clippy::option_as_ref_cloned: cloning an `Option<_>` using `.as_ref().cloned()`

What you see

warning: cloning an `Option<_>` using `.as_ref().cloned()`
 --> main.rs:4:9
  |
4 |     bar.as_ref().cloned()
  |         ^^^^^^^^^^^^^^^
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/stable/index.html#option_as_ref_cloned
  = note: `-W clippy::option-as-ref-cloned` implied by `-W clippy::pedantic`
help: this can be written more concisely by cloning the `Option<_>` directly
  |
4 -     bar.as_ref().cloned()
4 +     bar.clone()
  |

Real output of Clippy 0.1.99 (Rust 1.99) on the example below. Names and line numbers in yours will differ.

Does it matter?

This can be written more concisely by cloning the Option directly.

Stricter lints with some false positives. Off by default; opt in with clippy::pedantic.

How to fix it

Clippy can fix this one for you: run cargo clippy --fix (add --allow-dirty if you have uncommitted changes). Review the diff before you commit.

Flagged

fn foo(bar: &Option<Vec<u8>>) -> Option<Vec<u8>> {
    bar.as_ref().cloned()
}

Write this instead

fn foo(bar: &Option<Vec<u8>>) -> Option<Vec<u8>> {
    bar.clone()
}

Turn it off, or on

It is off by default. To use it, set it to warn or deny:

[lints.clippy]
option_as_ref_cloned = "warn"

#![warn(clippy::option_as_ref_cloned)]

cargo clippy -- -W clippy::option-as-ref-cloned

The [lints] table needs Rust 1.74 or newer. In a workspace, put it under [workspace.lints.clippy] and add [lints] workspace = true to each member.