Rust supports both synchronous and asynchronous message passing over its channels. It's true that asynchronous message passing is generally associated with actor systems and not specifically with CSP, but it's also seen in many extensions of CSP, and in fact CSP and actor systems are duals of each other.
I was wrong about synchronous communication. Since most rust example use async channels, I missed the existence of sync_channel.
However, even if that exists, rust's concurrency doesn't follow CSP as much as go's. Like I mentioned in my previous comment, it doesn't have a way to do everything the select statement in go does. This is not necessarily a bad thing, but rust definitely doesn't share the same concurrency concepts as go. It offers everything that Java/C++ does along with data race protection.
Speaking of data race protection, the current type system rejects a lot of very common "non-racy" code too. There is work in progress to address some of them and may be most of them will be addressed eventually.
Considering you've backpedaled from "Rust isn't CSP" (because you misunderstood Rust channels) to "Rust doesn't have select" (which it does, and you didn't realize) to "Rust's select isn't as mature as Go's", that's probably for the best.
Perhaps you should try to be more informed about Rust before you try to have an argument about it in the future!
I said 2 things in very first comment. I never claimed rust doesn't have select. This is quoted from my very first comment in this thread,
AFAIK, rust also doesn't allow selecting between a send and receive on channels. It only allows selecting over a set of receivers and even there it doesn't offer something like the default clause of Go's select statement.
Perhaps you should try to read my comments in their entirety before making accusations.
Yes I missed sync_channel, but if that is all CSP was, Java does CSP too. It has Threads and SynchronousQueue exactly like rust 1.0 will.
Rust supports both approaches.