Start using clippy

[nnethercote]

Clippy is a useful tool. This PR fixes/silences all the warnings it finds, and enables it in CI.

[nnethercote]

Using clippy is very common. It has a lot of lints and not all of them are equally useful or important, so customizing the setup to ignore lints you don't care about is certainly an option, but I haven't done that here.

My first contribution here, so let me know if I've done anything wrong, and I'm happy to adjust things as necessary.

[nnethercote]

Info on individual lints is here: https://rust-lang.github.io/rust-clippy/master/index.html

[jk-ozlabs]

I certainly had a todo for clippifying the tree, thanks for the series. Will take a look through shortly.

[jk-ozlabs]

Looks like we need a reformat as part of 144710b. Otherwise all looks good!

[jk-ozlabs]

(and no issues with the MSRV, we don't have/need any specific guarantees there)

[mkj]

Looks like we need a reformat as part of 144710b. Otherwise all looks good!

Ah, that's the problem where on embedded platforms it's optionally using defmt::info!() which doesn't support named parameters (one day!). But clippy assumes its log::info!().

[mkj]

optionally using defmt::info!()

Sorry ignore that, those parts weren't touched in this PR.

[nnethercote]

I fixed the fmt error.

[jk-ozlabs]

hm, may also need a component add clippy. @mkj : any issues with this staying in ci.sh, rather than handling the rust env in the github workflow?

[mkj]

hm, may also need a component add clippy. @mkj : any issues with this staying in ci.sh, rather than handling the rust env in the github workflow?

ci.sh should work fine, the same as the existing for rustfmt. Or in rust-toolchain.toml. I thought both of them were in the default rustup set though, https://ehuss.github.io/rustup/concepts/profiles.html

[nnethercote]

There was a needless_lifetime warning on CI that I wasn't seeing locally. CI is running on thumbv7em-none-eabihf and my local machine is x86_64-unknown-linux-gnu, though I don't know why that would cause a difference. Weird.

[mkj]

Thanks!

Looks like the needless_lifetime failure before was during the x86_64-unknown-linux-gnu build, I guess it was just some other environment difference.