Add waker_clone_and_wake lint to check needless Waker clones

[a1phyr]

Check for patterns of waker.clone().wake() and replace them with waker.wake_by_ref().

An alternative name could be waker_clone_then_wake

changelog: [ waker_clone_wake]: new lint

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[Alexendoo]

This'd be a good one @y21

[y21]

Implementation looks pretty good already! Most of my comments are just nits.

Unsure about the lint name. What about just waker_clone_wake? I think that would go well with how some other lints are named after a chain of method calls, e.g. filter_map_bool_then

[y21]

Can you add a changelog entry to the PR description?
Something like

changelog: [waker_clone_wake]: new lint

should be good enough

[a1phyr]

Isn't that the role of release ?

Where should I put that ? Section for 1.75 isn't there yet.

[y21]

Where should I put that ? Section for 1.75 isn't there yet.

Sorry, I meant the PR body. The text area where you're currently describing what the PR does.

The changelog entry should go there (doesn't really matter where I don't think, could put that at the bottom). This is all normally explained in the input box when you (are about to) open a PR, it might be that you skipped that part. :)
You can take a look at other open PR descriptions for how this should look like.

Isn't that the role of release ?

For every release, someone manually reviews all the changelog comments from all merged PRs in that timeframe and prepares the changelog.md for that release.
These changelog comments are automatically extracted by a script.
So, every PR must have a changelog: ... entry in the description, or else it can't be merged.
(That's how I understand it, anyway)

[a1phyr]

Done!

[y21]

This looks good to me. cc @Alexendoo

[Alexendoo]

Looks good, thanks!

@bors r=y21

[bors]

📌 Commit ebf6667 has been approved by y21

It is now in the queue for this repository.

[bors]

⌛ Testing commit ebf6667 with merge 2f0f4dd...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: y21
Pushing 2f0f4dd to master...

[y21]

Thanks for implementing this lint @a1phyr! :)