<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/149746>149746</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            CTAD fails for a trailing sub-aggregate with a base that is a pack expansion
        </td>
    </tr>

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

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

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

<pre>
    CTAD fails for a trailing sub-aggregate with a base that is a pack expansion. clang (x86-64 clang 20.1.0 and trunk) fails to compile but gcc (x86-64 gcc 15.1) does not. [godbolt link](https://godbolt.org/z/5rEq399hM).
```
#include <iostream>

template <typename T, typename... U>
struct L1
{
    T dm1;

    struct A1 : U...
    {
        using U::operator()...;
    } a11;

    // expected aggregate deduction candidate:
    // template <typename T, typename... U>
 // L1(T, U...) -> L1<T, U...>
};

int main()
{
    auto l11 = L1
 {
        0,
        [](char c) { std::cout << 1 << std::endl; },
 [](bool b) { std::cout << 2 << std::endl; }
    };
    l11.a11('a');
 l11.a11(true);
}
```
</pre>
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