Is there a lint to prevent underscore prefixed bindings (_foo) for must_use types?

[frederikrothenberger]

Hi

I'm working on a code base where we would like to make sure that #[must_use] types are really used (specifically for Result).

I see that let_underscore_must_use exists, however this does not trigger on bindings that use _ as a prefix with a name (let _foo = ...).

Is there any way to prevent the latter too?

[flip1995]

This could be added as a configuration of the existing lint you already mentioned or as a new pedantic/restriction lint. I would make this lint allow-by-default, as there are cases, where you want _foo, but not use it. E.g. lock guards or when something is only used with some features enabled.

But we're in a feature freeze right now. So a PR adding this won't be reviewed until the feature freeze ended (sometime September)