False negative clone-on-copy

[p3s]

Hi folks,
I ran this code under Clippy:

fn foo() {
    let mut vec = Vec::new();
    let key = (0, 0);

    vec.push(key.clone());

    let _ = key.clone();
}

Clippy produced this error:

error: using `clone` on a `Copy` type
 --> src/lib.rs:7:13
  |
7 |     let _ = key.clone();
  |             ^^^^^^^^^^^ help: try removing the `clone` call: `key`
  |
  = note: `-D clippy::clone-on-copy` implied by `-D warnings`
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#clone_on_copy

I expected to see same error in vec.push(key.clone()) but Clippy is silent about it. After removing .clone() in line 5 it does compile fine, so I assume it is redundant.

Can someone explain to me what is the difference here?

Output of cargo clippy -V
clippy 0.0.212 (4ee1206 2020-02-01)