mirror of https://github.com/rust-lang/rust
119 lines
2.4 KiB
Rust
119 lines
2.4 KiB
Rust
// Test that we don't duplicate storage for futures moved around in .await, and
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// for futures moved into other futures.
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//
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// The exact sizes can change by a few bytes (we'd like to know when they do).
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// What we don't want to see is the wrong multiple of 1024 (the size of BigFut)
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// being reflected in the size.
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//
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// See issue #59123 for a full explanation.
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//@ needs-unwind Size of Futures change on panic=abort
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//@ run-pass
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//@ edition:2018
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use std::future::Future;
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use std::pin::Pin;
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use std::task::{Context, Poll};
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const BIG_FUT_SIZE: usize = 1024;
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struct BigFut(#[allow(dead_code)] [u8; BIG_FUT_SIZE]);
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impl BigFut {
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fn new() -> Self {
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BigFut([0; BIG_FUT_SIZE])
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}
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}
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impl Drop for BigFut {
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fn drop(&mut self) {}
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}
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impl Future for BigFut {
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type Output = ();
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fn poll(self: Pin<&mut Self>, _ctx: &mut Context<'_>) -> Poll<Self::Output> {
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Poll::Ready(())
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}
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}
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#[allow(dead_code)]
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struct Joiner {
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a: Option<BigFut>,
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b: Option<BigFut>,
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c: Option<BigFut>,
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}
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impl Future for Joiner {
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type Output = ();
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fn poll(self: Pin<&mut Self>, _ctx: &mut Context<'_>) -> Poll<Self::Output> {
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Poll::Ready(())
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}
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}
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fn noop() {}
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async fn single() {
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let x = BigFut::new();
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x.await;
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}
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async fn single_with_noop() {
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let x = BigFut::new();
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noop();
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x.await;
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}
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async fn joined() {
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let a = BigFut::new();
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let b = BigFut::new();
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let c = BigFut::new();
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let joiner = Joiner {
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a: Some(a),
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b: Some(b),
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c: Some(c),
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};
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joiner.await
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}
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async fn joined_with_noop() {
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let a = BigFut::new();
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let b = BigFut::new();
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let c = BigFut::new();
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let joiner = Joiner {
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a: Some(a),
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b: Some(b),
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c: Some(c),
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};
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noop();
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joiner.await
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}
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async fn mixed_sizes() {
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let a = BigFut::new();
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let b = BigFut::new();
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let c = BigFut::new();
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let d = BigFut::new();
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let e = BigFut::new();
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let joiner = Joiner {
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a: Some(a),
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b: Some(b),
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c: Some(c),
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};
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d.await;
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e.await;
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joiner.await;
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}
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fn main() {
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assert_eq!(1025, std::mem::size_of_val(&single()));
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assert_eq!(1026, std::mem::size_of_val(&single_with_noop()));
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assert_eq!(3076, std::mem::size_of_val(&joined()));
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assert_eq!(3076, std::mem::size_of_val(&joined_with_noop()));
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assert_eq!(6157, std::mem::size_of_val(&mixed_sizes()));
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}
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