error[E0277]: the type `&mut i32` may not be safely transferred across an unwind boundary
  --> $DIR/not-panic-safe.rs:9:5
   |
LL |     assert::<&mut i32>();
   |     ^^^^^^^^^^^^^^^^^^ `&mut i32` may not be safely transferred across an unwind boundary
   |
   = help: the trait `UnwindSafe` is not implemented for `&mut i32`
   = note: `UnwindSafe` is implemented for `&i32`, but not for `&mut i32`
note: required by a bound in `assert`
  --> $DIR/not-panic-safe.rs:6:14
   |
LL | fn assert<T: UnwindSafe + ?Sized>() {}
   |              ^^^^^^^^^^ required by this bound in `assert`

error: aborting due to previous error

For more information about this error, try `rustc --explain E0277`.