<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/70064>70064</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang]: emits SIGSEGV when calling a generic lambda whos requires clauses contains another lambda expression.
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            clang
      </td>
    </tr>

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

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

<pre>
    [**Example**](https://godbolt.org/z/drarr49Pd):

```c++
// flag:
//    -std=c++23
// or -std=c++20
auto X = []<class = void>() 
    requires requires { []() {}; }
{ return 1; }();
```

**Version**:

Trunk, (clang 17 accepts it.):

```
clang version 18.0.0 (https://github.com/llvm/llvm-project.git cc455033d4d4f5731461a6d5fa72e0f9bf871a70)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /opt/compiler-explorer/clang-trunk-20231024/bin
```

**Expected behavior**:

accepts this, as `gcc` and `msvc` are shown above.

**Actual behavior**:

crashed. Even, there is no stack-trace log and no assertion triggered.

**Note**:

It's astonishing that clang crashes without outputting any valid information.
</pre>
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