<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=http://email.email.llvm.org/c/eJylVNtu2zAM_Rr5hahhy3GUPPghTVpgGLCn7ANki068KZIhye22rx9l59KkaYFhgazIJnl4qEOptup3td0jtFZr-9qZHTRWISiL3jAuAr0e-k4j42tQA0Kw0MvmJ-CvXhrfWeMBnbPOp8D4QmpvwSPCHh1NIfSeFSvGn2nsrKqtDql1O3r7Q4-1RYu-XBD4kmUblq2O8zybRtP305eAh17LgMCKdaOl97CNhKbld_q6gRfbKVY8Tf6NNQ32gaqyarQGNyArHt9meYeZpinBniAiXoynqi70xBEB6BexKXRLYTHoDC42N4k6E-AgO_MZEgGRW8SZnIq7Zir5Qy-HYXAGsisip428u7sE6u3gGhzpr-CLgXYwTSBRSUtxswFcRCUnhOtAXtIUn6kT4uK6RUC63XBAE_VwYKx5GO29dPKAAV3MRnoKsC2clIu9dxToruaUGt6qHPmd9oKXwMQaPhFptJ2dWPnExMfjXs2x3DyPpRobGa5AITFzqMbWv2SZqPxr_17zg7ssR8f1dDrdUX5UkUp-ljhRVaGWxVImcgh766rNt699nwxOVzeHswv7oU7psNOL1i-nv4fe2R_YUOs9d94P6GlR8mWWJfsK21kjigLlvBTLNuOt4Hm-aOtZLeaZopxa1qh9xcpHxrnBVxghaM3KTfL_DLqKZ5SR80XOM5HztKF8olZzkRXtnM8lm2VIB0-nESfeO4mrRsh62Hky6s4HfzGSFt3OII6EiWHogsZqMLFZ48V4FvHczmMb04m0l1akdP54Z1JMMlKuRr5_AYoxkmQ>52900</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            unpacking template argument pack into concept fails compiling
        </td>
    </tr>

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

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

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

<pre>
    The following code doesn't compile, due to pack expansions errors. (also see here https://godbolt.org/z/oo3fes58e)

```cpp
template <class T, class U = void>
concept food = true;

template <class... T>
void foo()
{
    food<T...>;
};

int main()
{
    foo<int>();
    foo<int, int>();
    return 0;
}```

```<source>: In function 'void foo()':
<source>:25:5: error: pack expansion argument for non-pack parameter 'T' of concept 'template<class T, class U> concept food'
   25 |     food<T...>;
      |     ^~~~~~~~~~
<source>:5:11: note: declared here
    5 | template <class T, class U = void>
      |           ^~~~~
Compiler returned: 1```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJyVVNtu2zAM_Rr5hahhy_ElD35IkxYYBuyp-wDZYhJtimRIcrvt60fZuTRZWmCBrEgmeXjEQ7mz8nf7skfYWq3tmzI76K1EkBa9YbwOtD0MSiPja5AjQrAwiP4n4K9BGK-s8YDOWedTYLwR2lvwiLBHR1MIg2fFivFnGjsrO6tDat2Odn_osbbYoi8bAl-ybMOy1XGusnn0wzC_CXgYtAgIrFj3WngPL5HQvPxObzfwapVkxdPs31vT4xDoVFZO1uBGZMXj-yz_YKZpSrAniIgX4-lUF3r1EQHoF7Ep9IXCYtAZvN7cJFImwEEo8xkSAZFbxJmdirtmOvKHXg7D6AxkV0ROhbxbXQL1dnQ9TvRX8MXAdjR9IFFJy_qmALyOSs4I14G8pCk-cyfExXWLgHC78YAm6uHAWPMw2QfhxAEDupiN9KzBbuGkXOy9o0B3NafU8F7lyO9UC14Cq9fwiUiT7ezEyidWfzzunTkeN8_jUY2NDFcgkZg5lFPrX7LMVP63f6_5wV2Wk-N6vp3uKD_KSCU_S5zItpDLYimSoILGdjSx8vGWnxmdtZk0ofayl7oKpf3xA0Axyeh0e3OnVdiPXUoutNH69fT3MDj7A3vq2Gfl_YieFiVfZlmyb7tyucybZlF3ghd10XeykVVT5F3VV_kCs0SLDrVvWfnIODf4BhMErVm5SVTLM57nnDc5z-qcpz15152s6qzYVrwSbJEh3TadRh7xY5O4dqLUjTtPRq188BcjCaB2BnFKR_hiDHvr2s23r8OQTInbifhfCW58lA">