swift

c6ce6ee1 - [SwiftCompilerSources][build] Bump the minimum supported compiler version to 5.9

[SwiftCompilerSources][build] Bump the minimum supported compiler version to 5.9 Building SwiftCompilerSources with a Swift 5.8 compiler is not tested anymore, and it might showcase bugs in the old compiler version that are already fixed. This bumps the minimum allowed version to Swift 5.9, which was shipped in Xcode 15.