<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/139668>139668</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Modules Header Unit Multiple Definition
        </td>
    </tr>

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

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

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

<pre>
    This following code.
```cpp
import <sstream>;
import <string>;
std::string s;
```
Compiled with
```
clang++ -std=c++20 -stdlib=libc++ -fmodule-file=sstream.pcm -fmodule-file=string.pcm -c PROGRAM.cc
```
Will produce a multiple definition error, saying that string is defined twice.

</pre>
<img width="1" height="1" alt="" src="http://email.email.llvm.org/o/eJxkkk9r3DAQxT_N-CLWyJL_ZA867J9uewkNoaVnWRrbU2TLSHKWfPuy9mZLUzAYzW_0ePM0OkbqJ0QF1RGqc6aXNPigTkuL9iX4PuhxxJC13r6rHwNF1nnn_JWmnhlvMQd-gJpvn5ln4AcaZx8SA3mKMQXUI8gvII__khRo6h8gJgvyAPKw1Vncyg9h4IeTH2dyaNmV0vCJGaenHsQRxJHtVq2z2Y6CrwVHLcizo9Z8dHWjt4vDXUcOQZ7vTvPZjP-z1dOGDHt5_f719fCcG_PJxC9yjs3B28Ug02xcXKLZIbPY0USJ_MQwBB9AnFjU77cx06ATu49McetEy9KVzBpsZpW0e7nXGaqiKZuiqEtRZINqmraqGrRPHbYVNrJtStMJK_ayaKqy0BkpwUXFq0Lymje8yMtuX_O2xqKUZl9aAyXHUZPLnXsbcx_6jGJcUBVyX9dPmdMturjuhBATXtlKQYjbigR1u7Rrlz5CyR3FFP_KJEoO1fOaYGTfUFsM7OdEiT1_JHJ-JJItwakhpTnenl9cQFx6SsPS5saPIC431ftvNwf_G00CcVm9RBCXu9k3Jf4EAAD__x5L39o">