As I did not have much time to focus on larger programming projects recently I’ve done several exercises on exercism Rust track. It was quite fun and I hope learned a bit. But I found one issue there – when looking at solutions of others, some of them, even when code look very nice and has stars from other users, is performing very badly. I consider this as quite bad practice – if one chooses a “Systems Programming Language” as Rust he should think about performance and understand implications of:

a) general algorithm complexity
So chosen solution should try to use sound algorithm, with complexity close to best possible

b) using complex fancy functional constructs
Rust is advertising “zero cost abstractions”, however while it works in many cases it has to be used with caution – you have to use a bit of common sense.