@hjupter have you found the solution ?

Any updates about this issue ? We need this feature so much

I've missed the read release notes, you can solve this problem by adding this lines Workaround: In the Xcode project Build Settings, set “Other Swift Flags” to: -external-plugin-path $(SYSTEM_DEVELOPER_DIR)/Platforms/iPhoneOS.platform/Developer/usr/lib/swift/host/plugins#$(SYSTEM_DEVELOPER_DIR)/Platforms/iPhoneOS.platform/Developer/usr/bin/swift-plugin-server