<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/69675>69675</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            `<algorithm>`: `value_type` should use direct-initialization in rangified algo
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          hewillk
      </td>
    </tr>
</table>

<pre>
    When a temporary `value_type` needs to be constructed, libc++ sometimes uses copy initialization through `value_type tmp = *first;` or `value_type tmp = ranges::iter_move(first);`
However, this is not exposed in the standard concept, both `indirectly_movable_storable` and `indirectly_copyable_storable` are composed by `constructible_from` instead of `convertible_to`, which indicates that this kind of initialization may not be valid.
I think we should consistently use direct-initialization to construct `value_type`s, i.e. `value_type tmp(*first);` or `value_type tmp( ranges::iter_move(first));`.
However, _Cpp17InputIterator_ ([[iterator.cpp17]](https://eel.is/c++draft/iterator.cpp17#tab:inputiterator)) seems to guarantee the validity of copy initialization. Not sure if this is a LWG.
[testcase](https://godbolt.org/z/6Mn5v7drh) (Content warning: Pedantic).
</pre>
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