22 lines
817 B
Rust
22 lines
817 B
Rust
// This test is intended to guard against the problem described in commit
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// 39bb1254d1eaf74f45a4e741097e33fc942168d5.
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//
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// As written, it might be considered UB in compiled Rust, but of course Miri gives it a safe,
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// deterministic behaviour (one that might not correspond with how an eventual Rust spec would
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// defined this).
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//
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// An alternative way to write the test without `unsafe` would be to use `Cell<i32>`, but it would
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// only surface the bug described by the above commit if `Cell<i32>` on the stack got represented
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// as a primitive `PrimVal::I32` which is not yet the case.
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fn main() {
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let mut x = 0;
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let y: *const i32 = &x;
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x = 1;
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// When the described bug is in place, this results in `0`, not observing the `x = 1` line.
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assert_eq!(unsafe { *y }, 1);
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assert_eq!(x, 1);
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}
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