Detect const in pattern with typo #132658
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Some changes occurred in match checking cc @Nadrieril |
Nadrieril
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Nov 9, 2024
| @@ -966,7 +974,10 @@ fn report_unreachable_pattern<'p, 'tcx>( | |||
| }); | |||
| } | |||
| [covering_pat] if pat_is_catchall(covering_pat) => { | |||
| lint.covered_by_catchall = Some(covering_pat.data().span); | |||
| // A binding pattern that matches all, a single binding name. | |||
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This comment is incorrect: pat_is_catchall also accepts patterns such as (a, b) or Struct { field, .. }. If you want only the case of a single binding/wildcard, check instead that pat.ctor() is Constructor::Wildcard. I'm thinking we should rename that function to pat_catches_all tbh.
Nadrieril
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Nov 9, 2024
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☔ The latest upstream changes (presumably #133212) made this pull request unmergeable. Please resolve the merge conflicts. |
When writing a constant name incorrectly in a pattern, the pattern will be identified as a new binding. We look for consts in the current crate, consts that where imported in the current crate and for local `let` bindings in case someone got them confused with `const`s.
```
error: unreachable pattern
--> $DIR/const-with-typo-in-pattern-binding.rs:30:9
|
LL | GOOOD => {}
| ----- matches any value
LL |
LL | _ => {}
| ^ no value can reach this
|
help: you might have meant to pattern match against the value of similarly named constant `GOOD` instead of introducing a new catch-all binding
|
LL | GOOD => {}
| ~~~~
```
Fix rust-lang#132582.
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Alright, the diagnostic wins are quite good and I can't think of a better way. Thanks for the work! @bors r+ |
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When writing a constant name incorrectly in a pattern, the pattern will be identified as a new binding. We look for consts in the current crate, consts that where imported in the current crate and for local
letbindings in case someone got them confused withconsts.Fix #132582.