FP redundant_clone: x.clone(); that clones & consumes

Summary

.

Lint Name

redundant_clone

Reproducer

I tried this code:

// run-pass
#![allow(unused_must_use)]
#![allow(unused_imports)]
// pretty-expanded FIXME #23616
#![allow(deprecated)]

use std::hash::{Hash, SipHasher};

// testing multiple separate deriving attributes
#[derive(PartialEq)]
#[derive(Clone)]
#[derive(Hash)]
struct Foo {
    bar: usize,
    baz: isize
}

fn hash<T: Hash>(_t: &T) {}

pub fn main() {
    let a = Foo {bar: 4, baz: -3};

    a == a;    // check for PartialEq impl w/o testing its correctness
    a.clone(); // check for Clone impl w/o testing its correctness
    hash(&a);  // check for Hash impl w/o testing its correctness
}

I saw this happen:
cargo clippy --fix -- -Aclippy::all -Wclippy::redundant_clone

    Checking clpy v0.1.0 (/tmp/clpy)
warning: failed to automatically apply fixes suggested by rustc to crate `clpy`

after fixes were automatically applied the compiler reported errors within these files:

  * src/main.rs

This likely indicates a bug in either rustc or cargo itself,
and we would appreciate a bug report! You're likely to see
a number of compiler warnings after this message which cargo
attempted to fix but failed. If you could open an issue at
https://github.com/rust-lang/rust/issues
quoting the full output of this command we'd be very appreciative!
Note that you may be able to make some more progress in the near-term
fixing code with the `--broken-code` flag

The following errors were reported:
error[E0382]: borrow of moved value: `a`
  --> src/main.rs:25:10
   |
21 |     let a = Foo {bar: 4, baz: -3};
   |         - move occurs because `a` has type `Foo`, which does not implement the `Copy` trait
...
24 |     a; // check for Clone impl w/o testing its correctness
   |     - value moved here
25 |     hash(&a);  // check for Hash impl w/o testing its correctness
   |          ^^ value borrowed here after move

error: aborting due to previous error

For more information about this error, try `rustc --explain E0382`.
Original diagnostics will follow.

warning: redundant clone
  --> src/main.rs:24:6
   |
24 |     a.clone(); // check for Clone impl w/o testing its correctness
   |      ^^^^^^^^ help: remove this
   |
note: cloned value is neither consumed nor mutated
  --> src/main.rs:24:5
   |
24 |     a.clone(); // check for Clone impl w/o testing its correctness
   |     ^^^^^^^^^
   = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#redundant_clone
   = note: requested on the command line with `-W clippy::redundant-clone`

warning: `clpy` (bin "clpy") generated 1 warning (run `cargo fix --bin "clpy"` to apply 1 suggestion)
warning: `clpy` (bin "clpy" test) generated 1 warning (1 duplicate)
    Finished dev [unoptimized + debuginfo] target(s) in 1.21s

I expected to see this happen:

Version

rustc 1.67.0-nightly (c5d82ed7a 2022-11-19)
binary: rustc
commit-hash: c5d82ed7a4ad94a538bb87e5016e7d5ce0bd434b
commit-date: 2022-11-19
host: x86_64-unknown-linux-gnu
release: 1.67.0-nightly
LLVM version: 15.0.4

Additional Labels

No response

Start at the redundant_clone lint and reproduce the reported cargo clippy --fix command with the Rust example in this issue. Check that removing the suggested clone does not move a non-Copy value still used by hash(&a), then add a regression test and verify the fixed command no longer produces E0382.