Swift 6.4 Brings New Language Features and Swift Testing/XCTest Interop

Currently available as a beta in Xcode 27, Swift 6.4 introduces a range of enhancements: better C interoperability, simplified OS availability check, fine-grained warning control, async support in defer, efficient iteration for non-noncopyable types, up to 4x faster URL parsing, and improved interoperability between Swift Testing and XCTest.

By Sergio De Simone