bjoernager/rust
bjoernager/rust
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Tweak diagnostics

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* Recover from invalid `'label: ` before block.
* Make suggestion to enclose statements in a block multipart.
* Point at `match`, `while`, `loop` and `unsafe` keywords when failing
  to parse their expression.
* Do not suggest `{ ; }`.
* Do not suggest `|` when very unlikely to be what was wanted (in `let`
  statements).
This commit is contained in:
Esteban Kuber 2022-01-12 20:43:24 +00:00
parent 97cde9fe08
commit f42b4f595e
26 changed files with 316 additions and 161 deletions
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53
compiler/rustc_parse/src/parser/diagnostics.rs
View file

@ -1,8 +1,8 @@
use super::pat::Expected;
use super::ty::{AllowPlus, IsAsCast};
use super::{
BlockMode, Parser, PathStyle, RecoverColon, RecoverComma, Restrictions, SemiColonMode, SeqSep,
TokenExpectType, TokenType,
BlockMode, CommaRecoveryMode, Parser, PathStyle, RecoverColon, RecoverComma, Restrictions,
SemiColonMode, SeqSep, TokenExpectType, TokenType,
};
use rustc_ast as ast;
@ -2245,12 +2245,32 @@ impl<'a> Parser<'a> {
first_pat
}
crate fn maybe_recover_unexpected_block_label(&mut self) -> bool {
let Some(label) = self.eat_label().filter(|_| {
self.eat(&token::Colon) && self.token.kind == token::OpenDelim(token::Brace)
}) else {
return false;
};
let span = label.ident.span.to(self.prev_token.span);
let mut err = self.struct_span_err(span, "block label not supported here");
err.span_label(span, "not supported here");
err.tool_only_span_suggestion(
label.ident.span.until(self.token.span),
"remove this block label",
String::new(),
Applicability::MachineApplicable,
);
err.emit();
true
}
/// Some special error handling for the "top-level" patterns in a match arm,
/// `for` loop, `let`, &c. (in contrast to subpatterns within such).
crate fn maybe_recover_unexpected_comma(
&mut self,
lo: Span,
rc: RecoverComma,
rt: CommaRecoveryMode,
) -> PResult<'a, ()> {
if rc == RecoverComma::No || self.token != token::Comma {
return Ok(());
@ -2270,20 +2290,25 @@ 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) {
const MSG: &str = "try adding parentheses to match on a tuple...";
err.span_suggestion(
seq_span,
MSG,
format!("({})", seq_snippet),
Applicability::MachineApplicable,
);
err.span_suggestion(
seq_span,
"...or a vertical bar to match on multiple alternatives",
seq_snippet.replace(',', " |"),
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,
);
}
}
Err(err)
}