diff options
Diffstat (limited to 'src/libsyntax/parse/parser.rs')
| -rw-r--r-- | src/libsyntax/parse/parser.rs | 29 |
1 files changed, 27 insertions, 2 deletions
diff --git a/src/libsyntax/parse/parser.rs b/src/libsyntax/parse/parser.rs index bd0ca0e6704..e3812ce159a 100644 --- a/src/libsyntax/parse/parser.rs +++ b/src/libsyntax/parse/parser.rs @@ -3804,6 +3804,12 @@ impl<'a> Parser<'a> { /// Parse a pattern. pub fn parse_pat(&mut self) -> PResult<'a, P<Pat>> { + self.parse_pat_with_range_pat(true) + } + + /// Parse a pattern, with a setting whether modern range patterns e.g. `a..=b`, `a..b` are + /// allowed. + fn parse_pat_with_range_pat(&mut self, allow_range_pat: bool) -> PResult<'a, P<Pat>> { maybe_whole!(self, NtPat, |x| x); let lo = self.span; @@ -3824,7 +3830,7 @@ impl<'a> Parser<'a> { err.span_label(self.span, "unexpected lifetime"); return Err(err); } - let subpat = self.parse_pat()?; + let subpat = self.parse_pat_with_range_pat(false)?; pat = PatKind::Ref(subpat, mutbl); } token::OpenDelim(token::Paren) => { @@ -3863,7 +3869,7 @@ impl<'a> Parser<'a> { pat = self.parse_pat_ident(BindingMode::ByRef(mutbl))?; } else if self.eat_keyword(keywords::Box) { // Parse box pat - let subpat = self.parse_pat()?; + let subpat = self.parse_pat_with_range_pat(false)?; pat = PatKind::Box(subpat); } else if self.token.is_ident() && !self.token.is_reserved_ident() && self.parse_as_ident() { @@ -3968,6 +3974,25 @@ impl<'a> Parser<'a> { let pat = Pat { node: pat, span: lo.to(self.prev_span), id: ast::DUMMY_NODE_ID }; let pat = self.maybe_recover_from_bad_qpath(pat, true)?; + if !allow_range_pat { + match pat.node { + PatKind::Range(_, _, RangeEnd::Included(RangeSyntax::DotDotDot)) => {} + PatKind::Range(..) => { + let mut err = self.struct_span_err( + pat.span, + "the range pattern here has ambiguous interpretation", + ); + err.span_suggestion( + pat.span, + "add parentheses to clarify the precedence", + format!("({})", pprust::pat_to_string(&pat)), + ); + return Err(err); + } + _ => {} + } + } + Ok(P(pat)) } |