<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/59332>59332</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Build error with message "no viable conversion from 'llvm::Optional<llvm::Reloc::Model>' to 'std::optional<Reloc::Model>'"
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          Colloportus0
      </td>
    </tr>
</table>

<pre>
    When I build MLIR ( at https://github.com/llvm/llvm-project/commit/fb84dad58b00d8515f3d8c30fa6fc2dea2f99712), it failed with:

```console
/Users/haoyu/workspace/llvm-project/llvm/examples/Kaleidoscope/Chapter8/toy.cpp:1248:69: error: no viable conversion from 'llvm::Optional<llvm::Reloc::Model>' to 'std::optional<Reloc::Model>'
 Target->createTargetMachine(TargetTriple, CPU, Features, opt, RM);
```

Looks like the namespace is confused.
</pre>
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