https://mvega.dev/tags/generics/Recent content in Generics on Moises VegaHugoen-usMoises VegaSun, 16 Aug 2026 00:00:00 +0000https://mvega.dev/posts/go-generics-loosening/Sun, 16 Aug 2026 00:00:00 +0000https://mvega.dev/posts/go-generics-loosening/<p>Notes from Naoki Kuroda&rsquo;s GopherCon 2026 talk, &ldquo;Loosening the Reins: Go Generics Get More Flexible.&rdquo;</p> <p>The talk starts from one line in the Go 1.26 release notes:</p> <div class="highlight"><pre tabindex="0" style="color:#f8f8f2;background-color:#272822;-moz-tab-size:4;-o-tab-size:4;tab-size:4;-webkit-text-size-adjust:none;"><code class="language-go" data-lang="go"><span style="display:flex;"><span><span style="color:#66d9ef">type</span> <span style="color:#a6e22e">Ordered</span>[<span style="color:#a6e22e">T</span> <span style="color:#a6e22e">Ordered</span>[<span style="color:#a6e22e">T</span>]] <span style="color:#66d9ef">interface</span> { <span style="color:#f92672">...</span> } </span></span></code></pre></div><p>A constraint that refers to itself. Go 1.25 rejected it as an invalid recursive type; Go 1.26 accepts it. Kuroda went through the spec history, issues, and the <code>go/types</code> checker to find out what changed — and the answer wasn&rsquo;t &ldquo;we found a clever fix.&rdquo; The original rule had simply been drawn wider than the problem it was guarding against.</p>