Extend needless_collect

[Jarcho]

Extends when is_empty and contains are linted.

is_empty will be linted when <IterTy as Iterator>::Item is the same as <CollectTy as IntoIterator>::Item. This can be a false positive if the FromIterator implementation filters out items, but I don't know of any which do that also implement IntoIterator with a matching Item type.

contains will be linted when the argument type is &<IterTy as Iterator>::Item. It has the same false positives as is_empty with the same note that I know of nothing that actually causes that in practice.

changelog: Lint needless_collect when is_empty or contains is called on some non-std types

[rust-highfive]

r? @camsteffen

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[bors]

☔ The latest upstream changes (presumably #8802) made this pull request unmergeable. Please resolve the merge conflicts.

[Jarcho]

r? @llogiq
Assign this to somebody still doing reviews.

[llogiq]

This looks good in general, although some of the stuff goes over my head.

Unfortunately I got some pink eye today, so my first review is rather cursory, as I try to limit my screen time. Will come back to this once I got some antibiotics, but today is a bank holiday here in 🇩🇪.

[llogiq]

Ok, I'm back. My eyes have fully recovered. Also, this looks good in general, and if you don't want to refactor it, I'm fine with merging it after a rebase and doing the refactor myself later (if nobody beats me to it).

[Jarcho]

I'll get to it this sometime this week.

[llogiq]

Ping @Jarcho anything I can do to help?

[Jarcho]

This is still on my todo list. Ended up getting sick instead of working on this. Better now though.

[llogiq]

Ping! So I guess this fell off the top of your Todo list. No hard feelings here, but it would be great to see this through.

@rustbot author

[Jarcho]

Should be good now.

[llogiq]

The current commit fails dogfood. Apparently because of the recently introduced format args lint.

[llogiq]

Thanks!

@bors r+

[bors]

📌 Commit 8bfc8bc has been approved by llogiq

It is now in the queue for this repository.

[bors]

⌛ Testing commit 8bfc8bc with merge 5857a01...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: llogiq
Pushing 5857a01 to master...