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// Check that constants with interior mutability inside unions are rejected
// during validation.
//
//@ build-fail
//@ stderr-per-bitwidth
use std::cell::Cell;
use std::mem::ManuallyDrop;
#[repr(C)]
struct S {
x: u32,
y: E,
}
#[repr(u32)]
enum E {
A,
B(U)
}
union U {
cell: ManuallyDrop<Cell<u32>>,
}
const C: S = {
let mut s = S { x: 0, y: E::A };
let p = &mut s.x as *mut u32;
// Change enum tag to E::B. Now there's interior mutability here.
unsafe { *p.add(1) = 1 };
s
};
fn main() { //~ ERROR it is undefined behavior to use this value
// FIXME the span here is wrong, sould be pointing at the line below, not above.
let _: &'static _ = &C;
}
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