bjoernager/rust
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Fix "missing match arm body" suggestion involving !

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Include the match arm guard in the gated span, so that the suggestion to add a body is correct instead of inserting the body before the guard.

Make the suggestion verbose.

```
error: `match` arm with no body
  --> $DIR/feature-gate-never_patterns.rs:43:9
   |
LL |         Some(_) if false,
   |         ^^^^^^^^^^^^^^^^
   |
help: add a body after the pattern
   |
LL |         Some(_) if false => { todo!() },
   |                          ++++++++++++++
```
This commit is contained in:
Esteban Küber 2025-02-22 18:29:12 +00:00
parent dc37ff82e8
commit a8f8b8de66
5 changed files with 94 additions and 16 deletions
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9
compiler/rustc_ast_passes/src/errors.rs
View file

@ -804,7 +804,14 @@ pub(crate) struct NegativeBoundWithParentheticalNotation {
pub(crate) struct MatchArmWithNoBody {
#[primary_span]
pub span: Span,
#[suggestion(code = " => todo!(),", applicability = "has-placeholders")]
// We include the braces around `todo!()` so that a comma is optional, and we don't have to have
// any logic looking at the arm being replaced if there was a comma already or not for the
// resulting code to be correct.
#[suggestion(
code = " => {{ todo!() }}",
applicability = "has-placeholders",
style = "verbose"
)]
pub suggestion: Span,
}

3
compiler/rustc_parse/src/parser/expr.rs
View file

@ -3125,10 +3125,11 @@ impl<'a> Parser<'a> {
let mut result = if armless {
// A pattern without a body, allowed for never patterns.
arm_body = None;
let span = lo.to(this.prev_token.span);
this.expect_one_of(&[exp!(Comma)], &[exp!(CloseBrace)]).map(|x| {
// Don't gate twice
if !pat.contains_never_pattern() {
this.psess.gated_spans.gate(sym::never_patterns, pat.span);
this.psess.gated_spans.gate(sym::never_patterns, span);
}
x
})