Lint map.iter().map(|(_,v)| v)

[hotate29]

What it does

Warning to iterator operations that are equivalent to .keys() and .values().

Similar lint: https://rust-lang.github.io/rust-clippy/stable/index.html#for_kv_map

Lint Name

iter_kv_map

Category

style

Advantage

Simpler and readable than the original code.

Drawbacks

No response

Example

let map = HashMap::new();

let keys = map.iter().map(|(key, _)| key).collect::<Vec<_>>();
let values = map.iter().map(|(_, value)| value).collect::<Vec<_>>();

Could be written as:

let map = HashMap::new();

let keys = map.keys().collect::<Vec<_>>();
let values = map.values().collect::<Vec<_>>();

[didibear]

Just mentioning that the lint also works when the key or value is used to create another value.

For example, these two lines are equivalent:

map.iter().map(|(key, _)| key.to_uppercase());

map.keys().map(|key| key.to_uppercase());

[kartva]

@rustbot claim