<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/150709>150709</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang] Accepts ill-formed program containing function call via member pointer to member in sibling class during constant evaluation
        </td>
    </tr>

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

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

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

<pre>
    Clang accepts the following C++ program that is ill-formed (see https://godbolt.org/z/hGooP8MxY)

```
struct A { };
struct B : A { };
struct C : A {
    constexpr void foo() {}
};

consteval void test() {
    auto p = &C::foo;
    auto q = static_cast<void (A::*)()>(p);
    B b;
    A& a = b;
    (a.*q)();
}

int main() { test(); }
```

The program should be ill-formed, because the most derived object `b` does not contain the member `C::foo` which the member pointer `a` references, causing the call to have undefined behavior. 

This is a variation of https://github.com/llvm/llvm-project/issues/150705 with the `virtual` keyword removed, which instead causes a crash.
</pre>
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