#![feature(untagged_unions)] // Non-copy struct A; struct B; union U { a: A, b: B, } fn main() { unsafe { { let mut u = U { a: A }; let a = u.a; let a = u.a; //~ ERROR use of moved value: `u` } { let mut u = U { a: A }; let a = u.a; u.a = A; let a = u.a; // OK } { let mut u = U { a: A }; let a = u.a; u.b = B; let a = u.a; // OK } } }