error[E0277]: the type `&mut Context<'_>` may not be safely transferred across an unwind boundary --> $DIR/async-is-unwindsafe.rs:12:19 | LL | is_unwindsafe(async { | ___________________^ LL | | LL | | use std::ptr::null; LL | | use std::task::{Context, RawWaker, RawWakerVTable, Waker}; ... | LL | | drop(cx_ref); LL | | }); | | ^ | | | | |_____`&mut Context<'_>` may not be safely transferred across an unwind boundary | within this `[async block@$DIR/async-is-unwindsafe.rs:12:19: 29:6]` | = help: within `[async block@$DIR/async-is-unwindsafe.rs:12:19: 29:6]`, the trait `UnwindSafe` is not implemented for `&mut Context<'_>` = note: `UnwindSafe` is implemented for `&std::task::Context<'_>`, but not for `&mut std::task::Context<'_>` note: future does not implement `UnwindSafe` as this value is used across an await --> $DIR/async-is-unwindsafe.rs:25:18 | LL | let cx_ref = &mut cx; | ------ has type `&mut Context<'_>` which does not implement `UnwindSafe` LL | LL | async {}.await; // this needs an inner await point | ^^^^^ await occurs here, with `cx_ref` maybe used later ... LL | }); | - `cx_ref` is later dropped here note: required by a bound in `is_unwindsafe` --> $DIR/async-is-unwindsafe.rs:3:26 | LL | fn is_unwindsafe(_: impl std::panic::UnwindSafe) {} | ^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `is_unwindsafe` error: aborting due to previous error For more information about this error, try `rustc --explain E0277`.