diff options
Diffstat (limited to 'tests/ui/dyn-star/dispatch-on-pin-mut.rs')
-rw-r--r-- | tests/ui/dyn-star/dispatch-on-pin-mut.rs | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/tests/ui/dyn-star/dispatch-on-pin-mut.rs b/tests/ui/dyn-star/dispatch-on-pin-mut.rs new file mode 100644 index 000000000..5774c8b2a --- /dev/null +++ b/tests/ui/dyn-star/dispatch-on-pin-mut.rs @@ -0,0 +1,52 @@ +// run-pass +// edition:2021 +// check-run-results + +#![feature(dyn_star)] +//~^ WARN the feature `dyn_star` is incomplete and may not be safe to use and/or cause compiler crashes + +use std::future::Future; + +async fn foo(f: dyn* Future<Output = i32>) { + println!("value: {}", f.await); +} + +async fn async_main() { + foo(Box::pin(async { 1 })).await +} + +// ------------------------------------------------------------------------- // +// Implementation Details Below... + +use std::pin::Pin; +use std::task::*; + +pub fn noop_waker() -> Waker { + let raw = RawWaker::new(std::ptr::null(), &NOOP_WAKER_VTABLE); + + // SAFETY: the contracts for RawWaker and RawWakerVTable are upheld + unsafe { Waker::from_raw(raw) } +} + +const NOOP_WAKER_VTABLE: RawWakerVTable = RawWakerVTable::new(noop_clone, noop, noop, noop); + +unsafe fn noop_clone(_p: *const ()) -> RawWaker { + RawWaker::new(std::ptr::null(), &NOOP_WAKER_VTABLE) +} + +unsafe fn noop(_p: *const ()) {} + +fn main() { + let mut fut = async_main(); + + // Poll loop, just to test the future... + let waker = noop_waker(); + let ctx = &mut Context::from_waker(&waker); + + loop { + match unsafe { Pin::new_unchecked(&mut fut).poll(ctx) } { + Poll::Pending => {} + Poll::Ready(()) => break, + } + } +} |