw">for </span>slice::IterMut<<span class="lifetime">'a</span>, T> {} |
| <span class="kw">impl</span><<span class="lifetime">'a</span>, T> TrivialDrop <span class="kw">for </span>option::IntoIter<<span class="kw-2">&</span><span class="lifetime">'a </span>T> {} |
| <span class="kw">impl</span><<span class="lifetime">'a</span>, T> TrivialDrop <span class="kw">for </span>option::IntoIter<<span class="kw-2">&</span><span class="lifetime">'a </span><span class="kw-2">mut </span>T> {} |
| |
| <span class="attribute">#[test] |
| </span><span class="kw">fn </span>test_needs_drop() { |
| <span class="kw">use </span>std::mem::needs_drop; |
| |
| <span class="kw">struct </span>NeedsDrop; |
| |
| <span class="kw">impl </span>Drop <span class="kw">for </span>NeedsDrop { |
| <span class="kw">fn </span>drop(<span class="kw-2">&mut </span><span class="self">self</span>) {} |
| } |
| |
| <span class="macro">assert!</span>(needs_drop::<NeedsDrop>()); |
| |
| <span class="comment">// Test each of the types with a handwritten TrivialDrop impl above. |
| </span><span class="macro">assert!</span>(!needs_drop::<iter::Empty<NeedsDrop>>()); |
| <span class="macro">assert!</span>(!needs_drop::<slice::Iter<NeedsDrop>>()); |
| <span class="macro">assert!</span>(!needs_drop::<slice::IterMut<NeedsDrop>>()); |
| <span class="macro">assert!</span>(!needs_drop::<option::IntoIter<<span class="kw-2">&</span>NeedsDrop>>()); |
| <span class="macro">assert!</span>(!needs_drop::<option::IntoIter<<span class="kw-2">&mut </span>NeedsDrop>>()); |
| } |
| </code></pre></div> |
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