The author wanted “a more powerful type of inference that can actually infer the whole type of a function by analyzing the body of the function”, which Rust doesn’t have by design.
Which I personally think is a good decision, although I like the clean looking syntax of Haskell, it’s often not obvious what the function takes (which is why most are type annotating their function)
But Rusts type annotations have non the less its limitations, when excessively using traitbounds (but I hope that will be soon better with impl everywhere (see e.g. https://smallcultfollowing.com/babysteps/blog/2022/09/22/rust-2024-the-year-of-everywhere/))
I really prefer rust’s approach. The function signature is the contract. It makes it much easier to debug compared to overly generic pure functional code or c++ templates where everything is auto and perfect forwarded.
The only time in rust where this isn’t true is with async functions. That’s because the compiler adds a ton of sugar to make it easier to write.
