What's that ATS thing?

ATS rocks the shootout, and now grandmaster Chris Double shows how to achieve remarkable feats using its (dependent and linear) type system:

By defining ‘curl_easy_cleanup’ in this way we enforce a contract which states that the programmer must call this function if they have a live ‘CURLptr l’ object. You can see this in practice if you remove the cleanup call and try to compile. A compile error will result. A compile error will also occur if you try to use the curl handle after the cleanup call.

You get a compile error if you don't dispose of our objects correctly or use them after they've been disposed of! Now that sounds like progress.