Also, internally, quickcheck now uses panic::catch_unwind instead of spinning up a thread for every test (which was previously the only way to catch a panic on Rust stable).
Nice, thanks for making it happen. I see you chose the simple way. There's a more advanced version in itertools test suite that uses "tt-munching" to support mut and patterns by counting : tokens, but I didn't feel sure about submitting that one to quickcheck, because it might be more fragile or confusing to use.