Build failure: swift on darwin

[mio-19]

Nixpkgs version

• Unstable (26.05)

Steps to reproduce

build a dotnet package like ryubing

┃                   ┌─ ⏸ clang-wrapper-21.1.8 waiting for 1 ⚠
┃                   ├─ ⚠ swift-5.10.1 failed with exit code 1 after ⏱ 1h59m6s
┃                ┌─ ⏸ swift-wrapper-5.10.1
┃             ┌─ ⏸ dotnet-vmr-8.0.23
┃          ┌─ ⏸ Microsoft.NETCore.App.Ref-8.0.23

Can Hydra reproduce this build failure?

Hydra is currently rebuilding this package.

Link to Hydra build job

https://hydra.nixos.org/job/nixpkgs/unstable/swift.aarch64-darwin

Relevant log output

In file included from /nix/var/nix/builds/nix-build-swift-5.10.1.drv-0/b/src/swift/tools/SourceKit/lib/SwiftLang/SwiftASTManager.cpp:16:
In file included from /nix/var/nix/builds/nix-build-swift-5.10.1.drv-0/b/src/swift/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.h:30:
In file included from /nix/var/nix/builds/nix-build-swift-5.10.1.drv-0/b/src/swift/include/swift/IDETool/CompileInstance.h:16:
In file included from /nix/var/nix/builds/nix-build-swift-5.10.1.drv-0/b/src/swift/include/swift/Frontend/Frontend.h:43:
In file included from /nix/var/nix/builds/nix-build-swift-5.10.1.drv-0/b/src/swift/include/swift/Subsystems.h:20:
In file included from /nix/var/nix/builds/nix-build-swift-5.10.1.drv-0/b/src/swift/include/swift/AST/TBDGenRequests.h:24:
In file included from /nix/var/nix/builds/nix-build-swift-5.10.1.drv-0/b/src/swift/include/swift/IRGen/Linking.h:23:
In file included from /nix/var/nix/builds/nix-build-swift-5.10.1.drv-0/b/src/swift/include/swift/SIL/SILFunction.h:26:
In file included from /nix/var/nix/builds/nix-build-swift-5.10.1.drv-0/b/src/swift/include/swift/SIL/SILBasicBlock.h:24:
/nix/var/nix/builds/nix-build-swift-5.10.1.drv-0/b/src/swift/include/swift/SIL/SILInstruction.h:1150:17: warning: 'offsetof' on non-standard-layout type 'NonSingleValueInstruction' [-Winvalid-offsetof]
 1150 |                 offsetof(NonSingleValueInstruction, kind),
      |                 ^                                   ~~~~
/nix/store/rzggksbv3l3rp8appk6dw71b0wn4ar18-clang-wrapper-21.1.8/resource-root/include/__stddef_offsetof.h:16:24: note: expanded from macro 'offsetof'
   16 | #define offsetof(t, d) __builtin_offsetof(t, d)
      |                        ^                     ~
7 warnings generated.
ninja: build stopped: subcommand failed.

Additional context

No response

System metadata

• system: "aarch64-darwin"
• host os: Darwin 24.6.0, macOS 15.7.4
• multi-user?: yes
• sandbox: no
• version: nix-env (Lix, like Nix) 2.93.3 System type: aarch64-darwin Additional system types: x86_64-darwin Features: gc, signed-caches System configuration file: /etc/nix/nix.conf User configuration files: /Users/user/.config/nix/nix.conf:/Users/user/.nix-profile/etc/xdg/nix/nix.conf:/etc/profiles/per-user/user/etc/xdg/nix/nix.conf:/run/current-system/sw/etc/xdg/nix/nix.conf:/nix/var/nix/profiles/default/etc/xdg/nix/nix.conf Store directory: /nix/store State directory: /nix/var/nix Data directory: /nix/store/98457fs34arnx4davas2zcsnb5lzcjsp-lix-2.93.3/share
• nixpkgs: /nix/store/i07gh1w1s6ddp00fj70hp1ybs7gdnk1v-source

Notify maintainers

@dduan @Samasaur1 @stephank @trepetti

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Note for maintainers: Please tag this issue in your pull request description. (i.e. Resolves #ISSUE.)

I assert that this issue is relevant for Nixpkgs

• I assert that this is a bug and not a support request.
• I assert that this is not a duplicate of an existing issue.
• I assert that I have read the NixOS Code of Conduct and agree to abide by it.

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[mirkolenz]

Maybe related to #483276 ?

[gador]

Maybe related to #483276 ?

Why should swift be broken if dotnet is not a dependency of swift? I see the build failure for swift on darwin as well (same as e.g. #483276 (comment))

This is my error log:

