> the important thing to realize is that changing the lifetime parameters in a function will never change the user-visible semantics of the code To reiterate:

> the important thing to realize is that changing the lifetime parameters in a function will never change the user-visible semantics of the code To reiterate: the lifetime parameters are used only to check the code for errors, they are discarded after that and don't affect the code generation. There's even an alternative compiler for Rust (mrustc) which completely ignores them and the rest of the borrow checking stuff, assuming the code is correct.