New issue from Jiang An: "§[const.wrap.class] "operator decltype(auto)" is ill-formed"

Author: Dani-Hub

xml/issue4468.xml

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+<?xml version='1.0' encoding='utf-8' standalone='no'?>
+<!DOCTYPE issue SYSTEM "lwg-issue.dtd">
+
+<issue num="4468" status="New">
+<title>&sect;[const.wrap.class] "`operator decltype(auto)`" is ill-formed</title>
+<section><sref ref="[const.wrap.class]"/></section>
+<submitter>Jiang An</submitter>
+<date>07 Nov 2025</date>
+<priority>99</priority>
+
+<discussion>
+<p>
+Following the approval of <a href="https://wg21.link/cwg1670">CWG 1670</a> in Kona 2025, the 
+following declaration in class template `constant_wrapper`, <sref ref="[const.wrap.class]"/>, 
+is ill-formed:
+</p>
+<blockquote><pre>
+constexpr operator decltype(auto)() const noexcept { return value; }
+</pre></blockquote>
+</discussion>
+
+<resolution>
+<p>
+This wording is relative to <paper num="N5014"/>.
+</p>
+
+<ol>
+<li><p>Modify <sref ref="[const.wrap.class]"/>, class template `constant_wrapper`synopsis, as indicated:</p>
+
+<blockquote>
+<pre>
+[&hellip;]
+template&lt;<i>cw-fixed-value</i> X, class>
+struct constant_wrapper : <i>cw-operators</i> {
+  static constexpr const auto &amp; value = X.<i>data</i>;
+
+  using type = constant_wrapper;
+  using value_type = typename decltype(X)::<i>type</i>;
+
+  [&hellip;]
+  constexpr operator decltype(<del>auto</del><ins>value</ins>)() const noexcept { return value; }
+};
+</pre>
+</blockquote>
+</li>
+</ol>
+
+</resolution>
+
+</issue>