1error[E0499]: cannot borrow `*self` as mutable more than once at a time 2 --> $DIR/unboxed-closures-recursive-fn-using-fn-mut.rs:22:21 3 | 4LL | (self.func)(self, arg) 5 | ----------- ^^^^ second mutable borrow occurs here 6 | | 7 | first mutable borrow occurs here 8 | first borrow later used by call 9 10error: aborting due to previous error 11 12For more information about this error, try `rustc --explain E0499`. 13