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<title>Issue 3276: Class split_view::outer_iterator::value_type should inherit from view_interface</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#C++20">C++20</a> status.</em></p>
<h3 id="3276"><a href="lwg-defects.html#3276">3276</a>. Class <code>split_view::outer_iterator::value_type</code> should inherit from <code>view_interface</code></h3>
<p><b>Section:</b> 25.7.16.4 <a href="https://wg21.link/range.lazy.split.outer.value">[range.lazy.split.outer.value]</a> <b>Status:</b> <a href="lwg-active.html#C++20">C++20</a>
 <b>Submitter:</b> Eric Niebler <b>Opened:</b> 2019-09-09 <b>Last modified:</b> 2023-02-07</p>
<p><b>Priority: </b>0
</p>
<p><b>View all other</b> <a href="lwg-index.html#range.lazy.split.outer.value">issues</a> in [range.lazy.split.outer.value].</p>
<p><b>View all issues with</b> <a href="lwg-status.html#C++20">C++20</a> status.</p>
<p><b>Discussion:</b></p>
<p>
It is a view. It should have all the view goodies. Suggested priority P1 because it affects ABI.
<p/>
The proposed change has been implemented and tested in range-v3.
</p>

<p><i>[2019-09-24 Issue Prioritization]</i></p>

<p>Status to Tentatively Ready and priority to 0 after six positive votes on the reflector.</p>


<p id="res-3276"><b>Proposed resolution:</b></p>
<p>This wording is relative to <a href="https://wg21.link/n4830">N4830</a>.</p>

<ol>
<li><p>Modify  [range.split.outer.value], class <code>split_view::outer_iterator::value_type</code>
synopsis, as indicated:</p>

<blockquote>
<pre>
namespace std::ranges {
  template&lt;class V, class Pattern&gt;
  template&lt;bool Const&gt;
  struct split_view&lt;V, Pattern&gt;::outer_iterator&lt;Const&gt;::value_type 
    <ins>: view_interface&lt;value_type&gt;</ins> {
  private:
    outer_iterator i_ = outer_iterator(); <i>// exposition only</i>
  public:
    value_type() = default;
    constexpr explicit value_type(outer_iterator i);

    constexpr inner_iterator&lt;Const&gt; begin() const;
    constexpr default_sentinel_t end() const;
  };
}
</pre>
</blockquote>
</li>
</ol>





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