Compiler error - mismatched types when trying to implement a proxy pattern in rust - rust

Question

I trying to implement a proxy in Rust, allowing me to read a model, but also to perform mutable operations. To avoid having two different implementations of the proxy (one mutable, one immutable), I made the proxy implementation generic.
I would like the proxy to create other instances of self, in different situations, and this is where I got a type mismatch.
The code below reproduces the problem I have:
use std::borrow::{Borrow, BorrowMut};
struct Model {
data: Vec<u32>,
}
impl Model {
fn get_proxy(&self) -> Proxy<&Model> {
Proxy::new(self)
}
fn get_proxy_mut(&mut self) -> Proxy<&mut Model> {
Proxy::new(self)
}
}
struct Proxy<M: Borrow<Model>> {
model: M
}
impl<M: Borrow<Model>> Proxy<M> {
fn new(model: M) -> Self {
Self {model}
}
fn get_another(&self) -> Proxy<M> {
// FIRST ERROR here
self.model.borrow().get_proxy()
}
}
impl<M: BorrowMut<Model>> Proxy<M> {
fn get_another_mut(&mut self) -> Proxy<M> {
// SECOND ERROR here
self.model.borrow_mut().get_proxy_mut()
}
}
The first compiler error looks like
error[E0308]: mismatched types
--> src\sandbox.rs:28:9
|
21 | impl<'m, M: Borrow<Model>> Proxy<M> {
| - this type parameter
...
26 | fn get_another(&self) -> Proxy<M> {
| -------- expected `Proxy<M>` because of return type
27 | // FIRST ERROR here
28 | self.model.borrow().get_proxy()
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected type parameter `M`, found `&Model`
|
= note: expected struct `Proxy<M>`
found struct `Proxy<&Model>`
Any idea how to fix the first error? (I assume the second one will be fixed in a similar way).