error[E0277]: the type `UnsafeCell` may contain interior mutability and a reference may not be safely transferrable across a catch_unwind boundary --> $DIR/not-panic-safe-3.rs:10:14 | LL | assert::>>(); | ^^^^^^^^^^^^^^^^^ `UnsafeCell` may contain interior mutability and a reference may not be safely transferrable across a catch_unwind boundary | = help: within `RefCell`, the trait `RefUnwindSafe` is not implemented for `UnsafeCell` = note: required because it appears within the type `RefCell` = note: required for `Arc>` to implement `UnwindSafe` note: required by a bound in `assert` --> $DIR/not-panic-safe-3.rs:7:14 | LL | fn assert() {} | ^^^^^^^^^^ required by this bound in `assert` error[E0277]: the type `UnsafeCell` may contain interior mutability and a reference may not be safely transferrable across a catch_unwind boundary --> $DIR/not-panic-safe-3.rs:10:14 | LL | assert::>>(); | ^^^^^^^^^^^^^^^^^ `UnsafeCell` may contain interior mutability and a reference may not be safely transferrable across a catch_unwind boundary | = help: within `RefCell`, the trait `RefUnwindSafe` is not implemented for `UnsafeCell` = note: required because it appears within the type `Cell` = note: required because it appears within the type `RefCell` = note: required for `Arc>` to implement `UnwindSafe` note: required by a bound in `assert` --> $DIR/not-panic-safe-3.rs:7:14 | LL | fn assert() {} | ^^^^^^^^^^ required by this bound in `assert` error: aborting due to 2 previous errors For more information about this error, try `rustc --explain E0277`.