[1157/1373] Building swift module Basic
FAILED: bootstrapping1/SwiftCompilerSources/Basic.o /nix/var/nix/builds/nix-79692-3916204861/build/swift/bootstrapping1/SwiftCompilerSources/Basic.o 
cd /nix/var/nix/builds/nix-79692-3916204861/src/swift/SwiftCompilerSources && /nix/var/nix/builds/nix-79692-3916204861/build/swift/bootstrapping0/bin/swiftc -c -o /nix/var/nix/builds/nix-79692-3916204861/build/swift/bootstrapping1/SwiftCompilerSources/Basic.o -sdk /nix/store/8pk2m0fn7z5dlb86z5qlv1pxa8w68idx-apple-sdk-14.4/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.sdk -I /nix/var/nix/builds/nix-79692-3916204861/build/swift/bootstrapping0/bin/../lib -I /nix/store/8pk2m0fn7z5dlb86z5qlv1pxa8w68idx-apple-sdk-14.4/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.sdk/usr/lib -target arm64-apple-macosx14.0 -module-name Basic -emit-module -emit-module-path /nix/var/nix/builds/nix-79692-3916204861/build/swift/bootstrapping1/SwiftCompilerSources/Basic.swiftmodule -parse-as-library /nix/var/nix/builds/nix-79692-3916204861/src/swift/SwiftCompilerSources/Sources/Basic/SourceLoc.swift /nix/var/nix/builds/nix-79692-3916204861/src/swift/SwiftCompilerSources/Sources/Basic/Utils.swift -wmo -Xfrontend -validate-tbd-against-ir=none -Xfrontend -enable-experimental-cxx-interop -Xcc -std=c++17 -Xcc -UIBOutlet -Xcc -UIBAction -Xcc -UIBInspectable -Xfrontend -disable-implicit-string-processing-module-import -O -cross-module-optimization -Xcc -DNDEBUG -Xcc -I -Xcc /nix/var/nix/builds/nix-79692-3916204861/src/llvm-project/llvm/include -Xcc -I -Xcc /nix/var/nix/builds/nix-79692-3916204861/build/llvm/include -Xcc -I -Xcc /nix/var/nix/builds/nix-79692-3916204861/src/llvm-project/clang/include -Xcc -I -Xcc /nix/var/nix/builds/nix-79692-3916204861/build/llvm/tools/clang/include -Xcc -I -Xcc /nix/var/nix/builds/nix-79692-3916204861/src/swift/include -Xcc -I -Xcc /nix/var/nix/builds/nix-79692-3916204861/build/swift/SwiftCompilerSources/../include -I /nix/var/nix/builds/nix-79692-3916204861/build/swift/bootstrapping1/SwiftCompilerSources
Warning: supplying the --target arm64-apple-macosx14.0 != arm64-apple-darwin argument to a nix-wrapped compiler may not work correctly - cc-wrapper is currently not designed with multi-target compilers in mind. You may want to use an un-wrapped compiler instead.
<unknown>:0: warning: the '-enable-experimental-cxx-interop' flag is deprecated; please pass '-cxx-interoperability-mode=' instead
<unknown>:0: note: Swift will maintain source compatibility for imported APIs based on the selected compatibility mode, so updating the Swift compiler will not change how APIs are imported
Please submit a bug report (https://swift.org/contributing/#reporting-bugs) and include the crash backtrace.
Stack dump:
0.      Program arguments: /nix/var/nix/builds/nix-79692-3916204861/build/swift/bootstrapping0/bin/swift-frontend-unwrapped -frontend -c /nix/var/nix/builds/nix-79692-3916204861/src/swift/SwiftCompilerSources/Sources/Basic/SourceLoc.swift /nix/var/nix/builds/nix-79692-3916204861/src/swift/SwiftCompilerSources/Sources/Basic/Utils.swift -emit-module-path /nix/var/nix/builds/nix-79692-3916204861/build/swift/bootstrapping1/SwiftCompilerSources/Basic.swiftmodule -emit-module-doc-path /nix/var/nix/builds/nix-79692-3916204861/build/swift/bootstrapping1/SwiftCompilerSources/Basic.swiftdoc -emit-module-source-info-path /nix/var/nix/builds/nix-79692-3916204861/build/swift/bootstrapping1/SwiftCompilerSources/Basic.swiftsourceinfo -target arm64-apple-macosx14.0 -Xllvm -aarch64-use-tbi -enable-objc-interop -sdk /nix/store/8pk2m0fn7z5dlb86z5qlv1pxa8w68idx-apple-sdk-14.4/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.sdk -I /nix/var/nix/builds/nix-79692-3916204861/build/swift/bootstrapping0/bin/../lib -I /nix/store/8pk2m0fn7z5dlb86z5qlv1pxa8w68idx-apple-sdk-14.4/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.sdk/usr/lib -I /nix/var/nix/builds/nix-79692-3916204861/build/swift/bootstrapping1/SwiftCompilerSources -I /nix/store/ilmqr9k0qfyh5icd8nzzmphrcyjaqn5p-apple-swift-core/lib/swift -I /nix/store/6mp7w55mz9frcya56aqzny2y7d6pi9ws-libSystem-B/include -I /nix/store/0s2nwdax6l24grm24x17idddy65y8x89-libxcrypt-4.5.2/include -I /nix/store/1kr9hamyz14ac9v64bg7wb6qkbsizygw-python3-3.12.12-env/include -I /nix/store/ba2k0xm0m7vwgi7f0625kbxckgrx2zfs-libcxx-20.1.0+apple-sdk-26.0/include -I /nix/store/47d3ak31qp8qavc3w6np7p48ccylwqwd-compiler-rt-libc-21.1.8-dev/include -I /nix/store/ab43gk9xl2ssnz3yzs484csd5axv1kqk-libxml2-2.15.1-dev/include -I /nix/store/yamly6ym3hyi0589isqyb5w0y4n2fdbg-libiconv-109.100.2-dev/include -I /nix/store/nq7w9cx2jhqxi2ha92clba1fjgqns1xg-libresolv-91-dev/include -I /nix/store/3ifp90k41wpp3pmy8wgc6iafc86xy24w-libsbuf-14.1.0-dev/include -I /nix/store/0s2nwdax6l24grm24x17idddy65y8x89-libxcrypt-4.5.2/include -I /nix/store/1kr9hamyz14ac9v64bg7wb6qkbsizygw-python3-3.12.12-env/include -I /nix/store/ba2k0xm0m7vwgi7f0625kbxckgrx2zfs-libcxx-20.1.0+apple-sdk-26.0/include -I /nix/store/47d3ak31qp8qavc3w6np7p48ccylwqwd-compiler-rt-libc-21.1.8-dev/include -I /nix/store/ab43gk9xl2ssnz3yzs484csd5axv1kqk-libxml2-2.15.1-dev/include -I /nix/store/yamly6ym3hyi0589isqyb5w0y4n2fdbg-libiconv-109.100.2-dev/include -I /nix/store/nq7w9cx2jhqxi2ha92clba1fjgqns1xg-libresolv-91-dev/include -I /nix/store/3ifp90k41wpp3pmy8wgc6iafc86xy24w-libsbuf-14.1.0-dev/include -I /nix/var/nix/builds/nix-79692-3916204861/build/libcxx/include/c++/v1 -O -validate-tbd-against-ir=none -enable-experimental-cxx-interop -disable-implicit-string-processing-module-import -external-plugin-path /nix/store/8pk2m0fn7z5dlb86z5qlv1pxa8w68idx-apple-sdk-14.4/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.sdk/usr/lib/swift/host/plugins#/nix/store/8pk2m0fn7z5dlb86z5qlv1pxa8w68idx-apple-sdk-14.4/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.sdk/usr/bin/swift-plugin-server -external-plugin-path /nix/store/8pk2m0fn7z5dlb86z5qlv1pxa8w68idx-apple-sdk-14.4/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.sdk/usr/local/lib/swift/host/plugins#/nix/store/8pk2m0fn7z5dlb86z5qlv1pxa8w68idx-apple-sdk-14.4/Platforms/MacOSX.platform/Developer/SDKs/MacOSX14.4.sdk/usr/bin/swift-plugin-server -external-plugin-path /nix/store/8pk2m0fn7z5dlb86z5qlv1pxa8w68idx-apple-sdk-14.4/Platforms/MacOSX.platform/Developer/usr/lib/swift/host/plugins#/nix/store/8pk2m0fn7z5dlb86z5qlv1pxa8w68idx-apple-sdk-14.4/Platforms/MacOSX.platform/Developer/usr/bin/swift-plugin-server -external-plugin-path /nix/store/8pk2m0fn7z5dlb86z5qlv1pxa8w68idx-apple-sdk-14.4/Platforms/MacOSX.platform/Developer/usr/local/lib/swift/host/plugins#/nix/store/8pk2m0fn7z5dlb86z5qlv1pxa8w68idx-apple-sdk-14.4/Platforms/MacOSX.platform/Developer/usr/bin/swift-plugin-server -plugin-path /nix/var/nix/builds/nix-79692-3916204861/build/swift/bootstrapping0/lib/swift/host/plugins -plugin-path /nix/var/nix/builds/nix-79692-3916204861/build/swift/bootstrapping0/local/lib/swift/host/plugins -Xcc -mmacos-version-min=14.0 -Xcc -fno-omit-frame-pointer -Xcc -mno-omit-leaf-frame-pointer -Xcc -Werror=unguarded-availability -Xcc -std=c++17 -Xcc -UIBOutlet -Xcc -UIBAction -Xcc -UIBInspectable -Xcc -DNDEBUG -Xcc -I -Xcc /nix/var/nix/builds/nix-79692-3916204861/src/llvm-project/llvm/include -Xcc -I -Xcc /nix/var/nix/builds/nix-79692-3916204861/build/llvm/include -Xcc -I -Xcc /nix/var/nix/builds/nix-79692-3916204861/src/llvm-project/clang/include -Xcc -I -Xcc /nix/var/nix/builds/nix-79692-3916204861/build/llvm/tools/clang/include -Xcc -I -Xcc /nix/var/nix/builds/nix-79692-3916204861/src/swift/include -Xcc -I -Xcc /nix/var/nix/builds/nix-79692-3916204861/build/swift/SwiftCompilerSources/../include -Xcc -B/nix/store/6mp7w55mz9frcya56aqzny2y7d6pi9ws-libSystem-B/lib/ -Xcc -idirafter -Xcc /nix/store/6mp7w55mz9frcya56aqzny2y7d6pi9ws-libSystem-B/include -Xcc -fmacro-prefix-map=/nix/store/6mp7w55mz9frcya56aqzny2y7d6pi9ws-libSystem-B/include=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-libSystem-B/include -Xcc -B/nix/store/3027pfic50ihg817fhvmgxffgy9p5z3i-clang-21.1.8-lib/lib -Xcc -frandom-seed=h8jlj4jnxb -Xcc -isystem -Xcc /nix/store/0s2nwdax6l24grm24x17idddy65y8x89-libxcrypt-4.5.2/include -Xcc -fmacro-prefix-map=/nix/store/0s2nwdax6l24grm24x17idddy65y8x89-libxcrypt-4.5.2=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-libxcrypt-4.5.2 -Xcc -isystem -Xcc /nix/store/1kr9hamyz14ac9v64bg7wb6qkbsizygw-python3-3.12.12-env/include -Xcc -fmacro-prefix-map=/nix/store/1kr9hamyz14ac9v64bg7wb6qkbsizygw-python3-3.12.12-env=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-python3-3.12.12-env -Xcc -isystem -Xcc /nix/store/ba2k0xm0m7vwgi7f0625kbxckgrx2zfs-libcxx-20.1.0+apple-sdk-26.0/include -Xcc -fmacro-prefix-map=/nix/store/ba2k0xm0m7vwgi7f0625kbxckgrx2zfs-libcxx-20.1.0+apple-sdk-26.0=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-libcxx-20.1.0+apple-sdk-26.0 -Xcc -isystem -Xcc /nix/store/47d3ak31qp8qavc3w6np7p48ccylwqwd-compiler-rt-libc-21.1.8-dev/include -Xcc -fmacro-prefix-map=/nix/store/47d3ak31qp8qavc3w6np7p48ccylwqwd-compiler-rt-libc-21.1.8-dev=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-compiler-rt-libc-21.1.8-dev -Xcc -isystem -Xcc /nix/store/ab43gk9xl2ssnz3yzs484csd5axv1kqk-libxml2-2.15.1-dev/include -Xcc -fmacro-prefix-map=/nix/store/ab43gk9xl2ssnz3yzs484csd5axv1kqk-libxml2-2.15.1-dev=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-libxml2-2.15.1-dev -Xcc -isystem -Xcc /nix/store/yamly6ym3hyi0589isqyb5w0y4n2fdbg-libiconv-109.100.2-dev/include -Xcc -fmacro-prefix-map=/nix/store/yamly6ym3hyi0589isqyb5w0y4n2fdbg-libiconv-109.100.2-dev=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-libiconv-109.100.2-dev -Xcc -isystem -Xcc /nix/store/nq7w9cx2jhqxi2ha92clba1fjgqns1xg-libresolv-91-dev/include -Xcc -fmacro-prefix-map=/nix/store/nq7w9cx2jhqxi2ha92clba1fjgqns1xg-libresolv-91-dev=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-libresolv-91-dev -Xcc -isystem -Xcc /nix/store/3ifp90k41wpp3pmy8wgc6iafc86xy24w-libsbuf-14.1.0-dev/include -Xcc -fmacro-prefix-map=/nix/store/3ifp90k41wpp3pmy8wgc6iafc86xy24w-libsbuf-14.1.0-dev=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-libsbuf-14.1.0-dev -Xcc -isystem -Xcc /nix/store/0s2nwdax6l24grm24x17idddy65y8x89-libxcrypt-4.5.2/include -Xcc -fmacro-prefix-map=/nix/store/0s2nwdax6l24grm24x17idddy65y8x89-libxcrypt-4.5.2=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-libxcrypt-4.5.2 -Xcc -isystem -Xcc /nix/store/1kr9hamyz14ac9v64bg7wb6qkbsizygw-python3-3.12.12-env/include -Xcc -fmacro-prefix-map=/nix/store/1kr9hamyz14ac9v64bg7wb6qkbsizygw-python3-3.12.12-env=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-python3-3.12.12-env -Xcc -isystem -Xcc /nix/store/ba2k0xm0m7vwgi7f0625kbxckgrx2zfs-libcxx-20.1.0+apple-sdk-26.0/include -Xcc -fmacro-prefix-map=/nix/store/ba2k0xm0m7vwgi7f0625kbxckgrx2zfs-libcxx-20.1.0+apple-sdk-26.0=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-libcxx-20.1.0+apple-sdk-26.0 -Xcc -isystem -Xcc /nix/store/47d3ak31qp8qavc3w6np7p48ccylwqwd-compiler-rt-libc-21.1.8-dev/include -Xcc -fmacro-prefix-map=/nix/store/47d3ak31qp8qavc3w6np7p48ccylwqwd-compiler-rt-libc-21.1.8-dev=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-compiler-rt-libc-21.1.8-dev -Xcc -isystem -Xcc /nix/store/ab43gk9xl2ssnz3yzs484csd5axv1kqk-libxml2-2.15.1-dev/include -Xcc -fmacro-prefix-map=/nix/store/ab43gk9xl2ssnz3yzs484csd5axv1kqk-libxml2-2.15.1-dev=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-libxml2-2.15.1-dev -Xcc -isystem -Xcc /nix/store/yamly6ym3hyi0589isqyb5w0y4n2fdbg-libiconv-109.100.2-dev/include -Xcc -fmacro-prefix-map=/nix/store/yamly6ym3hyi0589isqyb5w0y4n2fdbg-libiconv-109.100.2-dev=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-libiconv-109.100.2-dev -Xcc -isystem -Xcc /nix/store/nq7w9cx2jhqxi2ha92clba1fjgqns1xg-libresolv-91-dev/include -Xcc -fmacro-prefix-map=/nix/store/nq7w9cx2jhqxi2ha92clba1fjgqns1xg-libresolv-91-dev=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-libresolv-91-dev -Xcc -isystem -Xcc /nix/store/3ifp90k41wpp3pmy8wgc6iafc86xy24w-libsbuf-14.1.0-dev/include -Xcc -fmacro-prefix-map=/nix/store/3ifp90k41wpp3pmy8wgc6iafc86xy24w-libsbuf-14.1.0-dev=/nix/store/eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee-libsbuf-14.1.0-dev -Xcc -Wno-error=unguarded-availability -Xcc -isystem -Xcc /nix/var/nix/builds/nix-79692-3916204861/build/libcxx/include/c++/v1 -Xcc -stdlib=libc++ -target-sdk-version 14.4 -parse-as-library -module-name Basic -cross-module-optimization -o /nix/var/nix/builds/nix-79692-3916204861/build/swift/bootstrapping1/SwiftCompilerSources/Basic.o
1.      Swift version 5.10.1 (swift-5.10.1-RELEASE)
2.      Compiling with the current language version
Stack dump without symbol names (ensure you have llvm-symbolizer in your PATH or set the environment var `LLVM_SYMBOLIZER_PATH` to point to it):
0  swift-frontend-unwrapped 0x0000000108dacfa4 llvm::sys::PrintStackTrace(llvm::raw_ostream&, int) + 72
1  swift-frontend-unwrapped 0x0000000108dac040 llvm::sys::RunSignalHandlers() + 108
2  swift-frontend-unwrapped 0x0000000108dad65c SignalHandler(int) + 384
3  libsystem_platform.dylib 0x000000019199b744 _sigtramp + 56
4  swift-frontend-unwrapped 0x00000001045b9edc swift::performFrontend(llvm::ArrayRef<char const*>, char const*, void*, swift::FrontendObserver*) + 700
5  swift-frontend-unwrapped 0x0000000104559db4 swift::mainEntry(int, char const**) + 3624
6  dyld                     0x00000001915c9d54 start + 7184

