bjoernager/rust
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Detect attempts to expand a macro to a match arm again

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Because a macro invocation can expand to a never pattern, we can't rule
out a `arm!(),` arm at parse time. Instead we detect that case at
expansion time, if the macro tries to output a pattern followed by `=>`.
This commit is contained in:
Nadrieril 2023-11-27 00:50:51 +01:00
parent 80bdcbf50a
commit 0bfebc6105
8 changed files with 27 additions and 29 deletions
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37
compiler/rustc_parse/src/parser/diagnostics.rs
View file

@ -2823,7 +2823,6 @@ impl<'a> Parser<'a> {
pub(crate) fn maybe_recover_unexpected_comma(
&mut self,
lo: Span,
is_mac_invoc: bool,
rt: CommaRecoveryMode,
) -> PResult<'a, ()> {
if self.token != token::Comma {
@ -2844,28 +2843,24 @@ impl<'a> Parser<'a> {
let seq_span = lo.to(self.prev_token.span);
let mut err = self.struct_span_err(comma_span, "unexpected `,` in pattern");
if let Ok(seq_snippet) = self.span_to_snippet(seq_span) {
if is_mac_invoc {
err.note(fluent::parse_macro_expands_to_match_arm);
} else {
err.multipart_suggestion(
format!(
"try adding parentheses to match on a tuple{}",
if let CommaRecoveryMode::LikelyTuple = rt { "" } else { "..." },
),
vec![
(seq_span.shrink_to_lo(), "(".to_string()),
(seq_span.shrink_to_hi(), ")".to_string()),
],
err.multipart_suggestion(
format!(
"try adding parentheses to match on a tuple{}",
if let CommaRecoveryMode::LikelyTuple = rt { "" } else { "..." },
),
vec![
(seq_span.shrink_to_lo(), "(".to_string()),
(seq_span.shrink_to_hi(), ")".to_string()),
],
Applicability::MachineApplicable,
);
if let CommaRecoveryMode::EitherTupleOrPipe = rt {
err.span_suggestion(
seq_span,
"...or a vertical bar to match on multiple alternatives",
seq_snippet.replace(',', " |"),
Applicability::MachineApplicable,
);
if let CommaRecoveryMode::EitherTupleOrPipe = rt {
err.span_suggestion(
seq_span,
"...or a vertical bar to match on multiple alternatives",
seq_snippet.replace(',', " |"),
Applicability::MachineApplicable,
);
}
}
}
Err(err)

8
compiler/rustc_parse/src/parser/pat.rs
View file

@ -155,11 +155,7 @@ impl<'a> Parser<'a> {
Err(err) => return Err(err),
};
if rc == RecoverComma::Yes && !first_pat.could_be_never_pattern() {
self.maybe_recover_unexpected_comma(
first_pat.span,
matches!(first_pat.kind, PatKind::MacCall(_)),
rt,
)?;
self.maybe_recover_unexpected_comma(first_pat.span, rt)?;
}
// If the next token is not a `|`,
@ -201,7 +197,7 @@ impl<'a> Parser<'a> {
err
})?;
if rc == RecoverComma::Yes && !pat.could_be_never_pattern() {
self.maybe_recover_unexpected_comma(pat.span, false, rt)?;
self.maybe_recover_unexpected_comma(pat.span, rt)?;
}
pats.push(pat);
}