cloned_instead_of_copied fails to respect msrv

[dtolnay]

// src/main.rs

#![deny(clippy::pedantic)]

fn main() {
    let _ = Some(()).iter().cloned();
}

# .clippy.toml

msrv = "1.35.0"

$ cargo clippy

error: used `cloned` where `copied` could be used instead
 --> src/main.rs:4:29
  |
4 |     let _ = Some(()).iter().cloned();
  |                             ^^^^^^ help: try: `copied`
  |
note: the lint level is defined here
 --> src/main.rs:1:9
  |
1 | #![deny(clippy::pedantic)]
  |         ^^^^^^^^^^^^^^^^
  = note: `#[deny(clippy::cloned_instead_of_copied)]` implied by `#[deny(clippy::pedantic)]`
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#cloned_instead_of_copied

However, Clippy's suggested replacement involving .copied() does not compile on rustc 1.35.0.

error[E0658]: use of unstable library feature 'iter_copied' (see issue #57127)
 --> src/main.rs:4:29
  |
4 |     let _ = Some(()).iter().copied();
  |                             ^^^^^^

@camsteffen @Manishearth

Meta

• cargo clippy -V: clippy 0.1.53 (42816d6 2021-04-24)
• rustc -Vv:

  rustc 1.53.0-nightly (42816d61e 2021-04-24)
  binary: rustc
  commit-hash: 42816d61ead7e46d462df997958ccfd514f8c21c
  commit-date: 2021-04-24
  host: x86_64-unknown-linux-gnu
  release: 1.53.0-nightly
  LLVM version: 12.0.0