C++

Inclusive scan does not require an initial value. Exclusive scan does, and it does initialize the first element. There's like 16 different flavors of all these scans,. The choice that Rust has made is to include a short-circuiting, optional thing being encoded in the binary operation. It doesn't hard code, which is just a design choice. But you don't get that in C++ either, do you? Oh, no, you do. Yes, you do...