记录技术和生活 Zola 2026-10-03T00:00:00+00:00 https://blog.laofu.online/tags/xue-xi-bi-ji/atom.xml 2026-10-03T00:00:00+00:00 2026-10-03T00:00:00+00:00 bigfish https://blog.laofu.online/blog/20261003-rust-ownership/

<p>读 Rust 代码时，很容易卡在这样两行上：</p> <pre class="giallo z-l-code z-d-code" ><code data-lang="rust"><span class="giallo-l"><span class="z-l-2 z-d-8">let</span><span class="z-l-3"> tools</span><span class="z-d-8"> =</span><span class="z-l-9 z-d-6"> build_tools</span><span>(</span><span class="z-d-8">&amp;</span><span class="z-l-3">ctx</span><span>,</span><span class="z-l-3"> args</span><span>)</span><span>;</span></span> <span class="giallo-l"><span class="z-l-2 z-d-8">let</span><span class="z-l-2 z-d-8"> mut</span><span class="z-l-3"> tools</span><span class="z-d-8"> =</span><span class="z-l-3"> tools</span><span>;</span></span></code></pre> <p>同一个名字怎么能声明两次？第二行已经拿到了所有权，为什么还要写 <code>mut</code>？既然东西归我，难道还不能改吗？</p> <p>如果之前主要写 Java、C# 或 JavaScript，这种困惑很自然。我们习惯了把对象交给另一个变量，再从任何一个变量修改它。Rust 把这里的几件事分开了，需要稍微换一下思路。</p> <p>这篇笔记从这些具体问题讲起。先看常见场景，最后留几道题，可以自己判断一下，不用急着记术语。</p>