Make ParsableArguments inherit from SendableMetatype

[leuski]

In Swift 6.2 the compiler complains about statements like this

static let commands: [ParsableCommand.Type] = [ ... ]

It believes them to be unsafe, because the metadata type ParsableCommand.Type is no longer assumed to be Sendable. Would be possible to make ParsableArguments inherit from SendableMetatype? This way the warning will be gone.

[natecook1000]

Thanks for opening this issue, @leuski! Can you add some information about your OS, Xcode, and Swift compiler versions?

[leuski]

OS 15.6.1, Xcode 26.0.1, swift-driver version: 1.127.14.1 Apple Swift version 6.2 (swiftlang-6.2.0.19.9 clang-1700.3.19.1)

[natecook1000]

Are you using the latest ArgumentParser version? 1.6.1 added SendableMetatype conformance to ParsableArguments through a separate marker protocol (_SendableMetatype) for source compatibility reasons. #792

Edit: Seems like it was added in 1.6.0 and converted to a marker protocol in 1.6.1… #789

[leuski]

Agh! You are right, I did not upgrade my packages fully and I was still using 1.5.1 version. My mistake. Thank you for figuring it out.