# Is the Swift 6 dev snapshot toolchain supposed to be using system 5.10 runtime dylibs?

**URL:** <https://forums.swift.org/t/is-the-swift-6-dev-snapshot-toolchain-supposed-to-be-using-system-5-10-runtime-dylibs/74593>\
**Category:** Using Swift\
**Tags:** toolchain, swiftpm, swift6\
**Created:** [September 13, 2024, 11:54pm UTC](https://forums.swift.org/t/is-the-swift-6-dev-snapshot-toolchain-supposed-to-be-using-system-5-10-runtime-dylibs/74593 "2024-09-13T23:54:54Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![corbeling](https://avatars.discourse-cdn.com/v4/letter/c/6f9a4e/32.png) [@corbeling](https://forums.swift.org/u/corbeling)\
**Post date:** [September 13, 2024, 11:54pm UTC](https://forums.swift.org/t/is-the-swift-6-dev-snapshot-toolchain-supposed-to-be-using-system-5-10-runtime-dylibs/74593/1 "2024-09-13T23:54:54Z")

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I'm running macOS 14.6.1 and I installed the 2024-09-11 dev snapshot of Swift 6 from [swift.org](http://swift.org). I have `TOOLCHAINS=org.swift.600202409111a` in my shell's environment and I've verified that eg. `swift --version` gives me `Apple Swift version 6.0-dev`. I'm using SwiftPM on the command line and not Xcode for all of this, although I did select the new toolchain in Xcode as well.

Now, I noticed that if I build one of my SwiftPM projects and look at the output of `otool -L` for the binary, all the `libswift*` dylibs it's using (like `libswiftCore.dylib`) are the ones under `/usr/lib/swift` even though the toolchain has them available under `/Library/Developer/Toolchains/swift-6.0-DEVELOPMENT-SNAPSHOT-2024-09-11-a.xctoolchain/usr/lib/swift/macosx`.

Is this expected? Is the toolchain even supposed to use those dev snapshot dylibs in my case since I'm still on macOS 14 and not on the 15 beta?

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**Author:** ![taylorswift](https://sea2.discourse-cdn.com/swift/user_avatar/forums.swift.org/taylorswift/32/43413_2.png) [@taylorswift](https://forums.swift.org/u/taylorswift)\
**Post date:** [September 14, 2024, 12:06am UTC](https://forums.swift.org/t/is-the-swift-6-dev-snapshot-toolchain-supposed-to-be-using-system-5-10-runtime-dylibs/74593/2 "2024-09-14T00:06:18Z")

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on macOS, Swift is ABI stable, so there is no requirement that the compiler version and runtime version match exactly.

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<div class="post-metadata">

**Author:** ![corbeling](https://avatars.discourse-cdn.com/v4/letter/c/6f9a4e/32.png) [@corbeling](https://forums.swift.org/u/corbeling)\
**Post date:** [September 14, 2024, 12:19am UTC](https://forums.swift.org/t/is-the-swift-6-dev-snapshot-toolchain-supposed-to-be-using-system-5-10-runtime-dylibs/74593/3 "2024-09-14T00:19:02Z")

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Right, but I guess my question is whether I can make the Swift 6 toolchain use the Swift 6 runtime too? Seems odd that it's using the 5.10 one.

I did notice that clang and swiftc are getting called with `-rpath /usr/lib/swift […] -Xlinker -rpath -Xlinker /Library/Developer/Toolchains/swift-6.0-DEVELOPMENT-SNAPSHOT-2024-09-11-a.xctoolchain/usr/lib/swift-5.5/macosx` which was pretty weird considering there is no `/usr/lib/swift-5.5/macosx` under the toolchain, so somehow this feels like my rpath is wrong.

**Edit:** ah looks like that `-rpath /usr/lib/swift` and `swift-5.5` linker rpath are only getting used with `swift-case-paths` for some reason. Still, it's odd that the binary I get only has runtime libs from under `/usr/lib/swift`