How can I call a mutating method while holding a reference to
self
(e.g. from within afor
-loop)?
You can’t, that’s exactly what the borrowing rules prevent.
The main idea is that in your code, the borrow checker cannot possibly know that self.modify_self_but_not_xxx(..)
will not modify xxx
.
However, you can mutate self.yyy
or any other parameters, so either you can:
- do the computations of
modify_self_but_not_xxx(..)
directly in your loop body -
define a helper function taking mutable references to update them:
fn do_computations(item: Foo, a: &mut Bar, b: &mut Baz) { /* ... */ } /* ... */ for item in self.xxx.iter() { do_computations(item, &mut self.bar, &mut self.baz); }
- define a helper struct that has helper methods