new lint: `vec.drain(..)` instead of `vec.clear()`

[philpax]

What it does

Checks for usage of vec.drain(..) (iterator dropped immediately) which can be replaced with vec.clear()

Lint Name

unnecessary_vec_drain

Category

style

Advantage

• Makes intent clearer
• Marginally more efficient, especially in debug builds

Drawbacks

No response

Example

vec.drain(..);

Could be written as:

vec.clear();

[carloosaf]

@rustbot claim

[koka831]

@rustbot claim

[lana99]

@rustbot claim

[czotomo]

Hi @lana99, are you working on this or is this up for grabs?

[lana99]

I’ve been busy but I will probably push code for the issue this weekend. @czotomo