32 lines
645 B
Rust
32 lines
645 B
Rust
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#![allow(suspicious_auto_trait_impls)]
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struct Always<T, U>(T, U);
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unsafe impl<T, U> Send for Always<T, U> {}
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struct Foo<T, U>(Always<T, U>);
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trait False {}
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unsafe impl<U: False> Send for Foo<u32, U> {}
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trait WithAssoc {
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type Output;
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}
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impl<T: Send> WithAssoc for T {
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type Output = Self;
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}
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impl WithAssoc for Foo<u32, ()> {
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type Output = Box<i32>;
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}
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fn generic<T, U>(v: Foo<T, U>, f: fn(<Foo<T, U> as WithAssoc>::Output) -> i32) {
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//~^ ERROR `Foo<T, U>` cannot be sent between threads safely
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f(foo(v));
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}
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fn foo<T: Send>(x: T) -> <T as WithAssoc>::Output {
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x
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}
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fn main() {
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generic(Foo(Always(0, ())), |b| *b);
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}
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