diff options
Diffstat (limited to 'src/librustc_parse/parser/generics.rs')
| -rw-r--r-- | src/librustc_parse/parser/generics.rs | 19 |
1 files changed, 8 insertions, 11 deletions
diff --git a/src/librustc_parse/parser/generics.rs b/src/librustc_parse/parser/generics.rs index 59fd5f7c4be..3442c5081c1 100644 --- a/src/librustc_parse/parser/generics.rs +++ b/src/librustc_parse/parser/generics.rs @@ -181,7 +181,7 @@ impl<'a> Parser<'a> { // We are considering adding generics to the `where` keyword as an alternative higher-rank // parameter syntax (as in `where<'a>` or `where<T>`. To avoid that being a breaking // change we parse those generics now, but report an error. - if self.choose_generics_over_qpath() { + if self.choose_generics_over_qpath(0) { let generics = self.parse_generics()?; self.struct_span_err( generics.span, @@ -257,7 +257,7 @@ impl<'a> Parser<'a> { } } - pub(super) fn choose_generics_over_qpath(&self) -> bool { + pub(super) fn choose_generics_over_qpath(&self, start: usize) -> bool { // There's an ambiguity between generic parameters and qualified paths in impls. // If we see `<` it may start both, so we have to inspect some following tokens. // The following combinations can only start generics, @@ -274,15 +274,12 @@ impl<'a> Parser<'a> { // we disambiguate it in favor of generics (`impl<T> ::absolute::Path<T> { ... }`) // because this is what almost always expected in practice, qualified paths in impls // (`impl <Type>::AssocTy { ... }`) aren't even allowed by type checker at the moment. - self.token == token::Lt - && (self.look_ahead(1, |t| t == &token::Pound || t == &token::Gt) - || self.look_ahead(1, |t| t.is_lifetime() || t.is_ident()) - && self.look_ahead(2, |t| { - t == &token::Gt - || t == &token::Comma - || t == &token::Colon - || t == &token::Eq + self.look_ahead(start, |t| t == &token::Lt) + && (self.look_ahead(start + 1, |t| t == &token::Pound || t == &token::Gt) + || self.look_ahead(start + 1, |t| t.is_lifetime() || t.is_ident()) + && self.look_ahead(start + 2, |t| { + matches!(t.kind, token::Gt | token::Comma | token::Colon | token::Eq) }) - || self.is_keyword_ahead(1, &[kw::Const])) + || self.is_keyword_ahead(start + 1, &[kw::Const])) } } |