What's with this fascination with making python fast? It's not supposed to be fast, it's supposed to be simple. If you want speed use a compiled language. Trying to make python fast is like trying to strap a turbocharger to a tricycle.
I mean regardless of whether mypy was going to make my code run faster I would have used it for the shear confidence it gives wrt to my code correctness. The fact that I can use that same code (untouched) to speed it up... that's just means I get to have my cake and eat it too :P
But there is a disconnect between Python programming simplicity and Python speed, which stems from the fact that under the hood Python is doing much more than its minimal asm 'spiritual equivalent'.
But in a pure abstract theory sense, it shouldn't "need" to. I don't really care about the intricacies of garbage collection or global interpreter lock or page misses etc - what if I just care about "can I make this nice idea into reality in 10 minutes". The reality is that I'm just barely working with the tip of an iceberg composed of 60+ years of computer abstractions. But who can blame me - I am but a mere mortal.
If we could have a programming language that is both simple for the programmer and simple for the computer, it would be great. It's not that unreasonable that people start from the user experience side - making a simple language faster, by getting rid of unnecessary work - rather than the opposite extreme: making it simpler to come up with optimal machine code whose simplicity withstand contact with hundreds of vestigial appendages that just have to be dealt w bc of computer history (spanning from how to do a syscall to how to make a gui in some particular os)
Many pieces of code run only a handful times but potentially move a lot of data. Sometimes reimplementing existing code in C/Haskell/Rust, including finding equivalent libraries, writing tests, and debugging, only because the computation turned out to be heavier than I had expected is not a good use of time. If that’s the place where I’m at, PyPy, mypyc, etc., might just do the trick.