Hashmap in a struct

help
1

i use a hashmap to store data in a struct, like this:

struct A {
}



struct B {
members: HashMap<u32, A>
}

impl B {

/// do something by key
fn fn_a(&mut self, key: u32) {
  let value = self.members.get_mut(&key).unwrap(); // 

  /// do something

  self.fn_b(); // no problem

 // depending on value, need to call fn_c to modify other data.
  self.fn_c(); // problem arise: E0499/E0502

}

fn fn_b(&self) {
}

fn fn_c(&mut self) {

}



}

when calling fn_c in fn_a, the E0499: brrow as mutable more than once at a time comes out.

My problem is not why E0499 comes out, but how to deal with problem in this case:

in a function, i have to modify data stored in a map, but also, i need to call another function to modify other data depend on this data, but in a E0499 restriction, how to do this.

2

Your minimized example compiles, so it's hard to give specific advice, but the scenario sounds like an interprocedural conflict more generally. The post covers some workarounds.

1 Like
3

thanks for your reply.
figured out how to deal with this case.

4

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