What's the current state of compilation times of Rust? How many times slower than C does it compile? Any links to statistics? I know it's hard to compare, but I am interested in developing a gut feeling of what to expect.
Still slower than we'd like. Some folks are putting in a heroic amount of effort to improve this significantly, but it's going to be a long time before it really happens. Smaller stuff is helping all the time, but has less dramatic impact.
> How many times slower than C does it compile?
Really impossible to say, because it varies along so many different factors. C will almost always compile faster though, it's true.
> Any links to statistics? I know it's hard to compare, but I am interested in developing a gut feeling of what to expect.
The closest we have is a few bits of basically anecdotal evidence; we have projects demonstrating that rustc got about 3x faster since 1.0, and we have had at least one (in my mind) pretty reasonable C++/Rust comparison that showed them as being roughly equal. But it's just really hard to get good data here.
You should expect something roughly C++-like.