I still don't see why value structs need to be immutable; ints are mutable in all languages, and structs are mutable in C, C++, and Rust (if you `let mut`) and

I still don't see why value structs need to be immutable; ints are mutable in all languages, and structs are mutable in C, C++, and Rust (if you `let mut`) and it's a feature of the language.