bjoernager/rust
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Rollup merge of #59453 - estebank:recover-tuple-parse, r=petrochenkov

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Recover from parse error in tuple syntax
This commit is contained in:
Mazdak Farrokhzad 2019-03-30 07:51:36 +01:00 • committed by GitHub
commit c28704c2a8
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13 changed files with 228 additions and 34 deletions
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83
src/libsyntax/parse/parser.rs
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@ -2626,7 +2626,13 @@ impl<'a> Parser<'a> {
let mut trailing_comma = false;
let mut recovered = false;
while self.token != token::CloseDelim(token::Paren) {
es.push(self.parse_expr()?);
es.push(match self.parse_expr() {
Ok(es) => es,
Err(err) => {
// recover from parse error in tuple list
return Ok(self.recover_seq_parse_error(token::Paren, lo, Err(err)));
}
});
recovered = self.expect_one_of(
&[],
&[token::Comma, token::CloseDelim(token::Paren)],
@ -3237,36 +3243,54 @@ impl<'a> Parser<'a> {
}
if self.expr_is_complete(&e) { break; }
match self.token {
// expr(...)
token::OpenDelim(token::Paren) => {
let es = self.parse_unspanned_seq(
&token::OpenDelim(token::Paren),
&token::CloseDelim(token::Paren),
SeqSep::trailing_allowed(token::Comma),
|p| Ok(p.parse_expr()?)
)?;
hi = self.prev_span;
// expr(...)
token::OpenDelim(token::Paren) => {
let seq = self.parse_unspanned_seq(
&token::OpenDelim(token::Paren),
&token::CloseDelim(token::Paren),
SeqSep::trailing_allowed(token::Comma),
|p| Ok(p.parse_expr()?)
).map(|es| {
let nd = self.mk_call(e, es);
let hi = self.prev_span;
self.mk_expr(lo.to(hi), nd, ThinVec::new())
});
e = self.recover_seq_parse_error(token::Paren, lo, seq);
}
let nd = self.mk_call(e, es);
e = self.mk_expr(lo.to(hi), nd, ThinVec::new());
}
// expr[...]
// Could be either an index expression or a slicing expression.
token::OpenDelim(token::Bracket) => {
self.bump();
let ix = self.parse_expr()?;
hi = self.span;
self.expect(&token::CloseDelim(token::Bracket))?;
let index = self.mk_index(e, ix);
e = self.mk_expr(lo.to(hi), index, ThinVec::new())
}
_ => return Ok(e)
// expr[...]
// Could be either an index expression or a slicing expression.
token::OpenDelim(token::Bracket) => {
self.bump();
let ix = self.parse_expr()?;
hi = self.span;
self.expect(&token::CloseDelim(token::Bracket))?;
let index = self.mk_index(e, ix);
e = self.mk_expr(lo.to(hi), index, ThinVec::new())
}
_ => return Ok(e)
}
}
return Ok(e);
}
fn recover_seq_parse_error(
&mut self,
delim: token::DelimToken,
lo: Span,
result: PResult<'a, P<Expr>>,
) -> P<Expr> {
match result {
Ok(x) => x,
Err(mut err) => {
err.emit();
// recover from parse error
self.consume_block(delim);
self.mk_expr(lo.to(self.prev_span), ExprKind::Err, ThinVec::new())
}
}
}
crate fn process_potential_macro_variable(&mut self) {
let (token, span) = match self.token {
token::Dollar if self.span.ctxt() != syntax_pos::hygiene::SyntaxContext::empty() &&
@ -4253,7 +4277,14 @@ impl<'a> Parser<'a> {
// Trailing commas are significant because (p) and (p,) are different patterns.
fn parse_parenthesized_pat_list(&mut self) -> PResult<'a, (Vec<P<Pat>>, Option<usize>, bool)> {
self.expect(&token::OpenDelim(token::Paren))?;
let result = self.parse_pat_list()?;
let result = match self.parse_pat_list() {
Ok(result) => result,
Err(mut err) => { // recover from parse error in tuple pattern list
err.emit();
self.consume_block(token::Paren);
return Ok((vec![], Some(0), false));
}
};
self.expect(&token::CloseDelim(token::Paren))?;
Ok(result)
}