Cannot access struct field when using Borrow constraint

user_6206458 0
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Why I cannot access path field? Can I do something with that?

use std::borrow::Borrow;

struct Node{
    path: String,
}

fn foo<T: Borrow<Node>>(a: T) {
    let x = a.path;
}

fn main(){
    let node = Node {path:"test".to_string()};
    foo(&node);
    foo(&mut node);
}

error[E0609]: no field `path` on type `T`
 --> src/main.rs:8:15
  |
7 | fn foo<T: Borrow<Node>>(a: T) {
  |        - type parameter 'T' declared here
8 |     let x = a.path;
  |               ^^^^

code on rust playground

rust
1 Answers

The Borrow trait does not provide any syntactical sugar, it simply defines a borrow() method that returns the &T. So getting the path field would be:

a.borrow().path

With that said, you may also be interested in the Deref trait, which does have syntactical sugar to access the field directly:

fn foo<T: Deref<Target = Node>>(a: T) {
    let x = a.path.clone();
}

See it working on the playground.

user_21891300
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