#![allow(unused)] #![feature(nll)] #[derive(Clone, Copy, Default)] struct S { a: u8, b: u8, } #[derive(Clone, Copy, Default)] struct Z { c: u8, d: u8, } union U { s: S, z: Z, } fn main() { unsafe { let mut u = U { s: Default::default() }; let mref = &mut u.s.a; *mref = 22; let nref = &u.z.c; //~^ ERROR cannot borrow `u.z.c` as immutable because it is also borrowed as mutable [E0502] println!("{} {}", mref, nref) } }