<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/125079>125079</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [TySan] False positives accessing base class member variables
        </td>
    </tr>

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

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

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

<pre>
    ```
class Base{
public:
    void* first;
    void* second;
};

class Derrived : public Base{};

Derrived derr;

int main(){
    derr.second = nullptr;
    return 0;
}
```
Results in the following false positive
```
==191047==ERROR: TypeSanitizer: type-aliasing-violation on address 0x64fe5b465d00 (pc 0x64fe5ab0df8f bp 0x7ffc691b0050 sp 0x7ffc691af7f8 tid 191047)
WRITE of size 8 at 0x64fe5b465d00 with type p1 void (in Base at offset 8) accesses part of an existing object of type Derrived that starts at offset -8
    #0 0x64fe5ab0df8e in main inherited_member.cpp:12:17
```
</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJxcU9GOqzgM_ZrwYrUKoUB54IFRb6V92F2pd6R9XCXEabNKExSHzsz9-lUot9MZCUF0Yvsc-2BJZM8esWf1CxPirP6UKf3FhGD1oZBzuoTYr2Chgv7oWcPXhw-jk0TwIglZ-8L4MM3K2ZFVA-MDAMAtWM3EAMZGSqx6-QYTjsHrO87aw3r4XfaAMdobamDVAPfKD6qn4EeYxhgfqPUJrtJ6JvZMdHd1mToHbe-8wKoD-Nm5KcVPbRHTHD3wT1V8eG75hDS7RGA9pAuCCc6FN-vPYKQjhCmQTfaG37JYdWDVoexKvmvv5x-n09-n3Nnrx4Q_pbfJ_sKYgfQx4UY6K8n68-Zmg5PJBg_Bg9Q6IhHw92ZnsFa7ptacAxP7afwNSsW12RtQE_D31pix6UrFec2BnhBpWrOHZDWsokTH-PDP6Y_XHxAMkP2FsAeZvlO92XRZFMJULj5mcusXY3J4MIYwQR46yHFEIiSYZMw3ID3gu6WUxxXUfzgu6FLt4WK6yASUZEz0VG-zX-1houJfO8VsRbYarL9gtAn1v1e8KozbcZpYNZQiv9pnRwrdV7qrOllgX7bVXtSi7Zri0rdKtSWXqpNtt2t4o1uhu9GMbSN4tROysL3gouZlxcu67upmKxthqnZvRtSm0npkO45Xad3Wudt1G-K5sEQz9qWoedsVTip0tC6bxzdYbtd1i31O2qj5TGzHnaVEn2WSTW7Z0tePn9Kz-gDHL38crfPOw1XZjfsW3UcBNxmtVA6pmKPrLylNlNdUHJk4nm26zGo7hisTx8y3fjZTDNkkJo6LSmLiuLZx68X_AQAA___hKkwb">