bjoernager/rust
bjoernager/rust
1
Fork 0
Code Issues Pull requests Activity

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

Browse source 
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
Download patch file Download diff file Expand all files Collapse all files

4
compiler/rustc_parse/src/parser/pat.rs
View file

@ -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))