rust - Cannot borrow `*self` as mutable because `self.history[..]` is also borrowed as immutable` -

the code following, in function implementation context struct, defined following:

struct context {     lines: isize,     buffer: vec<string>,     history: vec<box<instruction>>, } 

and function, of course implementation:

fn _execute_history(&mut self, instruction: &instruction) -> reaction {     let num = instruction.suffix.parse::<usize>();     match num {         ok(number) => {             match self.history.get(number) {                 some(ins) => { return self.execute(*ins); },                 _         => { /* error handling */ }             }         }         err(..) => { /* error handling */ }     } } 

this doesn't compile , don't understand error message. searched online similar problems , cannot seem grasp problem here. python background. full error:

hello.rs:72:23: 72:35 note: previous borrow of `self.history[..]` occurs here; immutable borrow prevents subsequent moves or mutable borrows of `self.history[..]` until borrow ends 

i aware function not conforming type system, because simplified code demonstrative purposes only.

you borrow value self.history get , borrow still "alive" when call execute on self (that requires &mut self can see error)

in case return value match , call self.execute after match:

fn _execute_history(&mut self, instruction: &instruction) -> reaction {     let num = instruction.suffix.parse::<usize>();     let ins = match num {         ok(number) => {             match self.history.get(number) {                 some(ins) => ins.clone(),                 _         => { /* error handling */ panic!() }             }         }         err(..) => { /* error handling */ panic!() }     };     self.execute(ins) }