rust/tests/ui/union/union-deref.rs

Ignoring revisions in .git-blame-ignore-revs. Click here to bypass and see the normal blame view.

30 lines
1.4 KiB
Rust
Raw Normal View History

// revisions: mirunsafeck thirunsafeck
// [thirunsafeck]compile-flags: -Z thir-unsafeck
2020-08-16 03:07:33 -05:00
//! Test the part of RFC 2514 that is about not applying `DerefMut` coercions
//! of union fields.
use std::mem::ManuallyDrop;
union U1<T> { x:(), f: ManuallyDrop<(T,)> }
union U2<T> { x:(), f: (ManuallyDrop<(T,)>,) }
2020-08-16 03:07:33 -05:00
fn main() {
let mut u : U1<Vec<i32>> = U1 { x: () };
2020-08-16 03:07:33 -05:00
unsafe { (*u.f).0 = Vec::new() }; // explicit deref, this compiles
unsafe { u.f.0 = Vec::new() }; //~ERROR not automatically applying `DerefMut` on `ManuallyDrop` union field
unsafe { &mut (*u.f).0 }; // explicit deref, this compiles
unsafe { &mut u.f.0 }; //~ERROR not automatically applying `DerefMut` on `ManuallyDrop` union field
unsafe { (*u.f).0.push(0) }; // explicit deref, this compiles
unsafe { u.f.0.push(0) }; //~ERROR not automatically applying `DerefMut` on `ManuallyDrop` union field
let mut u : U2<Vec<i32>> = U2 { x: () };
unsafe { (*u.f.0).0 = Vec::new() }; // explicit deref, this compiles
unsafe { u.f.0.0 = Vec::new() }; //~ERROR not automatically applying `DerefMut` on `ManuallyDrop` union field
unsafe { &mut (*u.f.0).0 }; // explicit deref, this compiles
unsafe { &mut u.f.0.0 }; //~ERROR not automatically applying `DerefMut` on `ManuallyDrop` union field
unsafe { (*u.f.0).0.push(0) }; // explicit deref, this compiles
unsafe { u.f.0.0.push(0) }; //~ERROR not automatically applying `DerefMut` on `ManuallyDrop` union field
2020-08-16 03:07:33 -05:00
}