error[E0499]: cannot borrow `*heap` as mutable more than once at a time --> $DIR/issue-85581.rs:9:22 | LL | match heap.peek_mut() { | --------------- | | | first mutable borrow occurs here | a temporary with access to the first borrow is created here ... LL | Some(_) => { heap.pop(); }, | ^^^^ second mutable borrow occurs here ... LL | } | - ... and the first borrow might be used here, when that temporary is dropped and runs the destructor for type `Option>` error: aborting due to previous error For more information about this error, try `rustc --explain E0499`.