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68 lines
1.8 KiB
Rust
68 lines
1.8 KiB
Rust
#![allow(unused)]
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// This tests the error messages for borrows of union fields when the unions are embedded in other
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// structs or unions.
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#[derive(Clone, Copy, Default)]
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struct Leaf {
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l1_u8: u8,
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l2_u8: u8,
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}
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#[derive(Clone, Copy)]
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union First {
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f1_leaf: Leaf,
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f2_leaf: Leaf,
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f3_union: Second,
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}
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#[derive(Clone, Copy)]
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union Second {
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s1_leaf: Leaf,
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s2_leaf: Leaf,
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}
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struct Root {
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r1_u8: u8,
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r2_union: First,
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}
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// Borrow a different field of the nested union.
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fn nested_union() {
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unsafe {
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let mut r = Root {
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r1_u8: 3,
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r2_union: First { f3_union: Second { s2_leaf: Leaf { l1_u8: 8, l2_u8: 4 } } }
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};
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let mref = &mut r.r2_union.f3_union.s1_leaf.l1_u8;
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// ^^^^^^^
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*mref = 22;
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let nref = &r.r2_union.f3_union.s2_leaf.l1_u8;
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// ^^^^^^^
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//~^^ 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]
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println!("{} {}", mref, nref)
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}
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}
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// Borrow a different field of the first union.
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fn first_union() {
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unsafe {
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let mut r = Root {
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r1_u8: 3,
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r2_union: First { f3_union: Second { s2_leaf: Leaf { l1_u8: 8, l2_u8: 4 } } }
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};
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let mref = &mut r.r2_union.f2_leaf.l1_u8;
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// ^^^^^^^
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*mref = 22;
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let nref = &r.r2_union.f1_leaf.l1_u8;
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// ^^^^^^^
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//~^^ 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]
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println!("{} {}", mref, nref)
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}
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}
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fn main() {}
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