Can I retrieve an associated type of the implemenattion of a trait?

Question

Given the following trait:

trait Trait { type Associated; }

and an impelmentation:

struct Struct {}
impl Trait for Struct { type Associated = u32; }

I would like to retrieve the associated type Associated of Struct. Somehting like (Struct as Trait is invalid rust):

struct AnotherStruct {
   prop: (Struct as Trait)::Associated
}

Is there any way to retrieve the asscoiated type?

Note that I am aware that I can impelment a function like:

fn f<T: Trait>(arg: T::Associated) -> T::Associated { arg }

However, I would like to get the associaetd type to set the type of a struct property.

Answer 1

You were so close. The correct fully qualified syntax is <Type as Trait>::AssociatedType. You can read more about it in The Book.

Your example should look like this.

trait Trait {
    type Associated;
}

struct Struct {}

impl Trait for Struct {
    type Associated = u32;
}

struct AnotherStruct {
   prop: <Struct as Trait>::Associated
}