1use std::hash::{Hash, Hasher}; 2 3#[derive(Eq, PartialEq, Debug)] 4pub struct MyType(pub i32); 5 6impl Hash for MyType { 7 fn hash<H: Hasher>(&self, state: &mut H) { 8 // New hash: reverse the value 9 (!self.0).hash(state); 10 } 11}