So I have 20,292 lines of Rust with 85%ish code coverage in my project (by current count), and I can't recall a failure in nightly since I enabled it in Travis. Mind you, that only gets run when a commit happens, so it's entirely possible it could have failed and I've just been lucky. It looks like from git log, I committed the change to Travis to start nightly builds on

  Date:   Sat Aug 22 11:45:08 2015 -0700

So, take that for what it's worth :)