[samestep]

I did a git bisect and this build error seems to have been introduced by #479279; that is, nix-build -A swift fails on 701f311 but succeeds on 70801e0. @vcunat do you happen to know which part of that staging PR might be the cause?

[vcunat]

I do not.

[xanth]

Seeing the same issue here

$ sudo darwin-rebuild switch --flake .
building the system configuration...
warning: Git tree '/Users/xanth/.config/nix' is dirty
evaluation warning: nixfmt-rfc-style is now the same as pkgs.nixfmt which should be used instead.
these 33 derivations will be built:
  /nix/store/lghszxcp38ydvdlmcmkk7w1fsszyp7cp-swift-5.10.1.drv
  /nix/store/ab6rm20gad0jbqp6wmx42f172f76nmx2-clang-wrapper-21.1.8.drv
  /nix/store/h9snh2pc6fx0rh33dh5z1rfj7mhfcp0q-swift-wrapper-5.10.1.drv
  /nix/store/3axxf6n03zx25hx33vxh3g46hrgx9l9z-swift-system.drv
  /nix/store/c2skv9nkfmhiajd3kxx8k94klgm9yzmd-swift-corelibs-xctest-5.10.1.drv
  /nix/store/ajq7vc5pryngd7lhgnfxx7h8hfyphxka-swift-asn1.drv
  /nix/store/chr6lz20zxzmp9xpbimp868fhc9habky-swift-tools-support-core.drv
  /nix/store/fpk79y5gf2h0s2sgwlaf9k84c16bd7x3-swift-crypto.drv
  /nix/store/nchfsxvy563h97jip25sk24csbmqv384-swift-argument-parser.drv
  /nix/store/6qmwgfbj2bq70pa7w53zvl3fv5836qqp-Yams.drv
  /nix/store/zpx1wh26597dr5m7602jdg798ci63w3z-llbuild.drv
  /nix/store/szyamf8z6a3db045vjddyax7bf2qlx80-swift-driver.drv
  /nix/store/yx3v1vjplwi5gkd6nsapqa1ma35nxhx3-swift-collections.drv
  /nix/store/z7ypjxnkzw11k8lgxsqkfh2b2hg12j7g-swift-certificates.drv
  /nix/store/zk982llvpzgdg4qxwcl7b5lrd2qghdnd-fix-stdlib-path.patch.drv
  /nix/store/y4avx96ldqn1f23az7k82aamgpqybdip-swiftpm-bootstrap-5.10.1.drv
  /nix/store/kvv8c5fdmx29v6qgvyd050kqm49kfq8k-swiftpm-5.10.1.drv
  /nix/store/dnnv2xay2kpmmq189cjnmm0jwbv8mfmn-swift-driver-5.10.1.drv
  /nix/store/90gi7sjbxghqcbzjwp4if8rnwkp7h959-swift-wrapper-5.10.1.drv
  /nix/store/qld4xwjhcrn9b9zz4pnq8dxlb9fzbaf3-dotnet-stage0-vmr-8.0.23.drv
  /nix/store/8h3zxgr7kqg16yjzc3384lqlpkrsxsb2-dotnet-stage0-sdk-8.0.123.drv
  /nix/store/wz16r6z2435qarwxmhzv497kih32vjzg-dotnet-vmr-8.0.23.drv
  /nix/store/3xxls063c019d77rijnrp0ymrdcjz841-dotnet-aspnetcore-runtime-8.0.23.drv
  /nix/store/7qnd5shqbxrcmkz4hwjwzf2z9yglmzd9-dotnet-runtime-8.0.23.drv
  /nix/store/bnnwqk69rz03m2zrc57hn905j81ndg82-dotnet-runtime-wrapped-8.0.23.drv
  /nix/store/ppryq5sr2z175hv95fy2znqjb0p2adbf-dotnet-aspnetcore-runtime-wrapped-8.0.23.drv
  /nix/store/f4zrvdh3vdgnmwa8ypnaz4fwmdpdh15i-dotnet-sdk-8.0.417.drv
  /nix/store/jq31db9iyfcg6nvr66rm1mrc76xmfmlv-dotnet-sdk-wrapped-8.0.417.drv
  /nix/store/w0nb2ixrrzq6vp0ilkk04c3zidrc3n18-pre-commit-4.5.1.drv
  /nix/store/i0512d0303vvdkdr0jdglip2gq1s7ypj-system-applications.drv
  /nix/store/xclhbzsq4gxjmgbfs4fzsjpiq1gcshyr-system-path.drv
  /nix/store/w9cvfs3fxsljnczpsa42ba56hwj93shm-etc.drv
  /nix/store/v521cvbwiaxa72mv12rb4xiqi4c53l44-darwin-system-26.05.0fc4e7a.drv
these 2 paths will be fetched (133.37 MiB download, 637.35 MiB unpacked):
  /nix/store/c305hbrc735iivdkz5dzwzsg0dk3syyk-dotnet-sdk-10.0.102
  /nix/store/xq393hiqysd2xgjadi4mm1w0cphqhpic-dotnet-sdk-wrapped-10.0.102
copying path '/nix/store/c305hbrc735iivdkz5dzwzsg0dk3syyk-dotnet-sdk-10.0.102' from 'https://cache.nixos.org'...
building '/nix/store/lghszxcp38ydvdlmcmkk7w1fsszyp7cp-swift-5.10.1.drv'...
copying path '/nix/store/xq393hiqysd2xgjadi4mm1w0cphqhpic-dotnet-sdk-wrapped-10.0.102' from 'https://cache.nixos.org'...
error: Cannot build '/nix/store/lghszxcp38ydvdlmcmkk7w1fsszyp7cp-swift-5.10.1.drv'.
       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/4xhl8sgydl4xmj9v1h4qknh011vbs5xr-swift-5.10.1-doc
         /nix/store/c97ysqzz9w49422qiq7jgbzk2zq38vg7-swift-5.10.1-man
         /nix/store/cz7q9k1h4mc94dnihm7dj5668zfjxk34-swift-5.10.1-lib
         /nix/store/h8jlj4jnxb2jisj0a895fr8171qgysws-swift-5.10.1
         /nix/store/jg5pi99pq36m55i8yvdhvhrgy7zmnccd-swift-5.10.1-dev
       Last 25 log lines:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILFunction.h:26:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILBasicBlock.h:24:
       > /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILInstruction.h:1149:17: warning: 'offsetof' on non-standard-layout type 'SingleValueInstruction' [-Winvalid-offsetof]
       >  1149 |   static_assert(offsetof(SingleValueInstruction, kind) ==
       >       |                 ^                                ~~~~
       > /nix/store/rzggksbv3l3rp8appk6dw71b0wn4ar18-clang-wrapper-21.1.8/resource-root/include/__stddef_offsetof.h:16:24: note: expanded from macro 'offsetof'
       >    16 | #define offsetof(t, d) __builtin_offsetof(t, d)
       >       |                        ^                     ~
