Suggest Arc::unwrap_or_clone() when appropriate

[cdisselkoen]

What it does

Suppose foo is an Arc<T>. The lint would suggest replacing things like (*foo).clone() with Arc::unwrap_or_clone(foo).

Advantage

As noted in the official docs on Arc::unwrap_or_clone, this is entirely equivalent except that it avoids cloning in the case this was already the last reference to the Arc.

Drawbacks

Arc::unwrap_or_clone was only stabilized in Rust 1.76, I'm not sure if Clippy avoids making suggestions that require recent Rust for some definition of "recent".

Example

let foo: Arc<String> = Arc::new("foo".into());
let bar: String = (*foo).clone();

Could be written as:

let foo: Arc<String> = Arc::new("foo".into());
let bar: String = Arc::unwrap_or_clone(foo);

[y21]

Arc::unwrap_or_clone was only stabilized in Rust 1.76, I'm not sure if Clippy avoids making suggestions that require recent Rust for some definition of "recent".

The MSRV for lints can be configured, so this should be fine as long as the lint respects that.

[lukaslueg]

Same for Rc::unwrap_or_clone