overhaul unnecessary_map_or

[ada4a]

Third commit moves .map_or(false, -> .is_some_and( and similar transformations to manual_is_variant_and

• resolves Add x.map_or(true, |n| n > 5) to manual_is_variant_and #15998, resolves Splitting unnecessary_map_or into 2 lints #15999.

Fourth and fifth commits add a new lint, needless_is_variant_and, which transforms .is_some_and(|n| n == 5) into == Some(5)

• resolves suggest == Some( for is_some_and if possible #14713
• "needless" was chosen in order to comply with RFC 344, but also for being shorter and easier to write than "unnecessary"
• the test suite is largely identical to that of unnecessary_map_or

For further reasoning, please see the documentation on manual_eq_optional.rs.

Diffs best viewed with whitespace ignored and --color-moved

cc @teofr

changelog: [unnecessary_map_or]: move .map_or(false, -> .is_some_and( and similar transformations to manual_is_variant_and
changelog: [needless_is_variant_and]: new lint

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[github-actions]

Lintcheck changes for 24e45b7

Lint	Added	Removed	Changed
clippy::manual_is_variant_and	22	0	1
clippy::unnecessary_map_or	0	22	1

This comment will be updated if you push new changes

[samueltardieu]

Those commits (except the dogfood one of course) should be separate PRs that can be judged on their own merit, especially if checks are moved from one lint to another and if a new lint is introduced.

Just make PR 3 depend on PR 1 and 2, and PR 4 (commits 4 and 5) depend on PR 3 if required, or PR 1 and 2 otherwise.

[ada4a]

Yeah fair enough.. Though I'm not sure the first commit really deserves to be its own PR? It's just a bunch of clean-up..

[samueltardieu]

It's just a bunch of clean-up..

…which have to be reviewed anyhow. The second commit can get approved much faster IMO in isolation.

[ada4a]

Opened the sub-PRs, see the mentions above this comment