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

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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:19:30
   |
LL |         println!("[{}]({})", title, url);
   |                              ^^^^^ not found in this scope
   |
note: `Website` has a field `title` which could have been included in this pattern, but it wasn't
  --> $DIR/struct-pattern-with-missing-fields-resolve-error.rs:17:12
   |
LL | / struct Website {
LL | |     url: String,
LL | |     title: Option<String> ,
   | |     ----- defined here
LL | | }
   | |_-
...
LL |       if let Website { url, .. } = website {
   |              ^^^^^^^^^^^^^^^^^^^ this pattern doesn't include `title`, which is available in `Website`
```

Fix #74863.
This commit is contained in:
Esteban Küber 2024-12-13 21:51:33 +00:00
parent 21fe748be1
commit 0f82cfffda
8 changed files with 158 additions and 7 deletions
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5
compiler/rustc_ast_pretty/src/pprust/state.rs
View file

@ -1653,11 +1653,14 @@ impl<'a> State<'a> {
},
|f| f.pat.span,
);
if *etc == ast::PatFieldsRest::Rest {
if let ast::PatFieldsRest::Rest | ast::PatFieldsRest::Recovered(_) = etc {
if !fields.is_empty() {
self.word_space(",");
}
self.word("..");
if let ast::PatFieldsRest::Recovered(_) = etc {
self.word("/* recovered parse error */");
}
}
if !empty {
self.space();