src/test/ui/union/union-derive-clone.rs

   1 // revisions: mirunsafeck thirunsafeck
   2 // [thirunsafeck]compile-flags: -Z thir-unsafeck
   3
   4 use std::mem::ManuallyDrop;
   5
   6 #[derive(Clone)] //~ ERROR the trait bound `U1: Copy` is not satisfied
   7 union U1 {
   8     a: u8,
   9 }
  10
  11 #[derive(Clone)]
  12 union U2 {
  13     a: u8, // OK
  14 }
  15
  16 impl Copy for U2 {}
  17
  18 #[derive(Clone, Copy)]
  19 union U3 {
  20     a: u8, // OK
  21 }
  22
  23 #[derive(Clone, Copy)]
  24 union U4<T: Copy> {
  25     a: T, // OK
  26 }
  27
  28 #[derive(Clone, Copy)]
  29 union U5<T> {
  30     a: ManuallyDrop<T>, // OK
  31 }
  32
  33 #[derive(Clone)]
  34 struct CloneNoCopy;
  35
  36 fn main() {
  37     let u = U5 { a: ManuallyDrop::new(CloneNoCopy) };
  38     let w = u.clone(); //~ ERROR the method
  39 }