[rust] How to avoid leaking trait bounds (to avoid such changes to be breaking changes)

containers-and-clone.rs

// https://rust-lang.github.io/api-guidelines/future-proofing.html

/*
The following traits should never be used in bounds on data structures:

* Clone
…
*/

#[derive(Clone, Debug)]
pub struct Item(i32);

// not good:
#[derive(Clone, Debug)]
pub struct LeakyContainer<T: Clone> {
    pub items: Vec<T>,
}

impl<T: Clone> LeakyContainer<T> {
    pub fn new(items: &[T]) -> Self {
        Self {
            // .to_vec requires T to be Clone;
            // this trait bound then starts leaking to the outside
            items: items.to_vec(),
        }
    }
}

// good:
#[derive(Clone, Debug)]
pub struct SolidContainer<T> {
    pub items: Vec<T>,
}

impl<T> SolidContainer<T> {
    pub fn new<I: Into<Vec<T>>>(items: I) -> Self {
        Self {
            items: items.into(),
        }
    }
}

fn main() {
    let items = [Item(1), Item(2), Item(3)];

    let leaky = LeakyContainer::new(&items[..]);
    let solid = SolidContainer::new(&items[..]);

    println!("{leaky:?}\n{solid:?}");
}

https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=64d26cd19a04a7cc28f5f8f1d8c45bfe