bjoernager/rust
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Tweak unclosed generics errors

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Remove unnecessary span label for parse errors that already have a
suggestion.

Provide structured suggestion to close generics in more cases.
This commit is contained in:
Esteban Küber 2023-11-15 00:18:26 +00:00
parent 64d7e0d0b6
commit 4e99db9e54
11 changed files with 65 additions and 46 deletions
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43
compiler/rustc_parse/src/parser/diagnostics.rs
View file

@ -674,15 +674,6 @@ impl<'a> Parser<'a> {
);
}
// Add suggestion for a missing closing angle bracket if '>' is included in expected_tokens
// there are unclosed angle brackets
if self.unmatched_angle_bracket_count > 0
&& self.token.kind == TokenKind::Eq
&& expected.iter().any(|tok| matches!(tok, TokenType::Token(TokenKind::Gt)))
{
err.span_label(self.prev_token.span, "maybe try to close unmatched angle bracket");
}
let sp = if self.token == token::Eof {
// This is EOF; don't want to point at the following char, but rather the last token.
self.prev_token.span
@ -819,6 +810,7 @@ impl<'a> Parser<'a> {
}
err.emit();
}
fn check_too_many_raw_str_terminators(&mut self, err: &mut Diagnostic) -> bool {
let sm = self.sess.source_map();
match (&self.prev_token.kind, &self.token.kind) {
@ -1994,6 +1986,39 @@ impl<'a> Parser<'a> {
}
}
/// When trying to close a generics list and encountering code like
/// ```text
/// impl<S: Into<std::borrow::Cow<'static, str>> From<S> for Canonical {}
/// // ^ missing > here
/// ```
/// we provide a structured suggestion on the error from `expect_gt`.
pub(super) fn expect_gt_or_maybe_suggest_closing_generics(
&mut self,
params: &[ast::GenericParam],
) -> PResult<'a, ()> {
let Err(mut err) = self.expect_gt() else {
return Ok(());
};
// Attempt to find places where a missing `>` might belong.
if let [.., ast::GenericParam { bounds, .. }] = params
&& let Some(poly) = bounds
.iter()
.filter_map(|bound| match bound {
ast::GenericBound::Trait(poly, _) => Some(poly),
_ => None,
})
.last()
{
err.span_suggestion_verbose(
poly.span.shrink_to_hi(),
"you might have meant to end the type parameters here",
">",
Applicability::MaybeIncorrect,
);
}
Err(err)
}
pub(super) fn recover_seq_parse_error(
&mut self,
delim: Delimiter,