Filter serde exported variants in wildcard_enum_match_arm

[mental32]

Hi there! I frequently encounter clippy::restriction hits for wildcard_enum_match_arm but for items that are generated by serde and are private/hidden (notice leading underscore convention).

Could arms like this be selectively filtered out for this lint? I don't think it'll improve readability if I add this arm (I don't even think I can add this arm since the item is private) and I think these are closer to informal artifacts generated by serde rather than an api that should be relied on.

At the moment my go to solution is to #[allow(...)] it for the function its found in but it ends up reading like tedious noise.

error: wildcard match will miss any future added variants
   --> src/lib.rs:166:13
    |
166 |             _ => continue,
    |             ^ help: try this: `foo::_IMPL_DESERIALIZE_FOR_Foo::_serde::export::Ok(..)`
    |
note: the lint level is defined here
   --> src/lib.rs:5:22
    |
5   | #![deny(clippy::all, clippy::restriction)]
    |                      ^^^^^^^^^^^^^^^^^^^
    = note: `#[deny(clippy::wildcard_enum_match_arm)]` implied by `#[deny(clippy::restriction)]`
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#wildcard_enum_match_arm

Curious to hear thoughts on this!

[ThibsG]

Thanks for reporting this!
Can you provide minimal code example (not only backtrace) or at a least show portion of code that is triggering this ?

[mental32]

No problem: https://play.rust-lang.org/?version=nightly&mode=debug&edition=2018&gist=b4adc23a8806145a48f45bf35f184082

[flip1995]

This just needs a check for in_external_macro

@mental32 FYI: enabling the complete restriction group is not recommended, since it includes really restrictive lints, that sometimes are in contrast with other lints or even go against idiomatic rust. These lints should only be enabled on a lint-by-lint basis and with careful consideration.

[mental32]

@flip1995 oh, nice to know! 😅

I tended to just switch all the groups on and filter away the stuff that annoyed me, It never occurred to me to work the other way.

[flip1995]

You can enable the whole pedantic group, if you don't mind sprinkling allows throughout the code (Clippy itself does this). But IMO picking out lints from pedantic and restriction one by one is the better approach. This is not an official recommendation, just my personal preference, though.

If you want even more lints, you can also look at the nursery group, but these lints are buggy in one way or another, so be extra careful there.