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Move unclosed delim errors to separate function

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This commit is contained in:
sjwang05 2023-11-11 13:39:08 -08:00
parent a49368f00b
commit f88cf0206f
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GPG Key ID: AB262FD6FFBFCFFE
2 changed files with 62 additions and 63 deletions
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111
compiler/rustc_parse/src/lexer/tokentrees.rs
View File

@ -117,59 +117,8 @@ fn parse_token_tree_open_delim(
// We stop at any delimiter so we can try to recover if the user
// uses an incorrect delimiter.
let (tts, res) = self.parse_token_trees(/* is_delimited */ true);
if let Err(mut errs) = res {
// If there are unclosed delims, see if there are diff markers and if so, point them
// out instead of complaining about the unclosed delims.
let mut parser = crate::stream_to_parser(self.string_reader.sess, tts, None);
let mut diff_errs = vec![];
// Suggest removing a `{` we think appears in an `if`/`while` condition
// We want to suggest removing a `{` only if we think we're in an `if`/`while` condition, but
// we have no way of tracking this in the lexer itself, so we piggyback on the parser
let mut in_cond = false;
while parser.token != token::Eof {
if let Err(diff_err) = parser.err_diff_marker() {
diff_errs.push(diff_err);
} else if parser.is_keyword_ahead(0, &[kw::If, kw::While]) {
in_cond = true;
} else if matches!(
parser.token.kind,
token::CloseDelim(Delimiter::Brace) | token::FatArrow
) {
// end of the `if`/`while` body, or the end of a `match` guard
in_cond = false;
} else if in_cond && parser.token == token::OpenDelim(Delimiter::Brace) {
// Store the `&&` and `let` to use their spans later when creating the diagnostic
let maybe_andand = parser.look_ahead(1, |t| t.clone());
let maybe_let = parser.look_ahead(2, |t| t.clone());
if maybe_andand == token::OpenDelim(Delimiter::Brace) {
// This might be the beginning of the `if`/`while` body (i.e., the end of the condition)
in_cond = false;
} else if maybe_andand == token::AndAnd && maybe_let.is_keyword(kw::Let) {
let mut err = parser.struct_span_err(
parser.token.span,
"found a `{` in the middle of a let-chain",
);
err.span_suggestion(
parser.token.span,
"consider removing this brace to parse the `let` as part of the same chain",
"", Applicability::MachineApplicable
);
err.span_note(
maybe_andand.span.to(maybe_let.span),
"you might have meant to continue the let-chain here",
);
errs.push(err);
}
}
parser.bump();
}
if !diff_errs.is_empty() {
errs.iter_mut().for_each(|err| {
err.delay_as_bug();
});
return Err(diff_errs);
}
return Err(errs);
if let Err(errs) = res {
return Err(self.unclosed_delim_err(tts, errs));
}
// Expand to cover the entire delimited token tree
@ -256,6 +205,62 @@ fn parse_token_tree_open_delim(
Ok(TokenTree::Delimited(delim_span, open_delim, tts))
}
fn unclosed_delim_err(&mut self, tts: TokenStream, mut errs: Vec<PErr<'a>>) -> Vec<PErr<'a>> {
// If there are unclosed delims, see if there are diff markers and if so, point them
// out instead of complaining about the unclosed delims.
let mut parser = crate::stream_to_parser(self.string_reader.sess, tts, None);
let mut diff_errs = vec![];
// Suggest removing a `{` we think appears in an `if`/`while` condition
// We want to suggest removing a `{` only if we think we're in an `if`/`while` condition, but
// we have no way of tracking this in the lexer itself, so we piggyback on the parser
let mut in_cond = false;
while parser.token != token::Eof {
if let Err(diff_err) = parser.err_diff_marker() {
diff_errs.push(diff_err);
} else if parser.is_keyword_ahead(0, &[kw::If, kw::While]) {
in_cond = true;
} else if matches!(
parser.token.kind,
token::CloseDelim(Delimiter::Brace) | token::FatArrow
) {
// end of the `if`/`while` body, or the end of a `match` guard
in_cond = false;
} else if in_cond && parser.token == token::OpenDelim(Delimiter::Brace) {
// Store the `&&` and `let` to use their spans later when creating the diagnostic
let maybe_andand = parser.look_ahead(1, |t| t.clone());
let maybe_let = parser.look_ahead(2, |t| t.clone());
if maybe_andand == token::OpenDelim(Delimiter::Brace) {
// This might be the beginning of the `if`/`while` body (i.e., the end of the condition)
in_cond = false;
} else if maybe_andand == token::AndAnd && maybe_let.is_keyword(kw::Let) {
let mut err = parser.struct_span_err(
parser.token.span,
"found a `{` in the middle of a let-chain",
);
err.span_suggestion(
parser.token.span,
"consider removing this brace to parse the `let` as part of the same chain",
"",
Applicability::MachineApplicable,
);
err.span_label(
maybe_andand.span.to(maybe_let.span),
"you might have meant to continue the let-chain here",
);
errs.push(err);
}
}
parser.bump();
}
if !diff_errs.is_empty() {
errs.iter_mut().for_each(|err| {
err.delay_as_bug();
});
return diff_errs;
}
return errs;
}
fn close_delim_err(&mut self, delim: Delimiter) -> PErr<'a> {
// An unexpected closing delimiter (i.e., there is no
// matching opening delimiter).

14
tests/ui/parser/brace-in-let-chain.stderr
View File

@ -38,12 +38,9 @@ error: found a `{` in the middle of a let-chain
|
LL | && let () = () {
| ^
|
note: you might have meant to continue the let-chain here
--> $DIR/brace-in-let-chain.rs:15:9
|
LL | && let () = ()
| ^^^^^^
| ------ you might have meant to continue the let-chain here
|
help: consider removing this brace to parse the `let` as part of the same chain
|
LL - && let () = () {
@ -55,12 +52,9 @@ error: found a `{` in the middle of a let-chain
|
LL | && let () = () {
| ^
|
note: you might have meant to continue the let-chain here
--> $DIR/brace-in-let-chain.rs:7:9
|
LL | && let () = ()
| ^^^^^^
| ------ you might have meant to continue the let-chain here
|
help: consider removing this brace to parse the `let` as part of the same chain
|
LL - && let () = () {