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/tools/SourceKit/lib/SwiftLang/SwiftEditor.cpp:15:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.h:30:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/IDETool/CompileInstance.h:16:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/Frontend/Frontend.h:43:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/Subsystems.h:20:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/AST/TBDGenRequests.h:24:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/IRGen/Linking.h:23:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILFunction.h:26:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILBasicBlock.h:24:
       > /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILInstruction.h:1150:17: warning: 'offsetof' on non-standard-layout type 'NonSingleValueInstruction' [-Winvalid-offsetof]
       >  1150 |                 offsetof(NonSingleValueInstruction, kind),
       >       |                 ^                                   ~~~~
       > /nix/store/rzggksbv3l3rp8appk6dw71b0wn4ar18-clang-wrapper-21.1.8/resource-root/include/__stddef_offsetof.h:16:24: note: expanded from macro 'offsetof'
       >    16 | #define offsetof(t, d) __builtin_offsetof(t, d)
       >       |                        ^                     ~
       > 7 warnings generated.
       > ninja: build stopped: subcommand failed.
       For full logs, run:
         nix log /nix/store/lghszxcp38ydvdlmcmkk7w1fsszyp7cp-swift-5.10.1.drv
error: Cannot build '/nix/store/lghszxcp38ydvdlmcmkk7w1fsszyp7cp-swift-5.10.1.drv'.
       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/4xhl8sgydl4xmj9v1h4qknh011vbs5xr-swift-5.10.1-doc
         /nix/store/c97ysqzz9w49422qiq7jgbzk2zq38vg7-swift-5.10.1-man
         /nix/store/cz7q9k1h4mc94dnihm7dj5668zfjxk34-swift-5.10.1-lib
         /nix/store/h8jlj4jnxb2jisj0a895fr8171qgysws-swift-5.10.1
         /nix/store/jg5pi99pq36m55i8yvdhvhrgy7zmnccd-swift-5.10.1-dev
       Last 25 log lines:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILFunction.h:26:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILBasicBlock.h:24:
       > /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILInstruction.h:1149:17: warning: 'offsetof' on non-standard-layout type 'SingleValueInstruction' [-Winvalid-offsetof]
       >  1149 |   static_assert(offsetof(SingleValueInstruction, kind) ==
       >       |                 ^                                ~~~~
       > /nix/store/rzggksbv3l3rp8appk6dw71b0wn4ar18-clang-wrapper-21.1.8/resource-root/include/__stddef_offsetof.h:16:24: note: expanded from macro 'offsetof'
       >    16 | #define offsetof(t, d) __builtin_offsetof(t, d)
       >       |                        ^                     ~
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/tools/SourceKit/lib/SwiftLang/SwiftEditor.cpp:15:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.h:30:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/IDETool/CompileInstance.h:16:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/Frontend/Frontend.h:43:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/Subsystems.h:20:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/AST/TBDGenRequests.h:24:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/IRGen/Linking.h:23:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILFunction.h:26:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILBasicBlock.h:24:
       > /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILInstruction.h:1150:17: warning: 'offsetof' on non-standard-layout type 'NonSingleValueInstruction' [-Winvalid-offsetof]
       >  1150 |                 offsetof(NonSingleValueInstruction, kind),
       >       |                 ^                                   ~~~~
       > /nix/store/rzggksbv3l3rp8appk6dw71b0wn4ar18-clang-wrapper-21.1.8/resource-root/include/__stddef_offsetof.h:16:24: note: expanded from macro 'offsetof'
       >    16 | #define offsetof(t, d) __builtin_offsetof(t, d)
       >       |                        ^                     ~
       > 7 warnings generated.
       > ninja: build stopped: subcommand failed.
       For full logs, run:
         nix log /nix/store/lghszxcp38ydvdlmcmkk7w1fsszyp7cp-swift-5.10.1.drv
error: Cannot build '/nix/store/lghszxcp38ydvdlmcmkk7w1fsszyp7cp-swift-5.10.1.drv'.
       Reason: builder failed with exit code 1.
       Output paths:
         /nix/store/4xhl8sgydl4xmj9v1h4qknh011vbs5xr-swift-5.10.1-doc
         /nix/store/c97ysqzz9w49422qiq7jgbzk2zq38vg7-swift-5.10.1-man
         /nix/store/cz7q9k1h4mc94dnihm7dj5668zfjxk34-swift-5.10.1-lib
         /nix/store/h8jlj4jnxb2jisj0a895fr8171qgysws-swift-5.10.1
         /nix/store/jg5pi99pq36m55i8yvdhvhrgy7zmnccd-swift-5.10.1-dev
       Last 25 log lines:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILFunction.h:26:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILBasicBlock.h:24:
       > /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILInstruction.h:1149:17: warning: 'offsetof' on non-standard-layout type 'SingleValueInstruction' [-Winvalid-offsetof]
