src/test/ui/async-await/issues/issue-65419/issue-65419-async-fn-resume-after-panic.rs

   1 // issue 65419 - Attempting to run an async fn after completion mentions generators when it should
   2 // be talking about `async fn`s instead. Should also test what happens when it panics.
   3
   4 // run-fail
   5 // error-pattern: thread 'main' panicked at '`async fn` resumed after panicking'
   6 // edition:2018
   7 // ignore-wasm no panic or subprocess support
   8 // ignore-emscripten no panic or subprocess support
   9
  10 #![feature(generators, generator_trait)]
  11
  12 use std::panic;
  13
  14 async fn foo() {
  15     panic!();
  16 }
  17
  18 fn main() {
  19     let mut future = Box::pin(foo());
  20     panic::catch_unwind(panic::AssertUnwindSafe(|| {
  21         executor::block_on(future.as_mut());
  22     }));
  23
  24     executor::block_on(future.as_mut());
  25 }
  26
  27 mod executor {
  28     use core::{
  29         future::Future,
  30         pin::Pin,
  31         task::{Context, Poll, RawWaker, RawWakerVTable, Waker},
  32     };
  33
  34     pub fn block_on<F: Future>(mut future: F) -> F::Output {
  35         let mut future = unsafe { Pin::new_unchecked(&mut future) };
  36
  37         static VTABLE: RawWakerVTable = RawWakerVTable::new(
  38             |_| unimplemented!("clone"),
  39             |_| unimplemented!("wake"),
  40             |_| unimplemented!("wake_by_ref"),
  41             |_| (),
  42         );
  43         let waker = unsafe { Waker::from_raw(RawWaker::new(core::ptr::null(), &VTABLE)) };
  44         let mut context = Context::from_waker(&waker);
  45
  46         loop {
  47             if let Poll::Ready(val) = future.as_mut().poll(&mut context) {
  48                 break val;
  49             }
  50         }
  51     }
  52 }