<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/63157>63157</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Class template specialisation doesn't always require constraints to match
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang:frontend,
            concepts
      </td>
    </tr>

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

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

<pre>
    [GCC test case `concepts-ttp.C` fails on Clang](https://godbolt.org/z/bW3rsfrsG).
```cpp
// PR c++/99904
// RUN: %clang_cc1 -std=c++20 -fsyntax-only -verify %s

template<class... Ts> concept C = (Ts::value && ...);
template<class... Ts> requires C<Ts...> struct A;
template<class T> requires true struct B;
template<template<class... Ts> requires C<Ts...> class TT> struct S;
using ty1 = S<A>;
using ty2 = S<B>; // expected-error{{}}
```
</pre>
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