<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=http://email.email.llvm.org/c/eJylk8Fu3CAQhp_GvqBYGNb2-uBDsmlOOfSQ-wrw2KZlwQK8yfbpO5BNGlXJoapk4TEwM9_8M5ZuvAzfAX5qOxMRSVyAjDBpq6N2lrgp76gtRHfSv0TeXJ22kTj5A1Qs-G1B7wt6XZcY15D22AM-s47LJivlTvhhzPntdbN6l53ZgzRO4ot3e9aynapZKxVVctrXU8OaGiZGW6WmlisF3cRSAC3Vywsa2iqzjYDW8eiFnSGgKfBeCNVSMP5Yt_Tmse72HwFTNZP2AfnP4I0TI3lGSrIKL04QwZOipcentWAtGkQJ1MCaC2oybgqIOQuzAfEwgQeLG_GyprwHIuyYpMIT5-HVJ7GsMbw5CT9vJ7AxVOQJKQIohz7vGIsIRBD0fhZ-TN34k-QzuMyXEsstEh0IBgvRC23hWhEe63D0OffxPdbxXPBDCsG_4YWKPDj_RdYU-5ruKoQFZH1TAr_9Z2Ikt-BQCmT6u0QPqetYpjEf1PjYnnsdo0s4KXWIYxolfnvtbrYV2DGRv94vx4GPPe9FKba4OD8cRIDLQXgUq9y8Gf55IHUIW56khvUNL5eB033X9NPUT6LlnezaWtJ-z0DS3Y43vC6NkGDCUDR3BWNym3HN2jGWRrVgd_lhRXNf_j-PHhhljNaU0a7Z8V3VCeSSbd2rqa6paoodhZPQpkpxKufn0g85JJIFPDQ6oObvhyIEPVuAjI-EUUcDw-fKS5i1zYP-ZWeuLc4dts7eYKfyYKYR8n_9BmUubch1_QbAZHo5>52953</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            std::ranges::cbegin and std::ranges::cend reject all non-`const` rvalue arguments
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            bug,
            libc++
      </td>
    </tr>

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

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

<pre>
    Peeking at the definition of the customization point object:

https://github.com/llvm/llvm-project/blob/3782624c126bc0cbf81f5251ef206ccf63cce7f2/libcxx/include/__ranges/access.h#L160-L178

the first overload with parameter `_Tp&` can only deduce lvalue reference types, and therefore only accepts lvalue arguments. The second overload has a forwarding reference parameter `_Tp&&`, but is constrained with `is_rvalue_reference_v<_Tp>`. For a forwarding reference, `_Tp` can never deduce an rvalue reference type, so this second overload rejects all arguments.

Ditto for `std::ranges::cend`.

</pre>
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