add new lint: rest_when_destructuring_struct
#15000
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| pat.span, | ||
| "struct destructuring with rest (..)", | ||
| None, | ||
| "consider explicitly ignoring remaining fields with wildcard patterns (x: _)", |
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I'd say we should add a suggestion. It'll probably need to be converted to a late pass if you want to.
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There is seemingly no way to get the span of .. in a late pass so I have to play a bit around with this to make it work I think.
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Hmm that's unfortunate. It's probably adequate enough to shrink the lo portion of the pattern's span to the end of the last PatField. Otherwise, maybe just replace the entire pattern? It might look ok in suggestions, but it often can be finicky...
I suggest we open the FCP now and get ideas on this. It's also ok to leave this as an early lint, so long as procedural macros are ignored.
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I made a bit of a hack to make something that seems to work.
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| impl EarlyLintPass for RestWhenDestructuringStruct { | ||
| fn check_pat(&mut self, cx: &EarlyContext<'_>, pat: &Pat) { | ||
| if let PatKind::Struct(_, _, _, PatFieldsRest::Rest) = pat.kind { |
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This should check if it's from macro expansion and also call is_from_proc_macro, the latter requires a late pass. I see this coming up a lot in proc macro code.
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I am not sure on what to call this on as WithSearchPat is not implemented on patterns as far as I can tell.
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Is it ok to do it on the containing expression? How would that work?
WithSearchPat is pretty easy to implement if you feel like it's worth doing so (I've needed this many times). Maybe there's a reason we shouldn't, but I dunno.
We can also leave a fixme, but this is quite common in proc macros so I think it's worthwhile doing it right.
Add a new lint that warns when using a rest pattern when destructuring a struct. This lint was requested in this comment #10666 (comment) by @xxchan.
changelog: [
rest_when_destructuring_struct] new lint