[drtse4]

Yes, not really a problem in that case. But let's not forget that this release also contains nearly 50 other source breaking swift-evolution proposals (full changelog here: https://github.com/apple/swift/blob/master/CHANGELOG.md).

But one of the things I like about how the language is begin developed is that everyone involved is aware that having the language in a constant state of flux is painful, and try to provide useful warning messages (or wizards if you use XCode) for those that will need to update their code to a newer release sooner or later.