I am a performance noob, but given that fortran can be faster than C due to increased information about aliasing, and given how much more aliasing information Rust has, I don't see why Rust couldn't eventually even beat C on certain kinds of things. (And obviously, aliasing is only a tiny part of performance, just something that comes to mind.)

That said, I am FAR more concerned about shipping a solid 1.0 than on a maximum performance one. It'll be a while, but we'll get there.