bjoernager/rust
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If a label is placed on the block of a loop instead of the header, suggest moving it to the header.

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This commit is contained in:
Zachary S 2025-03-17 00:25:15 -05:00
parent 227690a258
commit f478853f42
7 changed files with 296 additions and 25 deletions
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29
compiler/rustc_parse/src/parser/diagnostics.rs
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@ -2874,7 +2874,12 @@ impl<'a> Parser<'a> {
first_pat
}
pub(crate) fn maybe_recover_unexpected_block_label(&mut self) -> bool {
/// If `loop_header` is `Some` and an unexpected block label is encountered,
/// it is suggested to be moved just before `loop_header`, else it is suggested to be removed.
pub(crate) fn maybe_recover_unexpected_block_label(
&mut self,
loop_header: Option<Span>,
) -> bool {
// Check for `'a : {`
if !(self.check_lifetime()
&& self.look_ahead(1, |t| *t == token::Colon)
@ -2885,16 +2890,28 @@ impl<'a> Parser<'a> {
let label = self.eat_label().expect("just checked if a label exists");
self.bump(); // eat `:`
let span = label.ident.span.to(self.prev_token.span);
self.dcx()
let mut diag = self
.dcx()
.struct_span_err(span, "block label not supported here")
.with_span_label(span, "not supported here")
.with_tool_only_span_suggestion(
.with_span_label(span, "not supported here");
if let Some(loop_header) = loop_header {
diag.multipart_suggestion(
"if you meant to label the loop, move this label before the loop",
vec![
(label.ident.span.until(self.token.span), String::from("")),
(loop_header.shrink_to_lo(), format!("{}: ", label.ident)),
],
Applicability::MachineApplicable,
);
} else {
diag.tool_only_span_suggestion(
label.ident.span.until(self.token.span),
"remove this block label",
"",
Applicability::MachineApplicable,
)
.emit();
);
}
diag.emit();
true
}