> The solution was that I had to write a macro that extracted Y from S and call that macro every time I wanted to pass Y to a function. Why does that require a

> The solution was that I had to write a macro that extracted Y from S and call that macro every time I wanted to pass Y to a function. Why does that require a macro? ``` struct S { x:X, y:Y } fn do_with_y (y:&mut Y) {} fn do_with_s (y:&mut S) {} fn main_program (mut s: S) { do_with_s(&mut s); do_with_y(&s.y); /* ... */ } ``` I prefer seeing code like this rather than wrapping it in abstractions and macros/helpers because it's not particularly verbose and very clear where the borrowing happens ; you'd see the same in C++ or C, to be honest.