Compilation error when trying to compile a simple plugin with Windows SDK 10.0.26100.0

[yuyoyuppe]

Description

Compiling a simple plugin from my MRE repo produces the following error:

$ swift package plugin tmp_plugin_verb
error: plugin compilation failed: <PluginCompilationResult(
    succeeded: false,
    commandLine: %localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\bin\swiftc.exe -L %localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\lib\swift\pm\PluginAPI -lPackagePlugin -sdk %localappdata%\Programs\Swift\Platforms\6.0.3\Windows.platform\Developer\SDKs\Windows.sdk\ -libc MD -I %localappdata%\Programs\Swift\Platforms\6.0.3\Windows.platform\Developer\Library\XCTest-development\usr\lib\swift\windows -I %localappdata%\Programs\Swift\Platforms\6.0.3\Windows.platform\Developer\Library\XCTest-development\usr\lib\swift\windows\x86_64 -L %localappdata%\Programs\Swift\Platforms\6.0.3\Windows.platform\Developer\Library\XCTest-development\usr\lib\swift\windows\x86_64 -I %localappdata%\Programs\Swift\Platforms\6.0.3\Windows.platform\Developer\Library\Testing-development\usr\lib\swift\windows -L %localappdata%\Programs\Swift\Platforms\6.0.3\Windows.platform\Developer\Library\Testing-development\usr\lib\swift\windows\x86_64 -use-ld=lld -g -swift-version 6 -package-description-version 6.0.0 -I %localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\lib\swift\pm\PluginAPI -parse-as-library -Xfrontend -serialize-diagnostics-path -Xfrontend P:\projects\tmp\.build\plugins\tmp_plugin\cache\tmp_plugin.dia P:\projects\tmp\plugin\plugin.swift -o P:\projects\tmp\.build\plugins\tmp_plugin\cache\tmp_plugin.exe,
    executable: P:\projects\tmp\.build\plugins\tmp_plugin\cache\tmp_plugin.exe
    diagnostics: P:\projects\tmp\.build\plugins\tmp_plugin\cache\tmp_plugin.dia
    compilerOutput: "error: emit-module command failed with exit code 1 (use -v to see invocation)
%localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\lib\swift\clang\include\intrin.h:20:10: note: while building module '_Builtin_intrinsics' imported from %localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\lib\swift\clang\include\intrin.h:20:
 18 | /* First include the standard intrinsics. */
 19 | #if defined(__i386__) || defined(__x86_64__)
 20 | #include <x86intrin.h>
    |          `- note: while building module '_Builtin_intrinsics' imported from %localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\lib\swift\clang\include\intrin.h:20:
 21 | #endif
 22 |

<module-includes>:1:10: note: in file included from <module-includes>:1:
 1 | #include ""immintrin.h""
   |          `- note: in file included from <module-includes>:1:
 2 | #include ""x86intrin.h""
 3 | #include ""mm_malloc.h""

%localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\lib\swift\clang\include/immintrin.h:26:10: note: in file included from %localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\lib\swift\clang\include/immintrin.h:26:
 24 | #if !(defined(_MSC_VER) || defined(__SCE__)) || __has_feature(modules) ||      \
 25 |     defined(__SSE__)
 26 | #include <xmmintrin.h>
    |          `- note: in file included from %localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\lib\swift\clang\include/immintrin.h:26:
 27 | #endif
 28 |

%localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\lib\swift\clang\include\xmmintrin.h:31:10: note: in file included from %localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\lib\swift\clang\include\xmmintrin.h:31:
  29 |  * a standard library to provide allocation routines. */
  30 | #if __STDC_HOSTED__
  31 | #include <mm_malloc.h>
     |          `- note: in file included from %localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\lib\swift\clang\include\xmmintrin.h:31:
  32 | #endif
  33 |

%localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\lib\swift\clang\include\mm_malloc.h:13:10: error: cyclic dependency in module 'ucrt': ucrt -> _Builtin_intrinsics -> ucrt
11 | #define __MM_MALLOC_H
12 |
13 | #include <stdlib.h>
   |          `- error: cyclic dependency in module 'ucrt': ucrt -> _Builtin_intrinsics -> ucrt
14 |
15 | #ifdef _WIN32

