so to briefly answer the question in the title after reading the article : i dunno maybe prepared statements

Windows is as much to blame as any affected languages tbh.

For what its worth , the cache locality of Vec<Box<Dyn trait>> is terrible in general, i feel like if youre iterating over a large array of things and applying a polymorphic function you’re making a mistake.

Cache locality isnt a problem when youre only accessing something once though.

So imo polymorphism has its place for non iterative-compute type work, ie web server handler functions and event driven systems.

so if (somehow) the accumulator was an integer, this loop would autovectorize and the performance differences would be smaller ?

Haskell, because nobody knows haskell