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`. |