<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/76638>76638</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            [C++20][Modules] error: 'std::align_val_t' has different definitions in different modules
        </td>
    </tr>

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

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

    <tr>
      <th>Reporter</th>
      <td>
          Ivan171
      </td>
    </tr>
</table>

<pre>
    I could not create a minimal reproducer, but I've attached the preprocessed files, which I think is enough to reproduce the issue.

### Environment
Windows 10
Clang 18.0.0git (https://github.com/llvm/llvm-project 85c395393480a77736fc7ad10f35e67f6cae6fed)
MSVC 2022 (17.8.1)

### Reproducer

```c++
// mod2.cpp

module;

#include <utility>

export module mod2;
```

```c++
// mod1.cpp

module;

#include <memory>

export module mod1;

import mod2;
```

```
$ clang++.exe -std=c++20 -fno-delayed-template-parsing -fno-ms-compatibility -x c++-module mod2.cpp --precompile
$ clang++.exe -std=c++20 -fno-delayed-template-parsing -fno-ms-compatibility -x c++-module mod1.cpp -fprebuilt-module-path=.
In file included from mod1.cpp:3:
In file included from C:\Program Files (x86)\Microsoft Visual Studio 2022\VC\Tools\MSVC\14.38.33130\include\memory:10:
In file included from C:\Program Files (x86)\Microsoft Visual Studio 2022\VC\Tools\MSVC\14.38.33130\include\exception:8:
In file included from C:\Program Files (x86)\Microsoft Visual Studio 2022\VC\Tools\MSVC\14.38.33130\include\yvals.h:20:
In file included from C:\Program Files (x86)\Windows Kits\10\include\10.0.22621.0\ucrt\crtdbg.h:13:
In file included from C:\Program Files (x86)\Microsoft Visual Studio 2022\VC\Tools\MSVC\14.38.33130\include\vcruntime_new_debug.h:10:
[repro.zip](https://github.com/llvm/llvm-project/files/13799238/repro.zip)
[repro.zip](https://github.com/llvm/llvm-project/files/13799246/repro.zip)

C:\Program Files (x86)\Microsoft Visual Studio 2022\VC\Tools\MSVC\14.38.33130\include\vcruntime_new.h:27:16: error: 'std::align_val_t'
      has different definitions in different modules; defined here first difference is enum with specified type 'size_t'
 (aka 'unsigned long long')
   27 |     enum class align_val_t : size_t {};
      |     ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
C:\Program Files (x86)\Microsoft Visual Studio 2022\VC\Tools\MSVC\14.38.33130\include\vcruntime_new.h:27:16: note: but in
      'mod2.<global>' found enum with specified type 'size_t' (aka 'unsigned long long')
   27 |     enum class align_val_t : size_t {};
 |     ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
1 error generated.
```
</pre>
<img width="1px" height="1px" alt="" src="http://email.email.llvm.org/o/eJzMV02P2zYT_jX0ZWBBJK0PH3yw5RhYvAjwoinS44IWRxIbihRIyrubQ357QcleO4ug3W2LZglCsjDDmWdmOB8W3qvWIG5ItiPZfiHG0Fm3uTsJQwu6OFr5tLmD2o5agrEBaociIAjolVG90OBwcFaONTrCKjiOAe4IK04IIgRRdyghdAjDxFaj9yihURp95H7oVN3BHYROmS-gPKCxY9tBsFex03Hl_YgJSfck3Z6fjM8bPpiTctb0aMJM-k0ZaR880HT-rrQwLdAySZO0VQEIK7sQBk_4lrADYYdWhW48JrXtCTtofbq8loOzv2MdoMxqvs74mq_KVBRFwfOmLoSkacMzzIsmrwXmDUrC1rPKj58-V8BSxqIyWiRlQp9pL_H_cnXgLT1P510Ttov7fCrihd5KltTDcHugt3LUSPjuhRZlaj1KBMKrMSitwhPhH2558HGwLsB8fhJ9FXIB8RZk9G8g67G37i-B0RcyVH9heC3ki-4V1PFSzAYk-Iiw9EESvj_bxFJYNsYuJWrxhHIZsB-0CLgchPPKtDO198va9oMI6jg5FpaPcBawvHFn9Acsl4PDyK00_gwUdEbRDA6Po9LhTFoOInSE78-5dWem5IRzaCQ0zvbXoPItj0nzJ6xVpGfV_51tnejhEDM95sBjmccEyKqPqnbW2ybAZ-VHoeFTGKWyU7KQrPpckaz61VrtI--n6ZOuEl4mnFOekqw66yPZ86XZ0vQdocLHGoegrCF8W74jXE8noX3SEb5l_9hdlwr7PxWiZvq9JpomacJYzmgSCWPtAsmq2gV5bCcA9D3dolPtRhNUj_cGH-4lHsczyKuXSLab2lHyVQ0k27-5fxB2OLe8A-XFes14SdjhKvK5M_zbelb5j_XMbfFnOXm-hEX0cU74FtA56-IPwoqp_m0J3wqtWnN_Evo-EFbMiGFanfAgVdOgQxNAYqOMivnmQZkbwlzfPOG7mQcldOgQGuV8eOarcR47xh4eVOjAD1irRsWp5WnACZH6ircYCCvFFxEpo5lGJwnamnZ6RK6LkwGAFUCKagI9aai18B5uLINo9awASLEjxf65j822Xo5_uy6Sffj2w_XOompswPiOE6Ey3xnFiqktEl612h6Fjn2fFdDY0cjXxeI_i8LbA0Dn-wwtGnQioExezCALueFyzddigRtapHxdcLouF90mZ0VD-aqkK97wlBVS0FrmGec5ZoUo1wu1YSnjlPGU0YzTMhFp2RRHXuecSSqyhqxS7IXSSawKiXXtYhqcN0We83KhxRG1nwZ9xgw-zFM1iWHfL9xmqiTHsfVklWrlg79KCSro6R9CdRlMYnnKdh_POZbtX5PEb8zcxej05s0FcLIpVsDJ5j8CAAD__zo66H0">