At this point (April 2015) Rust is in 1.0.0-beta and there are no complete IDE integration (either Eclipse or Idea) so we need to go back to basics (no, no, no, not vim/emacs, relax :-) ) and use Kate for editing source files.
Frankly, so far I've never used Kate for programming and was totaly unaware how to configure it and I had some trouble setting Rust's syntax highlighting so here is the short explanation how to do it:
1. Download rust.xml from here:
Take care to save it in it's original XML form, not as HTML (as I did somehow the first time…)
2. Copy it in
3. Restart Kate
(btw, I use Kubuntu 14.04, other distros may have different location for the SH files…)