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 | move occurs because `*cb` has type `Option<&mut dyn FnMut()>`, which does not implement the `Copy` trait
10 note: this function takes ownership of the receiver `self`, which moves `*cb`
11 --> $SRC_DIR/core/src/option.rs:LL:COL
13 LL | pub const fn map<U, F>(self, f: F) -> Option<U>
15 help: consider calling `.as_ref()` to borrow the type's contents
17 LL | cb.as_ref().map(|cb| cb());
20 error[E0596]: cannot borrow `*cb` as mutable, as it is behind a `&` reference
21 --> $DIR/suggest-as-ref-on-mut-closure.rs:12:26
23 LL | cb.as_ref().map(|cb| cb());
24 | -- ^^ `cb` is a `&` reference, so the data it refers to cannot be borrowed as mutable
26 | help: consider changing this to be a mutable reference: `&mut &mut dyn FnMut()`
28 error: aborting due to 2 previous errors
30 Some errors have detailed explanations: E0507, E0596.
31 For more information about an error, try `rustc --explain E0507`.