<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=http://email.email.llvm.org/c/eJylU8uymzAM_Rqz0ZRxeIYFizzmdjqdrtrp3tgC3OvYFJvcm359BeQ-2iarMmAkSz6WzrEbpy71JwsWnwNIp5CG4UKD9WGcZHAj-F4YA9YFaChKNioQVoHsUT6S3aAUk0dwLZxoXtCay4qCRnvtLEt3jB8Z37GCX9_FXXeAHbByD-uzBmZrqQDPwsCOJVuWVHMWK4_3MhZvtgrKZen-Vt7ZaQXtDbjZeFmyjtoG6kbbd8mvgJS-312Xl8f4CvgG8Ir6Z7sfD4eFty9fv5MhJQ4BQo8L6zHspwAHI2wHyqGf6b5H22QVttoS8-9VYklJzZckkL1KRZoo0BbEmieoI3weRvSLJreQj3hytCv0IQx-3j55oLeTMu6capwJsRs7mvlFn_zcuG_pz7aIVJ2qKq1EJKbQu7F-QDVG02jqv2B06Kcmlu5EjjHnl9-HYXQ_UAZytfcTejLyNMnyqK8bLDKZ8TZtKp4UIsvaDLfbKs94kxc5lpERDRpfs3zPksTiEywQZLP8GP1_BbpOeJLwzabc5HzL8xgL5DlWoi2KlG9SyTKOdExMPOPM7ERjvUA2U-cpSBcg-LegIO47i7gUTBUGHQzWRPt8LlpS8Z_Lt0itAykGTz3aOzcMThMd_iAeEQYjJEZLH_XSxG_FPS8k>53245</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Demand for copy constructor definition when mandatory copy elision must take place
        </td>
    </tr>

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

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

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

<pre>
    In next code copy constructor shall not be called and checked because of mandatory copy elision:
```
struct A {       
    consteval A() {}
    consteval A(const A&);
    consteval void f() {}
};

int main() {
    A{A{}}.f();
}
```
GCC and MSVC accept the code. But Clang does not:
```
undefined constructor 'A' cannot be used in a constant expression
```
Demo: https://gcc.godbolt.org/z/cKboT3qf6
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJx1UkuPmzAQ_jXmMioiECAcOIREW1VVT616N_YA7jo2xSa76a_vYLKvNkHG_sYz883LrZWX-osBg88ehJVI23ihzTg_zcLbCdzAtQZjPbSkJYwSuJEgBhSPhFsUfHYItoMT3XPyuawsqJVT1rBsz5IjS_asSK4riGsE2AMrG1i_VbGgkAGeuYY9S3csrRYrVh7vWQRpQQXZsqy5ZXe2SkJ3g24BLy7rroynapR5Z_xKSObN_upeHuMr4RvBK-vHcj8fDqFv377_JCAEjh78gKHrMTSzh4Pmpgdp0S3tvte22UjslKHOv58SS0sqvqQBmeuoaCYSlAG-2nGqCJ_HCV2YyS3mI54sRYXB-9Et4dMHWr0QcW9la7WP7dTTzR_6xdfW_sh-d0Uk60xWWcUjr7zGmkiWKjvK6b-nFBJXnuLD04DmznuB00yj9PwRYdRcYDRPuv4nJ-WHuY2FPZGg9fnl-DRO9hcKT6JybkZHIM_SbR4NdVGlJaIQEkvZlVWabNot51LKKpFZ2e4izVvUrmZ5w9LU4BMECsIsP0aqTpOUfDblJk92SR5jgUmOFe-KIks2mWDbhCpXOl7yWBoVTXVIqZ17R0qqzbs3Jacx9AYxhCN-PvvBTvUDyikKceuQ919u0xrQ">