41 lines
1.6 KiB
Rust
41 lines
1.6 KiB
Rust
//@ stderr-per-bitwidth
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//@ compile-flags: -Zunleash-the-miri-inside-of-you
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// All "inner" allocations that come with a `static` are interned immutably. This means it is
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// crucial that we do not accept any form of (interior) mutability there.
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use std::sync::atomic::*;
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static REF: &AtomicI32 = &AtomicI32::new(42);
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//~^ ERROR it is undefined behavior to use this value
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static REFMUT: &mut i32 = &mut 0;
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//~^ ERROR it is undefined behavior to use this value
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// Different way of writing this that avoids promotion.
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static REF2: &AtomicI32 = {let x = AtomicI32::new(42); &{x}};
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//~^ ERROR it is undefined behavior to use this value
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static REFMUT2: &mut i32 = {let mut x = 0; &mut {x}};
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//~^ ERROR it is undefined behavior to use this value
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// This one is obvious, since it is non-Sync. (It also suppresses the other errors, so it is
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// commented out.)
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// static RAW: *const AtomicI32 = &AtomicI32::new(42);
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struct SyncPtr<T> { x : *const T }
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unsafe impl<T> Sync for SyncPtr<T> {}
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// All of these pass the lifetime checks because of the "tail expression" / "outer scope" rule.
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// (This relies on `SyncPtr` being a curly brace struct.)
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// Then they get interned immutably, which is not great. See
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// <https://github.com/rust-lang/rust/pull/128543> for why we accept such code.
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static RAW_SYNC: SyncPtr<AtomicI32> = SyncPtr { x: &AtomicI32::new(42) };
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// With mutable references at least, we can detect this and error.
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static RAW_MUT_CAST: SyncPtr<i32> = SyncPtr { x : &mut 42 as *mut _ as *const _ };
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//~^ ERROR mutable pointer in final value
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static RAW_MUT_COERCE: SyncPtr<i32> = SyncPtr { x: &mut 0 };
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//~^ ERROR mutable pointer in final value
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fn main() {}
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