mirror of https://github.com/rust-lang/rust
58 lines
1.2 KiB
Rust
58 lines
1.2 KiB
Rust
//@ run-pass
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#![feature(trait_alias)]
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use std::marker::PhantomData;
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trait Empty {} //~ WARN trait `Empty` is never used
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trait EmptyAlias = Empty;
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trait CloneDefault = Clone + Default;
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trait SendSyncAlias = Send + Sync;
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trait WhereSendAlias = where Self: Send;
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trait SendEqAlias<T> = Send where T: PartialEq<Self>;
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trait I32Iterator = Iterator<Item = i32>;
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#[allow(dead_code)]
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struct Foo<T: SendSyncAlias>(PhantomData<T>);
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#[allow(dead_code)]
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struct Bar<T>(PhantomData<T>) where T: SendSyncAlias;
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impl dyn EmptyAlias {}
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impl<T: SendSyncAlias> Empty for T {}
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fn a<T: CloneDefault>() -> (T, T) {
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let one = T::default();
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let two = one.clone();
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(one, two)
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}
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fn b(x: &impl SendEqAlias<i32>) -> bool {
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22_i32 == *x
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}
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fn c<T: I32Iterator>(x: &mut T) -> Option<i32> {
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x.next()
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}
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fn d<T: SendSyncAlias>() {
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is_send_and_sync::<T>();
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}
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fn is_send_and_sync<T: Send + Sync>() {}
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fn main() {
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let both = a::<i32>();
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assert_eq!(both.0, 0);
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assert_eq!(both.1, 0);
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let both: (i32, i32) = a();
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assert_eq!(both.0, 0);
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assert_eq!(both.1, 0);
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assert!(b(&22));
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assert_eq!(c(&mut vec![22].into_iter()), Some(22));
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d::<i32>();
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}
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