itoa VS rust-fnv

The hyper package for the crab language actually has a dependency on a package that does itoa (among others) so IMO the problem exist there too and most non trivial packages will be bloated

I see itoa which seems trivial on the surface. The implementation is highly optimized, but it's also covering all the different cases. I'm guessing this is for printing match counts or line numbers, and if this is actually a bottleneck for ripgrep — which seems unlikely — then maybe it's worth it. You know your own needs, and if it was a bottleneck, I bet you could do just as well, if not better, with a custom, smaller, simpler solution inside ripgrep. (i.e. just make sure the power-of-ten denominators are available at compile time so the compiler won't generate divisions.)

Use faster hashing function (e.g. fnv, there are other potentially faster options as well). By default Rust std uses a DoS-resistant function, which is relatively slow.

Looking at ripgrep myself, I'm seeing some trivial dependencies. One is fnv. Perhaps you're not aware, but FNV-1a is literally ~4 lines of code. It's about as sophisticated as left-pad. I've written it from scratch a dozen times off the top of my head (the official offset basis and prime are really not special, so you can just generate your own). It would take you about a minute to eliminate it.