<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/63496>63496</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Clang frontend C++ crash on referencing undeclared member during class initialization 
        </td>
    </tr>

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

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

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

<pre>
    To quickly reproduce: https://gcc.godbolt.org/z/Mxbvv6Y1s (assertion-trunk)

```cpp
#include <tuple>
#include <type_traits>

template < typename... T >
using variant_impl = std::tuple<int, int>;

template < typename... T >
struct variant : 
public std::conditional_t<
        false,
        int,
 variant_impl<T...>
> {
        // int value; // note if uncomment this line, code compiles correctly
        template < typename... T_ >
 constexpr variant(T_ &&... ts) : value(){};
};


int main() {
    variant<int> v{42};
    return 0;
}
```

Compiling the above code crashes clang `clang++ -x c++ `, crashes locally using clang-17.0 (a10019a), also on trunk with assertion (see godbolt link)

Note that adding back the `int value;` leads to successful compilation 
</pre>
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