Adding existing features in other langs

3074_consexpr_union_lifetime/constexpr-union-lifetime.md

@@ -281,6 +281,14 @@ So despite the fact that there was consensus to prefer a language solution over
 
 Having had more time to consider it, I believe the library solution to be superior.
 
+## Existing Practice
+
+There are two similar features in other languages that I'm aware of.
+
+Rust has [`MaybeUninit<T>`](https://doc.rust-lang.org/std/mem/union.MaybeUninit.html) which is similar to what's proposed here as `std::uninitialized<T>`.
+
+Kotlin has a [`lateinit var`](https://kotlinlang.org/docs/properties.html#late-initialized-properties-and-variables) language feature, which is similar to some kind of language annotation (although additionally allows for checking whether it has been initialized, which the language feature would not provide).
+
 # Wording
 
 Add to [memory.syn]{.sref}:

3074_consexpr_union_lifetime/p3074r2.html

@@ -4,7 +4,7 @@
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-  <meta name="dcterms.date" content="2024-02-12" />
+  <meta name="dcterms.date" content="2024-02-13" />
   <title>std::uninitialized&lt;T&gt;</title>
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@@ -538,7 +538,7 @@ <h1 class="title" style="text-align:center"><code class="sourceCode cpp">std<spa
   </tr>
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     <td>Date:</td>
-    <td>2024-02-12</td>
+    <td>2024-02-13</td>
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     <td style="vertical-align:top">Project:</td>
@@ -572,6 +572,7 @@ <h1 id="toctitle">Contents</h1>
 <ul>
 <li><a href="#a-library-type-stduninitializedt"><span class="toc-section-number">3.1</span> A library type: <code class="sourceCode cpp">std<span class="op">::</span>uninitialized<span class="op">&lt;</span>T<span class="op">&gt;</span></code><span></span></a></li>
 <li><a href="#a-language-annotation"><span class="toc-section-number">3.2</span> A language annotation<span></span></a></li>
+<li><a href="#existing-practice"><span class="toc-section-number">3.3</span> Existing Practice<span></span></a></li>
 </ul></li>
 <li><a href="#wording"><span class="toc-section-number">4</span> Wording<span></span></a></li>
 <li><a href="#bibliography"><span class="toc-section-number">5</span> References<span></span></a></li>
@@ -812,6 +813,10 @@ <h2 data-number="3.2" id="a-language-annotation"><span class="header-section-num
 </tbody>
 </table>
 <p>Having had more time to consider it, I believe the library solution to be superior.</p>
+<h2 data-number="3.3" id="existing-practice"><span class="header-section-number">3.3</span> Existing Practice<a href="#existing-practice" class="self-link"></a></h2>
+<p>There are two similar features in other languages that I’m aware of.</p>
+<p>Rust has <a href="https://doc.rust-lang.org/std/mem/union.MaybeUninit.html"><code class="sourceCode cpp">MaybeUninit<span class="op">&lt;</span>T<span class="op">&gt;</span></code></a> which is similar to what’s proposed here as <code class="sourceCode cpp">std<span class="op">::</span>uninitialized<span class="op">&lt;</span>T<span class="op">&gt;</span></code>.</p>
+<p>Kotlin has a <a href="https://kotlinlang.org/docs/properties.html#late-initialized-properties-and-variables"><code class="sourceCode cpp">lateinit var</code></a> language feature, which is similar to some kind of language annotation (although additionally allows for checking whether it has been initialized, which the language feature would not provide).</p>
 <h1 data-number="4" style="border-bottom:1px solid #cccccc" id="wording"><span class="header-section-number">4</span> Wording<a href="#wording" class="self-link"></a></h1>
 <p>Add to <span>20.2.2 <a href="https://wg21.link/memory.syn">[memory.syn]</a></span>:</p>
 <blockquote>