New issue from Dietmar Kühl: Missing rvalue reference qualification for task::connect()

Author: dietmarkuehl

xml/issue4341.xml

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+<?xml version='1.0' encoding='utf-8' standalone='no'?>
+<!DOCTYPE issue SYSTEM "lwg-issue.dtd">
+
+<issue num="4341" status="New">
+<title>Missing rvalue reference qualification for <code>task::connect()</code></title>
+<section><sref ref="[task.class]"/></section>
+<submitter>Dietmar Kühl</submitter>
+<date>31 Aug 2025</date>
+<priority>99</priority>
+
+<discussion>
+<p>
+Coroutines can't be copied. Thus, a <code>task</code> can be
+<code>connect()</code> just once.  To represent that
+<code>task::connect()</code> should be rvalue reference qualified
+but currently it isn't.
+</p>
+</discussion>
+
+<resolution>
+<p>
+In the synopsis in <sref ref="[task.class]"/> add rvalue
+reference qualification to <code>task::connect()</code>:
+<blockquote><pre>
+namespace std::execution {
+  template&lt;class T, class Environment&gt;
+  class task {
+    ...
+    template&lt;receiver Rcvr&gt;
+        <i>state</i>&lt;Rcvr&gt; connect(Rcvr&amp;&amp; rcvr) <ins>&amp;&amp;</ins>;
+    ...
+  }
+}
+</pre></blockquote>
+</p>
+<p>
+In the specification in <sref ref="[task.members]"/> paragraph 3 add rvalue
+reference qualification to <code>task::connect()</code>:
+<blockquote>
+<pre>
+template&lt;receiver Rcvr&gt;
+    <i>state</i>&lt;Rcvr&gt; connect(Rcvr&amp;&amp; rcvr) <ins>&amp;&amp;</ins>;
+</pre>
+<p>-3- <i>Precondition</i>: <code>bool(handle)</code> is <code>true</code>.</p>
+<p>-4- <i>Effects</i>: Equivalent to:</p>
+<pre>    return state&lt;Rcvr&gt;(exchange(handle, {}), std::forward&lt;Rcvr&gt;(recv));</pre>
+</blockquote>
+</p>
+</resolution>
+
+</issue>