<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/58456>58456</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Concept subsumption no longer works for deduction guides
        </td>
    </tr>

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

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

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

<pre>
    The following well-formed translation unit

```
template<typename>
struct s {
        constexpr s(auto) {
        }
};

template<typename T>
s(T) -> s<int>;

template<typename T> requires true
s(T) -> s<int>;

void f() {
        auto const y = s(0);
}
```

is rejected by clang trunk with

```
<source>:14:17: error: ambiguous deduction for template arguments of 's'
        auto const y = s(0);
                       ^
<source>:8:1: note: candidate function [with T = int]
s(T) -> s<int>;
^
<source>:11:1: note: candidate function [with T = int]
s(T) -> s<int>;
^
1 error generated.
Compiler returned: 1
```

This regression was introduced in 340eac01f7dad6c24cee35dd35f2484098dd6b1a.
</pre>
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