New issue from Giuseppe D'Angelo: "Missing Returns: element in optional<T&>::emplace"

Author: Dani-Hub

xml/issue4300.xml

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+<?xml version='1.0' encoding='utf-8' standalone='no'?>
+<!DOCTYPE issue SYSTEM "lwg-issue.dtd">
+
+<issue num="4300" status="New">
+<title>Missing <i>Returns:</i> element in <tt>optional&lt;T&amp;&gt;::emplace</tt></title>
+<section><sref ref="[optional.ref.assign]"/></section>
+<submitter>Giuseppe D'Angelo</submitter>
+<date>15 Jul 2025</date>
+<priority>99</priority>
+
+<discussion>
+<p>
+The specification for <tt>optional&lt;T&amp;&gt;::emplace</tt> in <sref ref="[optional.ref.assign]"/>
+is not specifying the returned value via a <i>Returns</i>: element; however the
+function does indeed return something (a <tt>T&amp;</tt>). Such a <i>Returns</i>: element is there
+for the primary template's `emplace` (cf. <sref ref="[optional.assign]"/>).
+</p>
+</discussion>
+
+<resolution>
+<p>
+This wording is relative to this 
+<a href="https://github.com/cplusplus/draft/actions/runs/16433597877/artifacts/3583518547">CD preview draft</a>.
+</p>
+
+<ol>
+
+<li><p>Modify <sref ref="[optional.ref.assign]"/> as indicated:</p>
+
+<blockquote>
+<pre>
+template&lt;class U&gt;
+  constexpr T&amp; emplace(U&amp;&amp; u) noexcept(is_nothrow_constructible_v&lt;T&amp;, U&gt;);
+</pre>
+<blockquote>
+<p>
+-4- <i>Constraints</i>: [&hellip;]
+<p/>
+-5- <i>Effects</i>: Equivalent to: <tt><i>convert-ref-init-val</i>(std::forward&lt;U&gt;(u))</tt>.
+<p/>
+<ins>-?- <i>Returns</i>: <tt>*<i>val</i></tt>.</ins>
+</p>
+</blockquote>
+</blockquote>
+</li>
+
+</ol>
+</resolution>
+
+</issue>