`clone_on_ref_ptr` adds an unnecessary `&`

[ada4a]

Summary

The lint turns rc.clone() into Rc::clone(&rc), even if rc is already a reference. That in turn causes clippy::needless_borrow to fire.

Reproducer

I tried this code:

#![allow(unused)]
#![warn(clippy::clone_on_ref_ptr)]

use std::rc::Rc;

fn foo(rc: &Rc<str>) {
    rc.clone();
}

I expected to see this happen:

 --> src/lib.rs:7:5
  |
7 |     rc.clone();
  |     ^^^^^^^^^^ help: try: `Rc::<str>::clone(rc)`
  |

Instead, this happened:

warning: using `.clone()` on a ref-counted pointer
 --> src/lib.rs:7:5
  |
7 |     rc.clone();
  |     ^^^^^^^^^^ help: try: `Rc::<str>::clone(&rc)`
  |

Version

rustc 1.92.0-nightly (f6092f224 2025-09-22)
binary: rustc
commit-hash: f6092f224d2b1774b31033f12d0bee626943b02f
commit-date: 2025-09-22
host: x86_64-unknown-linux-gnu
release: 1.92.0-nightly
LLVM version: 21.1.1

Additional Labels

@rustbot label -C-bug +C-enhancement

@rustbot claim