How to implement Eq and Hash for my own structs to use them as a HashMap key?

Question

I have two structs, A and B, and I want to use a HashMap. I have a piece of code like this:

use std::collec         


        

Answer 1

You can have the compiler derive these instances for you by inserting the following before your struct declaration:

#[derive(PartialEq, Eq, Hash)]
pub struct A {
    // ...
}

You could also implement them manually instead. If you want to do that, you should read the documentation on traits, Eq and Hash.