<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/135045>135045</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [clang-tidy] `bugprone-unchecked-optional-access`: support detection of unsafe `std::expected` access
        </td>
    </tr>

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

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

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

<pre>
    I'd like to propose extending the existing clang-tidy check `bugprone-unchecked-optional-access` to also detect unsafe access to `std::expected<T, E>` values.

Just like `std::optional<T>`, `std::expected<T, E>` requires validation (e.g. via `.has_value()` or `operator bool()`) before accessing the contained value via `.value()`, `operator*()`, or `operator->()`. The same kind of misuse patterns apply and can be caught using  `bugprone-unchecked-optional-access` .

>From my experience with `bugprone-unchecked-optional-access`  implementation,  code change should be quite straightforward.

**I am planning to work on draft PR in upcoming weeks, but want to start this issue to gather feedback**. I tried to search for existing opened issues but didn't find any.

Main questions for me:
- Would it make sense to include this support directly in `bugprone-unchecked-optional-access`, or would a new check like `bugprone-unchecked-expected-access` be preferable?
- Are there any `std::expected`-specific behaviors or edge cases I may have overlooked?


If we are happy to start supporting `std::expected<T, E>`, IMO we also should support `tl::expected<T,E>` [Link](https://github.com/TartanLlama/expected) because it is widely used in codebases which don't use C++ 23. 
</pre>
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