Rust-clippy: lint type `&Option<&T>`

[oli-obk]

since & is Copy, just suggest to use Option<&T>

[clarfonthey]

This applies to &mut Option<&mut T> too, because as_ref and as_mut exist. Ditto for Result.

[shepmaster]

This applies to &mut Option<&mut T> too

Does it though? With a &mut Option<T>, I could mem::replace or mem::swap it with a completely different option, or call Option::take on it, which does the same thing internally.

[clarfonthey]

@shepmaster I think you misunderstood; &mut Option<&mut T> should be written as Option<&mut T>, not &mut Option<T>. This is very similar to writing &&T instead of &T.

[Manishearth]

I think you misunderstood; &mut Option<&mut T> should be written as Option<&mut T>, not &mut Option.

@shepmaster's comment still applies. You cannot set the shared Option to None with Option<&mut T>