Don't lint match expressions with cfged arms

[Jarcho]

Somehow there are no open issues related to this for any of the affected lints. At least none that I could fine from a quick search.

changelog: Don't lint match expressions with cfged arms in many cases

[rust-highfive]

r? @flip1995

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[flip1995]

I'm not sure if re-lexing snippets on every match expression is a good idea. Also, every time I see something depending on so many span manipulations, I instantly think of ICEs.

[Jarcho]

This is only lexing everything in between each match arm, not the entire match expression. Lexing is also very quick. All of clippy_lints only takes half a second for me, including reading the files.

Doesn't snippet_opt not panic?

[flip1995]

This is only lexing everything in between each match arm

Ah, then I misunderstood what the code does. I guess this shouldn't be too bad then. Giving this a bit more thought during the review, I think all the span operations are save. The code could use a few more comments though.

[flip1995]

Thanks for adding the comments!

Let's get this merged before Thursday, so we get this into nightly as long as possible. I'm always nervous about ICEs when it comes to span manipulation.

@bors r+

[bors]

📌 Commit 78345b4 has been approved by flip1995

[bors]

⌛ Testing commit 78345b4 with merge 9e605ef...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: flip1995
Pushing 9e605ef to master...