39 lines
1.1 KiB
Rust
39 lines
1.1 KiB
Rust
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// check-pass
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// known-bug: #49206
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// Should fail. Compiles and prints 2 identical addresses, which shows 2 threads
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// with the same `'static` reference to non-`Sync` struct. The problem is that
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// promotion to static does not check if the type is `Sync`.
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#[allow(dead_code)]
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#[derive(Debug)]
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struct Foo {
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value: u32,
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}
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// stable negative impl trick from https://crates.io/crates/negative-impl
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// see https://github.com/taiki-e/pin-project/issues/102#issuecomment-540472282
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// for details.
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struct Wrapper<'a, T>(::std::marker::PhantomData<&'a ()>, T);
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unsafe impl<T> Sync for Wrapper<'_, T> where T: Sync {}
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unsafe impl<'a> std::marker::Sync for Foo where Wrapper<'a, *const ()>: Sync {}
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fn _assert_sync<T: Sync>() {}
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fn inspect() {
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let foo: &'static Foo = &Foo { value: 1 };
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println!(
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"I am in thread {:?}, address: {:p}",
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std::thread::current().id(),
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foo as *const Foo,
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);
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}
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fn main() {
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// _assert_sync::<Foo>(); // uncomment this line causes compile error
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// "`*const ()` cannot be shared between threads safely"
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let handle = std::thread::spawn(inspect);
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inspect();
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handle.join().unwrap();
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}
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