| error[E0502]: cannot borrow `foo` as mutable because it is also borrowed as immutable | |
| --> $DIR/borrowck-issue-49631.rs:20:9 | |
| | | |
| LL | while let Some(Ok(string)) = foo.get() { | |
| | --- immutable borrow occurs here | |
| LL | foo.mutate(); | |
| | ^^^ mutable borrow occurs here | |
| LL | | |
| LL | println!("foo={:?}", *string); | |
| | ------- immutable borrow later used here | |
| error: aborting due to previous error | |
| For more information about this error, try `rustc --explain E0502`. |