34 lines
901 B
Rust
34 lines
901 B
Rust
#[derive(PartialEq, Debug)]
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struct A;
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fn zst_ret() -> A {
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A
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}
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fn use_zst() -> A {
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let a = A;
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a
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}
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fn main() {
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// Not using the () type here, as writes of that type do not even have MIR generated.
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// Also not assigning directly as that's array initialization, not assignment.
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let zst_val = [1u8; 0];
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assert_eq!(zst_ret(), A);
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assert_eq!(use_zst(), A);
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let x = 42 as *mut [u8; 0];
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// reading and writing is okay
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unsafe { *x = zst_val; }
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unsafe { let _y = *x; }
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// We should even be able to use "true" pointers for ZST when the allocation has been
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// removed already. The box is for a non-ZST to make sure there actually is an allocation.
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let mut x_box = Box::new(((), 1u8));
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let x = &mut x_box.0 as *mut _ as *mut [u8; 0];
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drop(x_box);
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// reading and writing is okay
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unsafe { *x = zst_val; }
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unsafe { let _y = *x; }
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}
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