#[derive(Clone)] always require generic arguments to be Clone, which is too restrictive

[VFLashM]

[derive(Clone)] should not require generic arguments to be Clone if it's not necessary.

use std::rc::Rc;

struct S;

#[derive(Clone)]
struct Works(Rc<S>);

#[derive(Clone)]
struct Fails<T>(Rc<T>);

fn main() {
    let w = Works(Rc::new(S));
    w.clone(); // ok

    let f = Fails(Rc::new(S));
    f.clone(); // fails
}

[Stebalien]

Duplicate of #26925

[bluss]

Thank you @VFLashM; closing as a dup.