feat({unnecessary,panicking}_unwrap): lint field accesses #15949
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Oct 25, 2025
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| is_potentially_local_place(*local_id, place) | ||
| // If there were projections other than field projections, err on the side of caution and say that they | ||
| // _might_ be mutating something. | ||
| // | ||
| // The reason we use `<=` and not `==` is that a mutation of `struct` or `struct.field1` should count as | ||
| // mutation of the child fields such as `struct.field1.field2` | ||
| && place.projections.len() <= field_indices.len() | ||
| && iter::zip(&place.projections, field_indices.iter().copied().rev()).all(|(proj, field_idx)| { | ||
| match proj.kind { | ||
| ProjectionKind::Field(f_idx, _) => f_idx == field_idx, | ||
| // If this is a projection we don't expect, it _might_ be mutating something | ||
| _ => false, | ||
| } | ||
| }) |
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This effectively extends is_potentially_local_place with support for locals with field projections -- maybe this change should be incorporated into is_potentially_local_place directly?
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Oh hey look, the multi-step-field-access pattern does come up |
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Resolves #15321
Unresolved questions:
changelog: [
unnecessary_unwrap]: lint field accesseschangelog: [
panicking_unwrap]: lint field accesses