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#![allow(unused)]
// This tests the error messages for borrows of union fields when the unions are embedded in other
// structs or unions.
#[derive(Clone, Copy, Default)]
struct Leaf {
l1_u8: u8,
l2_u8: u8,
}
#[derive(Clone, Copy)]
union First {
f1_leaf: Leaf,
f2_leaf: Leaf,
f3_union: Second,
}
#[derive(Clone, Copy)]
union Second {
s1_leaf: Leaf,
s2_leaf: Leaf,
}
struct Root {
r1_u8: u8,
r2_union: First,
}
// Borrow a different field of the nested union.
fn nested_union() {
unsafe {
let mut r = Root {
r1_u8: 3,
r2_union: First { f3_union: Second { s2_leaf: Leaf { l1_u8: 8, l2_u8: 4 } } }
};
let mref = &mut r.r2_union.f3_union.s1_leaf.l1_u8;
// ^^^^^^^
*mref = 22;
let nref = &r.r2_union.f3_union.s2_leaf.l1_u8;
// ^^^^^^^
//~^^ ERROR cannot borrow `r.r2_union.f3_union` (via `r.r2_union.f3_union.s2_leaf.l1_u8`) as immutable because it is also borrowed as mutable (via `r.r2_union.f3_union.s1_leaf.l1_u8`) [E0502]
println!("{} {}", mref, nref)
}
}
// Borrow a different field of the first union.
fn first_union() {
unsafe {
let mut r = Root {
r1_u8: 3,
r2_union: First { f3_union: Second { s2_leaf: Leaf { l1_u8: 8, l2_u8: 4 } } }
};
let mref = &mut r.r2_union.f2_leaf.l1_u8;
// ^^^^^^^
*mref = 22;
let nref = &r.r2_union.f1_leaf.l1_u8;
// ^^^^^^^
//~^^ ERROR cannot borrow `r.r2_union` (via `r.r2_union.f1_leaf.l1_u8`) as immutable because it is also borrowed as mutable (via `r.r2_union.f2_leaf.l1_u8`) [E0502]
println!("{} {}", mref, nref)
}
}
fn main() {}
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