mirror of https://github.com/rust-lang/rust
32 lines
616 B
Rust
32 lines
616 B
Rust
#[derive(Clone, Copy)]
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struct S {
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a: u8,
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b: u16,
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}
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#[derive(Clone, Copy)]
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union U {
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s: S,
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c: u32,
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}
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fn main() {
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unsafe {
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{
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let mut u = U { s: S { a: 0, b: 1 } };
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let ra = &mut u.s.a;
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let b = u.s.b; // OK
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ra.use_mut();
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}
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{
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let mut u = U { s: S { a: 0, b: 1 } };
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let ra = &mut u.s.a;
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let b = u.c; //~ ERROR cannot use `u.c` because it was mutably borrowed
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ra.use_mut();
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}
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}
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}
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trait Fake { fn use_mut(&mut self) { } fn use_ref(&self) { } }
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impl<T> Fake for T { }
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