mirror of https://github.com/rust-lang/rust
32 lines
1.1 KiB
Rust
32 lines
1.1 KiB
Rust
//@ edition:2018
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fn is_unwindsafe(_: impl std::panic::UnwindSafe) {}
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fn main() {
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// A normal future created by an async block takes a `&mut Context<'_>` argument.
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// That should not leak through to the whole async block.
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is_unwindsafe(async {
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async {}.await; // this needs an inner await point
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});
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is_unwindsafe(async {
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//~^ ERROR the type `&mut Context<'_>` may not be safely transferred across an unwind boundary
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//~| ERROR the type `&mut (dyn Any + 'static)` may not be safely transferred across an unwind boundary
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use std::ptr::null;
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use std::task::{Context, RawWaker, RawWakerVTable, Waker};
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let waker = unsafe {
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Waker::from_raw(RawWaker::new(
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null(),
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&RawWakerVTable::new(|_| todo!(), |_| todo!(), |_| todo!(), |_| todo!()),
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))
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};
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let mut cx = Context::from_waker(&waker);
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let cx_ref = &mut cx;
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async {}.await; // this needs an inner await point
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// in this case, `&mut Context<'_>` is *truly* alive across an await point
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drop(cx_ref);
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});
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}
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