New issue from S.B. Tam: Make deref-move constexpr

Author: jwakely

xml/issue4452.xml

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+<?xml version='1.0' encoding='utf-8' standalone='no'?>
+<!DOCTYPE issue SYSTEM "lwg-issue.dtd">
+
+<issue num="4452" status="New">
+<title>Make <i>deref-move</i> constexpr</title>
+<section><sref ref="[specialized.algorithms.general]"/></section>
+<submitter>S.B. Tam</submitter>
+<date>05 Nov 2025</date>
+<priority>99</priority>
+
+<discussion>
+<p>
+`std::uninitialized_move` and `std::uninitialized_move_n` are constexpr and invoke <i>`deref-move`</i>,
+but <i>`deref-move`</i> is not constexpr. This looks like an obvious mistake.
+</p>
+
+<p>
+Jiang An pointed out that <paper num="P3508R0"/> and LWG <iref ref="3918"/>,
+both touching `std::uninitialized_move(_n)`, were adopted at the same meeting,
+and unfortunately none of them was aware of the other.
+</p>
+</discussion>
+
+<resolution>
+<p>
+This wording is relative to <paper num="N5014"/>.
+</p>
+
+<ol>
+<li><p>Modify <sref ref="[specialized.algorithms.general]"/>, as indicated:</p>
+
+<blockquote>
+<pre>
+template&lt;class I&gt;
+  decltype(auto) <i>deref-move</i>(I&amp; it) {
+  constexpr decltype(auto) <i>deref-move</i>(I&amp; it) {
+    if constexpr (is_lvalue_reference_v&lt;decltype(*it)&gt;)
+      return std::move(*it);
+    else
+      return *it;
+  }
+</pre>
+</blockquote>
+</li>
+</ol>
+
+</resolution>
+
+</issue>