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Rollup merge of #134284 - estebank:issue-74863, r=lcnr

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Keep track of patterns that could have introduced a binding, but didn't

When we recover from a pattern parse error, or a pattern uses `..`, we keep track of that and affect resolution error for missing bindings that could have been provided by that pattern. We differentiate between `..` and parse recovery. We silence resolution errors likely caused by the pattern parse error.

```
error[E0425]: cannot find value `title` in this scope
  --> $DIR/struct-pattern-with-missing-fields-resolve-error.rs:18:30
   |
LL |     if let Website { url, .. } = website {
   |            ------------------- this pattern doesn't include `title`, which is available in `Website`
LL |         println!("[{}]({})", title, url);
   |                              ^^^^^ not found in this scope
```

Fix #74863.
This commit is contained in:
Matthias Krüger 2024-12-16 20:00:22 +01:00 • committed by GitHub
commit 86db97e2b3
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8 changed files with 135 additions and 8 deletions
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4
compiler/rustc_parse/src/parser/pat.rs
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@ -1371,10 +1371,10 @@ impl<'a> Parser<'a> {
self.bump();
let (fields, etc) = self.parse_pat_fields().unwrap_or_else(|mut e| {
e.span_label(path.span, "while parsing the fields for this pattern");
e.emit();
let guar = e.emit();
self.recover_stmt();
// When recovering, pretend we had `Foo { .. }`, to avoid cascading errors.
(ThinVec::new(), PatFieldsRest::Rest)
(ThinVec::new(), PatFieldsRest::Recovered(guar))
});
self.bump();
Ok(PatKind::Struct(qself, path, fields, etc))