<module-includes>:27:10: note: in file included from <module-includes>:27:
25 | #include ""mbstring.h""
26 | #include ""process.h""
27 | #include ""wchar.h""
   |          `- note: in file included from <module-includes>:27:
28 |

C:\Program Files (x86)\Windows Kits\10\include\10.0.26100.0\ucrt/wchar.h:29:10: note: in file included from C:\Program Files (x86)\Windows Kits\10\include\10.0.26100.0\ucrt/wchar.h:29:
 27 | #include <vcruntime_string.h>

 28 | #if !defined(_M_CEE)

 29 | #include <intrin.h>

    |          `- note: in file included from C:\Program Files (x86)\Windows Kits\10\include\10.0.26100.0\ucrt/wchar.h:29:
 30 | #if defined(__clang__) && (defined(_M_ARM64) || defined(_M_ARM64EC))

 31 | #include <arm_neon.h>


<unknown>:0: error: could not build C module 'ucrt'
%localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\lib\swift\clang\include\intrin.h:20:10: error: could not build module '_Builtin_intrinsics'
 18 | /* First include the standard intrinsics. */
 19 | #if defined(__i386__) || defined(__x86_64__)
 20 | #include <x86intrin.h>
    |          `- error: could not build module '_Builtin_intrinsics'
 21 | #endif
 22 |
"
)>

What's weird is that picking that swiftc invocation line and appending the Windows sdk version produces another error:

$ %localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\bin\swiftc.exe  -L %localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\lib\swift\pm\PluginAPI -lPackagePlugin -sdk %localappdata%\Programs\Swift\Platforms\6.0.3\Windows.platform\Developer\SDKs\Windows.sdk\ -libc MD -I %localappdata%\Programs\Swift\Platforms\6.0.3\Windows.platform\Developer\Library\XCTest-development\usr\lib\swift\windows -I %localappdata%\Programs\Swift\Platforms\6.0.3\Windows.platform\Developer\Library\XCTest-development\usr\lib\swift\windows\x86_64 -L %localappdata%\Programs\Swift\Platforms\6.0.3\Windows.platform\Developer\Library\XCTest-development\usr\lib\swift\windows\x86_64 -I %localappdata%\Programs\Swift\Platforms\6.0.3\Windows.platform\Developer\Library\Testing-development\usr\lib\swift\windows -L %localappdata%\Programs\Swift\Platforms\6.0.3\Windows.platform\Developer\Library\Testing-development\usr\lib\swift\windows\x86_64 -use-ld=lld -g -swift-version 6 -package-description-version 6.0.0 -I %localappdata%\Programs\Swift\Toolchains\6.0.3+Asserts\usr\lib\swift\pm\PluginAPI -parse-as-library -Xfrontend -serialize-diagnostics-path -Xfrontend P:\projects\tmp\.build\plugins\tmp_plugin\cache\tmp_plugin.dia P:\projects\tmp\plugin\plugin.swift -o P:\projects\tmp\.build\plugins\tmp_plugin\cache\tmp_plugin.exe -windows-sdk-version 10.0.20348.0
error: emit-module command failed with exit code 1 (use -v to see invocation)
<unknown>:0: error: missing required module 'ucrt

The only way to reliably make Swift to not pick the latest SDK is to uninstall it system-wide:

"C:\Program Files (x86)\Microsoft Visual Studio\Installer\vs_installer.exe" modify --remove Microsoft.VisualStudio.Component.Windows11SDK.26100 --installPath "C:\Program Files\Microsoft Visual Studio\2022\Community" --quiet --norestart

Reproduction

• Make sure Windows SDK 10.0.26100.0 is installed
• git clone https://github.com/yuyoyuppe/swift_plugin_error_repro.git
• cd swift_plugin_error_repro
• swift package plugin tmp_plugin_verb

Expected behavior

Compilation without failure

Environment

swiftc -version

Swift version 6.0.3 (swift-6.0.3-RELEASE)
Target: x86_64-unknown-windows-msv

Additional information

No response