No, semantics and idiomatic code matters but I don't think performance oriented Swift code would be significantly slower than Rust. I might be wrong though - feel free to share relevant benchmarks.
Interesting, thanks! Ref counting has an overhead, of course. I wonder about the performance of the "performance oriented Swift code" - i.e. it would be non-idiomatic, but to avoid ref-counting - something you would write in your inner loop or other similar hot points.
Yes, they're programs from the benchmarks game that use a lot of UnsafeMutablePointer, which is:
> provides no automated memory management or alignment guarantees. You are responsible for handling the life cycle of any memory you work with through unsafe pointers to avoid leaks or undefined behavior. [1]
