It hasn't been packaged yet, but I've both bootstrapped rustc & cargo, and also compiled rustc & cargo on Haiku itself from the bootstrap packages, so it shall be self-hosting from here on out.
Re:Porting Swift to Haiku
by steveklabnik on Friday June 23, 2017 @12:14PM
(#14620242)
Excellent!
* i686-unknown-haiku
* x86_64-unknown-haiku
They're basically cross-compile only, Tier 3 supported at the moment.