1 error[E0507]: cannot move out of `*cb` which is behind a mutable reference
2 --> $DIR/suggest-as-ref-on-mut-closure.rs:7:5
4 LL | cb.map(|cb| cb());
7 | | `*cb` moved due to this method call
8 | help: consider calling `.as_ref()` or `.as_mut()` to borrow the type's contents
9 | move occurs because `*cb` has type `Option<&mut dyn FnMut()>`, which does not implement the `Copy` trait
11 note: `Option::<T>::map` takes ownership of the receiver `self`, which moves `*cb`
12 --> $SRC_DIR/core/src/option.rs:LL:COL
14 error[E0596]: cannot borrow `*cb` as mutable, as it is behind a `&` reference
15 --> $DIR/suggest-as-ref-on-mut-closure.rs:12:26
17 LL | cb.as_ref().map(|cb| cb());
18 | -- ^^ `cb` is a `&` reference, so the data it refers to cannot be borrowed as mutable
20 | consider changing this binding's type to be: `&mut &mut dyn FnMut()`
22 error: aborting due to 2 previous errors
24 Some errors have detailed explanations: E0507, E0596.
25 For more information about an error, try `rustc --explain E0507`.