37 lines
939 B
Rust
37 lines
939 B
Rust
// stderr-per-bitwidth
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// compile-flags: -Zunleash-the-miri-inside-of-you
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use std::cell::UnsafeCell;
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// this test ensures that our mutability story is sound
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struct Meh {
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x: &'static UnsafeCell<i32>,
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}
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unsafe impl Sync for Meh {}
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// the following will never be ok! no interior mut behind consts, because
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// all allocs interned here will be marked immutable.
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const MUH: Meh = Meh { //~ ERROR: it is undefined behavior to use this value
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x: &UnsafeCell::new(42),
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};
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struct Synced {
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x: UnsafeCell<i32>,
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}
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unsafe impl Sync for Synced {}
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// Make sure we also catch this behind a type-erased `dyn Trait` reference.
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const SNEAKY: &dyn Sync = &Synced { x: UnsafeCell::new(42) };
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//~^ ERROR: it is undefined behavior to use this value
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// Make sure we also catch mutable references.
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const BLUNT: &mut i32 = &mut 42;
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//~^ ERROR: it is undefined behavior to use this value
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fn main() {
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unsafe {
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*MUH.x.get() = 99;
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}
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}
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