#![feature(untagged_unions)]
#![allow(unused)]
-#[allow(unions_with_drop_fields)]
+use std::ops::{Deref, DerefMut};
+
+#[derive(Default)]
+struct MockBox<T> {
+ value: [T; 1],
+}
+
+impl<T> MockBox<T> {
+ fn new(value: T) -> Self { MockBox { value: [value] } }
+}
+
+impl<T> Deref for MockBox<T> {
+ type Target = T;
+ fn deref(&self) -> &T { &self.value[0] }
+}
+
+impl<T> DerefMut for MockBox<T> {
+ fn deref_mut(&mut self) -> &mut T { &mut self.value[0] }
+}
+
+#[derive(Default)]
+struct MockVec<T> {
+ value: [T; 0],
+}
+
+impl<T> MockVec<T> {
+ fn new() -> Self { MockVec { value: [] } }
+}
+
+impl<T> Deref for MockVec<T> {
+ type Target = [T];
+ fn deref(&self) -> &[T] { &self.value }
+}
+
+impl<T> DerefMut for MockVec<T> {
+ fn deref_mut(&mut self) -> &mut [T] { &mut self.value }
+}
+
+
union U {
- x: ((Vec<u8>, Vec<u8>), Vec<u8>),
- y: Box<Vec<u8>>,
+ x: ((MockVec<u8>, MockVec<u8>), MockVec<u8>),
+ y: MockBox<MockVec<u8>>,
}
fn use_borrow<T>(_: &T) {}
unsafe fn parent_sibling_borrow() {
- let mut u = U { x: ((Vec::new(), Vec::new()), Vec::new()) };
+ let mut u = U { x: ((MockVec::new(), MockVec::new()), MockVec::new()) };
let a = &mut u.x.0;
let b = &u.y; //~ ERROR cannot borrow `u` (via `u.y`)
use_borrow(a);
}
unsafe fn parent_sibling_move() {
- let u = U { x: ((Vec::new(), Vec::new()), Vec::new()) };
+ let u = U { x: ((MockVec::new(), MockVec::new()), MockVec::new()) };
let a = u.x.0;
let b = u.y; //~ ERROR use of moved value: `u`
}
unsafe fn grandparent_sibling_borrow() {
- let mut u = U { x: ((Vec::new(), Vec::new()), Vec::new()) };
+ let mut u = U { x: ((MockVec::new(), MockVec::new()), MockVec::new()) };
let a = &mut (u.x.0).0;
let b = &u.y; //~ ERROR cannot borrow `u` (via `u.y`)
use_borrow(a);
}
unsafe fn grandparent_sibling_move() {
- let u = U { x: ((Vec::new(), Vec::new()), Vec::new()) };
+ let u = U { x: ((MockVec::new(), MockVec::new()), MockVec::new()) };
let a = (u.x.0).0;
let b = u.y; //~ ERROR use of moved value: `u`
}
unsafe fn deref_sibling_borrow() {
- let mut u = U { y: Box::default() };
+ let mut u = U { y: MockBox::default() };
let a = &mut *u.y;
let b = &u.x; //~ ERROR cannot borrow `u` (via `u.x`)
use_borrow(a);
}
unsafe fn deref_sibling_move() {
- let u = U { x: ((Vec::new(), Vec::new()), Vec::new()) };
- let a = *u.y;
- let b = u.x; //~ ERROR use of moved value: `u`
+ let u = U { x: ((MockVec::new(), MockVec::new()), MockVec::new()) };
+ // No way to test deref-move without Box in union
+ // let a = *u.y;
+ // let b = u.x; ERROR use of moved value: `u`
}