add new lint [once_cell_lazy] to detect usage of static Lazy type

[J-ZhengLi]

partially fix: #12895

cc: @pitaj

This only checks for once_cell::sync::Lazy, I want to split the implementations to at least 2 prs, as checking lazy_static! might needs EarlyPass to be done properly. Also preventing this PR got too big (it already is...)

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changelog: add new lint [once_cell_lazy] to detect usage of static Lazy type.

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[pitaj]

Thanks for taking this on!

On my phone, so haven't looked at the implementation much yet. Just some minor changes so far.

@rustbot author

[J-ZhengLi]

@rustbot ready

[bors]

☔ The latest upstream changes (presumably #12999) made this pull request unmergeable. Please resolve the merge conflicts.

[xFrednet]

Hey @J-ZhengLi, could you rebase on master?

[pitaj]

Hello @J-ZhengLi,

Thanks again for working on this!

I ran a poll of clippy contributors and the conclusion is that we'd like both lazy_static and once_cell::sync::Lazy handled by a single lint.

I think it's okay if you want to do the implementation in two separate PRs, but please rename the lint you add here to match both cases.

[J-ZhengLi]

I ran a poll of clippy contributors and the conclusion is that we'd like both lazy_static and once_cell::sync::Lazy handled by a single lint.

Awesome~ Thank you for keep tracking this (although I almost forgot about it lol). I'll get back to this in a few days~

@rustbot author