Fix false positive for unused_unit #14962
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| @@ -109,6 +109,7 @@ impl<'tcx> LateLintPass<'tcx> for UnusedUnit { | |||
| && let AssocItemConstraintKind::Equality { term: Term::Ty(hir_ty) } = constraints[0].kind | |||
| && args.span_ext.hi() != poly.span.hi() | |||
| && !hir_ty.span.from_expansion() | |||
| && args.span_ext.hi() != hir_ty.span.hi() | |||
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Perhaps this should have been covered by !hir_ty.span.from_expansion(). Certainly, there are no explicit -> () tokens in the source. If this is the case, I'm happy to close this PR and file an issue upstream.
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Those expansion checks are quite finicky; sometimes you have an expression without expansion but a subexpression expanded, etc. So as long as this appears to fix the issue, it's better than nothing.
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| mod pr14962 { | ||
| #[allow(unused_parens)] |
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Since this is a targeted lint, could you please use #[expect(unused_parens)] instead? That doubles as an extra free test for unused_parens that would force us to think about it if its behavior changes.
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This does not actually emit a warning by rustc yet. I'm currently looking into why that is exactly. I can remove the attribute and change the name of the type alias if you want.
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Thank you. |
Given a type alias as follows, clippy would detect a false positive for
unused_unit.changelog: [
unused_unit]: fix false positive forFnbounds