Linting classical overflow checks

[martiansideofthemoon]

@Manishearth , @mcarton getting a compile error in cyclomatic_complexity.rs as follows :- https://pastebin.mozilla.org/8862490
Fix #656.

[mcarton]

@martiansideofthemoon Update your nightly

[mcarton]

You’re missing an i here

[mcarton]

I would reformulate that to insist on the fact that while those are classic in C, they won’t work in Rust. Also point out that Rust does not need them because of the overflowing_* and wrapping_* family of functions.

[martiansideofthemoon]

@Manishearth , @mcarton I hope it's okay 😄

[mcarton]

Can you put overflowing_* and wrapping_* between quotes? Looks better on the wiki.

`overflowing_*` and `wrapping_*`

[mcarton]

You need to run python util/update_lints.py to fix the error, you also have an “unused import” warning. Also can you squash your commits together if you know how to?

[llogiq]

For bonus points, you could also lint underflow checks, e.g a - b > a or a - b > b.

[martiansideofthemoon]

@llogiq I hope it's okay 😄

[llogiq]

Bonus points for you! 😄 My only small nit is that the lint docs could tell that we lint over- and underflow checks. Also perhaps one could unify some parts into a function to avoid duplication, but I'm fine with merging as it is.

[mcarton]

As discussed on IRC, don’t merge the PR yet. He‘ll also handle a < a - b not just a - b > a tomorrow.

[llogiq]

Even better, although those forms are much less common IIRC.

[martiansideofthemoon]

@Manishearth , @llogiq , @mcarton I hope it is alright

[llogiq]

Unfortunately, it fails the cyclomatic_complexity check. You could factor out some common expressions of both check blocks.

[oli-obk]

I've looked at the code, it shouldn't trigger cc, I'll investigate, just throw an allow(cyclomatic_complexity) on your function and I'll fix the lint

[martiansideofthemoon]

@oli-obk alright, thanks I'll do it in a bit 😄

[martiansideofthemoon]

@llogiq , @oli-obk , @mcarton I've written the allow

[llogiq]

Thanks! Good work 👍