       >  1149 |   static_assert(offsetof(SingleValueInstruction, kind) ==
       >       |                 ^                                ~~~~
       > /nix/store/rzggksbv3l3rp8appk6dw71b0wn4ar18-clang-wrapper-21.1.8/resource-root/include/__stddef_offsetof.h:16:24: note: expanded from macro 'offsetof'
       >    16 | #define offsetof(t, d) __builtin_offsetof(t, d)
       >       |                        ^                     ~
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/tools/SourceKit/lib/SwiftLang/SwiftEditor.cpp:15:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/tools/SourceKit/lib/SwiftLang/SwiftLangSupport.h:30:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/IDETool/CompileInstance.h:16:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/Frontend/Frontend.h:43:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/Subsystems.h:20:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/AST/TBDGenRequests.h:24:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/IRGen/Linking.h:23:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILFunction.h:26:
       > In file included from /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILBasicBlock.h:24:
       > /nix/var/nix/builds/nix-45555-2232101442/src/swift/include/swift/SIL/SILInstruction.h:1150:17: warning: 'offsetof' on non-standard-layout type 'NonSingleValueInstruction' [-Winvalid-offsetof]
       >  1150 |                 offsetof(NonSingleValueInstruction, kind),
       >       |                 ^                                   ~~~~
       > /nix/store/rzggksbv3l3rp8appk6dw71b0wn4ar18-clang-wrapper-21.1.8/resource-root/include/__stddef_offsetof.h:16:24: note: expanded from macro 'offsetof'
       >    16 | #define offsetof(t, d) __builtin_offsetof(t, d)
       >       |                        ^                     ~
       > 7 warnings generated.
       > ninja: build stopped: subcommand failed.
       For full logs, run:
         nix log /nix/store/lghszxcp38ydvdlmcmkk7w1fsszyp7cp-swift-5.10.1.drv
error: Cannot build '/nix/store/90gi7sjbxghqcbzjwp4if8rnwkp7h959-swift-wrapper-5.10.1.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/4vjp1fc62brcf9nrsl921x361ngxm9n5-swift-wrapper-5.10.1-man
         /nix/store/7nszilqipi279da6cbm7ap10x42wrhph-swift-wrapper-5.10.1
error: Cannot build '/nix/store/wz16r6z2435qarwxmhzv497kih32vjzg-dotnet-vmr-8.0.23.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/b57q56yvk67bibqpb0bn66zdrl2q7d46-dotnet-vmr-8.0.23-man
         /nix/store/f065j8c7z3cr6cm5wqlx6al5jrq31jvj-dotnet-vmr-8.0.23
error: Cannot build '/nix/store/3xxls063c019d77rijnrp0ymrdcjz841-dotnet-aspnetcore-runtime-8.0.23.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/0akm2rn1sm9zfadjnnahpsc08hgns58y-dotnet-aspnetcore-runtime-8.0.23
         /nix/store/5h3fkwsgicsdwij2fvr66fxcmlmcm70m-dotnet-aspnetcore-runtime-8.0.23-man
error: Cannot build '/nix/store/7qnd5shqbxrcmkz4hwjwzf2z9yglmzd9-dotnet-runtime-8.0.23.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/4fkziab0jmbwplzs6nwgwkqz9fpcc1ma-dotnet-runtime-8.0.23
         /nix/store/m8hfjfjak5zr4g6a1h9sxwvsbf87w2kv-dotnet-runtime-8.0.23-man
error: Cannot build '/nix/store/ppryq5sr2z175hv95fy2znqjb0p2adbf-dotnet-aspnetcore-runtime-wrapped-8.0.23.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/xckg1csas8zs87bldbd76wb1q25ldg4g-dotnet-aspnetcore-runtime-wrapped-8.0.23
         /nix/store/y54ws98k9hxj9cyxjm4hlmvv25zw85jb-dotnet-aspnetcore-runtime-wrapped-8.0.23-man
error: Cannot build '/nix/store/f4zrvdh3vdgnmwa8ypnaz4fwmdpdh15i-dotnet-sdk-8.0.417.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/7gc3jzxz7pa64z8ajai4mbxqgl4ndl9f-dotnet-sdk-8.0.417
error: Cannot build '/nix/store/jq31db9iyfcg6nvr66rm1mrc76xmfmlv-dotnet-sdk-wrapped-8.0.417.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/lsh83zvqzlg781hy0sh53aanq5whl6vb-dotnet-sdk-wrapped-8.0.417
error: Cannot build '/nix/store/w0nb2ixrrzq6vp0ilkk04c3zidrc3n18-pre-commit-4.5.1.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/416b43a1x26kmr5vgvhln3nccjnbycjf-pre-commit-4.5.1-dist
         /nix/store/qrcnnadhg06kdiimqlb4naf25gyngbhr-pre-commit-4.5.1
error: Cannot build '/nix/store/i0512d0303vvdkdr0jdglip2gq1s7ypj-system-applications.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/afxprl5p9a870h28fk2pfc6ndm9zs8n7-system-applications
error: Cannot build '/nix/store/xclhbzsq4gxjmgbfs4fzsjpiq1gcshyr-system-path.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/7h7590ca92q48kam380zki7bgh6wq4pi-system-path
error: Cannot build '/nix/store/v521cvbwiaxa72mv12rb4xiqi4c53l44-darwin-system-26.05.0fc4e7a.drv'.
       Reason: 1 dependency failed.
       Output paths:
         /nix/store/0sy8rcbyv4r394q5a1ks7rkqz2v635v1-darwin-system-26.05.0fc4e7a

