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<title>Issue 4117: generator::iterator should provide iterator_concept</title>
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<p><em>This page is a snapshot from the LWG issues list, see the <a href="lwg-active.html">Library Active Issues List</a> for more information and the meaning of <a href="lwg-active.html#New">New</a> status.</em></p>
<h3 id="4117"><a href="lwg-active.html#4117">4117</a>. <code>generator::<i>iterator</i></code> should provide <code>iterator_concept</code></h3>
<p><b>Section:</b> 25.8.6 <a href="https://wg21.link/coro.generator.iterator">[coro.generator.iterator]</a> <b>Status:</b> <a href="lwg-active.html#New">New</a>
 <b>Submitter:</b> Hewill Kang <b>Opened:</b> 2024-07-07 <b>Last modified:</b> 2024-08-02</p>
<p><b>Priority: </b>4
</p>
<p><b>View other</b> <a href="lwg-index-open.html#coro.generator.iterator">active issues</a> in [coro.generator.iterator].</p>
<p><b>View all other</b> <a href="lwg-index.html#coro.generator.iterator">issues</a> in [coro.generator.iterator].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#New">New</a> status.</p>
<p><b>Discussion:</b></p>
<p>
<code>generator::<i>iterator</i></code> currently does not provide an <code>iterator_concept</code>.
While this does not affect it being an <code>input_iterator</code>, providing <code>iterator_concept</code> 
does improve consistency given that other C++20 iterators have such a member type alias.
</p>

<p><i>[2024-08-02; Reflector poll]</i></p>

<p>
Set priority to 4 after reflector poll.
Six votes for P0 (tentatively ready) but one NAD vote saying that if this
has no effect on the category then there's no reason to add it.
</p>



<p id="res-4117"><b>Proposed resolution:</b></p>
<p>
This wording is relative to <a href="https://wg21.link/N4981" title=" Working Draft, Programming Languages — C++">N4981</a>.
</p>

<ol>
<li><p>Modify 25.8.6 <a href="https://wg21.link/coro.generator.iterator">[coro.generator.iterator]</a> as indicated:</p>

<blockquote><pre>
namespace std {
  template&lt;class Ref, class V, class Allocator&gt;
  class generator&lt;Ref, V, Allocator&gt;::<i>iterator</i> {
  public:
    <ins>using iterator_concept = input_iterator_tag;</ins>
    using value_type = value;
    using difference_type = ptrdiff_t;
    [&hellip;]
  };
}
</pre></blockquote>

</li>

</ol>





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