Gradually add in useful clippy lints that we currently don't check for

[mulkieran]

Ultimately this will be helpful. But we might have to add them in gradually. Some are hard to fathom.

[mulkieran]

Well, stratisd has about 40 warnings, and devicemapper has 0. Let's do it for devicemapper now, so we can catch as necessary. Or alternatively, let's grab one we like and do that.

[mulkieran]

needless_borrow, the one I was really interested in, is in the nursery. devicemapper has 0 needless borrows, stratisd seems to have about 80.

[mulkieran]

@jbaublitz If you find a lint in the nursery or pedantic categories that you find especially valuable, please feel free to propose it.

[jbaublitz]

The only ones that jump out at me immediately are some of the integer lints around wrapping and lossy conversions. It could be interesting to see if we guard against that everywhere.

[mulkieran]

@jbaublitz If you want to go ahead and try one of those out in a PR go right ahead.

[jbaublitz]

I'm not sure that the suggested lints are going to help here. Most of the warnings are about u64 to usize and given this is only a problem on 32-bit systems, I don't think we'll get much benefit out of this as stratisd is not meant for 32 bit. I don't think I can add anything in terms of lints to what we already have.

[mulkieran]

Ok! We'll let this sit until something does come up.

[mulkieran]

If we're just letting it sit, we can remove it from every board.

[mulkieran]

I'm thinking of going through these lints and turning on all the ones that make obvious sense and that we already don't infringe, in order to prevent future infringements. Then we can work on the more tricky ones, that we are actually infringing and that are important to us.

[mulkieran]

We stopped trying to keep our CLIPPY_PEDANTIC variable in the stratisd Makefile up-to-date and maintained a long time ago, because we got a really limited benefit from doing that. Maybe someday we'll remove that variable entirely and rely on clippy processes to promote the pedantic lints to more interesting categories. It is not in use for any of the other Rust projects.