[xanth]

Thanks @samestep pinning to that fixed the issue:

diff --git a/flake.nix b/flake.nix
index aa377c1..af80d74 100644
--- a/flake.nix
+++ b/flake.nix
@@ -2,7 +2,7 @@
   description = "Xanth nix-darwin system flake";

   inputs = {
-    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
+    nixpkgs.url = "github:NixOS/nixpkgs/70801e06d9730c4f1704fbd3bbf5b8e11c03a2a7";
     nix-darwin = {
       url = "github:nix-darwin/nix-darwin/master";
       inputs.nixpkgs.follows = "nixpkgs";

[Aurelian-Shuttleworth]

I have reported this upstream to the Swift project: swiftlang/swift#86789. It appears to be a strictness regression in newer Clang versions affecting the 5.10.x codebase.

[samestep]

@xanth glad to be of help! This is slightly off-topic and is a self-plug so feel free to ignore, but in the future you may find npc useful in situations like this. For instance, if you also have nom installed, you could use npc to find the last working commit that also passed all the usual checks from nixpkgs-unstable (rather than just some random commit from master):

git clone https://github.com/xanth/nix-config.git
cd nix-config
git checkout 89fbde66b3c0ed14a9df611a281ace74d6e3bf2d
git apply --reverse flake.patch
nix flake lock
npc bisect start
npc checkout e8d16d2186d6ed9f047eb30948e97e7e01886d10
nom build --no-link .#darwinConfigurations.rhys-lap-osx.system
npc bisect good
npc checkout 48698d12cc10555a4f3e3222d9c669b884a49dfe
npc bisect bad
nom build --no-link .#darwinConfigurations.rhys-lap-osx.system

Then you just keep alternating between those npc bisect and nom build commands (using ^C on the nom build if it looks like it's trying to build swift from source) until eventually you see that the last nixpkgs-unstable commit with a working swift was b579d44, with a1bab9e being the first broken nixpkgs-unstable commit:

done bisecting nixpkgs-unstable for flake input nixpkgs
a1bab9e494f5f4939442a57a58d0449a109593fe is the first bad commit
b579d443b37c9c5373044201ea77604e37e748c8 is the last good commit